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IWR6843: People Counting

Part Number: IWR6843

Dear Technical support,

I am wondering 2 things about the parameters embedded in the Point Cloud's structure:

A) How is calculated the SNR values:

- What is the unit? Linear, dBs?

- SNR is a ratio between the power of S Signal and the power of N noise : what is S, and what is N?

B) How is calculated the velocity?

- Is it calculated from the Doppler frequency as in classical radars with velocity being the radial velocity?

- Is it calculated as in your tutorial exploiting the phase change across chirps separated in time?

Thanks in advance for your support.

Best regards.

Anthony

  • Hi Anthony,

    A) SNR
    - SNR is a linear value.
    -SNR is estimated during CFAR. The Signal value is the peak value of the Cell under test during the CFAR calculation. The Noise is the average value of the reference cells during the CFAR calculation.

    B) Velocity
    The People Counting demo reports two different velocities - a velocity of each point in the point cloud, and a velocity of each tracked person.
    For each point in the point cloud, velocity is calculated as in the tutorial, using phase change in chirps across time.
    For each tracked person, a Kalman filter is used to determine their velocity. The initial velocity of a tracked object is the average velocity of the points associated with that track.

    Regards,
    Justin
  • Thank you Justin for this quick response.

    Anthony.