Synchronizing data for tracking moving targets with passive acoustic arrays.

Abstract

To accurately track targets moving at high speed with passive acoustic arrays, the propagation delay time needs to be accounted for in the signal processing algorithms. The data from each array need to be synchronized to a common reference time relative to the acoustic signal generated at the target. One approach is to synchronize the data at each array by simply delaying it, then estimates of the direction of arrival (DOA) and possibly the time of arrival (TOA) can be performed. Alternatively, non‐synchronized estimates of the DOA and TOA, calculated relative to a common sample time at the sensors, can be synchronized by interpolation based upon the estimated propagation delay time. For a kinematic target model with constant acceleration, the propagation delay time from the target to the acoustic array can be determined by solving a fourth‐order polynomial equation. For many scenarios, the propagation delay time can be accurately estimated by performing a second‐order or third‐order Machaurin series approximation. The target kinematics can be estimated using standard algorithms that initially assume no propagation delays in the data. As the delays are incorporated into the estimates of DOA and TOA, the results will improve.