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There are 3 main types of sensor used for AEB currently.
Ford adopted a LiDAR sensor fitted onto the windscreen. This works very well at lower speeds - although the earlier versions were easily confused by low sun and a dirty windscreen. Ford still use this for their Active City Stop tech, but not for their AEB system. Volvo and Mercedes and others also have variations for their low speed collision mitigation systems. I understand Bosch developed and supply all the systems.
The majority of manufacturers use a radar based system - either 2D with 1 sensor or 3D with a pair of sensors. Most use either a phased or switchable array with a number of sectors. This allows the steering wheel position to determine the course of the vehicle and hence the area to be monitored.
A growing number of vehicles now supplement the radar system with a camera and image recognition systems which are capable of detecting simple things like traffic signs and now more complex targets like cyclists and crossing traffic.
Autonomous vehicles generally also have a scanning LiDAR to build up a virtual 3D distance map of the road. This is coupled to high accuracy mapping and quite often 360 degree cameras. This sensor fusion is what sets these systems apart, as the decision process is made from multiple sensors and over a time period. Current AEB is generally 1 or 2 sensors and as an almost instantaneous decision once a hazard is first detected. |
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