SAR Processing and Parameter Estimation of Moving Targets

Abstract

In this document the effects on SAR imagery caused by moving targets are investigated. Only with the knowledge of these effects it will be possible to adapt existing or develop new algorithms for efficient and accurate ground moving target detection and motion parameter estimation. Range and Doppler histories of moving targets are investigated theoretically and verified by a "Ground Moving Target SAR Simulator" implemented in IDL. An overview of techniques for Doppler parameter estimation and focusing of moving target signals is given. The velocity estimation error evoked by unconsidered target acceleration is investigated in detail. Also the residual range cell migration of a moving target signal after range cell migration correction (RCMC) for stationary targets is examined. The knowledge of the residual range cell migration and the distribution of moving target’s signal energy is necessary for an optimal TRAMRAD system design, especially for choosing the PRF, the range bandwidth, the integration time and some other important system parameters. The classical two-channel techniques ATI and DPCA are explained and investigated in detail, also some improved ATI techniques are envisaged. At typical airborne geometries as well as at spaceborne geometries motion parameter ambiguities may occur. Principal methods for resolving such ambiguities to a certain degree are summarized. Furthermore an overview of some common moving target detector principles is given. The most promissing parameter estimation techniques are applied on experimental single- and two-channel E-SAR data.