Research Of Real Time Image Processing Algorithm For Airborne Synthetic Aperture Radar

The most advantage of the synthetic aperture radar(SAR) is the ability of observing the target in all weather and time. There are a lot of applications of SAR in military and civil aspect. At the same time, the application of high resolution real time SAR is very important.The effect of range cell migration to autofocus is analyzed in the dissertation. A new Shift-And-Correlate autofocus algorithm based on the limits of range bin is presented, which called Shift-And-Correlate within Gate Strategy (SACGS). The effect of range cell migration to autofocus is diminished. And the computation is very simple, which make it very suitable for real-time image processing. The efficiency of SACGS is proved by the simulation and actual SAR data.After dealt with a lot of actual strip map SAR data, the factor which effects the precision and iterative times of PGA was found. In order to meet the request of real time imaging of high resolution SAR, the shift and correlate (SAC) algorithm, SACGS algorithm, PGA algorithm and Range Doppler (RD) algorithm are integrated. With the integrated algorithm, the iteration does not need any more. And the computation is decreased. The real time imaging system can be turned into reality easier. The integrated algorithm is checked out with real high resolution SAR data. And the result is good.Several classic algorithms are introduced. After analyzed the relationship of the two-dimensional spectrum, an easy implemented squint real time imaging method is presented. With the method, the problems of image-joint and azimuth focus depth are solved. The problem of azimuth spectrum overlap is also solved in the paper.