Performance Analysis of Reference Channel Equalization Using the Constant Modulus Algorithm in an FM-based PCL system

A frequency-modulation (FM)-based passive coherent location (PCL) system is a passive radar system for detecting a target using commercial FM broadcasting signals. A cross-correlation function between the direct-path signal propagating line-of-sight of the FM transmitter and the receiver, and the target echo signal, can be derived to detect the target. When clutter is received on the reference channel, the target detection probability can be reduced. In order to improve the detection performance, the direct-path signal on the reference channel should be essentially recovered. In this paper, we apply the constant modulus algorithm (CMA) to remove the clutter received on the reference channel and analyze the amount of removed clutter by simulation. Furthermore, we show that the reference channel equalization plays a very important role in removing ghost targets in the cross-correlation function.