Based On Sar Imaging Technology To The Fm Processing

Synthetic Aperture Radar (SAR) is a kind of high resolution imaging radar. Using SAR we can obtain high-resolution radar images under all weather, day and night and long distance conditions. So it is of high value in military and civil applications. Currently, to obtain high resolution airborne SAR image is one of the most important directions of SAR. In order to obtain high range resolution, wideband or ultra-wideband waveform is used to radar system, which makes great trouble for data collection. Since the limitation of A/D technology is a bottleneck in the implementation, A/D sampling rate must be lowered. For Chirp waveform, dechirp provides the ability to alleviate the A/D problem by easing the requirement on the sampling rate and reduce the quantity of data. The research work of this dissertation mainly focuses on high-resolution imaging algorithm of dechirped airborne SAR signals in stripmap mode. In the introduction to this dissertation, the research significations and developments of SAR imaging techniques are reviewed. The main contribution of the dissertation is also summarized.In chapter 2, the principles of high-resolution and imaging are introduced. In chapter 3, dechirp technology is applied to Synthetic Aperture Radar, and furthermore, both the theory analysis and simulation results show the validity of the method.In chapter 4, based on Range-Doppler Algorithm of SAR, refined Range-Doppler Algorithm, which suits dechirped SAR signals, is studied ；Frequency Scaling Algorithm, which suits spotlight mode SAR, is applied to stripmap mode SAR. In chapter 5, the feasibility and validity of the imaging algorithms are proved by computer simulations and by the processing of real raw data of the experimental SAR system. In the end, conclusions are made.In a word, this dissertation doesn't only introduce the theory and imaging algorithms of dechiped signals of airborne SAR, but also applies them in computer simulation and practice, and proves their validity.