Robust maximum-likelihood estimation of local environmental parameters in shallow water

This paper presents a new, robust algorithm for estimating unknown environment parameters in a bounded propagation medium, such as shallow water. The proposed algorithm is based on the fact that if there are no model uncertainties, the corresponding modal spectrum of the received signal is strictly band-limited to an a-priori known band. Any mismatch in the assumed local model causes the modal spectrum out of this band to be non-zero. The proposed estimator is independent of the emitter characteristics. We demonstrate its performance by applying it (via computer simulations) to a practical scenario.