Influence of Random Phase Noise on SAR Imaging and Its Improvement

Abstract

Random phase error in the radar data will badly influence the pulse compress effect and blur the image, due to the difficulty of removing this multiplicative phase noise. Document〔5,6〕 threat the noise by computation of the high order statistics of received. However, this method requires large number of sampling data to satisfy the stability of the statistics, which limits the application of this method. Document〔7〕 brought out a new way to enhance Chirp signal from strong additive background random noise by rotating the short time Fourier transform of the signal, singular value decomposition and line approximation. \;This paper analyzes the influence of random phase noise from azimuth on SAR imaging first. Then on the base of document〔7〕, a novel and effective way of rotation of Ambiguity Function and singular value decomposition to take place of matched filter is put forward, which is applicable to moving targets detecting and imaging since it is always presumed several strong reflecting point from the moving target. Simulation results are presented to confirm the theoretical results, showing that the method in this paper is more effective than filters in time or frequency domain. However, a shortcoming is that the number of echo signals will affect the filtering result by this method.