Analysis of some modified cell-averaging CFAR processors in multiple-target situations

Techniques are considered for the prevention of the degradation of detection probability, caused by the presence of an interfering target, in the reference cells of a cell averaging-constant false alarm rate (CA-CFAR) detector. It is demonstrated, for the case of a Rayleigh target, that the 'greatest of' selection between the leading and lagging sets of cells, or GO-CFAR technique, makes the detection of closely separated targets nearly impossible. The alternative use of a 'smallest of' technique is considered through the derivation of an analytic expression for its detector, and it is shown that while preventing the suppression effect of excessive false alarms at clutter edges, a large sensitivity loss is introduced unless the number of reference cells is sufficiently large. A modified GO-CFAR detector which incorporates a sensoring circuit is proposed for automatic detection in a complex, nonhomogeneous environment.