Source location from multiple independent observables

Estimation of source range from direction-of-arrival measurements at hydrophone arrays is considered. Many array systems provide measurements that support multiple independent ranging mechanisms. An example is triangulation or depression/elevation measurements together with the bearings-only ranging mechanism. Implementation of a single, coupled filter incorporating multiple independent mechanisms can result in significant losses in practice. The presence of an unknown measurement bias and threshold nonlinearities are potential sources of estimation losses. Implementation of separate filters for each independent measurement source are shown to preserve a sufficient statistic for the estimation of deterministic processes. This decoupled approach prevents corruption of a good ranging mechanism from biases and/or threshold losses in an independent mechanism