Dual-mode Airborne SAR Image Formation And Implementation On Hardware

Synthetic aperture radar (SAR) is widely used in both fields of the military reconnaissance and civil remote sensing. Researching on airborne and space-borne SAR is a hot topic and the resolution is greatly improved.This thesis mainly studies the imaging algorithms of airborne SAR under the side-looking mode and circle-scanning mode, the live data imaging processing and the implementation of the algorithms in the general digital signal processing system.Chapter 1 is the introduction. The history of SAR technology is outlined. The background, application value and development of airborne, space-borne and missile-borne SAR systems are introduced. And the application of DSP technology in radar signal processing is also introduced. The background and main contents of this thesis are addressed in this part.Chapter 2 studies the imaging algorithm of airborne SAR under the side-looking mode. Some steps of the processing flow are added such as Doppler centroid estimation before the imaging processing to correct direction of the antenna beam, and the image transformation from the slant plan to the ground plane. The simulation and live data are processed. Their results show that the improved algorithm is better for live data imaging, and the image matches the real scene.The airborne SAR under circle-scanning mode is studied in chapter 3. The imaging algorithm is modified for requirements of live data processing. The live data imaging result show that the algorithm is more effective and better for real time processing in circle-scanning mode imaging. And the influences of the image quality caused by the record errors of the radar system are analyzed.Chapter 4 introduces the hardware and software recourses of the general digital signal processing system. The setup of the developing environment is also introduced. And the program developing and debugging procedures on the system are discussed.Chapter 5 mainly studies the implementation of the aforementioned imaging algorithm on general digital signal processing system. According to the imaging algorithms and the hardware recourse of the system, the processing task and the principles to distribute the hardware recourses is analyzed to obtain better performances. And the image replay based on the ground processors is successfully realized.Chapter 6 concludes the work of this paper and the future work is pointed out.