Detection of ground moving objects with synthetic aperture radar

Abstract

This thesis investigates Ground Moving Target Indication (GMTI) using a multi-aperture Synthetic Aperture Radar (SAR). GMTI relevant methods to process the SAR data collected from a strip-map system are presented. Techniques for mitigation of processing ambiguities are proposed, and a map-drift based automatic focus algorithm for the moving targets is developed. Target detectors based on the multi-channel covariance matrix are presented. Comparisons of the proposed detectors with classical methods, such as Displaced Phase Centre Antenna (DPCA), or Along Track Interferometry (ATI), show increased capability in non-ideal terrain types. By decomposing the complex Wishart probability distribution of the covariance matrix into probability distributions of the eigenvalues and eigenvectors, we derive the receiver operating characteristics (ROCs) of the new detection metrics in ideal terrain. The complete analysis is presented for a two-channel system as well as for special cases of the three-channel system. Finally, since implementation of the Constant False Alarm Rate (CFAR) detectors using the new metrics requires estimation of the local scene parameters, a new parameter estimation method is presented. This parameter estimation technique suggests an extension of the current statistical model of the SAR data; an extension that is also examined.