Signal based parameter estimation for precise circular-scanning SAR imaging

Images obtained from circular-scanning synthetic aperture radar (SAR) are mainly used for self-guidance system using the well-known scene matching techniques, where the geometry accuracy of the images is very important for high precision target location. Due to the existence of errors in parameters measurement from inertial navigation system (INS), for example, velocity and beam scanning azimuth angle especially, imaging is not optimal and geometry distortion correction also not absolute. In this paper, a new method of velocity error and scanning azimuth angle error compensation is proposed based on echo data. Doppler navigation instrument can be used to measure velocity based on Doppler shift, so Doppler measuring velocity technique is adopted in the compensation of velocity and scanning azimuth angle error. The experimental result of a circular-scanning SAR system is given to demonstrate the validity of the proposed methodology.