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IWR6843AOPEVM: Unsure of which sensor/configuration/demo is best for drone altimetry

Parker Lloyd
Prodigy 10 points
Part Number: IWR6843AOPEVM
Other Parts Discussed in Thread: IWR6843AOP,

Hi,

My team and I have successfully ran the level sensing demo using the high accuracy visualizer and the IWR6843AOP sensor. The distances we obtained seemed reasonable, howevever, our issue is that we are only interested in the distance between our drone and the ground (up to 60m). So if there are any nearby objects, the sensor will return the distance to those objects instead, which is not desired. We have been attempting to integrate this sensor for almost 2 months so we want to be sure we are aware of any limitations of this sensor.

So far we have tested 3 modes for the sensor:
     - Sensor returns a single distance measurement
     - Sensor returns 3 distance measurements (3 strongest peaks)
     - Sensor returns a point cloud

As mentioned before, the single distance measurement and 3 distance measurements are often unlikely to return the ground distance if there are nearby objects. And for the point cloud, it appears that the range is limited to 20m for this specific sensor.

The demos/tutorials/videos on the TI website appear to suggest that these mmWave sensors are intended to be used for height measurements. We even found a TI video using it specifically for drone altimetry, however there were no resources included to show how it was achieved.

So, considering all of this, what would be our best path forward? Is drone altimetry possible with the IWR6843AOP? If it is possible, does TI possess any resources for proven examples of this application? At this moment, it appears narrowing the field of view with a lens is our only option, but we are open to other suggestions/sensors/configurations.

Any help is appreciated.

Thanks,

Parker

  • 0
    TI__Guru 50240 points

    Hi Parker

    I'll need some time to put together a response but will have an update for you on Monday.

    Regards,

    AG

  • 0
    TI__Guru 50240 points

    Hi Parker

    The 68xx chirp config with the high accuracy lab has a maximum range of 20m. It is possible to edit the chirp config for a further maximum distance but it would trade-off with range resolution and would impact accuracy.

    • What are the accuracy requirements for your application? It is possible that the High Accuracy Lab might be overkill.
    • Let me know if you need assistance with editing the chirp config.

    You will likely want to leverage the point cloud in order to determine objects in your scene as well as the ground. An example is the MRR video (the lab is in the Automotive Toolbox), is this the kind of software that would be of use to you?

    Regards,

    AG

  • 0
    Prodigy 10 points

    Hi Akash,

    Thanks for your response. We are hoping to measure distances up to 60m with a resolution of at most 1m (worst case). So are you saying that we can configure the range for the point cloud to be 60m for the IWR6843AOP? We will check out the MRR lab and let you know how it goes.

    Thanks again,

    Parker

  • +1 in reply to Parker Lloyd
    TI__Guru 50240 points

    Hi Parker

    Yes you will need to configure the chirp for a maximum of 60m. Let me know if you need assistance with this.

    • Expected accuracy will be 10 cm or better.

    Regards,

    AG

  • 0 in reply to Akash Gondalia
    Prodigy 10 points

    Hi Akash,

    I read through the MRR lab and it seems very applicable to what we are doing. I tried running the lab but it did not display any points in the GUI. I am assuming it failed either because we only have an IWR6843AOPEVM (industrial, not automotive) or because we do not have a BOOST board. We do not intend to use a BOOST board because we want to keep size/weight to a minimum.

    I understand how to change the configuration to increase the number of points returned. But even after setting the maximum range to 60m we are unable to read distances greater than 20m. We are running the binary for the "Out-of-the-Box 68xx AoP - mmWave SDK Demo". This is the configuration we are using:

    dfeDataOutputMode 1
    channelCfg 15 7 0
    adcCfg 2 1
    adcbufCfg -1 0 1 1 1
    profileCfg 0 60 359 7 57.14 0 0 70 1 496 10093 0 0 158
    chirpCfg 0 0 0 0 0 0 0 1
    chirpCfg 1 1 0 0 0 0 0 2
    chirpCfg 2 2 0 0 0 0 0 4
    frameCfg 0 2 16 0 100 1 0
    lowPower 0 0
    guiMonitor -1 1 1 0 0 0 1
    cfarCfg -1 0 2 8 4 3 0 1 1           // very low threshold to maximize number of points
    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
    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 5 121 0
    CQSigImgMonitor 0 123 8
    analogMonitor 0 0
    aoaFovCfg -1 -90 90 -90 90
    cfarFovCfg -1 0 0 60                // 60m range
    cfarFovCfg -1 1 -1 1.00
    calibData 0 0 0

    Are we overlooking another parameter that is limiting our range? Or is the ground signal too weak compared to the nearby structures (e.g. walls, roofs)?

    Parker

  • 0 in reply to Parker Lloyd
    Prodigy 10 points

    We realized we were creating a configuration for "Best Accuracy" and not "Best Range". Now we are able to read up to 50m. That should suffice for now but it would be ideal to strectch that to 60m.

    It seems that there isn't a single parameter in the config file that corresponds to the range resolution. It appears to depend on the profileCfg parameters. Is there a simple formula/guide for manually increasing the range and range resolution in the config file? I know where to change the range value but I'm wondering if the resolution will still limit the range if not updated as well.