Acoustic tracking from closest point of approach time, amplitude, and frequency at spatially distributed sensors
Evangelos Milios, S. Hamid Nawab · The Journal of the Acoustical Society of America · 1990
This paper addresses 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 novel 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. The method is used as the basis for determining the qualitative location of a straight source path with respect to a square grid of calibrated sensors, assuming that the amplitude of the sensor signal at CPA varies monotonically with the distance between source and sensor. 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). Experimental results with real data are presented for the source-velocity computation, together with a sensitivity analysis.