In this video we show how the CFAR can help to display targets clearly in the radar scopes (A-Scopes and PPI).

CFAR (also referred to as C-FAR) stands for Constant False Alarm Rate.

CFAR dynamically adapts to the constellation of noise and targets at each specific point.

It uses a sliding window around a target, which calculates the mean value of neighboring reflections to determine the threshold for a specific cell under test (highlighted in green). Cells under test are called CUT.


The cell under test is surrounded by "guard cells" (red). The blue cells (including the red and the green ones) define the sliding window of observation.

There are various variants of algorithm for the detection of the false alarm rate. We used the perhaps most common version. It has the following parameters:

  • alpha - defining the threshold for the probability of false alarm (pfa) and detection (pf)
  • window - the size of the observation window to estimate the noise floor (noise power)
  • guard cells - they are the cells around the CUT which we ignore because of side-lobes from the target.

You will see how playing around with these parameters will impact the image in PPI and A-Scope.  Enjoy the video.

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