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AWR1642: Out of phase chirps because of multiple radars

Shraavan nnv
Intellectual 280 points
Part Number: AWR1642

We are using AWR1642 in SRR/USRR configuration

Scenario 1 : Two radar units are placed nearby on field with active Tx antennas, the chirps reflected(chirps of both units ) from the object are received by both the radar units , which then generates IF signal which will be processed . What can be done to avoid processing of the out of phase Rx chirps .

Scenario 2 : Two radar units are placed opposite to each other , the Tx chirps from a radar is received and processed by another radar . How to avoid this scenario ?

  • 0
    TI__Expert 4720 points

    Hi Shraavan,

    Interference in radar systems is an interesting problem with no easy solution. Here are my suggestions.

    1. Use a pseudo-random BPM code for each chirp (read up on the binary phase modulation and per-chirp BPM API). Using such a code will spread the effect of interference after 2D processing. Note that you need to correct for the BPM code during the 1D-FFT processing. 

    2. Use different bands (if possible) for different radars.

    a. For, e.g, use 76 to 76.4 for radar 1, 76.4 to 76.8 for radar 2 etc.

    b. If the full bandwidth is used (as is the case with the USRR mode), this method will not work. However, some randomization would still help.

    3. Introduce randomized time-dither per chirp (using different idle times pattern for different chips - (i.e. changing idletimeVar per chirp)). This will prevent chirps from colliding (in time and frequency) and affecting each other. This has the side-effect of increasing the noise floor.

    4. Time-stagger the frames from different chips so that they do not overlap (i.e.  generate frames with a random time offset). This will require that you configure only one frame in the FrameConfig command, and then trigger sensor start with a random offset.

    Regards

    Anil