Research Of Universal SAR Distributed Simulation And Imaging Technology

Synthetic Aperture Radar(SAR)is a kind of high resolution imaging Radar,which forms a large size virtual antenna through the motion of the carrier platform,and then combines with the pulse compression technology.With the development of SAR technology,more and more SAR systems have emerged to adapt to various platforms and application fields,SAR simulation is an important method for SAR academic research,algorithm research,system design and testing,and imaging analysis can verify its performance.This thesis mainly studies SAR simulation modeling,unified SAR echo model,BP algorithm,and parallel implementation of SAR simulation and imaging.Finally,the imaging results are analyzed through simulated data and measured data,the main contents and innovations of this thesis are as follows:1.This thesis gives the parameters of SAR simulation modeling,summarizes the unified SAR echo model,and introduces the principle of BP algorithm.Firstly,this thesis analyzes the transmit-receive identical SAR echo model,the transmit-receive separate SAR echo model and the linear array SAR echo model,gives the parameters which are transmit-receive identical array element ID number,transmitting antenna position,receiving antenna position,azimuth angle,pitch angle,roll angle and antenna installation angle required for SAR simulation modeling;Second,this thesis summarizes generalized SAR echo model for general SAR;finally,this thesis analyzes the imaging principle and processing of BP algorithm,and illustrates the advantages of BP algorithm are compared with traditional frequency domain algorithm.2.This thesis analyzes the distributed parallel computing,proposes the SAR simulation and imaging optimization method,studies the modeling of various modules of SAR simulation,and proposes the SAR simulation and imaging task decomposition method.Firstly,this thesis introduces the distributed parallel computing,proposes a distributed parallel computing method for SAR simulation and imaging based on static scheduling combining the SAR simulation hardware platform and SAR principle.Second,this thesis studies the modeling of SAR simulation module,according to the process of SAR simulation.This thesis analyzes the irrelevance of the target electromagnetic simulation problem and the realization of SAR simulation and imaging,uses the surface current of FEKO simulation target instead of the target scattering property,realizes the scattering modeling;studies the conversion between the geocentric coordinate system,the North East Tian coordinate system and the local imaging coordinates,implements platform modeling;researches the antenna pattern representation in radar platform,implements antenna modeling;analyzes basic SAR working process,gives a method which uses sinc function instead of basic SAR signal pulse compression result,implements radar modeling.Then,this thesis analyzes the process of SAR simulation,and proposes two decomposition methods for SAR simulation task,namely azimuth decomposition and scattering point decomposition,and verifies the correctness of the two task decomposition by simulation.Finally,this thesis proposes a method of SAR imaging task decomposition based on BP algorithm and verifies its correctness.3.This thesis analyzes the imaging effects of multiple modes of SAR simulation and measured data,and studies the characteristics of moving targets based on near space.Firstly,this thesis analyzes the using field and common working modes of unmanned airborne SAR,analyzes the imaging effect of strong point target of SAR simulation data,and proposes an error compensation method to improve the strong point target imaging effect by analyzing the imaging effect of large-distance measurement data.Secondly,this thesis theoretically analyzes the principle of interferometric SAR,analyzes the imaging effect of the interferometric SAR simulation point target,and analyzes the imaging effect,interferometric phase and coherence of the interferometric SAR measurement data.Then,this thesis uses the simulation and measured data to analyze the imaging effect of the circular SAR,and analyzes the imaging effect of the linear array SAR simulation data.Finally,this thesis studies the front squint SAR moving target model,analyzes the characteristics of sea clutter,and studies the characteristics of sea moving targets based on the near space from the resolution ratio,signal-to-noise ratio,radial velocity,and azimuth velocity.