Adaptive realization of a maximum likelihood time delay estimator

ABSTRACT This paper presents an adaptive maximum likelihood method for estimating the time difference of arrival of a source signal at two spatially separate sensors. It is well-known that the maximum likelihood technique achieves the Cramer-Rao lower bound for time delay estimation error for certain signal conditions. The a-β tracker is a heuristic mechanism that is heavily used in target tracking applications. In this work, we combine an adaptive realization of the maximum likelihood time delay estimator with the a-β tracker to obtain significant improvement in the performance of the tracker. Experimental results showing 2 to 8 dB improvement in the mean-square estimation error over the conventional a-β tracker for various signal-to-noise ratios are also included in the paper.