Design And Implementation Of FPGA-based Video SAR Integrated Digital Processing System

With the development of radar imaging technology,the concept of video SAR imaging has been put forward in recent years.Video SAR is a film-like method to reproduce the scene information.It is widely used to monitor the scene information in real time and dynamically observe the mobile target.In order to realize the imaging processing of video SAR data,its corresponding video SAR data acquisition hardware system has become a research hotspot.Since the video SAR imaging system is suitable for continuous imaging with high frame rate and high resolution,and the SAR frame rate is proportional to the radar operating frequency,and its resolution depends on the transmitting signal bandwidth,the difficulty in designing the video SAR hardware system lies in how to generate stable high-frequency broadband signals and high-speed acquisition and storage of echo data.Therefore,this master's thesis designs a video SAR integrated digital processing system based on FPGA for the above difficulties.The main research contents and completed work of this master's thesis are as follows: 1.This master's thesis focuses on the research of video SAR imaging hardware system,designs the overall structure and each sub-module,and completes the hardware design and software development of the system.According to the system design requirements,the overall structure of the system is designed,and the selection of high-performance and equipped with soft core processor syling V7 series FPGA as the main processing chip,soft and hard collaborative development,reducing the complexity of the system design.2.A generation method of if signal is presented.Aiming at the demand of high frequency and high bandwidth of transmitting signal in video SAR imaging system,the wideband if signal generation module is designed.The current mainstream signal generation method is direct frequency synthesis(DDS)technology.According to the sampling theorem,the output frequency of single-channel DDS should be less than half of the system clock frequency,so the output frequency of the signal generated by single-channel DDS is limited.This master's thesis USES the distributed thought,adopts the multichannel parallel DDS technology,the multichannel DDS phase-to-amplitude conversion output is done and then sent to the highspeed digital-to-analog converter after the serial conversion,this method can reduce the frequency of a single DDS core,that is,the system clock is reduced,so as to facilitate the generation of wideband if signal.3.A high-speed acquisition and storage method is presented.Aiming at the demand of high-speed data acquisition in video SAR imaging system,an if signal acquisition module is designed.Based on the principle of band-pass sampling,the wideband if signal is directly collected after demodulation and deskew processing,which reduces the sampling frequency and improves the acquisition efficiency.Aiming at the problem of large amount of data and high rate in the process of data acquisition,a data storage module is designed,and 12 m SATA disks are used for parallel storage,which not only increases the rate but also reduces the volume.Finally,a file system is built in the solid disk to facilitate the direct access of the upper computer to the data in the solid disk.4.A soft hard cooperative control method is presented.Aiming at the problem that the system can be controlled in real time according to the demand,the soft core communication control module is designed.With the flexible and convenient features of Microblaze soft core in FPGA,the serial port is used to receive and analyze the instructions of the host computer and the receiving of the external information in the soft core,and the soft and hard collaborative control is realized,which makes the design more simplified and the control more convenient.5.After completing the system design,set up the experimental test environment to test the whole and each module.The power,spurious-free dynamic range and phase noise of the generated signal were measured by a spectrum analyzer.By processing the collected data with Matlab,the SNR,SNR and total harmonic distortion of the sampled signal are observed.The data storage rate was tested by ILA core in Vivado software.The soft core communication part was tested by controlling the system by issuing instructions on the upper computer interface.Finally,the system design was verified.