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MMWCAS-RF-EVM: Wrong target range estimation with Antenna Calibration

Hang
Intellectual 755 points
Part Number: MMWCAS-RF-EVM
Other Parts Discussed in Thread: AWR2243, , MMWCAS-DSP-EVM

Hello,

I was using MMWCAS-RF-EVM (AWR2243) and MMWCAS-DSP-EVM for antenna calibration referring to C:\ti\mmwave_studio_03_00_00_14\docs\mmwave_studio_cascade_user_guide.pdf on page 30.

Everything goes smoothly and the calibrateResults_high.mat can be generated from the captured data with MIMO configuration (with file Cascade_Configuration_MIMO.lua and Cascade_Capture.lua). 

However, I got wrong target range estimation when I run cascade_MIMO_antennaCalib.m, "Target is estimated at range 4.7477"

Actually, the target was placed at a distance of 5.2 m to the corner reflector. Below was the setup. As you can see there was no other strong reflector around. 

I also tried to set "targetRange = 5.2;" in cascade_MIMO_antennaCalib.m. I still have "Target is estimated at range 4.7477".

Since I got wrong target (corner reflector) range estimation, the generated calibrateResults_high.mat might not be valid. 

My question is that what was the possible reason I go this wrong target estimation? Or what I should do to fix it?

Thank you very much for the help!

Best,

Hang

  • 0
    TI__Genius 13715 points

    Hi,

          It appears there is some missing steps or cal procedure miss.

    May I ask if you have tried varying the distance and observed the similar behavior or delat in actual vs measured?

    Regards

  • 0 in reply to Abhed Misra
    Intellectual 755 points

    Hi Abhed,

    Thank you very much for reply.

    I didn't change the distance very much. It was 5 meters to 5.2 meters.

    To me "Target is estimated at range 4.7477" was a fixed value (I am not 100% sure). I have no idea why. 

    I stick to the steps in mmwave_studio_cascade_user_guide.pdf 

    (1) Collection data for antenna calibration using Cascade_Configuration_MIMO.lua and Cascade_Capture.lua

    (2) Set up the path in matlab and environment variable.

    (3) Set up the path for the collected data and run cascade_MIMO_antennaCalib.m

    (4) The matrix did generated. However, the target range estimation was wrong.

    Any possible missings?

    Thanks again!

    Best,

    Hang

  • 0 in reply to Hang
    TI__Genius 13715 points

    Hi,

          Thanks for the confirmation. May i request you to put it in larger distance then 6 meters and check.

    Regards

  • 0 in reply to Abhed Misra
    Intellectual 755 points

    Hi Abhed,

    Thank you for your suggestion!

    This time the estimation is very good. I also deleted all the previous captured data on the SSD that connected to the DSP board.

    May I ask where is the origin of XYZ when I use this radar for capturing data? I understand that I used the geometric center of the RF board for antenna calibration alignment. It might not be the origin of XYZ. From AWRx Cascaded Radar RF Evaluation Module.pdf page 23, there is one definition as below. I want to make sure whether it is the origin of the XYZ after the antenna calibration?

    Thank you very much!

    Best,

    Hang

  • +1 in reply to Hang
    TI__Genius 13715 points

    Hi,

         This is good. Yes the figure in the document/figure indicates correct origin to be considered.

    Regards

  • 0 in reply to Abhed Misra
    Intellectual 755 points

    Thank you very much!

    Best,

    Hang