Multipath Mitigation in Calibration Range Estimation Algorithm

Range splitting algorithms are used in radar signal processing to accurately estimate the range of a detected target by "splitting" the range bin and estimating where within the range bin the target is located. One particular algorithm, calibration range estimation (CRE), calibrates the response in the mainlobe of the matched filter to incremental delays and then accurately estimates the target's range from the received signal by linear interpolation of the calibration curve. The CRE algorithm is computationally efficient and empirically proven to achieve the Cramer-Rao lower bound (CRLB) in the presence of a single scatterer. However, CRE is not inherently immune to the multipath phenomenon and its performance degrades when the received signal is corrupted by a multipath reflection. In this paper we investigate the effects of multipath on the performance of the CRE algorithm and determine how much its performance deviates from the CRLB in the presence of multipath. Moreover, we provide a solution to the multipath problem by using the CLEAN algorithm to remove the multipath signal and return the performance of CRE closer to the CRLB.