Threshold Computation for the Summation CFAR Detector: Non-Overlapped versus Overlapped FFT Processing

S. Wang, R. Inkol, S. Rajan, and F. Patenaude (Canada)


Fast Fourier transform, window, constant false alarm rate, detection and estimation.


The summation CFAR detector is widely used for the de tection of narrowband signals. The normalized detection threshold determines the detection performance and must be appropriately chosen in practical applications. However, numerical problems often occur in the theoretical compu tation of the normalized detection threshold, particularly when channel power estimates are summed over a large number of overlapped input data blocks. This paper shows that the correlation between power estimates at the output of an FFT filter bank for successive input data blocks can be neglected for most common windows when the over lap ratio is less than or equal to 1/2. Under this con straint the normalized detection thresholds computed for overlapped and non-overlapped input data blocks are prac tically identical and the results for the probability of false alarm for a given threshold derived for non-overlapped in put data blocks are applicable to overlapped input data blocks. This substantially simplifies the problem of com puting the normalized detection threshold for overlapped input data blocks.

Important Links:

Go Back