Algorithm Research On High Squint Missileborne SAR Imaging

Synthetic aperture radar(SAR) is a kind of active electromagnetic wave imaging sensor. It can obtain high resolution radar images around all day. By now, SAR imaging is already applied in space-borne and airborne platform very mature, but is not used very mature in missile platform.SAR obtains the two-dimensional signals of range and azimuth. Compared with the traditional range imaging sensor and the infrared imaging sensor, SAR has some huge advantages. It can work all-time protected from the sun radiation and bad weather condition. Besides SAR can detect enemy camouflages of military equipment because electromagnetic wave can penetrate vegetation. In addition, based on the azimuth information, SAR can provide abundant electromagnetic information of target and can get the strength of the scattering points. But one dimensional range imaging cannot achieve this purpose. Because of these, this thesis studies the squint SAR imaging algorithms in missile platform, the main work done is as follows:1. Through the study of airborne SAR imaging algorithm, missile-borne SAR large squint imaging algorithm is studied. First of all, instantaneous slant distance equation is studied.Using the principle of POSP to derive the two-dimensional frequency domain expression in this mode. Then combining the method of time-domain distance correcting, the improved range-doppler algorithm is given. The algorithms are verified by MATLAB to prove the validity of the algorithms.2. The missile-borne SAR algorithms for side-looking mode and squint mode during the diving acceleration(velocity and acceleration exist both in azimuth and vertical dimension) are studied. First of all, instantaneous slant distance equation is studied in this mode. Then the Taylor series expansion and series inversion are used to derive the two-dimensional frequency domain expression. At last, the imaging algorithms are indicated and verified by MATLAB.3. Completing the design of SAR imaging simulation software. The Matcom software is used to realize combined programming of Visual C++ and MATLAB. The powerful visual programming ability of Visual C++ and ultra strong computing ability of MATLAB are applied, so that this simulation software will possess good portability and do not depend on MATLAB environment.Finally, the research is summarized in this thesis. The summary and outlook about the development tendency and application prospects in the subject research direction are given, and the problems about further study and solution are pointed out.