Research On Airborne SAR Geolocation Accuracy

Geolocation accuracy is an important criterion of synthetic aperture radar (SAR)system. It plays a key role in the sides of military target reconnoitering, missilenavigating and map mapping, therefore it is significant to research the SARgeolocation accuracy. This paper mainly investigates the factors influencing theairborne SAR geolocation accuracy and the methods improving the SAR geolocationaccuracy, and analyses the INSAR geolocation accuracy.The paper firstly analyses the theory of the SAR geolocation based on the R-Dmodel. Secondly particularly analyses four factors influencing the airborne SARgeolocation accuracy, and deducts the expression, and discusses the relative parameterinfluence,this part provides the foundation for SAR system design, that is improvingthe SAR geolocation accuracy at the angle of the design.The paper researches the method of the SAR motion compensation to the planemotion error for improving the geolocation accuracy. The paper resolves the motionerror into two part,one is azimuth error and the other is range error. To the azimutherror,the autofocus method can be used, to the range error,it is proposed anarithmetic of range motion compensation. The simulation and the real data resultvalidate the arithmetic is feasible.The paper can calculate the antenna state vector with the ground control pointaccording to the Leberl model, then improving the geolocation accuracy. The paperanalyzes some kinds of models theory and advantages and disadvantages,andimproves the model according to the real aviation, overcomes the disadvantages ofinaccurate model in the case that antenna slants the center, by the improvingmodel,the single image geolocation and the three-dimensional image geolocation canrealize.The paper introduces the common method to resolves the INSAR elevation, asthe method need the phase unwrapping, the error is unavoidable. The paper proposeda close arithmetic to resolve the elevation according to the matrix least norm solutions. The arithmetic uses the geometry of INSAR, without the phaseunwrapping,improving the geolocation accuracy from the theory. The paper discussesthe parameter influencing INSAR geolocation accuracy.The paper analyzes and deduces the SAR geolocation accuracy, researches anddevelops a set of simulation system of SAR geolocation accuracy, the system can getthe form of SAR geolocation accuracy and SAR image geometry distortion. Thesystem is helpful to research the parameter influencing SAR geolocation accuracy,then improve the geolocation accuracy better.