Amplitude and phase error estimation and compensation technology for spaceborne SAR

To solve problems such as target defocus, signal distortion caused by amplitude and phase error of the spaceborne wideband SAR system, the paper proposed a new method to estimate and compensate radar signal errors. Amplitude and phase error of the X-SAR system signal were analyzed in detail which include quadratic error,periodic error and random error. To acquire these errors, phase gradient algorithm was used to estimate signal’s phase error. In addition, computer simulation experiments were conducted in the paper to verify above signal error compensates method. Meanwhile, signal generated by the real X-SAR system were presented and corrected by the method proposed in the paper. Result prove that the signal error estimate and correction method were effective,could be an useful method for spaceborne SAR signal error analysis and error compensation.

I. Introduction

Generally speaking, the range resolution of synthetic aperture radar (SAR) system is mainly affected by the signal bandwidth of the system. Its range resolution is generally obtained by dividing the speed of light by twice the signal bandwidth. It is important in target detection to find enemy and to improve radar performance [1]–[2]. The azimuth resolution is determined by the azimuth aperture length of the antenna. Theoretically, the azimuth resolution is half of the antenna azimuth aperture length. Meanwhile, resolutions of SAR system can be influenced by system signal’s amplitude and phase errors.