UNRESOLVED RAYLEIGH TARGET DETECTION USING MONOPULSE MEASUREMENTS

When the returns from two or more targets interfere (i.e., the signals are not resolved in the frequency or time domains) in a monopulse rad ar system, the direction-of-arrival (DOA) estimate indicated by the mo nopulse ratio can wander far beyond the angular separation of the targ ets. Generalized maximum likelihood (GML) detection of the presence of unresolved Rayleigh targets is developed with probability density fun ctions (pdfs) conditioned on the measured amplitude of the target echo es. The Neyman-Pearson detection algorithm uses both the in-phase and quadrature portions of the monopulse ratio and requires no a priori kn owledge of the signal-to-noise ratio (SNR) or DOA of either target. Re ceiver operating characteristic (ROC) curves are given along with simu lation results that illustrate the performance and application of the algorithm.