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IWR6843ISK: Detecting objects as the sensor moves in the OOB demo

JINHYEONG LEE
Intellectual 740 points
Part Number: IWR6843ISK
Other Parts Discussed in Thread: MMWAVE-SDK

Hi,

I'm using IWR6843ISK with OOB demo in SDK 3.5

I tested it below.

the sensor by fix at a sufficient height(to prevent reflections on the ground), and move it back and front.

and target is 3 poles standing side by side.

 

below is my config

% ***************************************************************
% Created for SDK ver:03.05
% Created using Visualizer ver:3.5.0.0
% Frequency:60
% Platform:xWR68xx
% Scene Classifier:best_range_res
% Azimuth Resolution(deg):15
% Range Resolution(m):0.039
% Maximum unambiguous Range(m):31.94
% Maximum Radial Velocity(m/s):1
% Radial velocity resolution(m/s):0.13
% Frame Duration(msec):100
% RF calibration data:None
% Range Detection Threshold (dB):15
% Doppler Detection Threshold (dB):15
% Range Peak Grouping:enabled
% Doppler Peak Grouping:enabled
% Static clutter removal:disabled
% Angle of Arrival FoV: Full FoV
% Range FoV: Full FoV
% Doppler FoV: Full FoV
% ***************************************************************
sensorStop
flushCfg
dfeDataOutputMode 1
channelCfg 15 5 0
adcCfg 2 1
adcbufCfg -1 0 1 1 1
profileCfg 0 60 425 7 200 0 0 20 1 1008 5250 0 0 158
chirpCfg 0 0 0 0 0 0 0 1
chirpCfg 1 1 0 0 0 0 0 4
frameCfg 0 1 16 0 100 1 0
lowPower 0 0
guiMonitor -1 1 1 0 0 0 1
cfarCfg -1 0 2 8 4 3 0 15 1
cfarCfg -1 1 0 4 2 3 1 15 1
multiObjBeamForming -1 1 0.5
clutterRemoval -1 0
calibDcRangeSig -1 0 -5 8 256
extendedMaxVelocity -1 0
bpmCfg -1 0 0 1
lvdsStreamCfg -1 0 0 0
compRangeBiasAndRxChanPhase 0.0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
measureRangeBiasAndRxChanPhase 0 1.5 0.2
CQRxSatMonitor 0 3 19 125 0
CQSigImgMonitor 0 125 16
analogMonitor 0 0
aoaFovCfg -1 -90 90 -90 90
cfarFovCfg -1 0 0 31.50
cfarFovCfg -1 1 -1 1.00
calibData 0 0 0
sensorStart

 

Q1. When moving, the object is detected, but the Rx power of the range profile is not detected. (left picture)

But when stopped, the Rx power of the range profile is detected. (right picture)

Why is the Rx power of the range profile not detected when moving?

 

Q2. When moving, It is frequently occur detected objects are separation.

below is when approaching the target. In order, normal(left), starting to separate(middle), separated(right).

How can I prevent that?

 

+) Q3. Where is the frame number of the output packet in the visualizer? 

 

Thanks.

  • +1
    TI__Guru 50240 points

    Hello

    Q1. This is expected behavior. The Range Profile shows detected points given zero doppler.

    Q2. This behavior might be erratic as a result of the spurious change in the doppler bins. For this I would recommend raising the CFAR threshold in the doppler domain. Let me know if you need assistance performing this.

    Q3. Frame number is not output in the demo visualizer but is kept track of as part of the output data stream.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Thank you for reply,

    Q1, Q3. I got it. thank you.

    Q2. I'll try raising the CFAR threshold in the doppler domain. (using "cfarCfg" command)

    Akash Gondalia said:
    This behavior might be erratic as a result of the spurious change in the doppler bins

    Could you explain more about this?

     

    Thanks.

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Hi,

     

    I have new question about Q1.

    Why does the range profile only show points detected at zero Doppler?

    And how can I see the signal strength for all dopplers in the range profile?

     

    Thanks.

  • 0 in reply to JINHYEONG LEE
    TI__Guru 50240 points

    Hi Jinhyeong

    Q1 The Range Profile shows the result of the 1D Range FFT before any other fft processing  has been performed. This includes doppler (2D), Angle, and CFAR.

    Q2 If the CFAR threshold is left too low then it will detect more objects at the risk of too many false positives. This means you may see some objects that aren't actually objects. Though it is worth noting that these false positives tend to have low SNR and easier to filter out by some other user-defined method.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Hi, 

    Q1. I'm confused about the Range Profile and zero doppler. Sorry about that.

    Below is 1D Range FFT. That matrix is radar cube and row is range, column is chirp index.

    Is the meaning of zero doppler in the Range profile corresponding to the the Range-FFT value at 1st chirp(red box in picture)?

    (0th? or value is 0?)

    If yes, I don't understand that the Range-FFT result of a moving object isn't included in the Range profile.

    Could you more explain about this?

     

    Q2. Thank you for kindly explain.

     

    Thanks.

  • 0 in reply to JINHYEONG LEE
    TI__Guru 50240 points

    Hi Jinhyeong

    I will need more time to get you a response but we will continue discussion next week.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Hi,

    Ok, I'll wait for your reply.

    Thanks.

  • 0 in reply to JINHYEONG LEE
    TI__Guru 50240 points

    Thanks Jinhyeong

    Still looking into this, please allow a few more days.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Hi,

    Any updates? Still waiting for answer.

  • 0 in reply to JINHYEONG LEE
    TI__Guru 50240 points

    Thanks Jinhyeong

    How did you determine your chirp configuration? Is it taken from existing configuration in the Industrial Toolbox or did you derive it yourself? For this chirp there might be velocity restriction which makes detection of moving objects difficult at far distances.

    Also for CFAR levels you will want to edit the cfarCfg parameter thresholdScale. It is discussed in the mmWave-SDK User Guide on page 27.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Intellectual 740 points

    Hi,

    I used the visualizer to configure the chirp. please refer to the picture and code attached to the first question for details.

     

    Edit the CFAR parameters seems to be the answer to Q2, but I asked about the Range profile(Q1). 

    JINHYEONG LEE said:

    Q1. I'm confused about the Range Profile and zero doppler. Sorry about that.

    Below is 1D Range FFT. That matrix is radar cube and row is range, column is chirp index.

    Is the meaning of zero doppler in the Range profile corresponding to the the Range-FFT value at 1st chirp(red box in picture)?

    (0th? or value is 0?)

    If yes, I don't understand that the Range-FFT result of a moving object isn't included in the Range profile.

    Could you more explain about this?

     

    Again, I look forward to your reply.

    Thanks.

  • 0 in reply to JINHYEONG LEE
    TI__Guru 50240 points

    Thanks Jinhyeong

    I understand, I am saying that the maximum velocity spec might be limiting your detection in this case.

    Regards,

    AG