A Novel Motion Compensation Approach for SAS

Synthetic aperture systems rely on accurate knowledge of Transmitter (Tx) and Receiver (Rx) positions at each ping. In Synthetic Aperture Sonar (SAS), due to the nature of propagation and navigation in water, they have to be estimated by either physical sensors or raw data or a combination of these and employed to compensate motion errors. Hence, motion compensation is a major issue in SAS. In this paper we propose a new image domain based motion compensation approach which is intended to loosen the restrictions imposed by previously proposed approach such as Displaced Phase Center Approximation (DPCA) and the dependency on an accurate Inertial Navigation System (INS). The real bistatic observation model is replaced by a virtual bistatic model which allows for taking into account rotations between Txs and Rxs. The ping to ping displacements are then obtained by minimizing an error function between the projections on vector space intersections.