An alternative method for locating a passive source by using the bearing estimations

The traditional method of passive ranging in a sonar system is to estimate the time delay from a three-point array, usually by a cross-correlation method. The experimental results at sea show that the time dispersion due to signal propagation fluctuation is an unneglectable factor in passive sonar design. One can improve the ranging accuracy by enlarging the distance of subarray, but the time fluctuation will increase with distance. An alternative method for locating a passive source is proposed. By using three subarrays, each with its own split-beam system, the range of a passive source can be estimated by individual bearing data provided the distance of subarrays is large enough. The theoretical analysis shows that the method is actually robust for the time fluctuation in the process of signal propagation