CFAR Detection of Extended Targets for Medium Resolution Radars

We propose a Constant False Alarm Rate (CFAR) algorithm called Extended Target Cell-Averaging-CFAR (ET-CA-CFAR) for extended target detection. We investigate its performance in Medium Resolution Radars (MRR), under Gaussian clutter. Extended target detection has been widely studied in High Resolution Radars (HRR). However, HRRs require a first stage detector to confirm the presence of a target. The first stage detections are usually performed using a Low Resolution Radars (LRR). In this paper, we bring out the advantages of using MRR with ET-CA-CFAR against LRRs. We derive closed form expressions for probability of detection and false alarm for ET-CA-CFAR under Gaussian clutter and analytically show the detection gains over traditional CA-CFAR. Our approach has lower computational complexity compared to HRRs and improved detection performance compared to LRRs. Thus, our approach can be used to improve range performance of small aperture surveillance radars, specifically airborne surveillance radars with size limitations.