Analysis And Processing Of Range Data Of FMCW ISAR Imaging Radar Based On FPGA

Radar is one of the most important achievements in the development of science.In different kinds of radars,inverse synthetic aperture radar(ISAR)is widely used in various fields because it can image the moving targets.This paper mainly studies the distance data ofinverse synthetic aperture radar(ISAR)based on FPGA,the radar transmit and receive frequency modulated continuous wave(FMCW)to detect objects,and use the Artix-7 development board,vivado development kit of Xilinx company to collect the radar echo data,storage and processing in the distance in order to complete the 2-30m distance,RCS 0.1m~2-1m~2 low velocity moving target imaging.Compared with the traditional imaging radar equipment,the utility model has the advantages of portability,lower cost and convenient operation.The main research contents are as follows:(1)Using the new vivado development kit and Artix-7 series development board of Xilinx company to carry out the framework of the whole system software and the overall analysis.On the whole,the research is divided into three modules,namely echo acquisition module,distance data processing module,and data storage module.And analysis the clock of every modules,finally use the clocking wizard IP core in the vivado development kit to divide the crystal oscillator,and generate the clock rate required for each module.(2)In the echo acquisition and analog to digital conversion module,this paper uses the XADC analog to digital conversion card and the FIFO cache mechanism in the Artix-7 series development board to collect and convert the radar echo data.Without using a separate data acquisition card,thereby effectively improving the integrity and portability of the whole system.(3)Analysis and Research on the principle and the key algorithms of FMCW ISAR imaging radar,determined using RD(Range Dollper)classic algorithm and in the process of research and development,according to the echo signal processing of the hardware part radar front-end and development board resources,the RD algorithm in the distance is analyzed and improved to in order to make it more efficient and more effective.Finally,the improved algorithm is used as the processing algorithm of radar imaging in distance.It saves the resources of Artix-7 development board and makes the data processing of the whole imaging system more quicker.(4)In the data cache module,this paper uses the single channel DDR3 SDRAM chip and FIFO cache mechanism to store the processed data.Through the analysis of reading and writing timing and the memory address of the DDR3 SDRAM,use a unique way that reads the data non-address-sequence to transfer the data processed in the distance to the azimuth processing.This method can effectively improve the convenience and the speed of data processing.(5)Build the test platform of the system,using the test platform to complete the test of the imaging system in 2-30m,including the variation of echo integrity and frequency at different distances,and the final output of all processed data.The test results showed that the system can meet the requirements of the indicators.