ESPRIT-based Calibration of Multiple Sonobuoys Using a Moving Source

Distributed sonar arrays that are coherently processed offer high gain over diffuse noise and target resolution but with minimal hardware. The low-cost and ad-hoc nature of these arrays make them flexible and easy to scale but it also brings additional calibration challenges. The positions of individual sub-arrays may only be known up to the accuracy of an on-board GPS device, which will in general be inadequate for beamforming. In this paper we present a distributed array position calibration method using a single, tonal moving source of opportunity. The distributed array is re-partitioned into uncalibrated sparse arrays, whose steering matrices are estimated using the ESPRIT algorithm. The source and sub-array positions are then jointly estimated with the aid of noisy AIS data. We show this method to be effective for a minimum of a single moving source consisting of just two tones.