| Based on Synthetic Aperture Radar(SAR),Interferometric Synthetic Aperture Radar(In SAR)utilizes two or more complex SAR images to obtain the interferometric phase with a series of phase data processing steps,and the elevation of target scene by using the geometric information between the platform and the target terrain.At present,In SAR measurement technology is greatly developing in the fields of military and people’s livelihood.With the improvement of the hardware and the SAR/In SAR technology,the high-resolution,larger-width,distributed and multi-mode In SAR technology has become the latest development trend of interferometric measurement technology.In this paper,the high-resolution,high phase preservation In SAR Imaging algorithm is studied,and the main innovations and improvements are as follows:1.The algorithm of high-precision and high-phase preservation In SAR imaging based on frequency-domain back-projection is studied.In this article,the idea of back-project is applied to wavenumber-domain,and the In SAR imaging algorithm based on the frequency-domain back-project algorithm is proposed.FDBP algorithm utilizes the ideal of back projection to decouple the coupling caused by the relative motion of the target scene and the measuring platform.In comparison to conventional frequency-domain imaging algorithms,FDBP introduces the accurate positioning information and platform trajectory obtained by the positioning system and IMU in the correction process of back projection.Precise point-to-point phase compensation is carried out in the process of delay phase compensation to obtain the high resolution and high preservation phase.In comparison to the time-domain back-project imaging algorithm,FDBPA reduces the imaging complexity by avoiding the point-by-point calculation in each azimuth direction.The feasibility of the algorithm is verified by theoretical derivation,simulation experiment and measured data in this paper.2.A high-precision and high-phase preservation In SAR imaging algorithm assisted by curved surface is studied.In this paper,a curved surface assisted In SAR imaging algorithm is studied.The curved surface space is used as the projection space of the time-domain backward projection for imaging.Compared with In SAR imaging algorithm of plane projection,this method can reduce the impact of undulating terrain,correct terrain distortion,reduce interference fringes,and reduce the difficulty of phase unwrapping.In this paper,a geometric model of the surface-assisted In SAR imaging algorithm is established,and the effectiveness of the algorithm is verified by using the simulation and measured data.3.Imaging algorithm based on compressed sensing.With the decrease of the sample size,the sparse reconstruction algorithm is directly used to reconstruct the In SAR data.Since the complex In SAR image data is not sparse,the reconstruction results cannot meet the requirements of the high-phase preservation In SAR imaging algorithm.In this paper,the amplitude and phase separation compressed sensing In SAR imaging algorithm is studied.The algorithm uses sparse reconstruction algorithm and least square method to process the amplitude and phase information of the target.Compared with direct sparse reconstruction,this algorithm can improve the phase accuracy of In SAR data,which provides a theoretical basis for the research of In SAR imaging processing based on compressed sensing.Theoretical derivation,simulation experiment and measured data verify the effectiveness of the algorithm. |
