Research On Fast Processing Method For Ground-based Imaging Radar

Ground-based Synthetic Aperture Radar(GB-SAR)differential interference is a new type of telemetry technology developed for micro-deformation monitoring in recent years,it has irreplaceable advantages in surface deformation monitoring such as open pit mines,geological landslides,glacial displacement,and avalanches.At the same time,it has broad application prospects in the field of deformation monitoring of large buildings such as dams,bridges and towers.In order to obtain high-resolution,high-precision,real-time monitoring results of the observation area,GB-SAR system signal processing subsystem must have strong real-time processing capabilities,complete image focusing in a short time,and provide a good quality single-view complex image for subsequent high-precision differential interference processing.Due to the particularity of the observation geometry,GB-SAR echo data is mainly reflected in the sub-aperture mode,the resolution shows a more severe spatial variation,conventional imaging processing algorithms are difficult to apply directly,and it is urgent to study the fast GB-SAR imaging processing algorithm in combination with GBSAR imaging characteristics.1.The imaging principle and resolution characteristics of GB-SAR system are introduced.The GB-SAR imaging signal model based on linear orbit is established,and the two-dimensional resolution characteristics of GB-SAR are derived;The conventional distance Doppler imaging algorithm,BP algorithm and polar coordinate format algorithm are studied,and the processing functions and computational quantities of various algorithms are compared comprehensively.The polar coordinate format imaging algorithm is improved.Combined with the chirp Z transform,the imaging processing steps are simplified while ensuring the accuracy of imaging processing.The correctness of the algorithm is verified by simulation experiments.2.A new pseudo-polar coordinate format imaging algorithm is proposed.A new pseudopolar coordinate system is defined by variable substitution,only two-dimensional fast Fourier transform is needed to effectively achieve uniform sampling of data.At the same time,through the iterative parameter optimization design,the further accelerated convergence of the focused image is completed,which improves the efficiency of imaging processing and provides an efficient imaging processing algorithm for the GB-SAR imaging processing subsystem.Finally,the correctness of the algorithm is verified by numerical simulation and experimental data processing.