MTi User Manual
MTi User Manual
MTi 10-series and MTi 100-series
Document MT0605P, Revision E, 17 January 2014
Xsens Technologies B.V.
Pantheon 6a
P.O. Box 559
7500 AN Enschede
The Netherlands
Xsens North America, Inc.
phone
fax
e-mail
internet
+31 (0)88 973 67 00
+31 (0)88 973 67 01
[email protected]
www.xsens.com
10557 Jefferson Blvd,
Suite C
CA-90232 Culver City
USA
phone
fax
e-mail
internet
310-481-1800
310-416-9044
[email protected]
www.xsens.com
Revisions
Revision
Date
By
Changes
A
26 Sep 2012
MHA
Initial release
B
18 Dec 2012
MHA
Included MTi-G-700
C
07 May 2013
MHA
D
28 October 2013
MHA
Added NMEA, StartSampling,
vibration mounts
E
17 January 2014
MHA
Added product code, 3V3 and remark
on termination resistor
© 2005-2014, Xsens Technologies B.V. All rights reserved. Information in this document is subject to
change without notice. Xsens, MVN, MotionGrid, MTi, MTi-G, MTx, MTw, Awinda and KiC are
registered trademarks or trademarks of Xsens Technologies B.V. and/or its parent, subsidiaries and/or
affiliates in The Netherlands, the USA and/or other countries. All other trademarks are the property of
their respective owners.
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Table of Contents
1
REFERENCES ..................................................................................................................................... 2
2
INTRODUCTION ................................................................................................................................ 3
2.1 MTI 10-SERIES ................................................................................................................................. 3
2.1.1
MTi-30 AHRS ........................................................................................................................ 3
2.1.2
MTi-20 VRU ......................................................................................................................... 3
2.1.3
MTi-10 IMU ......................................................................................................................... 3
2.2 MTI 100-SERIES ............................................................................................................................... 4
2.2.1
MTi-G-700 GPS/INS .............................................................................................................. 4
2.2.2
MTi-300 AHRS ...................................................................................................................... 4
2.2.3
MTi-200 VRU ........................................................................................................................ 4
2.2.4
MTi-100 IMU ........................................................................................................................ 4
2.2.5
Identifying device functionality using the unique Device Identifier ............................................ 5
2.2.6
Product code ........................................................................................................................ 5
2.3 EVOLUTION OF MTI PRODUCTS .............................................................................................................. 6
2.4 OVERVIEW MTI DEVELOPMENT KIT ........................................................................................................ 7
2.4.1
Contents .............................................................................................................................. 7
2.5 INSTALLATION................................................................................................................................... 8
2.5.1
Transient accelerations ......................................................................................................... 8
2.5.2
Vibrations ............................................................................................................................ 8
2.5.3
Magnetic materials and magnets .......................................................................................... 9
2.6 TYPICAL USER SCENARIOS .................................................................................................................. 10
2.6.1
MT Software Suite .............................................................................................................. 10
2.6.2
Getting Started with the MT Manager.................................................................................. 11
2.6.3
Using the Software Development Kit (SDK) ........................................................................... 12
2.6.4
Direct low-level communication with MTi ............................................................................. 14
2.6.5
Migration from MT SDK 3.3 (CMT) ....................................................................................... 14
2.6.6
Terms of use MT Software Suite ........................................................................................... 15
3
MTI SYSTEM OVERVIEW .................................................................................................................. 16
3.1 CALIBRATION ................................................................................................................................. 16
3.2 XSENS KALMAN FILTER (XKF3I) FOR MTI 10-SERIES .................................................................................. 16
3.2.1
Using the acceleration of gravity to stabilize inclination (roll/pitch) ........................................ 16
3.2.2
Using the Earth magnetic field to stabilize yaw ..................................................................... 17
3.2.3
Initialization ....................................................................................................................... 17
3.2.4
XKF3i filter profiles.............................................................................................................. 17
3.3 XSENS SENSOR FUSION ALGORITHM FOR MTI 100-SERIES ............................................................................ 19
3.3.1
MTi 100-series filter ............................................................................................................ 19
3.3.2
Transient accelerations ....................................................................................................... 19
3.3.3
Magnetic distortions ........................................................................................................... 19
3.3.4
Loss of GPS ........................................................................................................................ 19
3.3.5
MTi 100-series filter profiles ................................................................................................ 19
3.3.6
MTi-G-700 filter profiles ...................................................................................................... 20
4
OUTPUT SPECIFICATION .................................................................................................................. 22
4.1 OVERVIEW OF DATA OUTPUTS ............................................................................................................. 23
4.1.1
MTData2 output in XBus protocol ........................................................................................ 23
4.1.2
NMEA protocol ................................................................................................................... 24
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4.2 COORDINATE SYSTEMS ...................................................................................................................... 25
4.2.1
Calibrated inertial data and magnetic field data ................................................................... 25
4.2.2
Delta_angle and delta_velocity............................................................................................ 25
4.2.3
Orientation data................................................................................................................. 26
4.2.4
Velocity data ...................................................................................................................... 27
4.2.5
Position data ...................................................................................................................... 27
4.3 ORIENTATION PERFORMANCE SPECIFICATION ........................................................................................... 30
4.4 POSITION AND VELOCITY PERFORMANCE SPECIFICATION (MTI-G-700) ............................................................ 31
4.5 ORIENTATION OUTPUT MODES............................................................................................................. 31
4.5.1
Quaternion orientation output mode ................................................................................... 32
4.5.2
Euler angles orientation output mode .................................................................................. 33
4.5.3
Rotation Matrix orientation output mode ............................................................................. 33
4.6 SENSOR DATA PERFORMANCE SPECIFICATION ........................................................................................... 35
4.6.1
Gyroscopes ........................................................................................................................ 35
4.6.2
Accelerometers and magnetometer ..................................................................................... 36
4.6.3
Y zBarometer ..................................................................................................................... 36
4.6.4
GPS receiver ....................................................................................................................... 37
4.7 BUILT-IN SELF-TEST .......................................................................................................................... 38
4.8 TEST AND CALIBRATION CERTIFICATE ..................................................................................................... 39
4.9 SENSORS DATA OUTPUTS.................................................................................................................... 40
4.9.1
Physical sensor model ......................................................................................................... 40
4.9.2
Calibrated delta_q and delta_v outputs ................................................................................ 41
4.9.3
Calibrated inertial and magnetic data outputs ...................................................................... 41
4.9.4
Free acceleration ................................................................................................................ 41
4.9.5
Uncalibrated raw output mode ............................................................................................ 42
4.10 LEGACY OUTPUT MESSAGES ................................................................................................................ 43
4.11 RESET OF OUTPUT OR REFERENCE CO-ORDINATE SYSTEMS ............................................................................ 44
4.12 TIMESTAMP AND PACKET COUNTER OUTPUT ............................................................................................ 47
4.12.1 Packet counter ................................................................................................................... 47
4.12.2 Time UTC ........................................................................................................................... 47
4.12.3 Time stamp (Sample Time Fine) ........................................................................................... 47
4.12.4 Setting UTC time on non-GPS MTi’s ...................................................................................... 47
4.13 STATUS BYTE .................................................................................................................................. 48
5
BASIC COMMUNICATION ................................................................................................................ 50
5.1 INTRODUCTION ............................................................................................................................... 50
5.2 STATES ......................................................................................................................................... 50
5.3 MESSAGES .................................................................................................................................... 51
5.3.1
Message structure .............................................................................................................. 51
5.3.2
Message usage .................................................................................................................. 52
5.3.3
Common messages ............................................................................................................. 53
5.4 COMMUNICATION TIMING ................................................................................................................. 54
5.5 TRIGGERING AND SYNCHRONIZATION ..................................................................................................... 57
5.5.1
External device triggers MTi (Send Latest) ............................................................................ 57
5.5.2
Marker in MT data (Trigger Indication) ................................................................................ 57
5.5.3
MTi triggers external devices (Interval Transition Measurement) ........................................... 58
5.5.4
Clock synchronization (Clock Bias Estimation) ....................................................................... 59
5.5.4.1 Clock Bias Estimation from GPS ........................................................................................... 59
5.5.5
StartSampling .................................................................................................................... 59
5.5.6
Combining synchronization functions ................................................................................... 60
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5.6 INTERNAL CLOCK ACCURACY ................................................................................................................ 61
5.6.1
Clock of MTi’s without GPS receiver ..................................................................................... 61
5.6.2
Clock of MTi-G-700 GPS/INS ................................................................................................ 61
5.7 DEFAULT SERIAL CONNECTION SETTINGS ................................................................................................ 61
5.7.1
General definitions for binary data ....................................................................................... 62
5.7.2
Serial or USB communication ............................................................................................... 62
6
PHYSICAL SPECIFICATIONS............................................................................................................... 63
6.1 PHYSICAL PROPERTIES OVERVIEW.......................................................................................................... 63
6.2 POWER SUPPLY ............................................................................................................................... 63
6.2.1
Alternative 3V3 power supply .............................................................................................. 64
6.3 MECHANICAL AND ELECTRICAL INTERFACE SPECIFICATIONS ........................................................................... 65
6.3.1
Encased MTi connectors overview ........................................................................................ 65
6.3.2
OEM connections overview ................................................................................................. 67
6.3.3
Additional interface specifications ....................................................................................... 69
6.3.4
Using the MTi MkIV with an external USB converter .............................................................. 70
6.4 HOUSING MECHANICAL SPECIFICATIONS.................................................................................................. 71
6.4.1
Environmental protection of the housing .............................................................................. 71
6.4.2
Dimensions MTi .................................................................................................................. 71
6.4.3
Mounting the MTi-OEM ...................................................................................................... 71
6.4.4
MTi 10-series technical drawing .......................................................................................... 72
6.4.5
MTi 100-200-300 technical drawing ..................................................................................... 73
6.4.6
MTi-G-700 technical drawing .............................................................................................. 74
6.4.7
MTi-OEM technical drawing ................................................................................................ 75
7
IMPORTANT NOTICES ...................................................................................................................... 76
7.1
7.2
7.3
7.4
7.5
7.6
7.7
SAFETY INSTRUCTIONS....................................................................................................................... 76
ABSOLUTE MAXIMUM RATINGS ............................................................................................................ 76
MAINTENANCE ............................................................................................................................... 76
CE DECLARATION OF CONFORMITY FOR THE MT DEVICES ............................................................................ 77
FCC DECLARATION OF CONFORMITY FOR THE MT DEVICES .......................................................................... 78
WARRANTY AND LIABILITY .................................................................................................................. 79
CUSTOMER SUPPORT ........................................................................................................................ 79
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1 References
Reference
id
Document description
[LLCP]
“MT Low-Level Communication Protocol Documentation.pdf”, document ID
MT0101P
[MTM]
“MT Manager User Manual.pdf”, document ID MT0216P
[XDA_DOC]
XDA doxygen HTML documentation. Found in Xsens folder structure
[MTI_TD]
“MTi Technical Datasheet.pdf”, document ID MT0503P
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2 Introduction
The MTi product portfolio from Xsens currently has 7 family members ranging in functionality from
inertial measurement units (IMU’s) to a fully integrated GPS/INS solution. All products contain a 3D
inertial sensor assembly (ISA: gyroscopes and accelerometers) and 3D magnetometers, with
optionally a barometer and GNSS receiver.
The MTi product range is divided in two series, the MTi 10-series and the MTi 100-series. The MTi 10series is Xsens’ entry level model with robust accuracy and a limited range of IO options. The 100series is a revolutionary new class of MEMS IMU’s, orientation and position sensor modules offering
unprecedented accuracies and a wide array of IO interfaces.
All MTi’s have a powerful multi-processor core design, capable of processing roll, pitch and yaw with
extremely low latencies, as well as outputting calibrated 3D linear acceleration, rate of turn (gyro),
(earth) magnetic field and atmospheric pressure (100-series only) data. The MTi-G-700 GPS/INS also
offers 3D position and 3D velocity. Over 50 various output formats can be provided directly from the
MTi interface. The various outputs per product can be found in section 4.1.
This documentation describes the use, basic communication interfaces and specifications of all the 7
MTi’s. Where they differ is clearly indicated. All products are designed to be interchangeable from a
mechanical and software interface point of view.
2.1
MTi 10-series
The MTi 10-series is the basic product range of the MTi
product portfolio, offering inertial data and orientation data at
an affordable price. The MTi 10-series consists of 3 products
that have various integration levels.
The MTi-10 series can easily be recognized by the silver base
plate. There are no visual differences between the MTi-10
IMU, MTi-20 VRU and MTi-30 AHRS, other than the label.
2.1.1 MTi-30 AHRS
The MTi-30 AHRS is a full gyro-enhanced Attitude and Heading Reference System (AHRS). It outputs
drift-free roll, pitch and true/magnetic North referenced yaw, plus sensors data: 3D acceleration, 3D
rate of turn and 3D earth-magnetic field data. All products of the MTi 10-series are also capable of
outputting data generated by the Strapdown integration algorithm (orientation and velocity increments
∆q and ∆v).
2.1.2 MTi-20 VRU
The MTi-20 VRU is a 3D vertical reference unit (VRU), which means that it outputs the same data as
the MTi-30, except for the referenced yaw. They yaw is unreferenced, though still superior to just
gyroscope integration.
2.1.3 MTi-10 IMU
The MTi-10 IMU is a 3D inertial measurement unit (IMU) that outputs 3D acceleration, 3D rate of turn
and 3D earth-magnetic field data, so it doesn’t process data to orientation. The MTi-10-IMU is also
capable of outputting data generated by the Strapdown integration algorithm (orientation and velocity
increments ∆q and ∆v).
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2.2
MTi 100-series
The MTi-100 series is the high-performance product
range of the MTi product portfolio, with accuracies
overpowering conventional MEMS AHRS’s, because
of the use of superior gyroscopes and a new
optimization filter, going beyond (Extended) Kalman
Filter implementations. In addition, the factory
calibration is more elaborate to make use of these
higher class gyroscopes.
The MTi 100-series can be recognized by the darkgrey base plate and the holes on one side of the
casing. These holes are used for the adaptation of
the inside air pressure to atmospheric pressure,
required for a proper working of the barometer. Note that the electronics inside is protected with a vent
that keeps the casing IP67 rated. There are no visual differences between the MTi-100 IMU, MTi-200
VRU and MTi-300 AHRS, other than the label. The MTi-G-700 has an extra SMA connector to allow a
GPS antenna to be attached.
2.2.1 MTi-G-700 GPS/INS
The flagship of the MTi product portfolio is the MTi-G-700 GPS/INS, a fully integrated solution that
includes an onboard GPS receiver. The MTi-G-700-GPS/INS is thus capable of not only outputting
GPS-enhanced 3D orientation, it can also output AHRS-augmented 3D position and velocity, so that
velocity and position accuracy significantly improve with respect to the accuracy of the GPS receiver
alone. Furthermore, it provides 3D sensors data, such as acceleration, rate of turn, magnetic field, the
navigation solution of the GPS receiver and static pressure. Data generated from the strapdown
integration algorithm (orientation and velocity increments ∆q and ∆v) are available, as all other
processed data, at 400 Hz.
2.2.2 MTi-300 AHRS
The MTi-300 AHRS is a full gyro-enhanced Attitude and Heading Reference System (AHRS). It
outputs drift-free roll, pitch and true/magnetic North referenced yaw. It also outputs sensors data and
data generated from the Strapdown integration algorithm as well as described in section 2.2.1.
2.2.3 MTi-200 VRU
The MTi-200 VRU is a 3D vertical reference unit (VRU) and this unit too runs the Xsens sensor fusion
algorithm from the MTi-G-700 and MTi-300. The difference between the data of the MTi-300 and MTi200 is that yaw is unreferenced, though the yaw is still much better than just integrating rate of turn.
2.2.4 MTi-100 IMU
The MTi-100 IMU is a 3D inertial measurement unit (IMU) that outputs 3D acceleration, 3D rate of turn
and 3D earth-magnetic field data. The MTi-10-IMU is also capable of outputting data generated by the
Strapdown integration algorithm (orientation and velocity increments ∆q and ∆v).
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2.2.5 Identifying device functionality using the unique Device Identifier
Each Xsens product is marked with a unique serial device identifier referred to as the DeviceID. The
DeviceID is categorized per MTi product configuration in order to make it possible to recognize the MTi
(and thus its functionality and interface) by reviewing the DeviceID. The second digit of the DeviceID
denotes the functionality (e.g. ‘1’ for MTi-10 and MTi-100), the third digit denotes the product series (6
for MTi 10-series, 7 for MTi 100-series) and the fourth digit denotes the interface (e.g. ‘0’ for
RS232+USB). The last four digits are unique for each device; these four digits have a hexadecimal
format.
Below is a list of the products and interfaced with their corresponding products.
Product
RS232+USB
RS422
RS485+USB
MTi-10 IMU
0160xxxx
0161xxxx
0163xxxx
MTi-20 VRU
0260xxxx
0261xxxx
0263xxxx
MTi-30 AHRS
0360xxxx
0361xxxx
0363xxxx
MTi-100 IMU
0170xxxx
0171xxxx
0173xxxx
MTi-200 VRU
0270xxxx
0271xxxx
0273xxxx
MTi-300 AHRS
0370xxxx
0371xxxx
0373xxxx
MTi-G-700 GPS/INS
0770xxxx
0771xxxx
0773xxxx
2.2.6 Product code
The product code of the MTi MkIV consists of a number of characters that represent the product type,
full ranges of the inertial sensors, the interface and the casing option. The table below shows the
product code build-up.
Format
MTi-
####
-
*
A*
G*
Example
MTi-
G-700
-
2
A5
G4
-OEM
10
IMU
2
RS232
A5
5g
G4
450 º/s
Blank
Alu casing
20
VRU
4
RS485
A8
15g
G0
1000 º/s
-OEM
No casing
30
AHRS
6
RS422
100
IMU
200
VRU
300
AHRS
G-700
GPS/INS
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2.3
Evolution of MTi products
The MTi 10-series and MTi 100-series are Xsens 4th generation products, building on knowledge and
products from over a decade. They may be designated as MkIV MTi’s. In source code or software, this
can be Mk4.
In this manual, the term legacy MTi, MTx or MTi-G may be used. In these cases, it is referred to the
previous generation products, which set the standard in MEMS Motion Tracking technology.
Also included in the Motion Tracker range is the wireless MTw, which has a close resemblance to the
MTi 10-series and MTi 100-series in terms of system architecture and interfacing.
The MTi 10-series and MTi 100-series are described in detail in section 2.1 and 2.2, for completeness
they are listed below as well:
Product name
Description
Availability
Product photo
Legacy MTi
The standard setting MTi is a full 3D
AHRS, comparable in function to the
MTi-30 and MTi-300. It has a plastic
casing and aluminum bottom plate.
Product codes are in the form of MTi28A53G35
Introduced:
2005
Available: at
least till Dec
2013
Legacy MTi-OEM
The OEM board of the legacy MTi.
The board is green (contrary to
orange MTi-10s and MTi-100s OEM
board)
Introduced:
2006
Available: at
least till Dec
2013
Legacy MTx
Designed as a Motion Tracker for
human movements, this low-weight
Motion Tracker has a fully plastic
casing. Product codes are in the form
of MTx-28A53G25
Introduced:
2005
Available: at
least till Dec
2013
Legacy MTi-G
The GPS-aided MTi-G offers reliable
orientation during accelerations. The
successor of the MTi-G is the MTi-G700. The casing is as the legacy
MTi’s casing. Product codes are in
the form of MTi-G-28A53G35.
Introduced:
2007
Available: at
least till Dec
2013
MTw
The wireless MTw is available as
single Motion Tracker or in a timesynchronized network together with
the Awinda station. Product codes are
in the form of MTw-38A70G20.
Introduced:
2010
MTi 10-series,
MTi 100-series
(including MTi-G700) and OEM
The latest 4th generation addition to
the Motion Trackers of Xsens (MkIV).
See section 2.1 and 2.2 for more
information. The OEM board is
orange. This manual focuses on
these products. Product codes are in
the form of e.g. MTi-30-2A5G4
Introduced:
2012
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2.4
Overview MTi Development Kit
The MTi development kit is a very easy to use
starter’s kit that allows for fast and easy
integration of the MTi in any user scenario. On
the right, the Development Kit is shown,
containing an MTi, USB cable, Software Suite
(on USB flash drive), a Quick Setup sheet and
license key (both in the lid).
The full content of the MTi DK is described
below.
2.4.1







Contents
Your MTi
Device specific Test and Calibration
Certificate
A letter with your individual software
license code
USB cable (CA-USB-MTi)
Multi-purpose cable (CA-MP-MTi) (optional)
Quick Setup Sheet
MT Software Suite on USB Flash Drive
o MT Low-level communication Documentation PDF [MT0101P]
o Quick Setup PDF
o MT Software Suite
 Xsens MTi USB driver
 MT Manager
 MT Software Development Kit (MT SDK)
 XsensDeviceApi.DLL, 32-bit and 64-bit
o DLL C and C++ interface
o COM interface
 XDA public source files (C, C++ wrapper)
 Example source code and examples
o MATLAB: DLL example supported from MATLAB 2010b
o C: DLL example
o C++: public source example and DLL example
 Linux SDK: beta release download from www.xsens.com
 Magnetic Field Mapper (MFM)
 Documentation
 MTi User Manual [MT0506P]
 MT Low level communication Documentation [MT0101P]
 MT Magnetic Field Mapper Documentation [MT0202P]
 XDA doxygen HTML API documentation
NOTE: the most recent version of the software, source code and documentation can always be
downloaded on the support section of www.xsens.com/en/support.
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2.5
Installation
2.5.1 Transient accelerations
The 3D linear accelerometers in the MTi are primarily used to estimate the direction of gravity to obtain
a reference for attitude (pitch/roll). During long periods (more than tens of seconds) of transient “free”
accelerations (i.e. 2nd derivative of position) the observation of gravity cannot be made. The sensor
fusion algorithms take these effects into account, but nonetheless it is impossible to estimate true
vertical without added information.
The impact of transient accelerations can be minimized when you take into account a few things when
positioning the device when installing it in the object you want to track/navigate/stabilize or control.
If you want to use the MTi to measure the dynamics of a moving vehicle/craft it is best to position the
measurement device at a position where you expect the least (smallest) transient accelerations. This
is typically close to the centre of gravity (CG) of the vehicle/craft since any rotations around the centre
of gravity translate into centripetal accelerations at any point outside the point of rotation, which is
usually close to the CG. The acceleration of the vehicle as a whole can of course not be taken into
account. For the MTi-G-700 however that have a valid GPS-fix, transient accelerations make the
orientation better observable.
The MTi 100-series cope better with transient “free” accelerations because of the higher-class
gyroscopes in the MTi 100-series. Next to the better hardware, the algorithm in the MTi 100-series is
superior in detecting and coping with challenging conditions, such as transient accelerations.
2.5.2 Vibrations
Although the MTi samples at 10kHz and includes a strap down integration algorithm with
coning/sculling compensation and vibration rejection, for best results it is recommended that the MTi is
mechanically isolated from vibrations as much as possible: since vibrations are measured directly by
the accelerometers, the following two conditions can make the readings from the accelerometers
invalid;
1. The magnitude of the vibration is larger than the measurement range of the accelerometer.
This will cause the accelerometer to saturate, which may be observed as a “drift” in the zerolevel of the accelerometer. This will show up as an erroneous roll/pitch.
2. The frequency of the vibration is higher than the bandwidth of the accelerometer. In theory,
such vibrations are rejected, but in practice they can still give rise to aliasing, especially if
close to the bandwidth limit. This can be observed as a low frequency oscillation. Further, high
frequency vibrations often tend to have large acceleration amplitudes (see item 1).
There is an effect on the gyroscopes as well and especially when the vibrations include high-frequent
coning motion, the gyroscope readings may become invalid. The MTi 100-series features vibration
rejecting gyroscopes, designed to better cope with these specific conditions.
Note that the sleeve on the Fischer connector can move by design in order to enable unmating.
Vibrations on the MTi, especially in the direction of the MTi’s x-axis, can make the sleeve vibrate
against the panel part of the connector. This may be visible in the accelerometer and gyroscope data.
To prevent this, the sleeve of the Fischer connector may be locked with the ring at the connector.
Xsens has tested a set of vibration dampeners on the MTi. Vibration dampeners are low-profile rubber
cylinders that allow the MTi to be mounted on an object without a direct metal to metal connection that
transduces vibrations from the object to the MTi. The vibration dampeners have been tested with
frequencies up to 1200 Hz that caused aliasing when the MTi was mounted directly on the vibration
table had no effect with the vibration dampeners fitted. The dampeners tested are manufactured by
Norelem and have part number 26102-00800855, www.norelem.com
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2.5.3 Magnetic materials and magnets
When an MTi is placed close to or on an object that is either magnetic or contains ferromagnetic
materials, the measured magnetic field is distorted (warped) and causes an error in measured yaw.
The earth magnetic field is altered by ferromagnetic materials, permanent magnets or very strong
currents (several amperes). In practice, the distance to the object and the amount of ferromagnetic
material determines the amount of disturbance. Errors in yaw (MTi-30, MTi-300 and MTi-G-700 only)
due to such distortions can become quite large, since the earth magnetic field is very weak in
comparison to the magnitude of many sources of distortion.
Whether or not an object is ferromagnetic should preferably be checked by using the MTi’s
magnetometers. It can also be checked with a small magnet, but be careful, you can easily magnetize
hard ferromagnetic materials, causing even larger errors. If you find that some object is magnetized
(hard iron effect), this is often the case with for example stainless steels that are normally not
magnetic, it may be possible to “degauss1” the object.
In most cases when the disturbance of the magnetic field caused by placement of the MTi on a
ferromagnetic object can be corrected for using a specialized calibration procedure commonly known
as a “hard- and soft iron calibration”. The calibration procedure (MTi-30, MTi-300 and MTi-G-700 only)
can be executed in a few minutes and yields a new set of calibration parameters that can be written to
the MTi non-volatile memory. This calibration procedure is implemented in the software module
“Magnetic Field Mapper” (MFM) that comes with the Software Suite.
Disturbance caused by objects in the environment near the MTi, like file cabinets or vehicles, that
move independently, with respect to the device cause a type of distortion that cannot be accounted
for2. With the MTi-300 and MTi-G-700, the effect of magnetic distortions will be lower than in the MTi30. Also, the choice for a filter profile greatly influences the total error amount because of the magnetic
distortion.
1
Degaussing is a procedure to apply strong alternating magnetic fields with decreasing magnitude in random
direction to an object that has been magnetized. The effect of the strong alternating fields is to remove any
magnetized (aligned) domains in the object. When degaussing, make sure the MTi is not attached to the object.
2 This type of disturbance is non-deterministic.
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2.6
Typical User Scenarios
This section is intended to help you find the right software component and corresponding
documentation for the way you want to use your MTi.
2.6.1 MT Software Suite
The MT Software Suite is a set of software components that can be used to communicate with the MTi
and to perform more high-level routines, such as logging, exporting, a magnetic field calibration and
updating of the firmware. Depicted below is a flow chart based on the software platform and the
preferred interface level.
On the left, three programs with GUIs are shown (Firmware Updater, Magnetic Field Mapper and MT
Manager). These programs offer the possibility to configure the MTi in a very easy way. The MT
Manager also can be used to communicate with the MTi.
The MT SDK contains all the developer code, such as a DLL, a shared object for x86 computers and
basic functionality in C source code for embedded systems. Of course it is possible to use lower level
communication options, down to the XBus low-level protocol; the most functionality however can be
found in the DLL and shared object.
The XBus low-level protocol is described in high detail in the Low Level Communication Protocol:
[LLCP].
The hardware driver of the USB interface for Linux can be found on http://github.com/xsens/xsens_mt.
The driver is also included in Linux kernel 3.9 and higher.
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2.6.2 Getting Started with the MT Manager
The easiest way to get started with your MTi is to use the MT Manager software for Windows XP/W7.
This easy to use software with a Windows user interface allows you to:
 record data and playback/review data
 view orientation, position and velocity in real-time (if available)
 view inertial and magnetic sensor data in real time
 view low-level communication and XDA communication via message terminals
 export log files to ASCII and KML/KMZ
 change and view various device settings and properties
 reprocess pre-recorded data, e.g. with different settings
The MT Manager is therefore an easy way to get to know and to demonstrate the capabilities of the
MTi and to configure the device easily to suit your needs.
With the MT Manager, it is possible to apply a configuration profile to multiple MTi’s. This allows
system integrators to configure MTi’s fast and accurate.
Applies to: Windows PC platform
Please refer to the MT Manager User Manual [MTM] for more information on this topic
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2.6.3 Using the Software Development Kit (SDK)
This chapter gives an introduction to the Xsens Device API (XDA). It serves as a starting point for
members of a software development department interested in assessing the basis of the SDK and
knowing about the background considerations. The main objective of the SDK is to facilitate easy
development of user-specific host applications based on Xsens motion trackers.
The MT SDK 4.x (and the MT Software Suite) are designed for the MTi 10-series and MTi 100-series.
The communication protocol is the same as in previous versions of the SDK. Obviously, new
functionality has been introduced. In some functions and messages a new term is introduced to point
specifically to the MTi 10-series and MTi 100-series. This term is MkIV (or Mk4 in functions) and is an
abbreviation for Mark IV: the 4th generation MTi.
2.6.3.1 Using the Source code and Dynamic Library
The MT SDK consists of Source code and a Dynamic Library. Source code is made available in C,
since this language can be handled by many other programming languages, such as C++, Java and
Python. Since C++ is a more convenient language
to use for first-time users of the MT SDK (lower risk
of making mistakes, easier to handle complex
functions), Xsens also supplies a C++ wrapper
around the C-compiled library. Depicted on the
right is a schematic overview of the MT SDK. As
can be seen, the host application developer can
choose to use a COM, C, C# or C++ interface.
However, only the C interface is delivered as a
compiled dynamic library. For the C# and C++
interface the source code of the wrapper classes
are supplied as part of the SDK. The interfaces are
discussed in more detail in the following sections.
Note that conceptually XDA makes no distinction
between the cases that the data source is real-time
data stream from a device or if it is a recorded file
data stream.
Using the Xsens XBus low-level communication
protocol is discussed in section 2.6.4.
Device management and global control functions
are grouped in the XsControl object. To access
Figure 1: Xsens Device API
functionality for a specific device the XsDevice
object is available. Typical steps are:
1. Enter a serial key with XsControl::setSerialKey
2. Scan for Xsens devices with XsScanner::scanPorts
3. Open port with XsControl::openPort and get device object with XsControl::device
4. Configure device with XsDevice functions
5. Start measuring
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C-interface libraries
XDA is implemented in two C-interface libraries that are supplied for MS Windows and Linux,
consisting of two parts:
 XDA that contains the access to functionality as implemented in devices, e.g. configuring the
Motion Trackers, requesting data etc (– Linux only available as beta via [email protected])
 XsTypes that contains generic types (vectors, matrices, quaternions, etc.) and some basic
operations on those types, e.g. converting quaternions coming from the MTi into Euler angles.
The C API exposes all possible functions that could be supported by an Xsens device. As such, a
certain functionality implemented in devices is accessible by a function call that takes at least an
XsDevice Object as a parameter. Not every Xsens device supports all functionality, e.g. an MTi does
not support getting a position estimate whereas the MTi-G does. This means that whether the function
returns a meaningful result depends on the connected device. The DeviceID indicates the MTi product
with associated functionality: a list of DeviceIDs can be found in section 2.2.5. Exposing all the
possible functionalities has the advantage that when changing the MTi in the application to a device
with other functionalities, the majority of the code can remain unchanged.
Internally the Xsens host software is implemented using an object oriented approach in which the
functionality is only implemented in subclasses, see schematic below.
Figure 2: Functionality implementation for specific products
It is important for the developer to use only functions supported by the connected device. During run
time, calling an unsupported function will generate an error status in line with the normal error handling
framework.
C++ interface
To offer the convenience of object-lifetime management to developers, the XDA is also offered as a
C++ interface which basically implements a convenience wrapper around the C API. This means that
the developer does not have to deal with memory management (i.e. easy object-lifetime management)
as the class implementation takes care of this. This means that for example functions named
XsDevice_<function name> in the C interface are available in the C++ interface as the
<function name> method of the XsDevice class.
COM interface
For MS Windows environments, all the functionality is also available via a COM interface.
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2.6.4 Direct low-level communication with MTi
The MTi features a powerful embedded multi-processor core. Since the MTi has an on-board nonvolatile memory that can store all settings, the MTi can conveniently be used without using a host
computer.
The low-level communication protocol (named XBus protocol) offers full control and functionality,
however without the convenience advantages that the Xsens Device API offers, such as threading,
object-oriented programming and error handling. Low-level communication is essential on platforms
that do not support the Xsens Device API, such as custom embedded computers.
The low-level communication is extensively described in the Low-Level Communication Protocol
Documentation. Next to that, source code is delivered to make driver development and Xbus message
parsing for the MTi as easy and quick as possible.
2.6.5 Migration from MT SDK 3.3 (CMT)
Programmers familiar with using the CMT interface from the MT SDK 3.x and lower (Xsens’ interface
for legacy MTi products) will find that changes need to be made in order to work with the new XDA.
Notable differences are shown below:
MT SDK 3.3 / CMT 3.3
MT SDK 4 / XDA 4.x
Xsens CMT (Communication for
Motion Trackers) library
XDA (Xsens Device API) library
Mixed C/C++ interface
Pure C interface with C++ wrapper interface. The C interface
supplies the same functionality as the C++ interface but uses
the class name as a function prefix (ie XsControl_openPort
instead of XsControl::openPort)
Preallocation of buffers is often
required
XDA-managed safe interface objects are passed between the
library and the application
Library functions are plain functions
using an instance number and
DeviceID for device identification
Library functions and structures are available as C++ classes
without the need for explicit identification per function
Only supports MT9-C and Xbus
Master devices
Supports all Xsens devices
Data output in fixed-rate all-in-one
format
Data output rates configurable per type of output. Also many
more output types are available.
All functions are prefixed with cmt
All structs are prefixed with Cmt
All global functions and objects are prefixed with Xs.
Source code is available including
logging and custom functions
Source code is limited to a message interface. However,
fewer messages are required to configure MTis and data
messages are easier to understand so the message interface
is more robust.
Linux functions in source code only
A shared object for Linux on x86 processors is available (beta)
XDA can be run side-by-side with CMT, but the libraries don’t interact. A full conversion to XDA is
recommended. The following coding steps are needed: replace all Cmt objects in the code by their Xs
counterparts and replace DeviceID storage by XsDevice storage and use XsDevice class functions
instead of global CMT-functions. In section 2.6.3.1, the typical workflow of XDA is explained. Also refer
to examples, to be found in the Xsens folder in Program Files of your computer.
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MTi 10-series and MTi 100-series devices are designed to be drop-in replaceable with legacy MTi and
MTx devices. When new MTi’s are configured to output orientation data in legacy output mode, CMT
will recognize the device. In this case only basic functionality is available, such as the reading of
orientation data. See section 4.10 for more information about the legacy output mode.
2.6.6 Terms of use MT Software Suite
The installer of the MT Software Suite can install 4 components of the MT Software Suite: the MT
Manager, the MT SDK, the MT Magnetic Field Mapper and the MT Firmware Updater. It is possible to
install only parts of the MT Software Suite, so every component has a separate EULA or Software
License Agreement that you need to read and accept. In the following table, the guidelines for use of
each component are described.
Component
EULA/SLA
Guidelines
MT Manager
EULA
For use with Xsens products only
Not allowed to re-distribute
Not allowed to reverse engineer
Not allowed to modify
Serial key required
MT SDK
SLA
For use with Xsens products only
Allowed to re-distribute “as is” or embed in programs
Not allowed to reverse engineer
Allowed to modify and extend source code; not allowed to modify DLL
Serial key required for use of DLL; not needed for source code
Include Software License Agreement with distribution
MT MFM
SLA
For use with Xsens products only
Allowed to re-distribute “as is”
Not allowed to reverse engineer
Not allowed to modify
No serial key required
Include Software License Agreement with distribution
MT FWU
SLA
For use with Xsens products only
Allowed to re-distribute “as is”
Not allowed to reverse engineer
Not allowed to modify
No serial key required
Include Software License Agreement with distribution
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3 MTi System Overview
3.1
Calibration
A correct calibration of the sensor components inside the MTi is essential for an accurate output.
Because of the importance of the calibration, each Xsens’ MTi is calibrated and tested by subjecting
each product to a wide range of motions and temperatures.
The MTi 10-series and the MTi 100-series feature different gyroscopes and a different sensor fusion
algorithm. Therefore, the high-performance MTi 100-series require a more elaborate calibration
method.
The individual calibration parameters are used to convert the sensor component readout (digitized
voltages) to physical quantities as accurately as possible, compensating for a wide range of
deterministic errors. Additionally, the calibration values are used in both Xsens sensor fusion
algorithms, as discussed below.
3.2
Xsens Kalman Filter (XKF3i) for MTi 10-series
The orientation of the MTi 10-series is computed by Xsens Kalman Filter. XKF3i uses signals of the
rate gyroscopes, accelerometers and magnetometers to compute a statistical optimal 3D orientation
estimate of high accuracy with no drift for both static and dynamic movements. XKF3 is a proven
sensor fusion algorithm, which can be found in various products from Xsens and partner products.
The design of the XKF3i algorithm can be summarized as a sensor fusion algorithm where the
measurement of gravity (by the 3D accelerometers) and Earth magnetic north (by the 3D
magnetometers) compensate for otherwise slowly, but unlimited, increasing (drift) errors from the
integration of rate of turn data (angular velocity from the rate gyros). This type of drift compensation is
often called attitude and heading referencing and such a system is referred to as an Attitude and
Heading Reference System (AHRS).
3.2.1 Using the acceleration of gravity to stabilize inclination (roll/pitch)
XKF3i stabilizes the inclination (i.e. roll and pitch combined) using the accelerometer signals. An
accelerometer measures gravitational acceleration plus acceleration due to the movement of the
object with respect to its surroundings.
XKF3i uses the assumption that on average the acceleration due to the movement is zero. Using this
assumption, the direction of the gravity can be observed and used to stabilize the attitude. The
orientation of the MTi in the gravity field is accounted for so that centripetal accelerations or
asymmetrical movements cannot cause a degraded orientation estimate performance. This
assumption is surprisingly powerful, almost all moving objects undergo accelerations if they are
moving, but in most cases the average acceleration with respect to the environment during some
period of time is zero. The key here is the amount of time over which the acceleration must be
averaged for the assumption to hold. During this time, the rate gyroscopes must be able to track the
orientation to a high degree of accuracy. In practice, this limits the amount of time over which the
assumption holds true. For the class of miniature MEMS rate gyroscopes used in the MTi-10 series
this period of time is about 10-20 seconds maximum.
However, for some applications this assumption does not hold. For example an accelerating
automobile may generate significant accelerations for time periods lasting longer than the maximum
duration the MT’s rate gyroscopes can reliably keep track of the orientation. This will degrade the
accuracy of the orientation estimates with XKF3i somewhat, because the application does not match
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the assumptions made in the algorithm. Note however, that as soon as the movement again matches
the assumptions made, XKF3i will recover and stabilize. The recovery to optimal accuracy can take
some time.
NOTE: To be able to accurately measure orientations as well as position in applications which can
encounter long term accelerations we offer a solution that incorporates a GPS receiver (the MTi-G-700
GPS/INS).
3.2.2 Using the Earth magnetic field to stabilize yaw
By default, yaw is stabilized using the local (earth) magnetic field (only in the MTi-30 AHRS). In other
words, the measured magnetic field is used as a compass. If the local Earth magnetic field is
temporarily disturbed, XKF3i will track this disturbance instead of incorrectly assuming there is no
disturbance. However, in case of structural magnetic disturbance (>10 to 30 s, depending on the filter
setting) the computed heading will slowly converge to a solution using the 'new' local magnetic north.
Note that the magnetic field has no direct effect on the inclination estimate.
In the special case the MTi is rigidly strapped to an object containing ferromagnetic materials,
structural magnetic disturbances will be present. Using a so-called 'magnetic field mapping' (MFM, i.e.
a 3D calibration for soft and hard iron effects), these magnetic disturbances can be completely
calibrated for, allowing the MTi to be used as if it would not be secured to an object containing
ferromagnetic materials.
3.2.3 Initialization
The XKF3i algorithm not only computes orientation, but also keeps track of variables such as sensor
biases or properties of the local magnetic field (magnetic field: MTi-30 AHRS only). For this reason,
the orientation output may need some time to stabilize once the MTi is put into measurement mode.
Time to obtain optimal stable output depends on a number of factors. An important factor determining
stabilizing time is determined by the time to correct for small errors on the bias of the rate gyroscopes.
The bias of the rate gyroscope may slowly change due to different effect such as temperature change
or exposure to impact.
3.2.4 XKF3i filter profiles
As described above, XKF3i uses assumptions about the acceleration and the magnetic field to obtain
orientation. Because the characteristics of the acceleration or magnetic field differ for different
applications, XKF3i makes use of filter profiles to be able to use the correct assumptions given the
application. This way, XKF3i can be optimized for different types of movement. For optimal
performance in a given application, the correct filter profile must be set by the user. For information on
how to specify a filter profile in XKF3i, please refer to the MT Manager User manual [MTM] or the MT
low-level communication protocol documentation [LLCP].
The different filter profiles are divided in several types of motion and are discussed below.
Number
Name
IMU
Magnetometer
Product
39
General
•
•
30-AHRS
40
High_mag_dep
•
•
30-AHRS
41
Dynamic
•
•
30-AHRS
42
Low_mag_dep
•
•
30-AHRS
43
VRU_general
•
30-AHRS, 20-VRU
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The general filter profile is the default setting. It assumes moderate dynamics and a homogenous
magnetic field. External magnetic distortions are considered relatively short (up to ~20 seconds).
Typical applications include camera tracking (e.g. TV camera’s), remotely operated robotic arms on
ROV’s etc
The high_mag_dep filter profile assumes homogenous magnetic field and an excellent Magnetic Field
Mapping. This filter profile heavily relies on the magnetometer for heading. Dynamics of the motion are
relatively slow. Typical applications are navigation of ROV’s or the control of small unmanned
helicopters.
The dynamic filter profile assumes jerky motions. However, the assumption is also made that there is
no GPS available and/or that the velocity is not very high. In these conditions a 100-series MTi may be
a better choice. The dynamic filter profile uses the magnetometer for stabilization of the heading, and
assumes very short magnetic distortions. Typical applications are where the MTi is mounted on
persons or hand-held (e.g. HMD, sports attributes etc.).
The low mag_dep filter profile assumes that the dynamics is relatively low and that there are longlasting external magnetic distortions. Also use this filter profile when it is difficult to do a very good
Magnetic Field Mapping (MFM). The use of the low_mag_dep filter profile can be useful to limit drift in
heading whilst not being in a homogenous magnetic field. Typical applications are large vessels and
unmanned ground vehicles in buildings.
The VRU_general filter profile assumes moderate dynamics in a field where the magnetic field cannot
be trusted at all. It is also possible to use this filter profile in situations where an alternative source of
yaw is available. Yaw from the VRU is unreferenced; note however, that because of the working
principle of the VRU, the drift in yaw will be much lower than when gyroscope signals would be
integrated. Typical applications are stabilized antenna platforms mounted on cars of ships and pipeline
inspection tools. This filter profile is the only one available for the MTi-20 VRU.
Every application is different and although example applications are listed above, results may vary
from setup to setup. It is recommended to reprocess recorded data with different filter profiles in MT
Manager to determine the best results in your specific application.
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3.3
Xsens sensor fusion algorithm for MTi 100-series
3.3.1 MTi 100-series filter
The Xsens sensor fusion algorithm in the MTi 100-series has several advanced features. It can handle
a multitude of data channels, to incorporate GPS and barometer data as well.
3.3.2 Transient accelerations
The overall accuracy and robustness of the MTi 100-series is significantly higher than the overall
accuracy of the MTi 10-series. The most important factor contributing to this is the use of higheraccuracy gyroscopes. The gyroscopes in the MTi-100 series are vibration-rejecting, quad-structure
MEMS-gyroscopes. Because of the excellent bias stability it is possible to integrate the rate of turn for
a long time, requiring less frequent reference updates for orientation. The Xsens sensor fusion
algorithm can detect transient accelerations and will use the gyroscopes for a longer time. Next to the
better gyroscopes, the MTi-G-700 algorithm adds robustness to the orientation and position estimates,
making the MTi 100-series the better choice in more demanding applications.
3.3.3 Magnetic distortions
As with transient accelerations, magnetic distortions are also detected by the sensor fusion algorithm
in the MTi 100-series. This makes it possible to use the magnetometers in periods of homogenous
magnetic fields but discarding magnetometer updates when the magnetic field is distorted. Because of
the superior gyroscopes in the MTi 100-series, the heading will be drifting at a relatively low rate.
3.3.4 Loss of GPS
When the MTi-G-700 GPS/INS has limited/mediocre GPS reception or even no GPS reception at all,
the MTi-G-700 sensor fusion algorithm seamlessly adjusts the filter settings in such a way that the
highest possible accuracy is maintained. The GPS status will be monitored continuously so that the
filter can take GPS data into account when available and sufficiently trustworthy. In case loss of GPS
lasts longer than 45-60 seconds (exact time depends on the filter profile), the MTi-G-700 will go into a
state where it no longer uses velocity estimates in the filter.
3.3.5 MTi 100-series filter profiles
Only the MTi-G-700 GPS/INS can use GPS updates; the MTi-300 AHRS and MTi-G-700 GPS/INS use
the magnetometers. The MTi-200 only uses the inertial sensors.
The sensor fusion algorithm uses assumptions about the acceleration and the magnetic field to obtain
orientation. Because the characteristics of the acceleration or magnetic field differ for different
applications, the filter makes use of filter profiles to be able to use the correct assumptions given the
application. This way, the filter can be optimized for different types of movement. For optimal
performance, the correct filter profile must be set by the user.
Number
Name
IMU
Magnetometer
Product
39
General
•
•
300-AHRS
40
High_mag_dep
•
•
300-AHRS
41
Dynamic
•
•
300-AHRS
42
Low_mag_dep
•
•
300-AHRS
43
VRU_general
•
300-AHRS, 200-VRU
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These are the same filter profiles as the MTi 10-series, but they are differently tuned in the MTi 100series to make better use of the gyroscopes and calibration. For descriptions on these filter profiles,
refer to section 3.2.4.
3.3.6 MTi-G-700 filter profiles
The MTi-G-700 GPS/INS uses different filter profiles as it is typically used in outdoor applications.
These filter profiles are described below. Please note the specific cautions with each of these filter
profiles.
Nr
Name
IMU
Magnetic
field
Barometric
pressure
GPS
Holonomic
constraints
Product
•
•
700-GPS/INS
•
700-GPS/INS
•
•
700-GPS/INS
1
General
•
2
GeneralNoBaro
•
3
GeneralMag
•
4
Automotive
•
•
•
•
700-GPS/INS
5
Automotive
UrbanCanyon
•
•
•
•
700-GPS/INS
•
The General filter profile is the default setting. It makes few assumptions about movements. Yaw is
referenced by comparing GPS acceleration with the on-board accelerometers, so the more movement
(when GPS is available) will result in a better yaw. Altitude (height) is determined by combining static
pressure, GPS altitude and accelerometers. The barometric baseline is referenced by GPS, so during
GPS outages, accurate height measurements are maintained because this barometric baseline is
monitored.
The GeneralNoBaro filter profile is very similar to the general filter profile. However, it does not use
the barometer for height estimation (it thus uses GPS and accelerometers only). Since airflows near
the venting holes in the MTi-G will lower the barometric pressure (and thus make height estimations
inaccurate), you can use this filter profile when the MTi-G is mounted in such airflow.
The GeneralMag filter profile bases it yaw mainly on magnetic heading, together with comparison of
GPS acceleration and the accelerometers. Although this combination makes the yaw more robust than
magnetic field alone, a homogenous or calibrated-for magnetic field is essential for good-performance
yaw. Other parameters are tuned the same as in the General filter profile.
The Automotive filter profile assumes that the yaw of the MTi-G is also the GPS course over ground
(holonomic constraints). This assumption holds for most automotive/ground vehicles, except for those
who experience side slip, such as racing cars, tracked vehicles, some articulated vehicles (depending
on where the MTi-G is mounted) and vehicles driving on rough terrain. The Automotive filter profile
thus uses GPS to determine the yaw. Note that it is essential to mount MTi-G exactly in the direction of
movement in order to prevent an offset. Please refer to 4.2.3 for proper mounting. When GPS is lost,
yaw will be determined by the velocity estimation algorithm for 60 seconds, before yaw is determined
by gyroscopes integration only. Should GPS outages recur regularly or if you have bad GPSavailability (e.g. in urban canyons), consider using AutomotiveUrbanCanyon.
In the Automotive filter profile, yaw is locked (e.g. gyro bias will be estimated and yaw will not change),
when GPS indicates that there is no movement. This is useful when standing still, as gyro bias would
otherwise induce a yaw drift.
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The AutomotiveUrbanCanyon filter profile is similar to the Automotive filter profile in that they both
use the same assumptions. The assumptions are triggered with the monitoring on the GPS receiver
measurements. The filter profile assumes the deteriorated GPS conditions and places less trust on
holonomic constraint updates. The user is advised to make use of this filter profile for robust
performance in deteriorated GPS conditions. Using the Automotive filter profile (instead of
AutomotiveUrbanCanyon) in applications where GPS conditions are deteriorated can result in long
position outages.
Every application is different and although example applications are listed above, results may vary
from setup to setup. It is recommended to reprocess recorded data with different filter profiles in MT
Manager to determine the best results in your specific application.
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4 Output Specification
In this chapter the various output modes of the MTi are described. The MTi’s have tens of various
output options; it is possible to select a different output frequency and/or output format (e.g. float or
double) per output or group of outputs. A full overview of outputs can be found section 4.1.
Performance specifications on orientation, position and sensor data can be found in section 4.3.
Before going into these sections, it is useful to read section 4.1.2, which explains the various
coordinate systems and position representations.
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4.1
Overview of data outputs
The MTi supports two different data protocols: the binary (hexadecimal) XBus protocol and NMEA.
Refer to [LLCP] to learn how to switch between data protocols.
XDA type name
Hex
Value
20
30
100
200
300
700
Group Name
10
4.1.1 MTData2 output in XBus protocol
In order to learn more on how to work with XDA type name and Hex Value, please refer to
[XDA_DOC] and [LLCP] respectively.
Type Name
XDI_TemperatureGroup
08x0
●
● ● ● ● ●
●
XDI_Temperature
081y
●
● ● ● ● ●
●
XDI_TimestampGroup
10x0
●
● ● ● ● ●
●
UTC Time
XDI_UtcTime
1010
●
● ● ● ● ●
●
Packet Counter
XDI_PacketCounter
1020
●
● ● ● ● ●
●
Integer Time of Week
XDI_Itow
1030
●
● ● ● ● ●
●
GPS Age
XDI_GpsAge
1040
Pressure Age (legacy)
XDI_PressureAge
1050
Sample Time Fine
XDI_SampleTimeFine
1060
●
● ● ● ● ●
●
Sample Time Coarse
XDI_SampleTimeCoarse
1070
●
● ● ● ● ●
●
Frame Range
XDI_FrameRange
1080
XDI_OrientationGroup
20xy
● ●
● ●
●
Quaternion
XDI_Quaternion
201y
● ●
● ●
●
Rotation Matrix
XDI_RotationMatrix
202y
● ●
● ●
●
Euler Angles
XDI_EulerAngles
203y
● ●
● ●
●
XDI_PressureGroup
30xy
● ● ●
●
XDI_BaroPressure
301y
● ● ●
●
XDI_AccelerationGroup
40xy
●
● ● ● ● ●
●
Delta V
XDI_DeltaV
401y
●
● ● ● ● ●
●
Acceleration
XDI_Acceleration
402y
●
● ● ● ● ●
●
Free Acceleration
XDI_FreeAcceleration
403y
● ●
●
XDI_IndicationGroup
4800
For MTw only; MTi see StatusWord
TriggerIn1
XDI_TriggerIn
4810
For MTw only; MTi see StatusWord
TriggerIn1
XDI_TriggerIn2
4820
For MTw only; MTi see StatusWord
XDI_PositionGroup
50xy
●
Altitude MSL
XDI_AltitudeMsl
501y
●
Altitude Ellipsoid
XDI_AltitudeEllipsoid
502y
●
Position ECEF
XDI_PositionEcef
503y
●
Temperature
Temperature
Timestamp
Orientation Data
Pressure
Baro Pressure
Acceleration
Trigger Indication
Position
Valid for MTi
product
Max
freq3
1 Hz
2000 Hz
●
● ●
400 Hz
50 Hz
2000 Hz
400 Hz
3
Maximum frequencies may differ on the chosen combination of outputs. Availability and frequency of outputs
may differ between onboard processing and processing in XDA, as SCR or delta_q/delta_v is needed for
processing data.
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LatLon
●
XDI_LatLon
504y
XDI_AngularVelocityGroup
80xy
●
● ● ● ● ●
●
Rate of Turn
XDI_RateOfTurn
802y
●
● ● ● ● ●
●
Delta Q
XDI_DeltaQ
803y
●
● ● ● ● ●
●
XDI_GpsGroup
88x0
●
DOP
XDI_GpsDop
8830
●
SOL
XDI_GpsSol
8840
●
Time UTC
XDI_GpsTimeUtc
8880
●
SV Info
XDI_GpsSvInfo
88A0
XDI_RawSensorGroup
A0x0
●
● ● ● ● ●
●
ACC + GYR + MAG +
temperature
XDI_RawAccGyrMagTemp
A010
●
● ● ● ● ●
●
Gyro temperatures
XDI_RawGyroTemp
A020
●
● ● ● ● ●
●
XDI_MagneticGroup
C0xy
●
● ● ● ● ●
●
XDI_MagneticField
C02y
●
● ● ● ● ●
●
XDI_VelocityGroup
D0xy
XDI_VelocityXYZ
D01y
XDI_StatusGroup
E0x0
●
● ● ● ● ●
●
Status Byte
XDI_StatusByte
E010
●
● ● ● ● ●
●
Status Word
XDI_StatusWord
E020
●
● ● ● ● ●
●
RSSI
XDI_Rssi
E040
Angular Velocity
GPS
Sensor Component Readout (SCR)
Magnetic
Magnetic Field
Velocity
Velocity XYZ
Status
2000 Hz
4 Hz
●
2000 Hz
100 Hz
●
400 Hz
●
2000 Hz
‘x’ = The hex value of the Type bits
‘y’ = The hex value of the Format bits (float, fixed point; coordinate system)
See the [LLCP] for more information.
4.1.2 NMEA protocol
The MTi also supports a variety of strings in NMEA protocol. Below is a list of the various strings that
can be outputted by the MTi.
Bit
String Type
Description
Bit 0
$HCHDM
Magnetic Heading
Bit 1
$HCHDG
Heading with HeadingOffset
Bit 2
TSS2
Heading, Heave (0), Status, Roll, Pitch, Heading Status flag (F)
Bit 3
$PHTRO
Pitch, Roll
Bit 4
$PRDID
Pitch, Roll, Heading
Bit 5
EM1000
Roll, Pitch, Heave (0), Heading
Bit 6
$PSONCMS
Quaternion, Acceleration, Rate of Turn, Magnetic Field, Temp.
Bit 7
$HCMTW
Temperature
Bit 8
$HEHDT
True Heading
Bit 9
$HEROT
Rate of Turn
Bit 10-15
Reserved
Reserved for future string types
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4.2
Coordinate systems
Data from the MTi is represented in various coordinate systems, which are explained below.
4.2.1
Calibrated inertial data and magnetic field data
The sensor coordinate system (S) is a right-handed coordinate Carthesian system that is body-fixed
to the device and is used to output rate-of-turn (DataID 0x8020), acceleration (DataID 0x4020) and
magnetic field (DataID 0xC020). The encased version of the MTi shows the coordinate system on the
sticker. Depicted below is the sensor coordinate system on the encased MTi and the OEM version.
Small x, y and z are used for (S) and the object coordinate system (O). Capital X, Y and Z are
generally, but not always, used for velocity. They stand for the local-earth fixed coordinate system (L),
see section 4.2.3.
z
z
x
x
y
Figure 3: coordinate system of the encased MTi
(Note: origin is located at the accelerometers)
y
Figure 4: Coordinate system of the MTi-OEM
(Note: origin is located at the accelerometers)
The aluminum base plate of the MTi is carefully aligned with the output coordinate system during the
individual factory calibration. The alignment of the bottom plane and sides of the aluminum base-plate
with respect to the sensor-fixed output coordinate system (S) is within 0.1 deg. Convenient alignment
points are designed in the base plate of the MTi.
The non-orthogonality between the axes of the body-fixed co-ordinate system, (S), is <0.05. This also
means that the output of 3D linear acceleration, 3D rate of turn (gyro) and 3D magnetic field data all
will have orthogonal xyz readings within <0.05 as defined in the figure above.
It is possible to rotate the sensor coordinate system to an object coordinate system (O) when the
MTi is not exactly aligned with the axes of the object or vehicle the MTi is attached to. When this
alignment matrix has been applied, calibrated inertial data and magnetic field data are outputted in
(O). See section 4.11 for more information on alignment matrices.
4.2.2 Delta_angle and delta_velocity
The SDI output of the MTi contain delta_angle (dq, DataID 0x8030) and delta_velocity (dv, DataID
0x4010). These values represent the orientation change and velocity change during a certain interval.
In the MTi, this interval is 2.5 ms (400 Hz) by default. The values dq and dv are always represented in
the same coordinate system as calibrated inertial data and magnetic field data (see section 4.2.1),
which can be (S) or (O).
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4.2.3 Orientation data
The MTi calculates the orientation (DataID 0x2010, 0x2020, 0x2030) between the calibrated inertial
data and magnetic field, represented in (S) or (O), and the local Earth-fixed coordinate system (L).
By default the local earth-fixed reference co-ordinate system used is defined as a right handed
Cartesian co-ordinate system with:



X positive to the East (E).
Y positive to the North (N).
Z positive when pointing up (U).
This coordinate system is known as ENU and is the standard in inertial navigation for aviation and
geodetic applications. Note that it is possible to change the coordinate system using an alignment
matrix or orientation reset.
The 3D orientation output is defined as the orientation between the body-fixed co-ordinate system, (S),
and the earth-fixed co-ordinate system, (L), using the earth-fixed co-ordinate system, (L), as the
reference co-ordinate system.
Interpretation of yaw as heading 4
Heading is defined as the angle between north and horizontal projection of the vehicle roll axis. Yaw is
defined for a particular local-level navigation frame as the angle from a horizontal navigation axis to
the projection of the longitudinal axis in the horizontal plane following the right-hand rule. Based on the
definition of heading and yaw, consider the use of the MTi in an aircraft which is stationary and
pointing north. Below, a table is displayed that shows the heading and yaw outputs for the three
reference coordinate system (available with MTi)
Reference coordinate
system
Direction of mounting,
aircraft pointing North
Heading value (not
outputted by MTi)
Yaw value
East-North-Up (ENU)
x-axis of MTi aligned with
vehicle (pointing North)
0 deg
90 deg
North-West-Up (NWU)
x-axis of MTi aligned with
vehicle (pointing North)
0 deg
0 deg
North-East-Down
(NED)
x-axis of MTi aligned with
vehicle (pointing North)
0 deg
0 deg
When using the ENU convention (default), the yaw output is 0º when the vehicle (x-axis of the MTi) is
pointing East. When it is required that the yaw output is 0º when the vehicle (x-axis of the MTi) is
pointing North, it is recommended to select NWU or NED as the reference coordinate system. In
section 4.11 the various alignment resets are described.
Note that for proper working of the MTi-G in the automotive filter profile, it is needed to mount the MTi
in such a way that the yaw indicates 0 deg in the direction of the vehicle. For ENU coordinate systems
without an alignment reset, this means that the y-axis of the MTi-G should point to the front of the
vehicle, in NWU and NED coordinate systems that means that the x-axis of the MTi-G should point to
the front of the vehicle.
4
IEEE Standard for Inertial Systems Terminology
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True North vs. Magnetic North
As defined above the output coordinate system of the MTi is with respect to local Magnetic North. The
deviation between Magnetic North and True North (known as the magnetic declination) varies
depending on the location on earth and can be roughly obtained from the World Magnetic Model
(Xsens uses WMM 2010-2015) of the earth’s magnetic field as a function of latitude and longitude.
The MTi accepts a setting of the declination value. This is done by setting the position in the MT
Manager, SDK or by direct communication with the sensor. The output will then be offset by the
declination calculated internally and thus referenced to “local” True North. The MTi-G-700 GPS/INS
calculates True North automatically when GPS-position is available.
4.2.4 Velocity data
Velocity data, calculated by sensor fusion algorithm (DataID 0xD010) is outputted in the same
coordinate system as the orientation data, and thus adopts orientation resets as well. It is available
only in the MTi-G-700.
Velocity data from the navigation solution from the GPS receiver (DataID 0x8840) is represented in
Earth Centered – Earth Fixed (ECEF).
4.2.5 Position data
Position data, calculated by the sensor fusion algorithm (DataID 0x5040) is represented in Latitude,
Longitude in the WGS84 datum. It is available only in the MTi-G-700.
It is possible to retrieve position data, calculated by sensor fusion algorithm, in Earth Centered – Earth
Fixed (ECEF) format. Use DataID 0x5030 to retrieve this output.
Altitude is outputted in WGS84 datum (DataID 0x5020).
Position data from the navigation solution from the GPS receiver (DataID 0x8840) is represented in
Earth Centered – Earth Fixed (ECEF).
4.2.5.1
Linearization errors and relation WGS84 and LTP
The following section describes in more detail the (linearization) errors made and other artefacts
introduced when using global coordinate systems. It also describes the relation between WGS84
(LLA) and ENU (LTP). Most users will not experience these artefacts; neither should they need to take
these into account. This section is primarily in the User Manual for completeness and accuracy
reasons.
World coordinates WGS84 and LTP
Navigating around the world (f)using GPS and inertial sensors requires an understanding of the
Cartesian and Spherical coordinate systems commonly used for describing a position on the Earth.
For purposes of measuring and determining the orbits of the GPS satellites, it is convenient to use an
Earth Centered Inertial (ECI) coordinate system in which the origin is at the centre of the mass of the
Earth and which axes are pointing in fixed direction with respect to the stars. For the purpose of
computing the position of a GPS receiver, it is more convenient to use a coordinate system that
rotates with the Earth, known as an Earth Centered Earth Fixed (ECEF) system.
In the ECEF system, the xy-plane coincides with the Earth’s equatorial plane, the x-axis points in the
direction of 0° longitude (Greenwich meridian) and the y-axis points in the direction of 90°E. It is typical
to transform these Cartesian coordinates to latitude, longitude and height (or altitude), which are often
projected on maps. In order to carry out this transformation, it is necessary to have a physical model
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describing the Earth. The standard physical model of the Earth used for GPS applications is the World
Geodetic System 1984 (WGS84). WGS84 is also what is used in the MTi-G.
WGS84 provides an ellipsoidal model of the Earth’s shape, as well as Earth’s gravitational
irregularities. Major parameters are the semi-major axis a (=6,378,137 m) and the semi-minor axis b
(=6,356,752 m), see figures below. There are several local models (datums) which will increase local
accuracy using modified a and b and shift parameters (x, y, z) of the origin. However, if a selected
datum is used beyond its ‘borders’, accuracy will deteriorate fast. The MTi-G uses the default WGS84
model and not a specific datum.
Earth Centered Earth Fixed – ECEF
WGS-84 parameters:
a = 6,378,317 meter
b = 6,356,752 meter
Figure 5: Earth-Centered Earth-Fixed Coordinate System
Spherical coordinates - LLA:
λ = longitude
φ = latitude
h = altitude
Figure 6: Definition of Ellipsoidal Coordinates (Latitude, Longitude, Altitude) in WGS-84 Ellipsoid
In order to combine the output of the GPS receiver with the IMU, both systems have to be converted to
an appropriate coordinate system. Inertial sensors measure properties in the ECI system. However,
the MEMS inertial sensors used in the MTi-G are not accurate enough to measure the Earth’s rotation
rate or the transport rate of the MTi-G over the curved Earth surface if the MTi-G has a velocity.
Therefore, we can work with a local linearized tangent plane without making any significant errors.
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This system is called the locally tangent plane (LTP) and is in fact a local linearization of the Ellipsoidal
Coordinates (Latitude, Longitude, Altitude) in the WGS-84 Ellipsoid.
When mapping the ellipsoidal coordinates defined by to latitude, longitude, and altitude to a local
tangent plane, a spatial distortion is introduced as shown in Figure 7.
linearized meridian
local meridian
latitude
N
53
52
E
6
7
longitude
Figure 7: Spatial Distortion as Result of Mapping Ellipsoidal Coordinates to Local Tangent Plane (LTP)
In order to minimize the linearization error, the reference coordinates should be chosen as close as
possible to the points that are being mapped. The MTi-G performs a local linearization for each valid
GPS update according to the following linearization scheme, given a reference coordinates defined by
a latitude-longitude pair (ref,ref). The height is the same for both coordinate systems.
{
𝐸 = 𝑅 . ∆𝜑. cos(𝜃)
𝑁 = 𝑅. ∆𝜃
Where R is the radius of Earth at a given latitude.
∆𝜃 = 𝜃 − 𝜃𝑟𝑒𝑓
{
∆𝜑 = 𝜑 − 𝜑𝑟𝑒𝑓
In this documentation we will refer to the WGS84 co-ordinates system as G. The output of position
data from the MTi-G is in Ellipsoidal Coordinates (Latitude, Longitude, Altitude) in the WGS84
Ellipsoid.
The MTi-G uses HE (Height over Ellipsoid) – Altitude above
the ellipsoid (WGS84).
Furthermore, the local gravity vector may differ from the
vector perpendicular to the local tangent plane
(perpendicular to the plane tangent to the ellipsoid) as
shown in the figure below. The imaginary shape that is
Figure 8: Difference between Geoid and
perpendicular to the natural gravity vector is called
Ellipsoid
“geoid”. The value of vertical deviation (or also called
vertical deflection) can be a small fraction of a degree.
For the continental US, the maximum vertical deviation can be about +/- 0.01 degrees.
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4.3
Orientation performance specification
In the MTi product portfolio, several products provide roll, pitch and (un)stabilized yaw. The table
below provides an overview of the specific products and orientation performances. The 10-IMU and
the 100-IMU are not listed, as they do not provide orientation.
Typical orientation errors are in 1σ RMS values; maximum errors are in degrees. Note that the
validation tests can be found in the Technical Datasheet (document MT0503P, [MTI_TD]). For yaw,
maximum errors cannot be provided, as this strongly depends on the environmental conditions.
MTi-20
VRU
Roll/Pitch
Static
5
Dynamic
MTi-30
AHRS
MTi-200
VRU
MTi-300
AHRS
MTi-G-700
GPS/INS
Typ
Max
Typ
Max
Typ
Max
Typ
Max
Typ
Max
0.2º
0.4º
0.2º
0.4º
0.2º
0.25º
0.2º
0.25º
0.2º
0.25º
0.5º
2.0º
0.5º
2.0º
0.3º
1.0º
0.3º
1.0º
0.3º
1.0º
1.0
N/A
1.0º
N/A
1.0º
N/A
Yaw6
Unref.
Unref.
Performance specifications highly depend on the conditions. The MTi Technical Datasheet [MTI_TD],
containing validation tests and more details on the specifications of orientation and individual sensors,
is available. The orientation performance of the MTi-G-700 is valid in an increased range of
applications and motions.
The performance specifications in this chapter are subject to the following assumptions (see also
footnotes);
 Correct filter profile: If an unsuitable filter profile is chosen, the sensor fusion algorithm will
use erroneous assumptions. Depending on the specific situation this can lead to large errors
or even instability of the filter. Take care to select the correct filter profile. If you are uncertain,
do not hesitate to contact Xsens or your local distributor.
 Magnetic distortions: In several filter profiles the on-board 3D magnetometer is used to
observe the heading. It is assumed that a magnetic field mapping is performed and that the
magnetometers are not distorted by nearby ferromagnetic materials in the environment.
 Long-lasting accelerations (all, except for MTi-G-700): every filter profile copes different
with long-lasting accelerations. Although the MTi’s are able to discard these transient
accelerations, they will have an effect after a certain period of time. In the MTi 10-series, this
period is shorter than in the MTi-100 series. The MTi-G-700 with a good GPS fix can
compensate for these long-lasting accelerations.
 Settling time: Parameters in the MTi’s such as the rate gyro bias or the pressure at sea level
are continuously estimated. The sensor fusion algorithms need some time to estimate such
parameters. Depending on the time since last calibration of the MTi’s, the chosen filter profile
and the quality of the GPS fix this can take up to 15 minutes. There is no need to have the
MTi’s static during the settling time, on the contrary, movement (accelerations, turns) of the
MTi’s will help to estimate for example the gyro bias quicker as they become observable.
 Good GPS fix (MTi-G-700 only):
o If there is no GPS fix the position estimates based on the IMU will degrade very
rapidly (in the order of a few seconds).
o If there is no GPS fix the MTi-G cannot calculate correct attitude and heading under
all dynamic conditions due to “apparent gravity” (e.g. centripetal and linear
5
6
Max error with respect to earth coordinate system
MTi-20 VRU and MTi-200 VRU: unreferenced (heading is yaw rate of gyroscopes)
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

4.4
accelerations). Based on the rate gyros the attitude and heading estimates will
degrade slowly (typically a degree every minute).
Valid holonomic constraints (MTi-G-700 only): In several filter profiles of the MTi-G-700 it is
assumed that the x-axis of the MTi-G is mounted in the driving direction of the vehicle. If this is
not the case within about 1 degree, the estimated heading and position specification may not
be obtained.
Barometric conditions (MTi 100-series only): In some of the filter profiles, the altitude of the
MTi-G-700 is partly estimated by the on-board barometer. It is assumed that the pressure near
the MTi-G reflects the atmospheric pressure outside of the vehicle. So, if you selected a filter
profile that uses barometer data, the MTi-G cannot be used in e.g. a pressurized cabin.
Furthermore, the height accuracy may reduce with very rapid changes in atmospheric
pressure that could occur in e.g. severe thunderstorms.
Position and velocity performance specification (MTi-G-700)
The MTi-G-700 has the ability to output position. The performance highly depends on the GPS
availability, placement of the GPS antenna etc.
The table below states the position and velocity accuracy according to Xsens’ reference trajectories,
as explained in [MTI_TD].
Parameter
Data source
Condition
Specification
AHRS augmented (400 Hz GPS/INS), SBAS
Horizontal
1.0 m STD
Vertical
2.0 m STD
Horizontal
2.0 m CEP
Vertical
5.0 m CEP
AHRS augmented (400 Hz GPS/INS)
@ 30 m/s
0.1 m/s 1σ
RMS
GPS receiver (4 Hz GPS navigation solution)
@ 30 m/s
0.1 m/s 1σ
RMS
Position
GPS receiver (4 Hz GPS navigation solution), SBAS
Velocity
4.5
Orientation output modes
The orientation as calculated by the MTi is the orientation of the sensor-fixed co-ordinate system (S)
with respect to a Cartesian earth-fixed co-ordinate system (L). The output orientation can be
presented in different parameterizations:

Unit Quaternions
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

Euler angles7: roll, pitch, yaw (XYZ Earth fixed type, also known as Cardan or aerospace
sequence)
Rotation Matrix (directional cosine matrix)
A positive rotation is always “right-handed”, i.e. defined according to the right hand rule (corkscrew
rule). This means a positive rotation is defined as clockwise in the direction of the axis of rotation.
NOTE: This section is intended to give detailed information on the definition of the various orientation
output modes of the MTi. The output sequence of the elements in the vectors and matrices defined
here holds for all interface options (Low-level communication protocol, API, GUI). For more detailed
information about the respective interfaces please refer to their specific documentation;
Low-level communication
 MTi Low-level Communication Documentation
GUI
 MT Manager User Manual
4.5.1 Quaternion orientation output mode
A unit quaternion vector can be interpreted to represents a rotation about a unit vector n through an
angle α.
𝛼
𝛼
𝑞𝐿𝑆 = (cos ( ) , 𝒏 sin ( ))
2
2
A unit quaternion itself has unit magnitude, and can be written in the following vector format;
𝑞𝐿𝑆 = (𝑞0 , 𝑞1 , 𝑞2 , 𝑞3 )
|𝑞 | = 1
Quaternions are an efficient, non-singular description of 3D orientation and a quaternion is unique up
to sign:
𝑞 = −𝑞
An alternative representation of a quaternion is as a vector with a complex part, the real component is
the first one, q0.
The inverse (qSL) is defined by the complex conjugate (†) of qLS. The complex conjugate is easily
calculated;
†
𝑞𝐿𝑆
= (𝑞0 , −𝑞1 , −𝑞2 , −𝑞3 ) = 𝑞𝑆𝐿
7
Please note that due to the definition of Euler angles there is a mathematical singularity when the sensor-fixed xaxis is pointing up or down in the earth-fixed reference frame (i.e. pitch approaches ±90). In practice this means
roll and pitch is not defined as such when pitch is close to ±90 deg. This singularity is in no way present in the
quaternion or rotation matrix output mode.
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As defined here qLS rotates a vector in the sensor co-ordinate system (S) to the global reference coordinate system (L).
†
𝒙𝐿 = 𝑞𝐿𝑆 𝒙𝑆 𝑞𝐿𝑆
= 𝑞𝐿𝑆 𝒙𝑠 𝑞𝑆𝐿
Hence, qSL rotates a vector in the global reference co-ordinate system (L) to the sensor co-ordinate
system (S), where qSL is the complex conjugate of qSL.
4.5.2 Euler angles orientation output mode
Euler angles describe the rotation of a rigid body by means of three successive rotations in a particular
sequence. The Euler angles used are ‘roll, pitch, yaw’, referred to in the literature as Cardan/TaitBryan angles. The sequence of rotations for Euler angles follows the aerospace convention (Z-Y’-X’’
sequence) for rotation from the global reference co-ordinate system (L) to the sensor co-ordinate
system (S).



ψ = yaw8 = rotation around ZL, defined from [-180…180]
θ = pitch9 = rotation around YL’ which is the current Y axis after the first rotation, defined from
[-90…90]
φ = roll10 = rotation around XL’’, which is the current X axis after the second rotation, defined
from [-180…180]
NOTE: Due to the definition of Euler angles there is a mathematical singularity when the sensor-fixed
x-axis is pointing up or down in the L co-ordinate system (i.e. pitch approaches ±90). This singularity
is not present in the quaternion or direction cosine matrix (rotation matrix) representation. Quaternion
and rotation matrix output modes can be used to access these orientation representations
respectively.
The Euler-angles can be interpreted in terms of the components of the rotation matrix, RLS, or in terms
of the unit quaternion, qLS;
𝑅32
2𝑞2 𝑞3 + 2𝑞0 𝑞1
𝜑𝐿𝑆 = 𝑡𝑎𝑛−1 ( ) = 𝑡𝑎𝑛−1 (
)
𝑅33
2𝑞02 𝑞32 − 1
𝜃𝐿𝑆 = −𝑠𝑖𝑛 −1 (𝑅31 ) = −𝑠𝑖𝑛−1 (2𝑞1 𝑞3 − 2𝑞0 𝑞2 )
ѱ𝐿𝑆 = 𝑡𝑎𝑛−1 (
𝑅21
2𝑞1 𝑞2 + 2𝑞0 𝑞3
) = 𝑡𝑎𝑛−1 (
)
𝑅11
2𝑞02 𝑞12 − 1
Here, the arctangent (tan-1) is the four quadrant inverse tangent function.
NOTE: that the output is in degrees and not radians.
4.5.3 Rotation Matrix orientation output mode
The rotation matrix (also known as Direction Cosine Matrix, DCM) is a well-known, redundant and
complete representation of orientation. The rotation matrix can be interpreted as the unit-vector
components of the sensor coordinate system S expressed in L-coordinate system. For RLS the unit
vectors of S are found in the columns of the matrix, so col 1 is XS expressed in L etc. A rotation matrix
“yaw” is also known as: “heading”, “pan” or “azimuth”
“pitch” is also known as: “elevation” or “tilt”
10 “roll” is also known as: “bank”
8
9
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norm is always equal to one (1) and a rotation RLS followed by the inverse rotation RSL naturally yields
the identity matrix I3.
|𝑅| = 1
𝑅𝐿𝑆 𝑅𝑆𝐿 = 𝐈 3
The rotation matrix, RLS, can be interpreted in terms of quaternions;
𝑅𝐿𝑆
𝑞02 + 𝑞12 − 𝑞22 − 𝑞32
2𝑞1 𝑞2 − 2𝑞0 𝑞3
2𝑞0 𝑞2 + 2𝑞1 𝑞3
2
2
2
2
= [ 2𝑞0 𝑞3 + 2𝑞1 𝑞2
𝑞0 − 𝑞1 + 𝑞2 − 𝑞3
2𝑞2 𝑞3 − 2𝑞0 𝑞1 ]
2𝑞1 𝑞3 − 2𝑞0 𝑞2
2𝑞2 𝑞3 + 2𝑞0 𝑞1
𝑞02 − 𝑞12 − 𝑞22 + 𝑞32
2𝑞02 + 2𝑞12 − 1 2𝑞1 𝑞2 − 2𝑞0 𝑞3 2𝑞1 𝑞3 + 2𝑞0 𝑞2
= [2𝑞1 𝑞2 + 2𝑞0 𝑞3 2𝑞02 + 2𝑞22 − 1 2𝑞2 𝑞3 − 2𝑞0 𝑞1 ]
2𝑞1 𝑞3 − 2𝑞0 𝑞2 2𝑞2 𝑞3 + 2𝑞0 𝑞1 2𝑞02 + 2𝑞32 − 1
or in terms of Euler-angles;
cos ѱ
= [ sin ѱ
0
cos θ cos ѱ
= [ cos θ sin ѱ
− sin 𝜃
− sin ѱ
cos ѱ
0
𝑅𝐿𝑆 = 𝑅ѱ𝑍 𝑅𝜃𝑌 𝑅𝜑𝑋
0 cos 𝜃 0 sin 𝜃 1
0] [ 0
1
0 ] [0
1 − sin 𝜃 0 cos 𝜃 0
sin 𝜑 sin 𝜃 cos ѱ − 𝑐𝑜𝑠𝜑 sin ѱ
sin 𝜑 sin 𝜃 sin ѱ + 𝑐𝑜𝑠𝜑 cos ѱ
sin 𝜑 cos 𝜃
0
cos 𝜑
sin 𝜑
0
− sin 𝜑 ]
cos 𝜑
cos 𝜑 sin 𝜃 cos ѱ + sin 𝜑 sin ѱ
cos 𝜑 sin 𝜃 sin ѱ − sin 𝜑 cos ѱ]
cos 𝜑 cos 𝜃
As defined here RLS, rotates a vector in the sensor co-ordinate system (S) to the global reference
system (L):
𝒙𝐿 = 𝑅𝐿𝑆 𝒙𝑠 = (𝑅𝑆𝐿 ) 𝑇𝒙𝑠
It follows naturally that, RSL rotates a vector in the global reference co-ordinate system (L) to the
sensor co-ordinate system (S).
For the rotation matrix (DCM) output mode it is defined that:
𝑎 𝑑 𝑔
𝑅11 𝑅12
𝑅𝐿𝑆 = [𝑏 𝑒 ℎ ] = [𝑅21 𝑅22
𝑅31 𝑅32
𝑐 𝑓 𝑖
𝑅𝑆𝐿
𝑎
𝑑
= [
𝑔
𝑏
𝑒
ℎ
𝑐
𝑅11
𝑓 ] = [𝑅21
𝑅31
𝑖
𝑅12
𝑅22
𝑅32
𝑅13
𝑅23 ]
𝑅33
𝑅13
𝑅23 ]
𝑅33
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4.6
Sensor data performance specification
This section describes the specifications of the physical sensors of the MTi’s. Not all MTi’s feature all
sensors. Per sensor, the applicable MTi’s are mentioned. For more detailed specifications, refer to
[MTI_TD].
4.6.1 Gyroscopes
The main difference between the MTi 10-series and the MTi 100-series is the type of gyroscopes
used. The two different specifications are listed below. A full range of 1000 º/s is available upon
request.
Gyroscopes in MTi 10-series: MTi-10, MTi-20, MTi-30
Gyroscopes in MTi 100-series: MTi-100, MTi-200, MTi-300, MTi-G-700
Gyroscope specification
MTi 10-series
Rate of turn
Typical
Max
MTi 100-series
Typical
Max
Standard full range
[deg/s]
450
-
450
-
Bias repeatability (1 yr)
[deg/s]
0.2
0.5
0.2
0.5
In-run bias stability
[deg/h]
18
-
10
-
Bandwidth (-3dB)
[Hz]
415
N/A
450
N/A
Noise density
[deg/s/√Hz]
0.03
0.05
0.01
0.015
g-sensitivity (calibrated)
[deg/s/g]
0.006
0.02
0.003
0.015
Non-orthogonality
[deg]
0.05
-
0.05
-
Non-linearity
[% FS]
0.03
0.1
0.01
-
A/D resolution
[bits]
16
N/A
16
N/A
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4.6.2 Accelerometers and magnetometer
The MTi 10-series and MTi 100-series use the same accelerometers and magnetometer. The output
of the magnetometer is in arbitrary units (a.u.), one a.u. is the magnetic field strength during calibration
at Xsens’ calibration lab. This is approximately 40 uT. An accelerometer range of 15g is available as
well.
Accelerometers/magnetometer: all products: MTi-10, MTi-20, MTi-30, MTi-100, MTi-200, MTi-300,
MTi-G-700
Accelerometers/magnetometers specification
MTi 10-series and
MTi 100-series
Acceleration
Typical
Max
Standard full range
[m/s2]
50
-
Bias repeatability (1 yr)
[m/s2]
0.03
0.05
In-run bias stability
[µg]
40
-
Bandwidth (-3dB)
[Hz]
375
N/A
Noise density
[µg/√Hz]
80
150
Non-orthogonality
[deg]
0.05
0.05
Non-linearity
[% FS]
0.03
0.5
A/D resolution
[bits]
16
N/A
Full range
[µT]
-
80
Noise density
[µGauss/√Hz]
200
-
Non-linearity
[% FS]
0.1
-
A/D resolution
[bits]
12
N/A
Magnetic field
4.6.3 Barometer
The barometer features barometric (atmospheric) pressure. The MTi-100 series feature this
barometer. The MTi 100-series has three holes with a protective vent in its casing in order to ensure
fast adaptation inside the MTi to atmospheric pressure. Typical latency because of the vent is <10 ms.
Barometer: MTi 100-series only: MTi-100, MTi-200, MTi-300, MTi-G-700
Barometer specification
Barometric pressure
Full range
[hpa]
N/A
Noise density
[hpa/√Hz]
-
300-1100
0.01
-
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4.6.4 GPS receiver
The MTi-G-700 is the only MTi that features a GPS receiver. It requires an active antenna, which is
delivered with the Development Kit and can be ordered separately from Xsens as well. It is possible to
use a different antenna that better suits your application.
GPS Receiver specification
MTi 100-series
Receiver Type:
50 channels, GPS L1, C/A code
Datum, reference frame
WGS84, ITRF2004
GPS Update Rate:
4 Hz
Horizontal Accuracy Position SPS:
2.5 m CEP
SBAS:
2.0 m CEP
Vertical Accuracy Position SPS:
5m
Velocity accuracy
0.1 m/s @ 30 m/s
Start-up Time Cold start:
27 s
Re-acquisition:
<1 s
Tracking Sensitivity:
-161 dBm
Timing Accuracy:
30 ns RMS
Maximum Altitude:
18 km
Maximum Velocity:
515 m/s
Max dynamics GPS:
4g
Note that when you are not using the default GPS antenna, it is important to use an antenna that is
suitable for the MTi-G-700. Please consult www.xsens.com/support.
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4.7
Built-in self-test
All MTi’s feature a built-in self-test (BIT). The self-test actuates the mechanical structures in the MEMS
accelerometer and gyroscope by inducing an electric signal. This allows checking the proper
functioning of the mechanical structures in the MEMS inertial sensors as well as the signal processing
circuitry. In the magnetometer, a magnetic field is induced by a coil designed around the component,
which will generate an offset in the signal.
During self-test the MTi will read out all sensors and in case of a successful self-test, a known offset
with respect to the signal prior to enabling self-test should be visible in the data. The MTi will internally
evaluate the sensors readings, the self-test will return the status of the self-test per individual sensor.
The status is stored into the non-volatile memory.
A passed self-test will result in a valid self-test flag in the status byte. Because the self-test influences
the sensor data, the self-test is only available in Config mode. For more information, refer to [LLCP],
function RunSelftest.
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4.8
Test and Calibration Certificate
Each MTi is accompanied by an individual Test and Calibration Certificate. This certificate states the
calibration values determined during the calibration of the MTi at Xsens’ calibration facilities. The
values are explained here in short:
The “IMU specifications” chapter contains the full ranges and bandwidths of the physical sensors
inside.
The “Basic test results” describes the noise of the all internal sensors and contains residuals in
orientation.
“Calibration data” are the values that describe the conversion from the physical phenomenon to a
digital output in an orthogonal coordinate system:
Gains (bits): Gains (or scale factor) describe the relation between the digital reading in bits and the
measured physical signal.
Offsets (bits): Digital reading in bits of the sensor when no physical signal is measured.
Alignment matrix: Non-orthogonality of the sensor triade. This includes non-orthogonality in the
orientation of the sensitive system inside the MEMS sensor, the mounting of the sensors on the PCB
of the MTi, the mounting of the PCB’s and the misalignment of the OEM board in the MTi housing.
Next to the basic Test and Calibration values documented in the certificate, each device is calibrated
according to more complicated models to ensure accuracy (e.g. non-linear temperature effect, cross
coupling between acceleration and angular rate11).
11 Also
known as “g-sensitivity”.
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4.9
Sensors data outputs
4.9.1 Physical sensor model
This section explains the basics of the individual calibration parameters of each MTi. This explains the
values found on the MT Test and Calibration Certificate that comes with each MTi.
The physical sensors inside the MTi (accelerometers, gyroscopes and magnetometers) are all
calibrated according to a physical model of the response of the sensors to various physical quantities,
e.g. temperature. The barometer and GPS receiver do not require calibration. The basic model is
linear and according to the following relation:
𝑠 = 𝐾𝑇−1 (𝑢 − 𝑏𝑇 )
The model really used is more complicated and is continuously being developed further. From factory
calibration each MTi has been assigned a unique gain matrix, KT and the bias vector, bT This
calibration data is used to relate the sampled digital voltages, u, (unsigned integers from the 16 bit
ADC’s) from the sensors to the respective physical quantity, s.
The gain matrix is split into a misalignment matrix, A, and a gain matrix, G. The misalignment specifies
the direction of the sensitive axes with respect to the ribs of the sensor-fixed coordinate system (S)
housing. E.g. the first accelerometer misalignment matrix element a1,x describes the sensitive direction
of the accelerometer on channel one. The three sensitive directions are used to form the misalignment
matrix:
𝑎1,𝑥
𝐴 = [𝑎2,𝑥
𝑎3,𝑥
𝑎1,𝑦
𝑎2,𝑦
𝑎3,𝑦
𝐺1
𝐾𝑇 = [ 0
0
0
𝐺2
0
𝑎3,𝑧
𝑎2,𝑧 ]
𝑎3,𝑧
0 𝑎1,𝑥
0 ] [𝑎2,𝑥
𝐺3 𝑎3,𝑥
𝐺1
𝐺 =[0
0
𝑎1,𝑦
𝑎2,𝑦
𝑎3,𝑦
0
𝐺2
0
0
0]
𝐺3
𝑎3,𝑧
𝑎2,𝑧 ] + 𝑂
𝑎3,𝑧
With O representing higher order models and temperature modelling, g-sensitivity corrections, etc.
Each individual MTi is modeled for temperature dependence of both gain and bias for all sensors and
other effects. This modeling is not represented in the simple model in the above equations, but is
implemented in the firmware.
The basic indicative parameters in the above model of your individual MTi can be found on the MT
Test and Calibration Certificate and in the MT Manager (MT Settings dialog).
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4.9.2 Calibrated delta_q and delta_v outputs
This output is coning- and sculling compensated strap down integrated data in the sensor-fixed
coordinate system (S) or (O). Note that the value of the output depends on the output frequency, as
the values are integrated over a specific time.
Delta_q can also be noted as dq, delta_angle, del_q or OriInc. Delta_v can also be noted as dv,
delta_velocity, del_v or VelInc.
Output
Unit
Delta_q (DataID 0x8030)
a.u. (quaternion values)
Delta_v (DataID 0x4010)
m/s
It is possible to multiply consecutive delta_q values to find the total orientation change over a specific
period. Note that this data is not drift free, as it has not been processed by the sensor fusion filters.
Use the orientation output for drift free orientation.
4.9.3 Calibrated inertial and magnetic data outputs
Output of calibrated 3D linear acceleration, 3D rate of turn (gyro) and 3D magnetic field data is in
sensor-fixed coordinate system (S) or (O).
The units of the calibrated data output are as follows:
Vector
Unit
Acceleration
m/s2
Angular velocity (rate of turn)
rad/s
Magnetic field
a.u.( arbitrary units) normalized to earth field strength)
Calibrated data has been going through Strapdown Integration and Inverse Strapdown Integration.
4.9.4 Free acceleration
Free acceleration (Data ID 0x4030) is the acceleration of which gravity is deducted. Output is in m/s 2.
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4.9.5 Uncalibrated raw output mode
The MTi can output sensor component readout (SCR), i.e. digitized voltages of all sensors, before
they are filtered or calibrated using Xsens’ proprietary firmware and calibration parameters. These
sensors are the gyroscopes (rate of turn), accelerometers (acceleration), magnetometer (magnetic
field), barometer (static pressure) and temperatures (gyroscope temperatures and a general
temperature sensor). When selecting sensor component readout, the following outputs are available:
Sensor
Digital/analog
Unit
Maximum frequency
Gyroscopes
Analog sensor, 16 bit ADC
2-byte integer
2000 Hz
Accelerometers
Analog sensor, 16 bit ADC
2-byte integer
2000 Hz
Magnetometer
Digital sensor
a.u.
100 Hz
Barometer
Digital sensor
Pa
50 Hz
Temperature sensors
Analog sensor, 12 bit ADC
ºC
1 Hz
Note that these SCR-values of the gyroscopes and accelerometers are not calibrated for offset, gain,
misalignment and temperature. Also, coning and sculling compensation is not applied. It is possible to
post-process SCR data with MT Manager, and this output is very suitable if you need to perform your
own calibration. Note that this output cannot be combined with any other output.
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4.10 Legacy output messages
The MTi 10-series and MTi 100-series are Xsens’ 4th generation MTi (MkIV). The 2nd and 3rd
generation products have been released in 2005 and 2008. The 4 th generation can be distinguished by
their aluminium casing (or orange PCB if you are using an OEM). A photo of the 4 th generation MTi
can be found on the cover of this manual.
The MTi 10-series and MTi 100-series use the same XBus
communication protocol as legacy MTi’s, MTx’s and MTi-G’s
(see photo on the right). However, because of increased
functionality and a different signal processing pipeline, the
MTi 10-series and MTi 100-series are not drop-in
replaceable in all cases. It is possible to configure the MTi’s
in such a way that they are drop-in replaceable in some
programs that are based on legacy classes and source
code. Note that it is only possible to use the MTi in legacy
mode when data is processed onboard the MTi. It is not
possible to process raw data (16-bit binary data) with legacy
source code into orientation, position or dynamic data.
Figure 9: Legacy MTi/x product
range
(3rd generation)
All outputs are only available at frequencies that can be are integer divisions of 400 Hz (400 Hz, 200
Hz, 100 Hz, 80 Hz, etc). The following outputs are available in the MTi legacy data message:
Available ‘legacy’ output modes
Orientation
Quaternions
NWU
Euler angles
NWU
Rotation Matrix
NWU
Calibrated data
Rate of turn
Acceleration
Magnetic Field
Note that at a frequency higher than 100 Hz,
magnetometer data will be sent out duplicate (200 Hz
will result in two duplicate values; 400 Hz will result in 4
duplicate values)
Sample counter
16-bits, wraps after 65536 samples
UTC
MTi-G-700 only
Timestamp
Position and velocity
3D Position
LLA
3D Velocity
ENU
Status byte
Self-test, valid XKF, GPS-fix (MTi-G-700), NoRotation
status
Status
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4.11 Reset of output or reference co-ordinate systems
In some situations it may occur that the MT sensor axes are not exactly aligned with the axes of the
object of which the orientation has to be recorded. It may be desired to output the orientation and/or
calibrated inertial data in different sensor-fixed frame (S’ instead of S) or a different earth-fixed local
frame (L’ instead of L). The transformations are defined by the rotation matrices L’LR and SS’R resulting
in the following equations affecting the rotation matrix LSR, the SDI data (S∆q and S∆v), the calibrated
data (Ss), and the sensor fusion algorithm output (Lx):
𝐿′𝑆 ′
𝑆′
𝑅=
𝐿′𝐿
′
𝑅 ∙ 𝐿𝑆𝑅 ∙ 𝑆𝑆 𝑅
′
∆𝑞 = ( 𝑆𝑆 𝑞)
𝑆′
∗
𝑆
′
∆𝑞 𝑆𝑆 ∆𝑞
′
∆𝑣 = ( 𝑆𝑆 𝑅 )
𝑆′
𝑇
𝑠
∆𝑣
𝑇
′
𝑠 = ( 𝑆𝑆 𝑅 ) ∙ 𝑆𝑠
𝐿′
𝑥=
𝐿′𝐿
𝑅 ∙ 𝐿𝑥
Five methods are available to facilitate in obtaining the output in the desired coordinate frames, which
are:
1. An inclination reset that levels the sensor by defining the S’ frame.
2. A heading reset that defines the L’ frame by setting the x-axis of L’ frame while maintaining the
z-axis along the vertical (also known as "bore sighting").
3. A combined inclination/heading reset, referred to as alignment reset.
4. Setting an arbitrary alignment rotation matrix to rotate S to the chosen frame S’ : SS’R.
5. Setting an arbitrary alignment rotation matrix to rotate L to the chosen frame L’ : L’LR.
The different orientation resets are explained using Figure 10, showing a side and top view of each of
the resets, with the standard orientation output LSR.
Orientation resets
The orientation reset functions aim to facilitate in aligning the sensor object it is strapped to, by
defining the L’ frame (heading reset) and the S’ frame (inclination reset) resulting in L’S’R, defined in the
equations above. The orientation reset is separated in an inclination reset (leveling) and a heading
reset (bore sighting). After a full orientation reset, the orientation of the L’ and S’ frames are equal, and
the coordinate axes are defined by:
• the L’ and S’ z-axis is the vertical (up, along gravity)
• the L’ and S’ x-axis equals the S x-axis, but projected on the horizontal plane
• the L’ and S’ y-axis is chosen as to obtain a right handed coordinate frame.
The coordinate rotation matrices L’LR and SS’R are calculated by:
𝐿′𝐿
𝑆𝑆 ′
𝑅 = ( 𝐿𝑋𝐿′ ,
𝐿
𝑌𝐿′ ,
𝑇
𝐿
𝑍𝐿′ )
𝑇
𝑇
𝑅 = ( 𝐿𝑆𝑅 ) ∙ 𝐿𝑆′𝑅 = ( 𝐿𝑆𝑅 ) ∙ ( 𝐿′𝐿𝑅 )
𝐿
𝑋𝐿′ = ⟨𝑅𝑛 ∙ 𝐿𝑆𝑅 ∙ (1 0 0)𝑇 ⟩
𝐿
𝐿
𝑍𝐿′ = (0 0 1)𝑇
𝑌𝐿′ = ⟨ 𝐿𝑍𝐿′ × 𝐿𝑋𝐿′ ⟩
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After an inclination and/or heading reset, the equation for L’S’R is applied (see above). It should be
noted that the inclination reset (SS’R) will not work if the sensor x-axis is aligned along the z-axis of the
object, since the sensor x-axis is used to describe the direction of the object x-axis. Furthermore, after
a heading reset, the yaw may not be exactly zero, especially when the x-axis is close to the vertical.
This is caused by the definition of yaw in Euler angles, which becomes unstable when the pitch
approaches 90 deg.
Figure 10: Top view and side view of an MT with coordinate frame S (left) strapped to an object and local
frame L. The different alignments and resets define the S’ and/or L’ frame. (a): the default orientation
output of S with respect to L: LSR; (b): after inclination reset, method 1: LS’R (c): after heading reset,
method 2: L’SR, (d): after alignment reset, method 3: L’S’R. All of these are also possible to set with
arbitrary alignments.
NWU and NED reference coordinate frames
The default reference coordinate frame in the MTi is ENU-frame, described in section 4.2.3, the MTi
supports two other reference coordinate systems that can be selected. These are NWU and NED.
NWU is the reference coordinate system that used to be the default up to the third generation MTi and
MTi-G. In order to configure the MTi to output in the NWU local frame, apply the following rotation
matrix in RotLocal.
0
RotLocal𝑁𝑊𝑈 : [−1
0
1
0
0
0
0]
1
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NED is a reference coordinate system often used in aerospace applications. NED is also a reference
coordinate system available in the third generation MTi and MTi-G. In order to configure the MTi in
NED, apply the following rotation matrix in RotLocal:
0
RotLocal𝑁𝐸𝐷 : [1
0
1
0
0
0
0]
−1
Arbitrary alignment
If the measured kinematics is required in a frame S’ and/or a frame L’ with known orientations with
respect to standard sensor coordinate frames S and L, the alignment matrices can be set with an
arbitrary but known orientation. This can be useful if for mechanical reasons the MT can only be
fastened in some specific orientation. The alignment matrices L’LR or SS’R are applied to the output
data according to the equations above. Refer to the MT Manager User Manual on how to use these
alignment matrices.
The different orientation resets can be summarized as follows
Inclination reset: Applying SS’R only
Heading reset: Applying L’LR only
- Alignment reset: Applying both L’LR, and SS’R
NOTE: when applying SS’R and outputting dq/dv only will result in double applying of SS’R when
outputting orientation from XDA. To prevent this, output orientation directly from the MTi.
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4.12 Timestamp and packet counter output
Each data message can be accompanied by a packet counter and/or timestamp.
4.12.1 Packet counter
The packet counter is an incremental number that comes with each packet, regardless of what data is
in the packet. It can also mean that time differences between packet counters may not be the same.
Note that the packet counter is a good indication if data is missed during transmission of the data, as
the packet counters are created when generating (composing) a data message prior to sending.
4.12.2 Time UTC
Time UTC is time in the format of UTC; note that this time does not have to be synchronized with GPS
UTC. The format is described below:
DATA (B)
Description
0
Nanoseconds of second, range 0 .. 1.000.000.000
4
Year, range 1999 .. 2099
6
Month, range 1..12
7
Day of Month, range 1..31
8
Hour of Day, range 0..23
9
Minute of Hour, range 0..59
10
Seconds of Minute, range 0..59
11
0x01 = Valid Time of Week
0x02 = Valid Week Number
0x04 = Valid UTC
When outputted, the Time UTC starts as following:
At 0.0 sec, unless
A time is available in the non-volatile memory, unless
GPS time is available (MTi-G-700 only)
When the time stamp wraps over 0.00h (midnight), the date progresses a day.
4.12.3 Time stamp (Sample Time Fine)
The time stamp is a 0.1 ms resolution 4 byte time stamp.
4.12.4 Setting UTC time on non-GPS MTi’s
It is possible to set a time in UTC format to an MTi. The MTi will count from this time using the internal
clock. As the moment of setting the time is different than the time the MTi receives the message and
sets the starting point, a message is implemented to adjust Time UTC in ticks of 0.1 ms. See [LLCP]
for more information about the messages SetUTCTime and AdjustUTCTime.
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4.13 Status byte
The status byte includes information about the status of the MTi, its sensors, the filter and user inputs.
The following information can be found in the status byte and status word:
Status byte (DataID 0xE010) is the short status byte (8 bits), identical to the status byte of the legacy
output message (see section 4.10).
Status word (DataID 0xE020) is an extended 32 bits status message. The bits in StatusWord are
defined in the following table (note that bit 0:7 are the same as Status Byte):
Bits
Field
Description
0
Selftest
This flag indicates if the MT passed the latest self-test
(RunSelftest).
1
Filter Valid
This flag indicates if input into the filter orientation filter is
reliable and / or complete. If for example the measurement
range of internal sensors is exceeded, orientation output cannot
be reliably estimated and the filter flag will drop to 0. For the
MTi-G, the filter flag will also become invalid if the GPS status
remains invalid for an extended period
2
GPS fix
This flag indicates if the GPS unit has a proper fix. The flag is
only available in MTi-G units.
3:4
NoRotationUpdate Status
(only available for legacy devices):
This flag indicates the status of the no rotation update
procedure in the filter after the SetNoRotation message has
been sent.
11: Running with no rotation assumption
10: Error: Rotation detected, procedure not started
(sticky)
01: Estimation complete, some samples rejected
(sticky)
00: Estimation complete, no errors
5
Timestamp GPS synced
6
Timestamp clock synced
7
On/Off
8
Clipflag Acc X
If set an out of range acceleration on the X axis is detected
9
Clipflag Acc Y
If set an out of range acceleration on the Y axis is detected
10
Clipflag Acc Z
If set an out of range acceleration on the Z axis is detected
11
Clipflag Gyr X
If set an out of range angular velocity on the X axis is detected
12
Clipflag Gyr Y
If set an out of range angular velocity on the Y axis is detected
13
Clipflag Gyr Z
If set an out of range angular velocity on the Z axis is detected
14
Clipflag Mag X
If set an out of range magnetic field on the X axis is detected
15
Clipflag Mag Y
If set an out of range magnetic field on the Y axis is detected
16
Clipflag Mag Z
If set an out of range magnetic field on the Z axis is detected
17:18
NoVelocityUpdate status
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19
Clipping indication
This flag indicates going out of range of one of the sensors (is
set when one or more bits from 8:16 are set)
20
Reserved
Reserved for future use
21
SyncIn Marker
When a SyncIn is detected, this bit will rise to 1
22
SyncOut Marker
When SyncOut is active this bit will rise to 1
23:25
Filter mode
Indicates the filter mode, only available for MTi-G-700
000: Without GPS (filter profile is in VRU mode, except
GeneralMag filter profile that continues to use magnetometers)
001: Coasting mode (GPS has been lost <60 sec ago)
011: With GPS (default mode of MTi-G-700)
26:31
Reserved
Reserved for future use
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5 Basic communication
5.1
Introduction
This section describes the basics of how to communicate with the MTi directly on low-level using RS232/422/485 serial communication or USB. For a detailed and complete list of all messages please
refer to the MT Low-level Communication Documentation. You can skip this chapter if you plan to
only interface with the device using Xsens’ MT Manager GUI software or SDK API.
The communication protocol, which is message based, enables the user to change the configuration
of the MTi and to retrieve the data from the device. The communication protocol used for the MTi is
mostly compatible with legacy MTi and MTx devices. The configuration is fully user-settable, e.g. data
output modes, in- & output synchronization, baud rate, can all be changed to fit your requirements.
All configuration changes must be made while the device is in the so-called Config State. In this state
the device accepts messages that set the output mode or changes to other settings. Whenever the
preferred configuration is completed the user can set the device to Measurement State. In this state
the device outputs data based the current configuration settings.
5.2
States
WakeUp
procedure
WakeUpAck
received by device
No WakeUpAck
received by device
GotoMeasurement
Config
Measurement
GotoConfig
The MTi has two states, i.e. Config State and Measurement State. In the Config State various settings
can be read and written. In the Measurement State the device will output its data message which
contains data dependent on the current configuration.
There are two different ways to enter the Config State or the Measurement State. At power-up the
device starts the WakeUp procedure, if no action is taken it will then enter Measurement State by
default, using its latest stored configuration. Prior to entering the Measurement State, the
Configuration and eMTS (extended Motion Tracker Specification messages are always sent to the
host. Configuration data is the configuration that is read from the internal non-volatile memory and will
be used in the Measurement State. The data in the Configuration message can always be used to
determine the output mode and settings. It is also possible to enter the Config State at power-up, see
WakeUp message description in the MT Low-Level Communication Document. Another way to
enter the Config State or Measurement State is to use the GoToConfig or GoToMeasurement
messages. The eMTS data is required to be able to later process the data by Xsens software to
calculate calibrated inertial data values as well as estimating orientation etc.
The default configuration of the MTi is shown in the following table.
Property
Value
Output data and frequency
Orientation-quaternion legacy @ 100 Hz
Sample Counter @ 100 Hz
Baud rate
115k2 bps (serial), for USB not applicable
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5.3
Messages
5.3.1 Message structure
The communication with the MTi is done by messages which are built according to a standard
structure. The standard MT message can contain zero to 254 bytes of data and the total length is five
to 259 bytes. An MT message contains the following fields:
PRE
BID
MID
LEN
DATA
CS
Field
Field width
Description
PRE
1 byte
Preamble, indicator of start of packet  250 (0xFA)
BID
1 byte
Bus identifier / address  255 (0xFF)
MID
1 byte
Message identifier
LEN
1 byte
Value equals number of bytes in DATA field
Maximum value is 254 (0xFE). Value 255 (0xFF) is reserved.
DATA
0 – 254 bytes
Data bytes (optional)
CS
1 byte
Checksum of message
Preamble (PRE)
Every message starts with the preamble. This field always contains the value 250 (=0xFA).
Bus identifier (BID) or Address
All messages used for the MTi and MTx use the address value 255 (0xFF) indicating a “master
device”. MT’s used on the Xbus have other BID’s.
Message Identifier (MID)
This message field identifies the kind of message. For a complete listing of all possible messages see
MTi and MTx Low-Level Communication Document. The message MTData2 is explained in section
5.3.3.
Length (LEN)
Specifies the number of data bytes in the DATA field. Value 255 (=0xFF) is reserved. This means that
a message has a maximum payload of 254 bytes. If Length is zero no data field exists.
Data (DATA)
This field contains the data bytes and it has a variable length which is specified in the Length field. The
interpretation of the data bytes are message specific, i.e. depending on the MID value the meaning of
the data bytes is different. See the description of the specific message for more details about
interpretation of the data bytes.
Checksum
This field is used for communication error-detection. If all message bytes excluding the preamble are
summed and the lower byte value of the result equals zero, the message is valid and it may be
processed. The checksum value of the message should be included in the summation.
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5.3.2 Message usage
Generally, a message with a certain MID value will be replied with a message with a MID value that is
increased by one, i.e. the acknowledge message. Depending on the type of message the
acknowledge message has no or a certain number of data bytes. In some cases an error message will
be returned (MID = 66 (0x42)). This occurs in case the previous message has invalid parameters, is
not valid, or could not be successfully executed. An error message contains an error code in its data
field.
Example
Requesting the device ID of an MTi:
Sending message:
ReqDID =
0xFA 0xFF 0x00 0x00 0x01 (hexadecimal values)
Receiving message (= Acknowledge):
DeviceID =
0xFA 0xFF 0x01 0x04 HH HL LH LL CS (hexadecimal values)
The requested Device ID is given in the acknowledged message DeviceID (here shown as: HH HL
LH LL, the checksum is CS). As you can see the MID (Message ID) of the acknowledgement is
increased by one in comparison with the sending message ReqDID.
Some messages have the same MID and depending on whether or not the message contains the data
field the meaning differs. This is the case with all the messages that refer to changeable settings. For
example, the MID of message requesting the output mode (ReqOutputMode) is the same as the
message that sets the output mode (SetOutputMode). The difference between the two messages is
that the Length field of ReqOutputMode is zero and non-zero for SetOutputMode.
Example
Request current output mode:
Sending message:
ReqBaudrate =
0xFA 0xFF 0x18 0x00 0xE9 (hexadecimal values)
Receiving message (= Acknowledge):
ReqBaudrateAck =
0xFA 0xFF 0x19 0x01 BR CS (hexadecimal values)
ReqBaudrateAck contains data which represents the current mode (= BR). CS stands for the
checksum value. To change the baud rate you must add the baud rate in the data field of the sending
message:
Set the output mode:
Sending message:
SetBaudrate =
0xFA 0xFF 0x18 0x01 BR CS (hexadecimal values)
Receiving message (= Acknowledge):
SetBaudrateAck =
0xFA 0xFF 0x19 0x00 0xE8 (hexadecimal values)
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5.3.3
Common messages
GoToConfig
MID
Data field
Direction
Valid in
48 (0x30)
n/a
To MTi
Measurement State & Config State
Switches the active state of the device from Measurement State to Config State. This
message can also be used in Config State to confirm that Config State is currently the active
state.
SetOutputConfiguration
MID
DATA
Valid in
192 (0xC0)
OutputConfig (N*4 bytes)
Config State
Set the output configuration of the device. This supersedes SetPeriod, SetOutputSkipFactor,
SetOutputMode and SetOutputSettings.
The data is a list of maximum 32 data identifiers combined with a desired output frequency.
The response message contains a list with the same format, but with the values actually used
by the device.
Each entry in the list contains:
Offset
Value
0
Data Identifier (2 bytes)
2
Output Frequency (2 bytes)
A full list of all Data Identifiers can be found in the MT Low Level Communication Protocol
documentation (under SetOutputConfiguration).
GoToMeasurement
MID
Data field
Direction
Valid in
16 (0x10)
n/a
To MTi / MTx
Config State
Switches the active state of the device from Config State to Measurement State. The current
configuration settings are used to start the measurement.
MTData2
MID
DATA
Direction
Valid in
54 (0x36)
DATA (length variable)
To host
Measurement State
The MTData2 message contains output data according the current OutputConfiguration. Unlike the
legacy MTData message an MTData2 message does not have to contain all configured output all the
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time. Instead of a single fixed output format for a particular configuration an MTData2 message
consists of one or more packets, each containing a specific output.
The layout of an MTData2 message is shown below:
The payload of the message consists of multiple (N) packets. Each packet starts with a two byte Data
Identifier followed by a one byte Size field. After that follows the Packet Data that is Size bytes long.
The Data Identifier determines the format of the Packet Data.
This packet scheme makes the output data format very flexible. If a particular output data is not
available the packet is omitted from the message. Also if during parsing of the message an unknown
Data Identifier is encountered the packet can be skipped using its Size field. It allows for more optimal
bandwidth usage and simplifies keeping future devices and/or software backwards compatible.
In the MT Low Level Communication Protocol documentation, format descriptions of all data packets
are described.
5.4
Communication Timing
For many applications it can be crucial to know exactly the various delays and latencies in a system. In
this section it is described how the timing between physical events and the device output are related in
the basic usage modes of the MTi
Sampling
and
ADC
Physical
calibration
Sensor fusion
Output formatting
and
message
generation
Data
Hardware/software
triggers
Triggering
When the MTi is in Measurement State, the internal processor core continuously controls a signal
processing pipeline, roughly according to the above diagram. Outputting data can be triggered by the
device internal clock, or by external software triggers (polling), or hardware triggers. For more
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information about triggering see section 5.5. Note that sampling of the sensors cannot be externally
triggered because of the high sampling rate of 10 kHz. It is possible to adjust the internal sampling
clock though by using the ClockSync functionality (see section 0).
The time delay between a physical event (e.g. an orientation change or acceleration) is dictated by two
factors;
1. Internal acquisition, calculation time and message generation (signal processing duration)
2. Serial transmission time
Thanks to the system architecture of the Xsens sensor fusion algorithm, the signal processing
duration is independent of the filter profile. Using a multi-core processing unit, it is possible to bring
down the total time from physical event to data transmission on the USB or serial output to far below 2
ms.
The serial transmission time can easily be calculated when the byte message and the baud rate is
known:
(𝑡𝑜𝑡𝑎𝑙 𝑏𝑦𝑡𝑒𝑠 𝑖𝑛 𝑚𝑒𝑠𝑠𝑎𝑔𝑒) ∗ 10 𝑏𝑖𝑡𝑠/𝑏𝑦𝑡𝑒
= transmission time
𝑐𝑜𝑚𝑚𝑢𝑛𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑏𝑎𝑢𝑑𝑟𝑎𝑡𝑒 (𝑏𝑖𝑡𝑠/𝑠)
These factors will be discussed using the example of two common output configurations of the MTi.
The bytes in the message consist of the Preamble, BusID, MessageID, length indicator, data itself and
the checksum:
PREAMBLE
BID
MID
LEN
DATA
CHECKSUM
The Preamble, BusID, MesssageID, length indicator and checksum together is always 5 bytes. The
length of the various data messages is discussed in [LLCP].
Example 1: Euler angels orientation data at 400 Hz and SDI data (delta_q and delta_v) at 100 Hz with
a baud rate of 230400 bps (RS232).
Euler angles is 12 bytes, SDI data is 24 bytes. This means that there will be one message of 41 bytes,
followed by three messages of 17 bytes, and then one message of 41 bytes again.
(36 + 5) ∗ 10 𝑏𝑖𝑡𝑠/𝑏𝑦𝑡𝑒
= 1.78 𝑚𝑠
230400 𝑏𝑖𝑡𝑠/𝑠
(12 + 5) ∗ 10 𝑏𝑖𝑡𝑠/𝑏𝑦𝑡𝑒
transmission time SDI only =
= 0.74𝑚𝑠
230400 𝑏𝑖𝑡𝑠/𝑠
transmission time Euler angles and SDI =
Note that, although the average data stream is lower than the baud rate, it is not possible to choose a
baud rate lower than 230400 bps in this particular case, as data comes at 400 Hz (every 2.5 ms) and
the longest transmission time at a baud rate of 115200 bps would be 3.56 ms.
Example 2: Quaternion data output at 100 Hz with a baud rate of 921600 bps (RS232).
Quaternion data is 16 bytes.
transmission time =
(16 + 5) ∗ 10 𝑏𝑖𝑡𝑠/𝑏𝑦𝑡𝑒
= 0.23 𝑚𝑠
921600 𝑏𝑖𝑡𝑠/𝑠
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USB communication timing
When the MTi is used with the USB cable, much of the timing depends on the scheduling of the host
(e.g. Windows) as the host needs to poll data from the USB devices. For real time interfaces, a serial
interface (RS232, RS422 or RS485) is recommended.
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5.5
Triggering and synchronization
In case multiple systems are used during a measurement it is important to have the measurement
data synchronized between the systems. Processing synchronised data is much easier because there
is no need to resample the data to compensate for timing inaccuracies like clock drift and clock
deviations. Synchronization using multiple systems involves 2 important issues: starting the
measurement at the same time and having a fixed time relationship of the sampling instances. This
section will explain how the MTi must be setup when using multiple measurement systems.
All MTi’s have a minimum of 3 GPIOs, offering the MTi capabilities to be triggered by external devices,
trigger external devices or synchronize clock drift. These three user scenarios are explained in the
following subsections.
5.5.1 External device triggers MTi (Send Latest)
In the following figure, a possible configuration is shown where a Motion Tracker and Device A are
synchronised. In this example, a clock generator triggers device A and an MTi ensuring that the two
devices are synchronized with each other.
The output of the clock generator can be directly connected to the MTi.
NOTE: Always check if the SyncIn specification matches with the trigger signal.
Once a SyncIn signal or a ReqData message is received, the MTi will output the latest available data.
It is possible to delay the data to be sent, to choose whether the SyncIn signal needs to be triggered
on rising edge or falling edge etc. The internal clock determines when data is available. This data is
transmitted only if a trigger is detected on the SyncIn line or when polled (ReqData). This means that
the trigger instance will not coincide with the availability of the data. Because two different clocks are
used the time difference between the trigger instance and the last sampling instance may vary during
the measurement and at most with a time equal to the used sampling period.
5.5.2 Marker in MT data (Trigger Indication)
Next to let the MTi send data to the computer, it is also possible to incorporate a trigger indication in
the MTData2 packet (Status Word). The data will not be affected by the trigger indication; the data is
marked with the pulse received.
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5.5.3 MTi triggers external devices (Interval Transition Measurement)
In case the clock specification of the MTi is accurate enough for the measurement, the MTi can
provide a sync pulse which is generated based on its internal clock at a frequency of 400 Hz,
regardless of the frequency of the data outputted. For more details on clock accuracy see section 5.6.
For example, when Interval Transition Measurement is set with a skip factor of 4 and a pulse width of
1000 µs, the following will be outputted: 1 ms sync pulse, 9 ms no sync pulse, 1 ms sync pulse, 9 ms
no sync pulse and so on. The data output (e.g. orientation) and frequency is irrelevant for the
functionality of Interval Transition Measurement.
A SyncOut marker is outputted in the data stream that shows the exact time of the transmission of the
SyncOut pulse. The signal can be set to either pulse or toggle mode and in case of pulse mode the
polarity can be set to negative or positive. For more information about enabling SyncOut and its
settings see [LLCP].
To connect the SyncOut signal to an external device you can either make a custom cable that wires
the SyncOut pin (see section 6.3.1.2) directly from the MTi/MTi-OEM or in case you use the CA-MPMTI cable you can connect directly to the appropriate pin of the Molex header.
NOTE: Always check if the input voltage levels and the input impedance of the external device
matches the SyncOut specifications.
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5.5.4 Clock synchronization (Clock Bias Estimation)
The MTi features clock synchronization: it is possible to adjust the bias of the MTi’s internal clock with
an external clock of which the frequency is known. Note that the adjusted bias is also used in the
calibration of the inertial sensors, so that no additional errors are introduced. When a pulse is missed,
e.g. because it was not sent or was lost on the input line, this will not have a bad influence on the
performance. The maximum time that the pulses may be absent is 30 seconds.
The clock synchronization can be used for two distinctive use cases:
 When a precise external clock is available (e.g. a GPS time pulse), this frequency can be sent
to the MTi to make sure that the time of the MTi follows the UTC time.
 When an external device has a time constant that differs from the MTi, the sensor readings
will at some point no longer be aligned to each other. If the external device accepts
synchronization pulses, it is possible to use SyncOut; if the external device can send
synchronization pulses at a frequency that is the same as the required output frequency of the
MTi, it is possible to use SyncIn. If these two options are not possible, the Clock Sync is an
alternative.
Specification
Value
MTi’s internal clock accuracy
10 ppm
Input frequency
0.1 – 1000 Hz
Maximum deviation from MTi’s internal clock
900 ppm
Initialisation time (per ppm difference between
internal clock and external clock)
0.72 ms/ppm
5.5.4.1 Clock Bias Estimation from GPS
The MTi-G-700 GPS/INS uses the clock bias estimation function to synchronize the MTi-G with the
GPS time (1 ppm). This synchronization is set by default, and although not recommended, it is
possible to disable this synchronization setting.
5.5.5 StartSampling
One of the advanced timing features of the MTi is the StartSampling synchronization function.
StartSampling will trigger the MTi to start processing data, so that the start time for sampling can be
chosen. This is useful when the timing of a data needs to be aligned with an external sensor or sensor
system at an accuracy of better than 2.5 ms. Timing specification is as following:
0 ms
External pulse
received at MTi
0.69 +/- 0.05 ms
First sample (10kHz) received
for signal processing
3.19 +/-0.05 ms
First inertial data available
(acc/gyr, 400 Hz)
10.69 +/- 0.05 ms
First orientation
available (400 Hz)
It is possible to delay the “First sample received”, and with that the entire data output, with up to
0.65536 seconds. For example, setting a delay of 6810 us (6.81 ms) will output data at exactly 10 ms
after the external pulse has been received.
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5.5.6 Combining synchronization functions
It is possible to configure multiple synchronization functions on the MTi. This can be useful if you need
to synchronize multiple devices, e.g. a GPS device (providing a 1 pulse per second (PPS) pulse), an
MTi-300 and an external camera that needs 0.2 seconds to make a picture.
In this example, you could use the GPS pulse to synchronize the clock of the MTi with the GPS clock
(use Clock Bias Estimation), but you also need to know the timing difference between the GPS and
MTi (so connect the 1 PPS to Trigger Indication as well: the 1 PPS trigger will be inside the MT Data2
packet). If you need orientation at a different rate than the camera images, you can send the Interval
Transition Measurement (SyncOut) at a SkipFactor and with an offset to give the camera time to make
the picture.
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5.6
Internal clock accuracy
5.6.1 Clock of MTi’s without GPS receiver
The internal clock jitter of the MTi is less than 25ns.
The internal clock of the MTi which generates the sample timing based on the set sample period is
accurate to ±10 ppm with a maximum of ±15 ppm (this differs per MTi) over the temperature operating
range. Using a typical MT (with an accuracy of 10 ppm), this means that the worst case deviation after
a 1 hour log is ± 0.036 seconds (= 3600 s ∙ 10 ppm) or 15 sample counts in 1,440,000 at 400 Hz
sample rate (± 25 ns/data packet @ 400 Hz).
5.6.2 Clock of MTi-G-700 GPS/INS
In the case that the MTi-G has a GPS fix the bias of the clock will be estimated and on the long term
there will on average be no deviation from GPS time. On the short time scale, the clock jitter is the
determining factor. The MTi-G is capable of generating a quite accurate hardware-synchronised time
pulse when GPS is available. The time pulse is synchronised to UTC time. This accurate Time Pulse
can be used to correct the sampling clock of the MTi-G. This clock bias estimation will improve the
accuracy of the crystal used in the MTi-G, under normal operating conditions to below 1ppm.
The time pulse used to correct the clock of the MTi-G has minor inaccuracies, caused by the following:
 Delay caused by distance between antenna phase centre to input pin of the GPS receiver
module in the MTi-G. The cable delay is 5.5ns/m for PFTE, resulting in 16.5ns delay with the
development kit antenna (PCTel 3910D).
 Quantisation loss, clock of 23.104MHz, results in a resolution of 43ns.
 Rise time of Timepulse 7-25ns, best results when loaded with a high impedance.
 Software delay, for handling the time pulse interrupt clock_ticks/300Mhz.
The first point is compensated in the MT GPS receiver, but will vary with cable length.
The internal clock jitter of the MTi is less than 25ns. The internal clock of the MTi which generates the
sample timing based on the set sample period is accurate to ±10 ppm with a maximum of ±15 ppm
(this differs per MTi) over the temperature operating range. f there is no GPS fix available. Using a
typical MT (with an accuracy of 80 ppm), this means that the worst case deviation after a 1 hour log is
± 0.288 seconds (= 3600 s ∙ 80 ppm) or 29 sample counts in 360,000 at 100 Hz sample rate (± 0.8
μs/sample @ 100 Hz).
5.7
Default Serial Connection Settings
Setting
Default Value
Bits/second (bps):
115200
Data bits:
8
Parity:
none
Stop bits:
2
Flow control:
none
These settings are the same for the RS-232 as the RS-422/RS485 versions. The baud rate (bps)
setting can be changed by the user. The maximum is 921600 bps and the minimum 4800 bps. Please
refer to the [LLCP] for details. Should the communication fail, it can be helpful to change the number of
stop bits to 1.
Note that there is no terminating resistor in the MTi with RS422/RS485 communication. Should
communication problems arise, terminate the connection either at the application side or alternatively
close to the MTi.
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5.7.1 General definitions for binary data
All binary data communication is done in big-endian format.
Example:
Un-calibrated 16 bits accelerometer output
1275 (decimal) = 0x04FB (hexadecimal)
Transmission order of bytes = 0x04 0xFB
Calibrated accelerometer output (float, 4 bytes)
9.81 (decimal) = 0x411CF5C3 (hexadecimal)
Transmission order of bytes = 0x41 0x1C 0xF5 0xC3
The bit-order in a byte is always:
[MSB…LSB]  [bit 7 …bit 0]
5.7.2 Serial or USB communication
The MTi has a parallel serial (RS232/RS422/RS485 or alternative UART) and USB interface.
However, it is not possible to have communication on both the serial and USB interfaces
simultaneously. Therefore, the MTi wakes up as a serial device, unless USB is detected. When a USB
interface is detected, the communication will be done via that USB interface.
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6 Physical Specifications
6.1
Physical properties overview
All products of the MTi product range have the same mechanical and communication interfaces. Note
that the RS422 version does not have an on-board USB interface.
MTi 10-series
MTi 100-series
MTi-##-%A#G#
Communication interface:
MTi-###-%A#G#
MTi-G-700-%A#G#
%=2: RS232, USB, UART (OEM only)
%=4: RS485, USB, UART (OEM only)
%=6: RS422, UART (OEM only); no USB
Additional interfaces:
3x SyncOut/SyncIn (GPIO)
Operating voltage:
4.5-30V
12
Power consumption :
530 mW @ 5V
650 mW @ 5V
Temperature operating
range:
-40 ºC – 85 ºC
Specified performance
operating range:
0 ºC – 55ºC
960 mW @ 5V
Altitude operating range:
N/A
N/A
-900 m – 9000 m
(baro)
< 18000 m (GPS)
Maximum velocity:
N/A
N/A
0-515 m/s
Outline dimensions:
57 x 42 x 24 mm
(W x L x H)
57 x 42 x 24 mm
(W x L x H)
57 x 42 x 24 mm
(W x L x H)
Weight:
55g (cased)
11g (OEM)
55g (cased)
11g (OEM)
58g (cased)
11g (OEM)
6.2
Power supply
The nominal power supply of the MTi is 5V DC.
The minimum operating supply voltage is >4.5V (for the external connector) and the absolute
maximum is <40V.




The sensor works at a power supply of >4.5-34V. Use only SELV (Separated or Safety extralow voltage) power supplies (double isolated) that are short-circuit proof.
The average operating power consumption is 530mW (~106 mA @ 5V) for the MTi 10-series.
The average power consumption may vary slightly with usage mode (DSP load).
The peak current at startup (power on) can be up to 200mA13.
When operated in room temperature the temperature inside the sensor will be
35-40°C in normal conditions.
12
Increasing baud rate from 115k2 to 460k8 will decrease 10% in power consumption for all configurations.
Please note that efficiency of the power input stage will decrease with increasing supply voltage.
13 If an alternative power supply is used check if it can supply these peak currents. Do not use a power supply if
the peak supply current is lower than stated.
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6.2.1 Alternative 3V3 power supply
From hardware revision 2.0 the OEM version of the MTi operates on 3V3. The 3V3 power supply can
be used when:
 there is only 3V3 available
 there are constraints on the power usage. 3V3 reduces the power usage with 20%.
The hardware of the MTi is designed in such a way that power is automatically drawn from either the
standard VCC (4.5-34V) or the alternative 3V3 power. When there is a voltage applied both to the
standard VCC and the alternative 3V3, the MTi will not start up and may be damaged.
Refer to section 6.3 for the pin configuration, including 3V3.
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6.3
Mechanical and electrical interface specifications
6.3.1
Encased MTi connectors overview
The MTi is available as OEM version and encased version. The encased version has an external 9pins connection for power and data and one SMA connector for the antenna (MTi-G-700 only). The
colour of the hexagonal nut, together with the colour of the base plate, indicates whether the MTi is an
MTi 10-series or MTi 100-series. A grey/silver base plate and nut indicates an MTi 10-series, a dark
grey/black base plate and nut indicates an MTi 100-series.
6.3.1.1 Power and data connection
For connection with the Fischer receptacle (Fischer part number: DBPU 102 A059-130), Xsens
supplies two cables. The cable with product code CA-USB-MTi can be used to connect the MTi to any
USB port (except for MTi’s with an RS422 interface). The cable with product code CA-MP-MTi allows
access to all 9 pins of the Fischer connector on the MTi.
6.3.1.2
Pin configuration casing receptacle
CA-USB-MTi
Connect the cable to the MTi and the USB cable to any USB port. Under Windows 7 and Windows XP,
the Xsens USB driver will be automatically installed if not already installed. In order to lock the CAMP-MTi to the casing (this will prevent vibration of the push-pull sleeve to be transferred to the casing
and MEMS sensors), screw the round nut clockwise. Be sure not to tighten too fast. To unplug the CAMP-MTi, screw the round locking counter clock wise and pull the connector out of the receptacle by
sliding the sleeve of the connector backwards.
2.90
m
Fisher SV 102 A 059-130
Functionality
Wire colour
Fisher pin no.
USB pin no.
10-pins OEM header
GND
Black
1
4
4, 8
1
1
NC
2
NC
3
Vin
Red
4
NC
5
NC
6
NC
7
USB DP (D+)
Green
8
3
9
USB DM (D-)
White
9
2
7
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CA-MP-MTi
Cable CA-MP-MTi allows for full control of the MTi. Hardware synchronization options are available, as
well as easy access to the serial interface. Although the USB connection wires of the CA-MP-MTi are
connected it is not recommended to use the USB connection as the shielding of the CA-MP-MTi cable
is not attached to the Molex header. In order to lock the CA-MP-MTi to the casing (this will prevent
vibration of the push-pull sleeve to be transferred to the casing and MEMS sensors), screw the round
nut clockwise. Be sure not to tighten too fast. To unplug the CA-MP-MTi, screw the round locking
counter clock wise and pull the connector out of the receptacle by sliding the sleeve of the connector
backwards.
Receptacle
2.90 m
Fisher SV 102 A 059-130
Functionality
Wire color
Fisher pin no.
Molex pin no.
Molex
PicoBlad
e
10-pins header
GND
Black
1
2
4,8
RS232 TX / RS422_Z (TX-)
Yellow
2
4
5
RS232 RX / RS422_Y (TX+)
Grey
3
5
3
Vin (4.5-30V)
Red
4
1
1
SyncIn
Blue
5
7
2
SyncOut
Pink
6
9
6
ClockSync
Brown
7
8
10
USB DP (D+) / RS422_A (RX+)
Green
8
3
9
USB DM (D-) / RS422_B (RX-)
White
9
6
7
6.3.1.3 GPS Antenna
The MTi-G-700 has an onboard GPS receiver that needs an active antenna. This antenna can be
connected to the SMA connector on the front panel of the MTi-G-700.
6.3.1.3.1 Not using the default PCTel 3910 D antenna
When using another GPS antenna than the one supplied as a part of the MTi-G-700 Development Kit,
one has to consider the antenna gain of the active antenna. It is recommended to only use active
antennas with gain between 15-50 dB. The voltage supplied by the MTi-G to the SMA or u.fl connector
(OEM) is 3.3V. The maximum current must be under 7.5mA.
Patch antennas are not suitable for hand-held devices, because of the de-tuning effect of the
hand/body. The hand/body will dielectrically load the patch antenna, which will de-tune the resonant
frequency of the patch. For this purpose a helix antenna is recommended.
In contrast to helix antennas, patch antennas require a ground plane for operation. Helix antennas can
be designed for use with or without a ground plane.
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6.3.2
OEM connections overview
6.3.2.1
Power en data
All MTi’s are available as OEM-board as well. The connection from the OEM board to the push-pull
connector of the encased version is a flexible PCB, which has put to vibration test according to MILSTD 202. The OEM board contains two headers, one 10-pins header and one 14-pins header. Details
of the headers are:
Description
Manufacturer
Part number
5x2 (10 pins dual row) box header, pitch 1.27 mm
Samtec
FTS-105-01-F-DV-P-K
7x2 (14 pins dual row) box header, pitch 1.27 mm
Samtec
FTS-107-01-F-DV-P-K
The two headers both have several functions, of which some are reserved for future use. The 10-pins
header offers basic functionality, the 14-pins header features advanced options. Note that MTi’s with
an RS422 interface don’t have a USB interface.
Pin
Functionality
Pin
Functionality
10_1
Vin (4.5-34V)
14_1
GND
10_2
SyncIn
14_2
3V314
10_3
RS232 RX / RS422_Y (TX+)
14_3
UART_TX
10_4
GND
14_4
UART_RX
10_5
RS232 TX / RS422_Z (TX-)
14_5
GND
10_6
SyncOut
14_6
Reserved
10_7
USB DP (D+) / RS422_A (RX+)
14_7
Reserved
10_8
GND
14_8
Reserved
10_9
USB DP (D+) / RS422_A (RX+)
14_9
Reserved
10_10
ClockSync
14_10
Reserved
14_11
Reserved
14_12
GND
14_13
Reserved
14_14
Reserved
Pin 1 and 10 of the 10-pins header and pin 1 and pin 14 of the 14-pins header are labelled on the
PCB.
14
3V3 available from hardware version 2.0
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Start-up procedure
The MTi starts up with communication over the serial (RS232/RS485/RS422) interface by default:
If alternative UART is set, the MTi will switch to alternative UART
If USB is detected, the MTi will switch to USB communication
WakeUp message sent
If WakeUp is not interrupted, the MTi will be put in Measurement Mode.
Plugging in USB at any time will let the MTi switch to USB immediately.
When for some reason, the MTi becomes unresponsive in serial mode and unplugging/connecting the
MTi does not solve the communication problem, just connect the MTi to a USB port and check the
settings of the device. For RS422 devices, there is a restore communication procedure (see [MTM],
not available for alternative UART).
Alternative UART
With the MTi-OEM, the alternative UART is available. This UART interface is a direct serial interface
with 3V3 CMOS levels. It can be used e.g. on embedded systems. To configure the MTi to
communicate via this alternative UART, use the command SetExtOutputMode (see [LLCP]). This
setting will be stored in the non-volatile memory, so the device will start up communicating over this
alternative UART, unless a USB connection is detected. Note that the maximum baud rate on the
alternative UART is 750 kbps.
6.3.2.2 GPS receiver
The MTi-G-700 GPS/INS needs an active antenna. The connection on the OEM board of the MTi-G700 is done with a u.FL miniature coax.
6.3.2.3 Connecting with the OEM board
Connecting to the OEM board is possible by using sockets with a pitch of 1.27 mm. Notable
manufacturers are Samtec, Molex and Hirose. Two examples of such sockets are:
Socket
Manufacturer
Part number
Farnell part number
10-pins 1.27 mm pitch
Samtec
FFSD-05-01-N
1753841
14-pins 1.27 mm pitch
Molex
90635-1143
1392991
These connectors can be connected to ribbon cables without tools to make a cable like below. On the
right is an application of such a cable.
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6.3.3 Additional interface specifications
The MTi has three GPIO lines on the main 10 pins connector (and thus on the 9-pins external Fischer
connector). These 3 lines can be configured individually for synchronization purposes (see section
5.5).
The three Sync lines are the following:
Name
Fischer
pin nr
OEM-1
pin nr
Value high/low
Input resistance/
output load
Absolute
max input
SyncIn
5
2
Low value: 0 - 0.8 V
High value: 2.5 -20 V
Input resistance: ~100 kΩ
0-20V
SyncOut
6
6
Low value: 0 - 0.4 V
High value: > 2.9 V
Output load: >330 Ω
N/A
ClockSync
7
10
Low value: 0 - 0.8 V
High value: 2.5 -20 V
Input resistance: ~100 kΩ
0-20V
For the descriptions of the synchronization functions, see [LLCP].
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6.3.4 Using the MTi MkIV with an external USB converter
Xsens offers a cable to use the MTi with USB and SyncIn. This cable also offers an interface via a
virtual COM-port instead of WinUSB. The following cables are available in Xsens’ webshop
(http://shop.xsens.com):
- CA-USB2-MTI: Multi-use cable for MTi MkIV (RS232)
- CA-USB4-MTI: Multi-use cable for MTi MkIV (RS485)
- CA-USB6-MTI: Multi-use cable for MTi MkIV (RS422)
It is possible to connect the MTi MkIV to legacy USB converter cables. Follow these instructions:
- disassemble a legacy CA-USB2, CA-USB4 or CA-USB6 USB converter cable.
- Only in case of an RS422 interface (CA-USB6), swap wires 3 and 5 of the MTi MkIV multiplug cable CA-MP-MTI (Grey and Green)
- Remove the cable of the legacy MTi and connect the (modified) MTi MkIV cable MP-MTI in
the 9-pins Molex receptacle.
- At the 7-pins receptacle of the USB converter, the following connections are now available:
Wire
color
Molex recept.
pin no.
Functionality
CA-USB2-MTI
Functionality
CA-USB4-MTI
Functionality
CA-USB6-MTI
Red
1
Vin (4.5-34V)
Vin (4.5-34V)
Vin (4.5-34V)
Black
2
GND
GND
GND
Green
3
USB DP (D+)
USB DP (D+)
RS422_Y
Yellow
4
RS232 TX
RS485 TX
RS422_Z
Grey
5
RS232 RX
RS485 RX
RS422_A
White
6
USB DM (D-)
USB DM (D-)
RS422_B
Blue
7
SyncIn / Active
SyncIn / Active
SyncIn / Active
Brown
8
Clock sync In
Clock sync In
Clock sync In
Pink
9
Sync IN/OUT
Sync IN/OUT
Sync IN/OUT
Pin 8 and 9 are only accessible by removing the two wires (brown/pink) from the 9-pins connector.
Pin 1 of 7-pins Molex
Pin 1 of 7-pins Molex
Pin 1 of 9-pins Molex
Pin 1 of 9-pins Molex
USB converter with cable of MTi
MkIV attached
USB converter with cable of legacy MTi
attached
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6.4
Housing mechanical specifications
The top casing of the MTi is made of anodized Aluminum 6060. The bottom plate is made of anodized
Aluminum 6060 The MTi connector socket and housing assembly features rubber O-ring sealing. The
MTi-100 series feature a vent that allows for the inside pressure to be the same as the ambient
pressure without compromising the ingress protection.
6.4.1 Environmental protection of the housing
All encased MTi’s are designed to withstand usage in application where dust and occasional water
splashing can be expected. However, Xsens in house testing has confirmed that the casing and
connector can withstand temporary environmental circumstances equivalent to Protection
Classification IP67 (sealed against dust, 30 minutes immersion at depth of 1 m).
6.4.2 Dimensions MTi
The MTi 10-series and the MTi 100-series (including MTi-G-700) have an identical footprint and
(position of the) connector. Differences in casings are limited to colour, barometer holes (MTi 100series only) and SMA connector (MTi-G-700 only).
6.4.3 Mounting the MTi-OEM
The MTi-OEM has four mounting holes (holes for M1.6 screws). In order to lower and tighten the
screws, it is convenient to use a piece of heat shrink tube placed over the holes.
Figure 11: Using a heat shrink tube to position the mounting screws
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6.4.4
MTi 10-series technical drawing
CAD drawings (STEP) are available at request via [email protected]
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6.4.5
MTi 100-200-300 technical drawing
CAD drawings (STEP) are available at request via [email protected]
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6.4.6
MTi-G-700 technical drawing
CAD drawings (STEP) are available at request via [email protected]
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6.4.7
MTi-OEM technical drawing
CAD drawings (STEP) are available at request via [email protected]
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7 Important notices
7.1
Safety instructions



7.2
It is recommended to study the instructions below
Do not place the MTi near strong magnetic fields.
Do not use cables or connectors other than described in this manual.
Absolute maximum ratings
Stresses above Absolute Maximum Ratings may cause permanent damage to the device.
Shock (any axis):
Standard Input Voltage:
Alternative Input Voltage:
Interface inputs:
SyncIn:
Bidirectional SyncIn:
Operating/Storage Temperature:
Humidity:
20000 m/s2 (2000 g) 0.5 ms (half-sine)
-0.3 V … 40 V
3.3 V +/- 0.1 V
-25 V … 25 V (RX, A and B inputs)
-0.3 V …3.6 V (alternative UART)
0 – 20 V
0 - 3.6V
-40 C … 85 C
Casing is IP67 (for OEM: 95% max, non-condensing)
Stresses beyond those listed here may cause permanent damage to the device. These are stress
ratings only, and functional operation of the MTi at these or any other conditions beyond those
indicated in section 4.6 of the specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
NOTE: Drops onto hard surfaces can cause shocks of greater than 20000 m/s2 (2000 g) exceed the
absolute maximum rating of the device. Care should be taken when handling to avoid damage. Drops
causing shock greater than absolute maximum ratings may not destroy the device but will permanently
alter the properties of the physical motion sensors, which may cause the device to become inaccurate.
7.3
Maintenance
The MTi will not require any maintenance if properly used (see also section 7.1 and 7.2). However, if
the Motion Tracker is not functioning according to the specifications please contact Xsens or your local
distributor (www.xsens.com/support).
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7.4
CE Declaration of Conformity for the MT devices
We, Xsens Technologies BV, of
Pantheon 6a
7521 PR Enschede, The Netherlands
declare under our sole responsibility that our products:
MTi-10-#A#G#
MTi-20-#A#G#
MTi-30-#A#G#
MTi-100-#A#G#
MTi-200-#A#G#
MTi-300-#A#G#
MTi-G-700-#A#G#
(MTi-10-2A5G4, MTi-10-2A5G0, MTi-10-4A5G4, MTi-104A5G0, MTi-10-6A5G4, MTi-10-6A5G0, MTi-10-2A8G4,
MTi-10-2A8G0, MTi-10-4A8G4, MTi-10-4A8G0, MTi-106A8G4, MTi-10-6A8G0)
(MTi-20-2A5G4, MTi-20-2A5G0, MTi-20-4A5G4, MTi-204A5G0, MTi-20-6A5G4, MTi-20-6A5G0, MTi-20-2A8G4,
MTi-20-2A8G0, MTi-20-4A8G4, MTi-20-4A8G0, MTi-206A8G4, MTi-20-6A8G0)
(MTi-30-2A5G4, MTi-30-2A5G0, MTi-30-4A5G4, MTi-304A5G0, MTi-30-6A5G4, MTi-30-6A5G0, MTi-30-2A8G4,
MTi-30-2A8G0, MTi-30-4A8G4, MTi-30-4A8G0, MTi-306A8G4, MTi-30-6A8G0)
(MTi-100-2A5G4, MTi-100-2A5G0, MTi-100-4A5G4, MTi-1004A5G0, MTi-100-6A5G4, MTi-100-6A5G0, MTi-100-2A8G4,
MTi-100-2A8G0, MTi-100-4A8G4, MTi-100-4A8G0, MTi-1006A8G4, MTi-100-6A8G0)
(MTi-200-2A5G4, MTi-200-2A5G0, MTi-200-4A5G4, MTi-2004A5G0, MTi-200-6A5G4, MTi-200-6A5G0, MTi-200-2A8G4,
MTi-200-2A8G0, MTi-200-4A8G4, MTi-200-4A8G0, MTi-2006A8G4, MTi-200-6A8G0)
(MTi-300-2A5G4, MTi-300-2A5G0, MTi-300-4A5G4, MTi-3004A5G0, MTi-300-6A5G4, MTi-300-6A5G0, MTi-300-2A8G4,
MTi-300-2A8G0, MTi-300-4A8G4, MTi-300-4A8G0, MTi-3006A8G4, MTi-300-6A8G0)
(MTi-G-700-2A5G4, MTi-G-700-2A5G0, MTi-G-700-4A5G4, MTiG-700-4A5G0, MTi-G-700-6A5G4, MTi-G-700-6A5G0, MTi-G-7002A8G4, MTi-G-700-2A8G0, MTi-G-700-4A8G4, MTi-G-7004A8G0, MTi-G-700-6A8G4, MTi-G-700-6A8G0)
to which this declaration relates, are in conformity with the essential requirements of the
EMC Directive: 2004/108/EC and the following Standards and other Normative Documents:
EMC Directive: 2004/108/EEC
EN 61326-1 (2006) ; EN 61000-3-2 (2006); EN 61000-3-3 (1995) + A1 (2001) + A2 (2005)
Environment to be used is light industrial/laboratory; Class of emission is B; performance criterion B.
Jan 17th 2014, Enschede, the Netherlands
Per Slycke
CTO
Xsens Technologies
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7.5
FCC Declaration of Conformity for the MT devices
We, Xsens Technologies BV, of
Pantheon 6a
7521 PR Enschede, The Netherlands
declare under our sole responsibility that our products:
MTi-10-#A#G#
MTi-20-#A#G#
MTi-30-#A#G#
MTi-100-#A#G#
MTi-200-#A#G#
MTi-300-#A#G#
MTi-G-700-#A#G#
(MTi-10-2A5G4, MTi-10-2A5G0, MTi-10-4A5G4, MTi-104A5G0, MTi-10-6A5G4, MTi-10-6A5G0, MTi-10-2A8G4,
MTi-10-2A8G0, MTi-10-4A8G4, MTi-10-4A8G0, MTi-106A8G4, MTi-10-6A8G0)
(MTi-20-2A5G4, MTi-20-2A5G0, MTi-20-4A5G4, MTi-204A5G0, MTi-20-6A5G4, MTi-20-6A5G0, MTi-20-2A8G4,
MTi-20-2A8G0, MTi-20-4A8G4, MTi-20-4A8G0, MTi-206A8G4, MTi-20-6A8G0)
(MTi-30-2A5G4, MTi-30-2A5G0, MTi-30-4A5G4, MTi-304A5G0, MTi-30-6A5G4, MTi-30-6A5G0, MTi-30-2A8G4,
MTi-30-2A8G0, MTi-30-4A8G4, MTi-30-4A8G0, MTi-306A8G4, MTi-30-6A8G0)
(MTi-100-2A5G4, MTi-100-2A5G0, MTi-100-4A5G4, MTi-1004A5G0, MTi-100-6A5G4, MTi-100-6A5G0, MTi-100-2A8G4,
MTi-100-2A8G0, MTi-100-4A8G4, MTi-100-4A8G0, MTi-1006A8G4, MTi-100-6A8G0)
(MTi-200-2A5G4, MTi-200-2A5G0, MTi-200-4A5G4, MTi-2004A5G0, MTi-200-6A5G4, MTi-200-6A5G0, MTi-200-2A8G4,
MTi-200-2A8G0, MTi-200-4A8G4, MTi-200-4A8G0, MTi-2006A8G4, MTi-200-6A8G0)
(MTi-300-2A5G4, MTi-300-2A5G0, MTi-300-4A5G4, MTi-3004A5G0, MTi-300-6A5G4, MTi-300-6A5G0, MTi-300-2A8G4,
MTi-300-2A8G0, MTi-300-4A8G4, MTi-300-4A8G0, MTi-3006A8G4, MTi-300-6A8G0)
(MTi-G-700-2A5G4, MTi-G-700-2A5G0, MTi-G-700-4A5G4, MTiG-700-4A5G0, MTi-G-700-6A5G4, MTi-G-700-6A5G0, MTi-G-7002A8G4, MTi-G-700-2A8G0, MTi-G-700-4A8G4, MTi-G-7004A8G0, MTi-G-700-6A8G4, MTi-G-700-6A8G0)
to which this declaration relates, have been tested and found to comply with the limits for a
Unintentional Radiator as described in 47 CFR 15 (2007 May, 04 Edition) Class B Digital
Device, pursuant to Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including interference that may cause
undesired operation.
Jan 17th 2014, Enschede, the Netherlands
Per Slycke
CTO
Document MT0605P.E
© Xsens Technologies B.V.
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MTi User Manual
7.6
Warranty and liability
Xsens Technologies B.V. warrants the products manufactured by it to be free from defects in material
and workmanship for a period of 1 year from the date of delivery. Products not subjected to misuse will
be repaired, replaced or credit issued at the sole option of Xsens Technologies B.V. Contact Xsens via
www.xsens.com/support for return material authorization (RMA) prior to returning any items for
calibration, repair or exchange. The product must be returned in its original packaging to prevent
damage during shipping.
The warranty shall not apply to products repaired or altered or removed from the original casing by
others than Xsens Technologies B.V. so as, in Xsens Technologies B.V. opinion, to have adversely
affected the product, products subjected to negligence, accidents or damaged by circumstances
beyond Xsens Technologies B.V.’s control.
NOTE: Xsens reserves the right to make changes in its products in order to improve design,
performance, or reliability.
Subject to the conditions and limitations on liability stated herein, Xsens warrants that the Product as
so delivered shall materially conform to Xsens’ then current specifications for the Product, for a period
of one year from the date of delivery. ANY LIABILITY OF XSENS WITH RESPECT TO THE SYSTEM
OR THE PERFORMANCE THEREOF UNDER ANY WARRANTY, NEGLIGENCE, STRICT LIABILITY
OR OTHER THEORY WILL BE LIMITED EXCLUSIVELY TO PRODUCT REPAIR, REPLACEMENT
OR, IF REPLACEMENT IS INADEQUATE AS A REMEDY OR, IN XSENS' OPINION IMPRACTICAL,
TO REFUND THE PRICE PAID FOR THE PRODUCT. XSENS DOES NOT WARRANT,
GUARANTEE, OR MAKE ANY REPRESENTATIONS REGARDING THE USE, OR THE RESULTS
OF THE USE, OF THE PRODUCT OR WRITTEN MATERIALS IN TERMS OF CORRECTNESS,
ACCURACY, RELIABILITY, OR OTHERWISE. Xsens shall have no liability for delays or failures
beyond its reasonable control.
7.7
Customer Support
Xsens is glad to help you with any questions you may have about the MTi, or about the use of the
technology for your application. Please use the FAQ, contact Xsens’ distributor or if you are a direct
customer of Xsens our Customer Support:




Internet and FAQ: http://www.xsens.com/support
Distributror network: http://www.xsens.com/en/company-pages/company/distributors
Telephone EMEA/Pacific: +31(0)88-9736700 (+31 88 XSENS 00)
telephone US (Los Angeles, CA): +1 310-481-1800
To be able to help you, please mention your Motion Tracker Device ID (on the side of the device) and
software license registration number in your e-mail.
Document MT0605P.E
© Xsens Technologies B.V.
79
MTi User Manual
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