Improving the localization estimates using Kalman filters

Localization of underwater targets is an important requirement in surveillance operations. A method for improving the accuracy of the estimated location of an unknown target using Kalman filters is presented in this paper. The localisation is carried out using a sensor network comprising of three fixed surface buoy systems, each consisting of steerable hydrophone arrays and support electronics, positioned at the vertices of a triangle. The system picks up the noise emanations from the targets of interest and the hydrophone arrays of each node gets aligned to the direction of maximum signal arrival (DOA). Using the DOAs measured at each buoy system, the distances of the target from the three nodes are computed using the triangulation technique.