ET-332
Version 1.3.1
GPS Engine Board
ET-332
Globalsat Technology Corporation
16F., No. 186, Jian-Yi Road, Chung-Ho City, Taipei Hsien 235,
Taiwan
Tel: 886-2-8226-3799/ Fax: 886-2-8226-3899
service@globalsat.com.tw
www.globalsat.com.tw
USGlobalSat, Inc.
1308 John Reed Court, City of Industry, CA 91745
Tel: 626-968-4145 / Fax: 626-968-4373
oem@usglobalsat.com
www.usglobalsat.com
Specifications are subject to be changed without notice.
Page 1 of 15
ET-332
Version 1.3.1
1. Product Information
„ Product Part I.D. ET-332
„ Product Description:
The ET-332 GPS engine board is low cost but maintains high reliability and accuracy making it an
ideal choice for integration with OEM/ODM systems.
„ Product Features:
9
9
9
9
9
9
9
9
9
9
9
9
SiRF Star III/ LP Single
Very high sensitivity (Tracking Sensitivity: -159dBm)
Compact PCB allows for easier integration into space limited environments.
Supports the NMEA 0183 data protocol
Foliage Lock for weak signal tracking
All-in-view 20-channel parallel processing
Snap Lock 100mc re-acquisition time
Enhanced algorithm for navigation stability
Superior urban canyon performance
WAAS / EGNOS MSAS support
Built-in SuperCap to maintain system data for rapid satellite acquisition
RoHS compliant
„ Product Specifications
GPS Receiver
Chipset
SiRF Star III/LP Single
Frequency
L1, 1575.42 MHz
Code
1.023 Mhz chip rate
Protocol
Electrical Level: TTL level,
Output Voltage Level: 0V~2.85V
Baud Rate: 4800 bps
Output Message: NMEA 0183 GGA, GSA,
GSV, RMC (VTG, GLL optional)
Channels
20
Sensitivity
-159dBm
Cold Start
42 seconds average
Specifications are subject to be changed without notice.
Page 2 of 15
ET-332
Version 1.3.1
Warm Start
38 seconds average
Hot Start
1 second average
Reacquisition
0.1 second average
Accuracy
Position: 10 meters, 2D RMS
5 meters, 2D RMS, WAAS
enabled
Velocity: 0.1 m/s
Time: 1us synchronized to GPS time
Maximum Altitude
18,000 meter (60,000 feet) max
Maximum Velocity
515 meter/second (1000 knots) max
Maximum Acceleration
4G
Jerk
20m/sec **3
Interface
I/O Connector Type
External Antenna Port
Physical Characteristics
Dimensions
1.6” x 1.4” x 0.4” (40.5 x 35 x 10 mm)
DC Characteristics
Power Supply
3.8V ~ 6.5V DC Input
Backup Voltage
2.5 ~ 3.6V 10uA backup current
Power Consumption
42mA (Continuous Mode)
25mA (Trickle Power Mode)
Environmental Range
Humidity Range
5% to 95% non-condensing
Operation Temperature
-40F to +176F (-40C to +85C)
Specifications are subject to be changed without notice.
Page 3 of 15
ET-332
Version 1.3.1
2. Technical Information
„ Physical Characteristics
Specifications are subject to be changed without notice.
Page 4 of 15
ET-332
Version 1.3.1
„ Pin Assignment
Pin
Name
Description
Type
1
GND
Ground
2
VBAT
Backup Battery
Input
3
VDC
3.8V~6.5V DC Power Input
Input
4
PBRES
Push Button Reset Input (Active Low)
Input
5
GPIO1
(Reserved)
6
TXA
Serial Data Output A (GPS Data)
Output
7
RXA
Serial Data Input A (Command)
Input
8
GND
Ground
9
GND
Ground
10
SELECT
(Reserved)
11
TIMEMARK
1PPS Time Mark Output
12
GND
Ground
Output
Specifications are subject to be changed without notice.
Page 5 of 15
ET-332
Version 1.3.1
„ Pin Explanation
VCC: (DC power input) This is the main DC supply for a 3.8V ~ 6.5V power module board.
VBAT: This is the battery backup input that powers the SRAM and RTC when main power is removed.
Typical current draw is 10uA. Without an external backup battery, the module/engine board will execute a
cold star after every turn on. To achieve the faster start-up offered by a hot or warm start, a battery
backup must be connected. To maximize battery lifetime, the battery voltage should be between 2.5v and
3.6v.
PBRES: (Push Button Reset) This pin provides an active-low reset input to the engine board. It causes
the engine board to reset and start searching for satellites.
SELECT: Do not connect (do not use)
TX: This is the main transmit channel for outputting navigation and measurement data to user’s
navigation software or user-written software.
Output TTL level, 0V ~ 2.85V
RX: This is the main receive channel for receiving software commands to the engine board from
SiRfdemo software or from user-written software. (NOTE: When not in use this pin must be kept “HIGH”
for operation. From Vcc connect a 470 Ohm resistor in series with a 3.2v Zener diode to Ground. Then,
connect the Rx input to Zener’s cathode to pull the input “HIGH”.)
TIME MARK (1PPS): This pin provides one pulse-per-second output from the engine board that is
synchronized to GPS time
GND: GND provides the ground for the engine boards. Be sure to connect all grounds
„ Mounting
Recommended mounting methods:
a.
Use industrial grade double-sided foam tape. Place it on the bottom side of the engine board.
b.
A recessed cavity in your housing design with a foam pad to eliminate shifting or movement.
c.
Use provided mounting holes on the GPS engine board PCB.
3. Software Commands
„ NMEA Output Command
GGA-Global Positioning System Fixed Data
Table B-2 contains the values for the following example:
$GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M,,,,0000*18
Specifications are subject to be changed without notice.
Page 6 of 15
ET-332
Version 1.3.1
Table B-2 GGA Data Format
Name
Example
Units
Description
Message ID
UTC Time
$GPGGA
161229.487
GGA protocol header
hhmmss.sss
Latitude
3723.2475
ddmm.mmmm
N/S Indicator
Longitude
N
12158.3416
N=north or S=south
dddmm.mmmm
E/W Indicator
W
E=east or W=west
Position Fix Indicator
1
See Table B-3
Satellites Used
HDOP
07
1.0
MSL Altitude1
9.0
meters
M
meters
M
meters
meters
Units
Geoid Separation
Units
1
Age of Diff. Corr.
Range 0 to 12
Horizontal Dilution of Precision
second
Diff. Ref. Station ID
Checksum
Null fields when DGPS is not used
0000
*18
<CR><LF>
End of message termination
SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights.
Table B-3 Position Fix Indicator
Value
Description
0
Fix not available or invalid
1
2
GPS SPS Mode, fix valid
Differential GPS, SPS Mode , fix valid
3
GPS PPS Mode, fix valid
GLL-Geographic Position-Latitude/Longitude
Table B-4 contains the values for the following example:
$GPGLL,3723.2475,N,12158.3416,W,161229.487,A*2C
Table B-4 GLL Data Format
Name
Message ID
Example
$GPGLL
Units
Description
GLL protocol header
Latitude
3723.2475
ddmm.mmmm
N/S Indicator
n
N=north or S=south
Longitude
E/W Indicator
12158.3416
W
dddmm.mmmm
E=east or W=west
Specifications are subject to be changed without notice.
Page 7 of 15
ET-332
Version 1.3.1
UTC Position
161229.487
hhmmss.sss
Status
A
A=data valid or V=data not valid
Checksum
*2C
<CR><LF>
End of message termination
GSA-GNSS DOP and Active Satellites
Table B-5 contains the values for the following example:
$GPGSA,A,3,07,02,26,27,09,04,15,,,,,,1.8,1.0,1.5*33
Table B-5 GSA Data Format
Name
Example
Message ID
$GPGSA
GSA protocol header
Mode1
A
See Table B-6
Mode2
Units
Description
3
See Table B-7
Satellite Used
1
07
Sv on Channel 1
Satellite Used
1
02
Sv on Channel 2
.
Satellite Used1
Sv on Channel 12
PDOP
1.8
Position dilution of Precision
HDOP
1.0
Horizontal dilution of Precision
VDOP
1.5
Vertical dilution of Precision
Checksum
*33
<CR><LF>
1. Satellite used in solution.
End of message termination
Table B-6 Mode1
Value
Description
M
Manual-forced to operate in 2D or 3D mode
A
2D automatic-allowed to automatically switch 2D/3D
Table B-7 Mode 2
Value
Description
1
Fix Not Available
2
2D
3
3D
GSV-GNSS Satellites in View
Table B-8 contains the values for the following example:
$GPGSV,2,1,07,07,79,048,42,02,51,062,43,26,36,256,42,27,27,138,42*71
Specifications are subject to be changed without notice.
Page 8 of 15
ET-332
Version 1.3.1
$GPGSV,2,2,07,09,23,313,42,04,19,159,41,15,12,041,42*41
Table B-8 GSV Data Format
Name
Example
Units
Description
Message ID
Number of Messages1
$GPGSV
2
GSV protocol header
Range 1 to 3
Message Number1
1
Range 1 to 3
Satellites in View
07
Satellite ID
Elevation
07
79
degrees
Channel 1(Range 1 to 32)
Channel 1(Maximum90)
Azimuth
048
degrees
Channel 1(True, Range 0 to 35
SNR(C/No)
…….
42
dBHz
Satellite ID
27
Elevation
27
Degrees
Channel 4(Maximum90)
Azimuth
SNR(C/No)
138
42
Degrees
dBHz
Channel 4(True, Range 0 to 35
Range 0 to 99,null when not tra
Checksum
*71
Range 0 to 99,null when not tra
…….
Channel 4 (Range 1 to 32)
<CR><LF>
End of message termination
Depending on the number of satellites tracked multiple messages of GSV data may be required.
Specifications are subject to be changed without notice.
Page 9 of 15
ET-332
Version 1.3.1
RMC-Recommended Minimum Specific GNSS Data
Table B-9 contains the values for the following example:
$GPRMC,161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10
Table B-9 RMC Data Format
Name
Example
Units
Description
Message ID
$GPRMC
RMC protocol header
UTC
161229.487
hhmmss.sss
Status
Latitude
A
3723.2475
A=data valid or V=data not valid
ddmm.mmmm
N/S Indicator
N
N=north or S=south
Longitude
E/W Indicator
12158.3416
W
dddmm.mmmm
E=east or W=west
Speed Over Ground
0.13
knots
Course Over Ground
309.62
degrees
True
Date
Magnetic Variation2
120598
degrees
ddmmyy
E=east or W=west
Checksum
*10
Time
<CR><LF>
End of message termination
SiRF Technology Inc. does not support magnetic declination. All “course over ground” data are
Geodetic WGS48 directions.
VTG-Course Over Ground and Ground Speed
$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E
Table B-9 VTG Data Format
Name
Example
Message ID
$GPVTG
Course
309.62
Reference
Course
T
Reference
M
Speed
0.13
Units
Speed
N
0.2
Units
K
Checksum
<CR><LF>
*6E
Units
Description
VTG protocol header
degrees
Measured heading
degrees
True
Measured heading
knots
Measured horizontal speed
Km/hr
Knots
Measured horizontal speed
Magnetic
Kilometers per hour
End of message termination
Specifications are subject to be changed without notice.
Page 10 of 15
ET-332
Version 1.3.1
■ NMEA Input Command
A.) Set Serial Port ID:100 Set PORTA parameters and protocol
This command message is used to set the protocol (SiRF Binary, NMEA, or USER1) and/or the
communication parameters (baud, data bits, stop bits, parity). Generally, this command is utilize to
switch the GPS module back to SiRF Binary protocol mode, where an extensive message
commands are readily available. In example, whenever users are interested in altering navigation
parameters, a valid message sent and is receive by the recipient module, the new parameters will be
stored in battery backed SRAM and then the receiver will restart using the saved parameters.
Format:
$PSRF100,<protocol>,<baud>,<DataBits>,<StopBits>,<Parity>*CKSUM
<CR><LF>
<protocol>
<baud>
<DataBits>
<StopBits>
<Parity>
0=SiRF Binary, 1=NMEA, 4=USER1
1200, 2400, 4800, 9600, 19200, 38400
8,7. Note that SiRF protocol is only valid f8 Data bits
0,1
0=None, 1=Odd, 2=Even
Example 1: Switch to SiRF Binary protocol at 9600,8,N,1
$PSRF100,0,9600,8,1,0*0C<CR><LF>
Example 2: Switch to User1 protocol at 38400,8,N,1
$PSRF100,4,38400,8,1,0*38<CR><LF>
**Checksum Field: The absolute value calculated by exclusive-OR the 8 data bits of each
character in the Sentence, between, but, excluding “$” and “*”. The hexadecimal value of the most
significant and least significant 4 bits of the result are converted to two ASCII characters (0-9,A-F)
for transmission. First, the most significant character is transmitted.
**<CR><LF>
: Hex 0D 0A
B.) Navigation initialization ID:101 Parameters required for start
This command is used to initialize the GPS module for a “Warm” start, by providing real-time position
(in X, Y, Z coordinates), clock offset, and time. This action enables the GPS receiver to search for
the necessary satellite signals at the correct signal parameters. The newly acquired and stored
satellite data will enable the receiver to acquire signals more quickly, and thus, generate a rapid
navigational solution.
When a valid Navigation Initialization command is receive, the receiver will restart using the input
parameters as a basis for satellite selection and acquisition.
Format
$PSRF101,<X>,<Y>,<Z>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,<chnlCount>,<ResetCfg>
*CKSUM<CR><LF>
<X>
X coordinate position
INT32
Specifications are subject to be changed without notice.
Page 11 of 15
ET-332
<Y>
<Z>
<ClkOffset>
<TimeOf Week>
<WeekNo>
<chnlCount>
<ResetCfg>
Version 1.3.1
Y coordinate position
INT32
Z coordinate position
INT32
Clock offset of the receiver in Hz, Use 0 for last saved value if available.
If this is unavailable, a default value of 75000 for GSP1, 95000 for GSP
1/LX is used.
INT32
GPS Time Of Week
UINT32
GPS Week Number
UINT16
Week No and Time Of Week calculation from UTC time
Number of channels to use.1-12. If your CPU throughput is not high
enough, you could decrease needed throughput by reducing the number
of active channels
UBYTE
bit mask
0×01=Data Valid warm/hotstarts=1
0×02=clear ephemeris warm start=1
0×04=clear memory. Cold start=1
UBYTE
Example: Start using known position and time.
$PSRF101,-2686700,-4304200,3851624,96000,497260,921,12,3*7F
C.) Set DGPS Port ID:102 Set PORT B parameters for DGPS input
This command is used to control Serial Port B, an input serial only port used to receive RTCM
differential corrections. Differential receivers may output corrections using different communication
parameters. The default communication parameters for PORT B are set for 9600 Baud, 8data bits, 0
stop bits, and no parity. If a DGPS receiver is used which has different communication parameters,
use this command to allow the receiver decode data correctly. When a valid message is received,
the parameters are stored in a battery backed SRAM. Resulting, GPS receiver using the saved
Parameters for restart.
Format:
$PSRF102,<Baud>,<DataBits>,<StopBits>,<Parity>*CKSUM<CR><LF>
<baud>
<DataBits>
<StopBits>
<Parity>
1200,2400,4800,9600,19200,38400
8
0,1
0=None,Odd=1,Even=2
Example: Set DGPS Port to be 9600,8,N,1
$PSRF102,9600,8,1.0*12
D.) Query/Rate Control ID:103 Query standard NMEA message and/or set output rate
Specifications are subject to be changed without notice.
Page 12 of 15
ET-332
Version 1.3.1
This command is used to control standard NMEA data output messages: GGA, GLL, GSA, GSV,
RMC, and VTG. Using this command message, standard NMEA message is polled once, or setup
for periodic output. In addition, checksums may also be enable or disable contingent on receiving
program requirements. NMEA message settings are stored in a battery-backed memory for each
entry when the message is accepted.
Format:
$PSRF103,<msg>,<mode>,<rate>,<cksumEnable>*CKSUM<CR><LF>
<msg>
<mode>
<rate>
<cksumEnable>
0=GGA,1=GLL,2=GSA,3=GSV,4=RMC,5=VTG
0=SetRate,1=Query
Output every <rate>seconds, off=0,max=255
0=disable Checksum,1=Enable checksum for specified message
Example 1: Query the GGA message with checksum enabled
$PSRF103,00,01,00,01*25
Example 2: Enable VTG message for a 1Hz constant output with checksum enabled
$PSRF103,05,00,01,01*20
Example 3: Disable VTG message
$PSRF103,05,00,00,01*21
E.) LLA Navigation initialization ID:104 Parameters required to start using Lat/Lon/Alt
This command is used to initialize the GPS module for a “Warm” start, providing real-time position
(Latitude, Longitude, Altitude coordinates), clock offset, and time. This action enables the GPS
receiver to search for the necessary satellite signals at the correct signal parameters. The newly
acquired and stored satellite data will enable the receiver to acquire signals more quickly, and thus,
generate a rapid navigational solution.
When a valid LLA Navigation Initialization command is receive, then the receiver will restart using
the input parameters as a basis for satellite selection and acquisition.
Format:
$PSRF104,<Lat>,<Lon>,<Alt>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,
<ChannelCount>, <ResetCfg>*CKSUM<CR><LF>
<Lat>
Latitude position, assumed positive north of equator and negative
south of equator float, possibly signed
<Lon>
Longitude position, it is assumed positive east of Greenwich
and negative west of Greenwich Float, possibly signed
<Alt>
Altitude position float, possibly signed
<ClkOffset>
available.
Clock Offset of the receiver in Hz, use 0 for last saved value if
Specifications are subject to be changed without notice.
Page 13 of 15
ET-332
Version 1.3.1
If this is unavailable, a default value of 75000 for GSP1, 95000 for
GSP1/LX is used.
INT32
<TimeOfWeek>
GPS Time Of Week
UINT32
<WeekNo>
GPS Week Number
UINT16
<ChannelCount>
Number of channels to use. 1-12
UBYTE
<ResetCfg>
bit mask
0×01=Data Valid warm/hot starts=1
0×02=clear ephemeris warm start=1
0×04=clear memory. Cold start=1
UBYTE
Example: Start using known position and time.
$PSRF104,37.3875111,-121.97232,0,96000,237759,922,12,3*37
F.) Development Data On/Off ID:105 Switch Development Data Messages On/Off
Use this command to enable development debug information if you are having trouble in attaining
commands accepted. Invalid commands will generate debug information that should enable the
user to determine the source of the command rejection. Common input rejection problems are
associated to invalid checksum or parameter out of specified range. Note, this setting is not
preserved across a module reset.
Format: $PSRF105,<debug>*CKSUM<CR><LF>
<debug>
0=Off,1=On
Example: Debug On
$PSRF105,1*3E
Example: Debug Off
$PSRF105,0*3F
G). Select Datum ID:106 Selection of datum to be used for coordinate transformations
GPS receivers perform initial position and velocity calculations using an earth-centered earth-fixed
(ECEF) coordinate system. Results may be converted to an earth model (geoid) defined by the
selected datum. The default datum is WGS 84 (World Geodetic System 1984) which provides a
worldwide common grid system that may be translated into local coordinate systems or map Datum.
(Local map Datum are a best fit to the local shape of the earth and not valid worldwide.)
Examples:
Datum select TOKYO_MEAN
$PSRF106,178*32
Specifications are subject to be changed without notice.
Page 14 of 15
ET-332
Name
Message ID
Example
$PSRF106
Datum
178
Checksum
<CR><LF>
*32
Units
Version 1.3.1
Description
PSRF106 protocol header
21= WGS84
178= Tokyo_Mean
179= Tokyo_Japan
180= Tokyo_Korea
181= Tpkyo_Okinawa
End of message termination
* *
*
Specifications are subject to be changed without notice.
Page 15 of 15
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