Research On Synthetic Aperture Radar Imaging And Processing Technology

Synthetic Aperture Radar (SAR) is a kind of radar which made use of the radar and the target relative motion to compose a less true wire aperture to an equivalent bigger aperture by data processing method. Synthetic Aperture Radar has all-weather, day/night, long range and high-resolution characteristics, which has tremendous effect on military and civil development.According to pulse compression theory and SAR principle, the paper firstly gives an analysis on the principle of high-resolution SAR imaging, then, notes that the SAR range resolution is dependent of signal bandwidth, while SAR azimuth resolution is dependent of the bandwidth of the LFM-featured Doppler signal generated from the relative movement between aircraft carrying the radar and the fixed ground target, thus, high azimuth resolution can be realized through pulse compression. And then, introduces the Frequency Scaling Algorithm (FSA) and Range Migration Algorithm (RMA), and analysis the merits and demerits both of them.In allusion to the adoption of Stolt interpolation in RMA reduces the computational efficient of the algorithm. NUFFT is introduced to replace Stolt interpolation and IFFT in RMA algorithm in this paper. The simulation results shows that this method guarantees the precision of the algorithm, synchronously it improves the computational efficient of the SAR imaging algorithm.The existence of speckle in SAR images affects greatly to the follow-up processing of the SAR images. This paper transforms the SAR images to the Curvelet domain by Fast Discrete Curvelet Transforms (FDCT), and then adopts adaptive thresholding processing to the Curvelet coefficients, finally reconstructs the SAR images. Experiment results show that this method achieves satisfactory results.