Research Of Airborne SAR Imaging

Synthetic Aperture Radar (SAR) imaging is widely used in the field of national economy and military. The demands of high resolution and high quality of SAR image have been important targets. Inevitably, in the transmission system of airborne high-resolution SAR, the errors existed in the chirp rate of emission signals would result in radar signal distortion which would have effects on range compression and in succession have effects on the quality of SAR image. So it becomes the emphases to research on how to reduce or restrain the effects of the errors existed in the chirp rate of emission signals in this article.SAR flat's flight path and motion attitudes are hardly controlled in the influence of airflow during the period of recording data, and it made the echos unstable.In this artile the method of motion compensating baesd on the raw data is provided. It's necessary to estimate Doppler parameters before making motion compensation.The dissertation provides a new methord to estimate the Doppler rate.This dissertation mainly studies on the method of phase error compensation for airborne high-resolution SAR, the estimation of Doppler rate, and the realization of the imaging algorithm by C coding language.The first chapter is mainly associated with the historical development and direction of SAR, and the model of SAR is introduced.The second chapter firstly describes the high resolution of SAR and then discusses the common imaging algorithms.The third chapter is concerned with phase errors compensation in range and motion compensation in azimuth based on radar echoes in unstable flat during SAR imaging.The fourth chapter proposes a new method of estimating the Doppler rate.Based the theory of Contrast Optimization Autofocusing Algorithm (COAA), using the enlightened research algorithm, the method can estimate the Doppler rate precisely and fast.The fifth chapter introduces the C coding language for realization of the SAR imaging algorithms.And in the last chapter, there are summary and prospect of this dissertation.