Ground Moving Target Indication And Velocity Estimation In Distributed Small Satellite SAR Systems

Space-borne synthetic aperture radar ground moving target indication (SAR-GMTI)is an important direction for radar. Unfortunately, the presence of strong clutter andnoise in space-borne mode makes the detection performance is worse in the singlespace-borne SAR. So the appearance of the distributed small satellite SAR systemsbrings the broader development space for space-borne SAR-GMTI. It is combinedwith several satellites. The satellites work together to accomplish one or more tasks,which has equivalent function with big satellite. The multi-satellite combination canprovide multi-baseline configurations and can supply more baseline combination. Itcan be realized by scale production, decreasing launch expense and circulating cost ofthe satellites.This dissertation mainly discusses the along track interferometric SAR (AT-INSAR)technology in the distributed satellite system and the velocity estimation using themulti-baseline configurations of distributed small satellite system. The thesis work isorganized as follows. First, I simulate the SAR echo of moving target, and thendiscuss the influence of target's motion on SAR imaging. Second, based on theprincipal of the AT-INSAR systems and the formation configuration design for theAT-INSAR using distributed small satellite, I establish the model of AT-INSARsystem and then I deduce and analyze the performance for critical baseline, velocityresolution and moving target detection. Third, I analyze the influence of clutter to theinterferometric phase, and the distribution of the phase and amplitude, and the CNR tofalse alarm. In this fundamental I compare the phase threshold only and thedual-threshold algorithm. Proposed one kind of auto-adapted threshold examines method. Forth, in this paper a method able to recover moving target radial velocitiesin along-track interferometric Synthetic Aperture Radar (AT-INSAR), which uses themulti-baseline configurations of distributed small satellite system, is presented. Basedon the Maximum Likelihood Estimation technique, the innovation method can obtainvery accurate velocity estimation capabilities, overcoming ambiguity intrinsic in thesingle-baseline AT-INSAR system.