• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 523 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

IWR6843: Device-to-device Ranging

Mustafa Homsi
Expert 1171 points
Part Number: IWR6843
Is the IWR6843 hardware capable of determining the range between two IWR6843 nodes (or similar TI ICs). ToF ranging between two active nodes is a common way to support a highly-accurate RTLS application. Please see this reference as an example https://www.decawave.com/product/dwm1004-module/. Since the current hardware is capable of making ToF measurement between an active node (IWR6843) and a passive object (ex: person), you would think it can do it between two active nodes. If the hardware is not capable of supporting this use case, can you please clarify why. Thanks!
  • Former Member
    0 Former Member

    Hello,

    You can familiarize yourself with how FMCW mmWave sensors operate with the following resources: http://www.ti.com/lit/spyy005

    Two active mmWave sensors could theoretically cause interfence with each other. Please refer to these resources to see how interference between sensors manifests: https://training.ti.com/mmwave-awr1x-interference-detection-crucial-step-effective-mitigation?context=1128486-1139154-1135822 

    https://training.ti.com/managing-interference-fmcw-radar-systems

    https://www.ti.com/lit/pdf/swra662

    It seems you are proposing to intentionally create interference? 

    Amanda

  • 0 in reply to Former Member
    Expert 1171 points

    I am proposing to measure the distance between two devices!

    Please refer to the example link I provided. In this implementation, wideband pulsed radar is utilized but in theory similar implementation can be achieved with wideband FMCW radar (or at least we think so). In the example, the transmitter sends a narrow pulse and starts a timer at the same instant, after x amount of time the signal is received at the receiver which gets retransmitted after a fixed and known amount of time. After another x period, the transmitter receives the retransmitted signal and has enough information to extract the distance btw the two devices. This is obviously over simplified but is the basis for this example. Modulation techniques might need to be implemented in a multi-sensor environment but that also can be done. Is there anything in the hardware that prevent us from doing something like this? Thanks!

  • Former Member
    0 Former Member in reply to Mustafa Homsi

    Hello,

    As in my previous post it seems referring to the interference resources would be relevant to your objective as the illustrate how one radar sensor can (typically unintentionally) receive transmission from another sensor. Of course in your case you would want to do the opposite of the interference mitigation techniques.

    In your scheme it should be possible to use have mmWave sensor configured with a zero slope chirp so the receivers are on but no transmission while another sensor is chirping. You can refer to the the TRM and DFP documentation for limitations that could affect this scheme: https://www.ti.com/lit/pdf/swru522 and http://downloads.ti.com/ra-processors/esd/MMWAVE-DFP/latest/exports/mmWave-Radar-Interface-Control.pdf

    Amanda

  • 0 in reply to Mustafa Homsi
    Prodigy 50 points

    Very interesting use of the radar. So, it is possible then it would seem to use two IWR6843 to measure distance between them by placing one end as transmitter and the other end as receiver?

    If distance were the only objective , wouldn't an IMU sensor give you similar data? i.e., knowing GPS co-ordinates one could calculate heading and distance when a magnetometer, accelerometer, gyroscope combo sensor at both ends?

    I'm interested in the same idea , but different application. Using IWR6843 as aiming tool besides sensing ,Assuming that there is an out of band control plane to reach both ends of the link.

    Venkat