Design And Implementation Of Micro SAR Real-time Imaging System

With the continuous in-depth study of synthetic aperture radar(SAR),the research of real-time imaging technology of high-resolution miniature SAR becomes a hot spot with small unmanned aerial vehicle(UAV)as the airborne platform.Compared with the traditional sar system,the miniature sar real-time imaging system adopts the linear frequency modulation continuous wave technology under the condition of meeting the resolution requirement.It has the characteristics of low cost,small volume,low power consumption,light weight and the like and can realize real-time imaging processing at the same time.Therefore,it is of great practical value to develop a real-time micro SAR imaging system suitable for UAV and other small platforms.This thesis focuses on the research of miniaturization and real-time processing of SAR imaging system.The system architecture design and sub-modules division are implemented.The system hardware development and imaging software development are accomplished.1.Based on system design requirements,the procedure of signal processing of the system is analyzed and the overall system framework is designed.The Zynq series chips with integrated dual-core ARM and FPGA architecture are selected as the main processing chip,which reduces the complexity of the card board design.2.In order to solve the problem of large size and complex structure of radar system,the design methods of radar transmitter,frequency source,and receiver are studied.The dechirp receiver structure is adopted to simplify the structure of radar hardware system.3.For the problem of huge data and high data rate in the imaging process,Under the condition that the signal is not distorted,digital down conversion and azimuth pre-filtering data are designed.It reduces the sampling rate of data and solves the problem of data congestion.4.In order to solve the problems of complex signal processing and real-time processing in the system imaging process,the implementation process of distance doppler algorithm is analyzed.The imaging algorithm is divided into sub-modules,and a parallel processing scheme of PS and PL based on timing relationship is designed and implemented.On the PL,the RVP and azimuth pulse pressure processing are mainly completed,and data transposition,Doppler parameter calculation,and grayscale quantization processing are completed on the PS,which solved the problem of slow data processing.5.After completing the system design,the functions test and system debug are taken.Finally,it is verified in the field scene test.