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AWR1843: The weird dynamic target appears in the front of the car

Rata Zhang
Expert 2840 points
Part Number: AWR1843

Hi,

   Now I encounter a strange situation: When the truck drives to the wall which is made of the metal, there is no any other object in front of the truck. The radar can receive the truck speed by CAN Line,then the radar can distinguish between static and dynamic targets. In this condition,  the radar recognizes the dynamic target , in fact  no any dynamic in front of the truck.And there is an interesting phenomenon, the the distance of dynamic target is twice as that of  static target, and the relative speed is also so.What is the reason for that？

BR

Rata

  • 0
    TI__Genius 15046 points

    Hi Rata,

    One possibility that fits well here is that some reflection is occurring, causing you to see a ghost object.

    Here is how waves travel for a typical detection with the radar: radar --> metal wall(object) --> radar. If this is the case, the object will be detected with correct distance and velocity.

    However, it is possible that some waves take a path with multiple reflections like so: radar --> metal wall --> body of truck --> metal wall --> radar. As you can see, the path taken by the wave in this case is twice of the original one, so a ghost object will be detected by the radar at twice the actual distance.

    If x were the original distance travelled by the wave, in this case, the distance is 2x. The velocity of an object is the rate of change of this distance. Hence, if the original velocity was dx/dt (let's say v), the velocity in the multiple reflection case would be d(2x)/dt = 2v.

    So, the velocity of the ghost detection/object is also double that of the actual object.

    Another property observed will be that the ghost detection will have a lower SNR than the actual detection. 

    Regards,

    Aayush

  • 0 in reply to Aniket Mahajan
    Expert 2840 points

    Hi Aayush，

       In this situation, if I want to delete the ghost target, is there any method for that?This situation can also be considered as belows:there is an oncoming car which velocity is the same with  the ego car's.How should we distinguish between the two cases?

    BR

    Rata

  • 0 in reply to Rata Zhang
    TI__Genius 15046 points

    Hi Rata,

    Ghost objects detected due to multiple reflections are an inherent challenge with radar. I am not aware of any algorithms that can identify ghost objects.

    Regards,

    Aayush