High Resolution And Wide Swath SAR Imaging Technology Based On Multichannel Systems

Because of its wide applicability and good adaption to weather and time,synthetic aperture radar technology is applied in many aspects both in civil and military.Among these,high-resolution and wide-swath(HRWS)has gradually become one of the most important research directions for the ever-increasing demand for SAR imaging.At the same time,many researchers focus on HRWS due to the diversity and difficulty of its implementation methods.This thesis will focus on the high-resolution and wide-swath SAR imaging technology under multi-channel conditions.First of all,the dissertation briefly introduces the research background and significance of the technology,the related concepts of SAR technology,the related research contents and the structure of the full text.Then,the dissertation introduces several key principles of synthetic aperture radar technology in detail,including the geometrical relationship of SAR position,the chirp signal,the quadrature demodulation,the pulse compression,the distance Doppler algorithm and the probability distribution of SAR image amplitude.Then,the paper introduces the HRWS related principles and techniques.The limitation of traditional single-channel SAR imaging technology is introduced,and the advantages of HRWS are introduced.Then the multi-channel SAR technology how to achieve HRWS is introduced,as well as the azimuth multi-channel SAR technology.The establishment of multi-channel SAR model provides the imaging basis for the subsequent spectral estimation algorithms.Next,the paper proposes a spectrum estimation algorithm for multi-channel HRWS.The characteristics of multi-channel SAR determine that this technique may encounter the problem of non-uniform sampling in the time domain.The spectral estimation algorithm proposed in this paper aims to establish a uniform frequency sampling sequence from non-uniform time-domain sampled signals.The algorithm is based on the basic formula of Discrete Fourier Transform,and the prior knowledge that the reconstruction signal does not completely need uniformly sampled signal.The formula of uniform frequency domain sampling signal can be derived from non-uniform time-domain sampled signal.Finally,the thesis uses the simulation signal experiment and the actual data to test the proposed spectral estimation algorithm.Simulation data includes chirp signals and three-point target imaging,while actual field data testing uses echo data from airborne radars for imaging.Both the simulation experiment and the field data test prove that the proposed spectral estimation algorithm can effectively suppress the ghosting problem caused by non-uniform time-domain signals.