Research On Dual Mode Imaging Algorithm For Circular-scanning SAR Data Processing

Synthetic aperture radar(SAR)is an important technology in modern remote sensing because of its all-weather, day and night, long distance capability to provide high-resolution maps of the Earth's surface, it is of great value both in military and civil applications. Classical SAR imaging modes include stripmap, spotlight and scanning, in which the imaging area is on one side of radar platform. Compared with the other classical operation modes of SAR, this paper focuses on two imaging modes——circular-scanning imaging mode and dual-stripmap imaging mode,the circular- scanning SAR system has the ability of imaging the circular area under the radar platform, the dual-stripmap SAR imaging mode is developed on such a basis, which satisfies wide imaging area and high resolution requirements and improves the imaging efficiency. The main contents are as follows:Chapter 1 reviews development and research situation of SAR at home and abroad. The main contents of this dissertation are outlined.Chapter 2 introduces the radar imaging algorithm in high squint-mode SAR, the Doppler beam sharpening technology and linear range Doppler algorithm. Relative merits and application fields of RBM,DBS and SAR are analyzed and compared, imaging performance is proved by means of processing of live data.Chapter 3 discusses imaging algorithm of circular scanning SAR, obtains the SAR image using point targets simulations when the radar platform moves with the a constant velocity along rectilinear trajectory and dive trajectory, and researches a new circular scanning imaging algorithm which improves the real-time without loss of the SAR imaging resolution.Chapter 4 researches the dual-stripmap imaging algorithm based on the circular scanning SAR, presents the rules of choosing the system parameters to fulfill the required image resolution and the seamless mosaicing performance. The point-target simulation and live data processing results are given to show the validity of the proposed methodology.Chapter 5 analyzes the impact of the measurement errors of scan angle and antenna phase center on the image quality, and researches a kind of method of radar APC height estimation which effectively improves the imaging quality of the circular scanning SAR based on echo signal.In Chapter 6, the work is concluded,deficiency in the work and the future work is pointed out.