Study Of Several Problems In Ultra-Wide Band Synthetic Aperture Radar Information Processing

This paper discusses several questions about the information processing technology of Ultra-WideBand SAR ( UWB-SAR). Mainly it discusses two imaging algorithms adapted to UWB-SAR. Still it analyses geometric correction and speckle suppression on SAR images. Design and realization of SAR information processing software is also in this paper.By the features of UWB-SAR in UHF/VHF band, the problems of wide processing angle and a great quantity of processing data must be taken into account when UWB-SAR imaging. Two algorithms, Range-Doppler(R-D) algorithm utilized invert Chirp-Z Transform (CZT"1) and improved nonlinear Chirp Scaling algorithm, have been studied and testified to be proper for UWB-SAR by processing results.Geometric distortion in SAR images is due to the measuring range characteristic of radar. The geometric correction is substantially the process to get a non-uniform sequence by interpolation from a uniform sequence. In this paper a method used SINC function to weight is put forward to complete the non-uniform sampling and that how to choose a weighting function has been analyzed.Speckle is a defect in all imaging systems including SAR based interference principle to image. From the reason of speckling, this paper analyses the degree of speckles in UHF/VHF band SAR images. Then speckle suppression algorithms, such as multilook de-speckling and space domain filtering, have been discussed and estimated by processing UWB-SAR data.Developing a SAR information processing system, an integrated and efficient environment integrating software and hardware, is to satisfy the requirements of attained data processing. This paper designs SAR information processing software and realized part modules. Finally, the results processed UWB-SAR echo data show its credibility and stabilization.