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AWR1642BOOST: High accuracy demo - range estimation and multi radar setup

Alain van der Kaap
Intellectual 320 points
Part Number: AWR1642BOOST
Other Parts Discussed in Thread: AWR1642

Dear TI,

I have two questions.

The first one is related to the high accuracy demo visualizer.
I was doing testing on short range with the AWR1642 (1 2 and 5 meters)
I wanted to test the range accuracy and resolution on different materials. Herefore i used 3 object:

- metal
- white plastic
- wooden plank

all with roughly the same dimentions of 15x50 cm.

I quickly found out when i was testing the metal object, that the radar had an offset of 8cm. This was confirmed at the web seminar last week as being due to the antenna amplifiers.
The metal object and the plastic object showed no abnormalities in further measurements but my issue was with the wooden boject.

at 1 meter i measured 1,284m
at 2 meters i measured 2,336m
at 5 meters i measured 5,324m

I did my best to find an open space with little to no object within the area to redude as much noise as possible. Is there any explanation for this?

My second question is about a situation i can't test myself.
What will happen if i put multiple radars facing each other in the same room? or a more specific setting, what will happen if 2 approaching cars use the same radar sensor?

will these interfere? is there any way to distinguish multiple radar from each other?

Thank in advance,

Alain




 

  • 0
    TI__Expert 4720 points
    Hi Alain,

    The results are not expected. Could you tell me what the 'range resolution' of your measurement was? If the resolution is ~
  • 0 in reply to Anil Mani
    Intellectual 320 points
    i think a part of your repsons is missing but the range resolution should be known because i use your high accuracy demo. I states that it is 0.1mm and i can confirm that this is the case when i measure with the metal object.

    Any insight on my second question?
  • 0 in reply to Alain van der Kaap
    TI__Expert 4720 points
    Hi Alain,

    Apologies. I think most of my reply got lost.

    Could you try the basic OOB application from the mmwave SDK? My suspicion is that the 'high accuracy demo' requires a certain level of SNR to give accurate results, and the wooden plank may not be giving that SNR. If you try the OOB application, it wouldn't do anything more complicated that an FFT, and the resolution/error that you see would be bounded by the range-resolution of the chirp that you've configured.

    Multiple radars in close proximity operating in the same frequency band can interfere with each other. The AWR1642 has a set of metrics delivered on a per-chirp basis (called the chirp quality metrics) that should allow a user to ascertain whether a chirp is corrupted by an interferer. If a chirp is corrupted, it can be discarded. Another method to combat interference is to use dithering (essentially randomization) of certain chirp parameters like the 'adc start time', the binary phase, the slope etc. Dithering dampens the effect of periodic interferers on a frame.

    Regards
    Anil
  • 0 in reply to Anil Mani
    Intellectual 320 points
    I do get a fail ammount of signal back from the wooden plank (80-90dB) and i've even tried reducing the noise by using high frequent dampening material. the OOB demo has a far lesser resolution (about 4cm).

    I am willing to try it out, but with the setup i have been using i can't see why i am getting these results.

    Thanks for answering my question about interference :)