Maximum likelihood estimation of time-varying delays in the presence of directional interference
Benoı̂t Champagne, Moshe Eizenman, S. Pasupathy · 1991
The structure and performance of the maximum likelihood (ML) estimator of slowly varying time delays when the received signals are contaminated by additive noise containing a strongly directional component, due to the presence of a fixed, localized source of interference in the acoustic environment is investigated. The ML estimator is obtained by maximizing the output of the log-likelihood processor. The latter is shown to consist of a slowly varying noise canceler followed by a minimum mean square error estimator of the source signal and a correlator. Closed-form expressions are obtained for the Cramer-Rao lower bound (CRLB) on the error covariance matrix of time-varying delay estimators. The effects of directional interference on the CRLB are investigated numerically for a simplified configuration consisting of two sensors and linearly varying time delays.>