Research On Scansar Imaging Algorithms Technology

Synthetic Aperture Radar (SAR) is an active microwave sensor working all-timeand all-weather, which obtains high azimuth resolution utilizing aperture synthesismethod, is one of important developing directions for modern radar technique.ScanSAR breaks the modern strip SAR’s limitations of mapping bandwidth in rangedirection by sacrificing azimuth resolution to acquire wider swath. The low and mediumresolution radar images can be got through dealing with interstitial echo data in rangedirection. ScanSAR as one of common wide swath mode have applied in many satelliteborne SAR systems to facilitate wider observation on earth surface. This thesisinvestigates the parameter setting of SAR, simulation imaging of echo data, sub imagesmontage and etc. Contributions in this thesis are listed below:(1). ScanSAR’s data acquisition process, imaging features of ScanSAR, datafeatures of Burst mode are investigated based on conventional strip SAR mode. Theoryof unique scalloping effects generation in range direction for Burst mode imaging isanalyzed and method to handle with scallopings effects is investigated.(2). The mathematical model of the procedure for dealing with ScanSAR imagingis derived and sequential relationship of ScanSAR is studied. Mapping bandwith,resolution, ambiguity, Noise backscatter coefficient and other key system parameters arediscussed and derived.(3). Contributions including investigating signal acquisition geometry model ofScanSAR, deriving echo signal’s formulae of single target in Burst mode have done,echo signal’s features and Doppler progress of single target are analyzed in detail andmatched filtering procedure in range direction for ScanSAR echo and Azimuthcompression response for target imaging are discussed in detail also.(4). Imaging algorithms of satellite borne ScanSAR including full aperturealgorithm, SPECAN algorithm and ECS algorithm are studied, phase keep features ofeach algorithm is analyzed, performance of each algorithm is verified by simulation.Each algorithm’s imaging characteristics and application conditions are compared bycomparing and analyzing simulation results, the difference of performance for each algorithm are pointed.(5). Basic information and related parameters of scan mode satellite borne SARplatform is introduced, features and differences of ASAR’s strip mode and scan modeare compared and analyzed, systematical parameters of ASAR are analyzed. Aiming tosub images stitching of ScanSAR, data spectral characteristics of strip SAR and Burstmode are investigated, coherent multi-Burst stitching method is studied, and algorithm’sfeasibility is verified by images stitching gotten from real measured data. Thecharacteristic of real ScanSAR measured data is analyzed, detailed imaging procedure isinvestigated, and imaging results are acquired finally through imaging of real ScanSARmeasured data.