3-DIMENSIONAL SOURCE LOCALIZATION IN A WAVE-GUIDE

This paper deals with three-dimensional (3-D) passive localization of a narrowband point source in a 2 1/2-dimensional waveguide using an ar ray of sensors, Two different maximum likelihood (ML) procedures for e stimating the source range, depth, and direction-of-arrival (DOA) base d on the normal mode representation of the received data are studied. In the first procedure, ML estimation of range and depth is applied on the data collected by a vertical array, and DOA is estimated using th e ML algorithm on the data received by a separate, horizontal array, I n the second procedure, the ML algorithm is applied on the data receiv ed by a two-dimensional (2-D), hybrid array for simultaneously estimat ing of all three source location parameters. Our study shows that alth ough a horizontal array is sufficient for 3-D localization, to reduce sensitivity of the localization algorithm, a 2-D array should be used. The presented performance analysis of the two algorithms enables one to determine the performance losses in using the stage-wise, suboptima l algorithm relative to the optimal one in any given scenario. Numeric al examples with channel parameters, which are typical to shallow wate r source localization, show performance losses of 0-3 dB. Simulation r esults of the two ML algorithms and their comparison with the Cramer-R ao bound (CRB) support the theory.