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RTOS/IWR1642: doppler graph

ks prasad
Expert 1255 points
Part Number: IWR1642

Tool/software: TI-RTOS

Hi Sir,

 we are using srr visualizer gui  and SRR code provided by TI for AWR 1642.

In doppler graph below 20 meter range the objects moving towards should be diaplayed at -10 below the origin only , but they are also replicating above the origin at +10 also. 

We are confusing why they are displaying above and below the origin. 

Please find the youtube video in given link.

https://youtu.be/DrDGxXxS4pk

Thanks and regards,

K Subrahmanim

  • 0
    TI__Expert 4720 points

    Hi Subramaniam,

    Every chirp design has a parameter called 'maximum unambiguous velocity' . If an object approaches the radar with a velocity that is greater than the maximum unambiguous velocity it will wrap around (i.e positive velocity will be seen by the radar as a negative velocity).

    In the SRR design, there are two chirp designs -

    1. SRR80 - which has a maximum unambiguous velocity of ~90+kmph (25+ m/sec) and,

    2. USRR20 which has a maximum unambiguous velocity of 36kmph (10m/sec).

    The SRR80 chirp design is intended to be used in highway traffic, and the USRR20 is intended for crowded lower-speed scenarios. In scenarios  where the target moves faster than 10m/sec,  the USRR20 chirp design's estimation of velocity is going to be wrong (and wrapped around).


    Regards

    Anil

  • 0 in reply to Anil Mani
    Expert 1255 points
    Hi Anil Mani,
    Thank you for the answers.

    yes.In the scenario we tested ,objects are moving >36kmph in <20m range towards radar. so from your answers ,we understood it is wrapped and displayed in two positions.we want to customize the graph display to "remove completely USRR objects from doppler graph only" .
    since objects will be recognized by SRR subframe also in <20m.Is it a good solution (or) any suggested solution.

    since the current display creates an impression that objects are approaching the radar in both directions(even though object is coming in one direction).one side affect of doing "remove completely USRR objects from doppler graph only" this is, static objects are also get removed from doppler display?

    Thanks,
    K Subrahmaniam.
  • 0 in reply to ks prasad
    TI__Expert 4720 points

    Hi Subrahmaniam

    That solution will work.

    Note that you can configure the 'SRR TI Design' to omit the USRR subframe - read through srr\common\srr_config_consts.h - read through the options given in that file.

    Alternatively, you can reconfigure the USRR chirp to meet your requirements - it is possible to improve the max-velocity to about 30kmph (but reducing the range-resolution) - You can study the training material that TI has provided to understand how to change these parameters.

    Regards

    Anil