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Original question:

IWR6843ISK: calcuating SNR using IWR6843

IWR6843ISK: How to calculate RCS using IWR6843+DCA1000EVM

John Park
Prodigy 90 points
Part Number: IWR6843ISK

Hello, Ti. 

I am trying to calculate SNR from the data(raw data). Range-fft on the obtained raw data, calculate the signal strength of the peak of the ffted result, and use that value as RCS. Then I calcuated SNR using above equation, but the value that I calculated  is different from the snr value that comes out after mmwave postproc(see figure below). I think other value is fine but the way RCS is calculated is wrong.

Looking at other questions, it says to find the peak after doppler fft and calculate the power, but I don't know how to do it. Can I simply find the peak of the ffted signal and calculate the power of the peak as RCS?

Also, I was wondering if there is a code for calculating the SNR or if there is any reference material.

  • 0
    TI__Mastermind 23177 points

    Hello,

    Please give us time until no later than Tuesday, July 26th in order to get back to you as I confirm with our teams. We appreciate your patience.

    Best Regards,

    Pedrhom Nafisi

  • 0
    TI__Mastermind 40495 points

    HI, there:

    The equation you mentioned there is the signal power vs. the noise floor.  But the SNR calculated in the application is using CFAR algorithm, which estimate the average signal power from the neighboring range bins, which is not really a close estimation of the noise floor.   So I would not try to correlate the SNR equation with the SNR listed in the postProc application. 

    The other thing I do not understand is that you want to use SNR as RCS value,  Where is that coming from?  The RCS is used in the SNR equation as highlighted in red below.   It is possible to use SNR to derive RCS based on this equation.

    Best,

    Zigang

     

  • 0 in reply to zigang Yang
    Prodigy 90 points

    Hello, Thanks for Reply. 

    1. In my opinion, the more accurate SNR method is more accurate using the corresponding formula, so why did you use the CFAR algorithm?

    2. I think the content of the question was vague. What I want to do is get the SNR of the target from the data. After looking at the Ti document, I understood that the formula for calculating the SNR was the formula mentioned earlier, and I am trying to find the value using that formula.I left a question because I did not know exactly how to calculate the RCS.

  • +1 in reply to John Park
    TI__Mastermind 40495 points

    Hi, John:

    1) You may be able to calculate SNR based on the ground truth information, like a known RCS and distance.  But in the radar target code, all these information is unknown and we still need to have a sense of SNR information.  That is why CFAR algorithm is used for peak detection as well as SNR calculation.  

    2) There is no easy way to calculate RCS.  If you are using corner reflector, there is some equation you can find online, an example is giving here:  https://www.radartutorial.eu/17.bauteile/bt47.en.html 

    Best,

    Zigang