The effect of an auxiliary source on the performance of a randomly perturbed array

A fundamental limitation in underwater source localization procedures using arrays of spatially distributed sensors is the uncertainty in sensor positions. This paper examines delay estimation in the presence of background noise, random array perturbations and an auxiliary source at a known location. Cramer-Rao bounds on the delay estimate are given, and the behavior of the bound as a function of the auxiliary source strength is examined. It is shown that the auxiliary source can be used to reduce estimation errors due to sensor displacements; at the same time it may add to the errors due to the background noise. It is concluded that under some conditions the auxiliary source can be used to reduce the total error in the delay estimate.