Rear obstacle detection systems: a boon for vehicle safety

Rear obstacle detection systems: a boon for vehicle safety
Measurement & instrumentation
Rear obstacle detection systems:
a boon for vehicle safety
by Neelu Singh, Frost & Sullivan
Automotive safety is a big concern for consumers around the world and car manufacturers are constantly looking for innovative ways to improve
their vehicles. Automotive rear obstacle detection systems offer one way of decreasing the risk of accidents by using radar and image sensors
to monitor the proximity of objects to the car.
The technology
A rear obstacle detection system monitors
a range of 3 to 6 m behind the vehicle and
sends a warning signal to the driver when the
vehicle is approaching an object in reverse.
The technology recognises targets by means of
radar or sonar. The system sends an advance
audible and/or visual distance-based alert to
the driver, helping to avoid collisions with objects
behind the vehicle.
The sonar (sound navigation and ranging)
technology detects obstacles by emitting a
transmitter pulse of ultrasonic energy. A receiver
fitted in the vehicle then perceives the resultant
echo reflected by the detected object. When
the inaudible sound wave sent by the emitter
encounters an object, it is reflected back to the
receiver circuit, which is tuned to the frequency
of the emitter. The receiver then transforms the
pulse and sends data to a driver display unit.
Radar (radio detection and ranging) technology
determines the range of objects by transmitting
ultra high frequency radio waves. These radio
waves are transmitted from the vehicle at defined
intervals within a specified coverage area. The
electromagnetic waves reflected by an object
behind the vehicle are then collected by the
sensors and are sent to a signal-processing unit
and communicated to a driver interface.
Application and benefits of radar and sonar
• The benefits of rear obstacle detection
systems are that it:
• Acts as a safety measure in reversing and
• Provides an advanced warning about
obstacles in low-visibility situations like rain,
snow, and fog
• Is useful in avoiding blind spot-linked vehicle
• Assists drivers reversing vehicles into unfamiliar
docks and tight parking spaces
• Reduces injuries, repair costs, and vehicle
downtime by avoiding collisions related to
backing up
Obstacle detection systems are intended to
increase driver alertness and therefore require
the driver’s attention and appropriate response
to avoid accidents.
Rear obstacle detection systems are installed
as original equipment in some high-end
vehicles, but they can also be purchased as an
aftermarket item. They are either sensor-based
(ultrasonic or radar) or visual-only systems.
The system sends an
advance audible and/or
visual distance-based alert
to the driver
Delphi dual-beam radar back-up aid
Delphi provides a 24 GHz dual-beam radar backup aid to detect obstacles behind the vehicle
and assist in parking. This new technology uses a
speed-sensitive algorithm and adaptive audible
and (optional) visual alerts to send advance
warnings to help the driver avoid accidents.
The system also provides distance-based alerts
to make parking easier, and is suitable for light,
medium, and heavy-duty vehicles.
The system detects moving and non-moving
objects in a 5 m sensor range. It also offers
the longest detection zone, giving the driver
more time to react to detected obstacles. The
back-up aid operates under a wide range of
environmental conditions, including rain, snow,
ice, fog, and noise, in daylight and in darkness.
Unlike camera-based systems, it does not
require the driver to monitor a visual display. It
features a CAN-based interface to enhance
collision mitigation countermeasures. The Ford
Explorer SUV uses this technology, featuring a
detection range of 5 m behind the vehicle.
Siemens blind-spot detection system
Siemens blind-spot detection and lane
change assist systems use radar sensors and
are designed to provide driver assistance by
expanding the rear view angle. The system
provides early visual warnings in case an object
is in a blind spot. The system expands the driver’s
limited viewing angle and helps in heavy traffic
areas, parking, and changing lanes. If a car is
in a blind spot, the blind spot detection warning
starts at 10 km/h. At 60 km/h, the lane change
assist function is activated additionally. The
company also offers Park Mate, an advanced
driver assistance system to facilitate parking.
The blind spot detection system will feature in
the 2008 BMW 5-series.
LS 460 featuring rear pre-crash safety system
Lexus, the luxury vehicle division of Japanese
automaker Toyota, offers the rear pre-crash
safety system in its LS 460 vehicle. The system
uses millimeter-wave radar set into the rear
bumper and stereo cameras to constantly scan
the area around the back of the car, both when
it is moving and when it is parked. The LS 460
also provides emergency steering assist aids in
substantially improving the vehicle’s response
to the driver’s steering input in the likelihood of
a collision, increasing the chances of avoiding
the obstacle. In the event of a collision, the
pre-collision seatbelt retracting mechanism
activates and the brakes are applied
automatically to help reduce the consequences
of the impact.
Lexus plans to be able to offer a complete
advanced pre-collision system package,
consisting of advanced obstacle detection,
emergency steering assist, lane-keeping assist,
and driver monitoring systems to avoid collisions.
TRW’s collision warning system
The collision warning system from TRW helps
to prevent or mitigate collisions by monitoring
the road through short- and long-range radars,
along with a video camera. The system sends
advance audio/visual alerts for an approaching
obstacle, and also activates emergency brake
assistance to provide full brake force. Using
a digital signal chip, the processor performs
target identification and tracking computations
needed to make sense of the signals from the
radar sensor.
Nov/Dec 2007 - EngineerIT
Eagle eye electronic obstacle detection
The Eagle Eye Electronic Obstacle Detection
System uses ultrasonic technology to provide
driver assistance through a single driver alert
module. It is mainly targeted at the heavy truck
segment. It consists of up to seven sensors and
has a 3 m detection zone. The system warns
drivers of obstacles when reversing or changing
lanes. The company offers this rear-obstacle
detection system as an aftermarket product,
which works well for both heavy trucks and
tractor-trailer combinations.
Frost & Sullivan expects radar sensor technology
to experience strong growth in the short to
medium term due to its persuasive technological
advantages, better adaptability to harsh
environmental conditions, and cost-effective
solutions. Safety concerns and market interest
could bode well for tier-one system developers
such as Delphi Corporation, Siemens VDO, Robert
Bosch Corporation, Continental AG, Hella Valeo,
and TRW Automotive Holdings. Furthermore,
integrated safety systems like radar-based
adaptive cruise control and automatic collision
mitigation systems are set to take automotive
safety to the next level.
Contact Patrick Cairns,
Frost & Sullivan, Tel 021 680-3274,
[email protected]
EngineerIT - Nov/Dec 2007
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