Combined numeric and symbolic processing of multidimensional signals for source tracking

The authors address the problem of passive acoustic tracking from closest point of approach (CPA) time, amplitude and frequency data at spatially distributed sensors in the case of finite sound propagation delay. A method is presented for the computation of source velocity (speed and direction) from the CPA times at three noncollinear sensors that lie on the same side of the source path. The method reduces the problem to the solution of a linear trigonometric equation, and can be used as the basis for robust localization of a straight source path using a square grid of calibrated sensors. In the case of a maneuvering source, qualitative relations are stated between the local shape of the source path, its relative position with respect to an acoustic sensor, and whether amplitude and frequency increase or decrease monotonically with (source) time at that sensor. These qualitative relations from multiple sensors are then used to segment the source path into straight and maneuvering segments (under negligible propagation delay)