Maximum likelihood approach to the estimate of target angular co-ordinates under a main beam interference condition

Modern phased array radars are required to detect, locate and track targets in the presence of natural and intentional interference. This paper illustrates the application of the MLE to determine the target direction of arrival (TDoA) in the presence of main beam interference (MBI) and the related CRLB (Cramer Rao lower bound) angular accuracy. Two different sets of high gain beams are considered. The first set includes three high gain beams: the sum and the two difference beams (azimuth and elevation); the second comprises also the so-called double difference beam. In this paper the following results are shown: conception of the MLE of the target angular coordinates and MLE implementation via the Newton-Raphson recursion; CRLB of the target angular coordinates; evaluation of the mean value and the standard deviation of the estimation errors via Monte Carlo simulation and comparison with the CRLB results