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Original question:

IWR1443BOOST: Synchronization of multiple radars

AWR1843: invalid detection at location (0, 0)

dev aitonomi
Prodigy 30 points
Part Number: AWR1843

Hi, 

I am using AWR 1843, and i am doing Out of The Box Lab (https://dev.ti.com/tirex/explore/node?node=A__ACG08uvVuwpX-4E74miWtw__radar_toolbox__1AslXXD__LATEST), but i get strange detection at XY (0, 0) almost as you can see in the following screenshot 

However, as in the following pic, there is now thing blocking the radar :

A following question is sometime, Radar given me really few spares point cloud like (6 detection ), and for the same FOV given more than 20 points, why, do i need to set up sth in the Firmware, to get stable like 20 points or so. 

Thanks!

Dev team aitonomi

  • 0
    TI__Guru*** 140784 points
    dev aitonomi said:
    However, as in the following pic, there is now thing blocking the radar :

    Hi,

    Special consideration is needed when trying to detect an object at a range less than 10cm.

    There is an effect called Rx Tx coupling that will limit the detection of static objects.

    dev aitonomi said:
    A following question is sometime, Radar given me really few spares point cloud like (6 detection ), and for the same FOV given more than 20 points, why, do i need to set up sth in the Firmware, to get stable like 20 points or so. 

    Hi,

    The demo should provide you with the best performance.

    The number of detected points will depend of the environment and the velocity of the objects detected

    thank you

    Cesar

  • 0 in reply to Cesar
    Prodigy 30 points

    Hi Cesar, 

    Thanks for your reply, I will consider 10 - 20 cm, to filter out the targets.

    but i still have the same issue with the number of targets , here a histogram for parking-lot, and the sensor mounted on rover 80-cm height , facing forward, no-orientation, i got really unstable detection on the same spot i got a big variance in the number of detection, 

    Also, a second observation, is for the velocity, i followed https://dev.ti.com/tirex/explore/node?node=A__AFIEVaaBoBCgo.VCtJenZQ__radar_toolbox__1AslXXD__LATEST TI mmWave ROS Driver Users Guide, and when i read out the velocity, i found all targets mostly have the same radial/doppler velocity regardless the azimuth angle of the target, here is a sample : 

    [ x, y,  z,  range,  azimuth, elevation,  intensity, velocity
    [ 0.07392576 -0.04635548 0. 0.08725737 -0.56007534 1.57079633 33.40000153 0. ]
    [ 0.38538569 -0.20450948 0. 0.4362869 -0.48787514 1.57079633 15.19999981 0. ]
    [ 0.38538569 0.20450948 0. 0.4362869 0.48787514 1.57079633 15.19999981 0. ]
    [ 1.07753527 0.3544831 0. 1.13434586 0.31782372 1.57079633 18.60000038 -0.78758407]
    [ 1.13212812 -0.07089662 0. 1.13434581 -0.06254077 1.57079633 18.60000038 -0.78758407]
    [ 0.95361376 0.76350206 0. 1.22160329 0.67513154 1.57079633 16.5 -0.78758407]
    [ 1.18281221 0.30540082 0. 1.22160321 0.25268027 1.57079633 16.5 -0.78758407]
    [ 3.02538753 -0.99527949 0. 3.18489418 -0.31782372 1.57079633 16.79999924 -0.78758407]
    [ 3.11372089 -1.13979948 0. 3.31578055 -0.35090732 1.57079633 18.89999962 -0.78758407]
    [ 3.32061958 -0.74441451 0. 3.40303796 -0.22053325 1.57079633 18. -0.78758407]
    [ 2.81362247 -1.91420877 0. 3.40303786 -0.59740641 1.57079633 18. -0.78758407]
    [ 4.12537766 -1.66879725 0. 4.45012641 -0.38439674 1.57079633 17.20000076 -0.78758407]
    [ 5.44922161 -1.22160327 0. 5.58447229 -0.22053325 1.57079633 31. -0.78758407]
    [ 6.00265837 -1.34567237 0. 6.15164544 -0.22053325 1.57079633 23.89999962 -0.78758407]
    [ 6.50546789 -1.67970455 0. 6.71881834 -0.25268025 1.57079633 19.20000076 -0.78758407]
    [ 8.14454269 -1.28840971 0. 8.24582169 -0.15689288 1.57079633 30.29999924 -0.78758407]
    [ 8.5323782 -1.34976256 0. 8.63848 -0.15689288 1.57079633 23.89999962 -0.78758407]]

    so, last column, same velocity for all target.

    and i plot it : 

    How it could be possible that all target gets the same velocity. 

    for my call back function : after subscribe to the published topic from ti-ros_pkg : 


     
    def pointcloud_callback(msg):
    # create array for the raw radar data
    raw_radar = np.zeros((msg.width, 8))

    # Iterate through each point in the point cloud
    for i, point in enumerate(pc2.read_points(msg, skip_nans=True)) : # each point is a tuple, x, y, z, intensity, velocity
    x, y, z, intensity, velocity = point[0], point[1], point[2], point[3], point[4]

    # convert cartesian to polar
    rho, azimuth, elevation = cartesian_to_spherical(x, y, z) ## internal fucntion 
    # Append targets
    raw_radar[i] = np.array([x, y, z, rho, azimuth, elevation, intensity, velocity])
     
    to summarize, 
     
    1 - how to overcome unstable total number of detection, what could be done.
    2 - why radial velocity the same for all targets 

    Thanks!

    Dev team aitonomi

  • 0 in reply to dev aitonomi
    Prodigy 30 points

    Hi  Cesar, 

     

    Any help how to fix that!

    Thank, Dev team aitonomi