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IWR6843ISK-ODS: RX antenna geometry to determine Range / Calibration

Mohan C
Prodigy 130 points
Part Number: IWR6843ISK-ODS
Other Parts Discussed in Thread: IWR6843

Hi team,

We are using IWR6843 ISK and ODS boards.

Is there anywhere in the FW that uses the Rx antenna locations/geometry to determine Range/Calibration? 

ISK:
The Tx antenna sends a signal out, reflects off an object/target and the return signal floods the 1x4 Rx array. The chirp is mixed and demodulated then sent to A/D for IQ processing.
ODS: 
The Tx antenna sends a signal out, reflects off an object/target and the return signal floods the 2x2 Rx array, but the center of the Rx antenna is not the same as the center of ISK too. The chirp is mixed and demodulated then sent to A/D for IQ processing.
In the IQ processor/generator that generates the (64x256x3x4), which is the (64DopplerBins x 256RangeBins x 3Tx x 4Rx) matrix, does the data get skewed or time-sampled from raw to account for the change in Rx antenna array alignment?

Thanks

Mohan

  • 0
    TI__Genius 15450 points

    Hello.

    Mohan C said:
    Is there anywhere in the FW that uses the Rx antenna locations/geometry to determine Range/Calibration? 

    I believe there is.  If you run the ODS example from the radar toolbox, it has a custom antenna_geometry.c file that calibrates the out of box demo specifically for the ODS board.  I believe this is the major change to account for the difference.

    Sincerely,

    Santosh

  • 0 in reply to Santosh Krishnan
    Prodigy 130 points

    Hi Santosh,

    Thank you for your reply.

    I would like to know, Does antenna geometry parameter is used to determine the range/calibration and angle calculation.

    In which the part of the radar firmware, antenna geometry parameters are used?

    Is it used in 1D-FFT processing or in 2D-FFT processing?

    I found: 

    The antenna_geometry.c file holds the antenna position offsets, and it is used in Azimuth and Elevation direction, scaling and Doppler Compensation.

    The range/calibration is not dependent on antenna geometry, but the maximum range of detection varies based on the antenna patch (3E, 1E) series.

    Please confirm.

    Thanks

    Mohan

  • 0 in reply to Mohan C
    TI__Genius 15450 points

    Hello Mohan.

    Mohan C said:
    Does antenna geometry parameter is used to determine the range/calibration and angle calculation.

    Yes you are correct.

    Mohan C said:
    In which the part of the radar firmware, antenna geometry parameters are used?

    It is used in the angle processing portion of the radar data processing chain.  You can search for the antenna parameter variables in the main code of the out of box demo to see exactly where in the code it may be being used, or check the AoAproc DPU in the SDK as well.

    Mohan C said:

    The antenna_geometry.c file holds the antenna position offsets, and it is used in Azimuth and Elevation direction, scaling and Doppler Compensation.

    The range/calibration is not dependent on antenna geometry, but the maximum range of detection varies based on the antenna patch (3E, 1E) series.

    This is correct.

    Sincerely,

    Santosh