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Original question:

AWR1843: lab0007_medium_range_radar ---The angle of tdm-mimo target is incorrect

AWR1843: MIMO Phase issue

Henry Lin
Prodigy 240 points
Part Number: AWR1843


Hi:

  Our team are using AWR1843 for automotive product design, we have designed our own waveform MIMO mode with Doppler compensation mechanism and antenna placement. When we test the radar performance on road, there some ambiguity angle happen from large angle (>60 degree),the targets are in low speed without velocity ambiguity .  It seems the signal wrapped around from the other side (negative large angle to positive large angle), I have calibrated the radar in chamber and give the precise angle results in FoV (in 75 degree for almost 1 degree error). I am asking is there any phase differences between MIMO aperture except spatial effect and Doppler effect?

Best regards,

Henry Lin

  • 0
    TI__Guru**** 151014 points

    Hi,

    Yes, we have seen this behavior for fft based angle estimation.

    Using high resolution angle estimation algorithms such as MVDR would improve the performance. 

    Thank you

    Cesar

  • 0 in reply to Cesar
    Prodigy 240 points

    Hi Cesar:

      I have implemented MVDR(capon beamforming) in our design and check the angle estimation results in champers, the error are smaller (in 80 degree for almost 1 degree error) than FFT based algorithm but above issue still happen, any idea?

    Another question, in mmwave_studio_03_00_00_14/mmWaveStudio/MatlabExamples/4chip_cascade_MIMO_example/modules/detection/@CFAR_CASO/datapath.m, using overlapped antenna to estimate velocity, why need to subtract FFTsize/2 in TDM-MIMO mode?

    Thanks for replying.

    BR 

    Henry Lin

  • 0 in reply to Henry Lin
    TI__Guru**** 151014 points

    Yes, MVDR will improve the performance but eventually as angle increases the same behavior will happen.

    This is a limitation of this technology and there is no definite solution.

    For your new question, since it is related to a different device, can you please start a new thread?

    Thank you

    Cesar