Research On Key Technologies Of Synthetic Aperture Millimeter Wave Radiometer Imaging

Array optimization,error calibration and image retrieval algorithm are three key technologies in the field of interferometric synthetic aperture radiometer imaging.This paper focused on array optimization and error calibration.Image retrieval algorithm was briefly introduced and applied to verify and compare the performance of the previous two technologies.First of all,this paper introduced the basic working principle of interferometric synthetic aperture millimeter radiometer imaging,then it discussed the main parameters of array optimization.Three kinds of typical error models were also analyzed.Besides,it briefly introduced the image retrieval algorithms.The theoretical basis for the follow-up study was provided.Secondly,this paper focused on the optimization of the circular array of the interferometric synthetic aperture radiometer.This kind of array is non-uniform grid sampling.Not only an improved objective function based on the pieces of holes was proposed,but also the invasive weed-particle swarm optimization algorithm was successfully applied to the field of interferometric synthetic aperture radiometer circular array optimization.The above constituted the optimization scheme of this paper.Compare to the traditional scheme,this scheme consumes about two orders of time consume and more accurate.The quality of the retrieval imaging is also better.Finally,this paper studied the error calibration technique of interferometric synthetic aperture radiometer.Aiming at the defect of the two existing algorithms of amplitude and phase error calibration for interferometric synthetic aperture radiometer relies heavily on accurate known auxiliary source location,this paper combined the advantages of active calibration and self-calibration and it researched on three kinds of array amplitude and phase error calibration method,which includes toeplitz pre-processing combined with auxiliary source method,covariance matrix off-diagonal elements' difference method,invasive weed-particle swarm optimization method.These methods first calibrate the amplitude error to eliminate the effect of amplitude error on noise at low SNR,and then calibrate the phase error.These methods do not need accurate known the auxiliary source azimuth and avoid the nonlinear high dimensional joint solution.In addition,the algorithm of toeplitz pre-processing combined with the eigenvalue reconstruction of array element position error calibration and invasive weeds-particle swarm optimization algorithm under the position error of array were also studied.These improved methods can be applied to the error calibration for interferometric synthetic aperture radiometer,and ideal results were achieved.