Failure modes of radar sensor

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JohnnyGood1
Posts: 3
Joined: Mon Jul 09, 2018 4:31 pm

Failure modes of radar sensor

Post by JohnnyGood1 » Mon Jul 09, 2018 4:38 pm

Hi everyone,

I got my hands on a Bosch mid-range radar (MRR) sensor that I believe belonged to a Tesla model S a while back. Now I'm working on a school project where we try to get the sensor to fail (i.e., output wrong or unusable data). Those of us involved in the project have defined a goal of understanding more about why radar fails in general but also what aspects of Bosch's specific sensor design might contribute to a failure.

So far, some preliminary research has revealed the following common failure types for automotive radars:

- External RF noise
- Ghost targets (e.g., multiple reflections from the same object resulting in targets with integer multiples of speed/distance)
- Obscurants on the sensor (e.g., snow, mud)

If anyone knows anything about other failure modes that exist, especially for Bosch radars and sensors, it would be interesting to discuss them on this thread.

Thanks!!

jessejay356
Posts: 31
Joined: Wed Jun 14, 2006 9:17 pm

Re: Failure modes of radar sensor

Post by jessejay356 » Tue Jul 10, 2018 5:51 pm

interesting. Is there code available to use this sensor?

JohnnyGood1
Posts: 3
Joined: Mon Jul 09, 2018 4:31 pm

Re: Failure modes of radar sensor

Post by JohnnyGood1 » Wed Jul 11, 2018 8:43 am

We can receive useful messages from it, yes.

millercommamatt
Posts: 7
Joined: Tue Jul 24, 2018 10:53 am

Re: Failure modes of radar sensor

Post by millercommamatt » Tue Jul 24, 2018 12:14 pm

Radar beams have side lobes which can be an additional source of noise or even produce a false return.

You can get back scatter from targets beyond the sensor range. That is, if you have the range configured for 100 meters and pick up backscatter from an object 150 meters away, the signal processor will think the object is 50 meters away.

Target may exceed the Nyquest velocity, but that's unlikely with this system.

Multiple CWFM radars close together but with different center frequencies can jam each other if the FM windows overlap. For pulsed radars you can use pulse coding. There's an analogous technique for CWFM radars but I'm not sure I've seen a commercial example. Of course, my expertise is in weather radar.

3-body scatter is a potential issue. Look up a radar hail spike.

Beam filling is an issue with small radars with wide beams. For instance, two objects moving in different directions and cancel out each others radial velocity returns. There are some signal processing things you can do to mitigate these types of errors if you're working with data at a low enough level.

JohnnyGood1
Posts: 3
Joined: Mon Jul 09, 2018 4:31 pm

Re: Failure modes of radar sensor

Post by JohnnyGood1 » Mon Jul 30, 2018 9:07 am

Thanks a lot for your suggestions. Very helpful!

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