Design And Implementation Of Signal Processor For Dual Beam SAR System

The observation of dynamic elements in the ocean has always been a necessary research topic for the development of human society.Sea current speed is an extremely important part of these elements.However,the traditional radar measurement methods of sea current velocity have certain defects,so a new method is urgently needed to make up for such defects.In this thesis,aiming at the problem of measuring the two-dimensional vector of ocean current velocity,the beamforming architecture scheme of simultaneous front and rear beam generation is given,the SAR two-dimensional imaging algorithm under the squint condition is studied,and the system scheme of the airborne dual-beam SAR signal processor is proposed,and functional modules such as waveform generation,timing control,digital reception and imaging processing are designed and implemented.This thesis first discusses the radar signal and imaging processing theory involved in the dual-beam SAR system,and studies the digital receiving processing and squint SAR imaging algorithm.Then the design objective and composition structure of the dual-beam SAR system are given,a simultaneous dual-beam forming architecture is proposed,the waveform of the transmitted signal is designed,and the transmission and reception dual beams are implemented by using time-frequency orthogonality and time-space-frequency orthogonality respectively.According to the system requirements,the development platform is selected,and the scheme design of the signal processor is completed.Then,a hardware subsystem based on a large-scale FPGA(Field Programmable Gate Array)device was designed and implemented,including radar waveform generation,timing control of the whole system,digital receiving and processing module,communication module and echo data inter-chip high-speed transmission module,and test and verify the functional completeness of each module.Subsequently,this thesis designs the software framework and data interface of the software subsystem,and designs the GUI interface and imaging algorithm module based on the Matlab development environment,and accomplishes the software control and data processing verification functions.Finally,the functional module of the signal processor was tested.The test sessions include the test verification of signal generating modules in the signal processing system hardware part,up and down conversion channels,communication interfaces,and data transmission recording function;functional verification of software sub-systems and joint testing of the entire radar system.The test results show that the system function has reached the design goal.