Research Of SAL Real-time Signal Processing Based On FPGA And DSP

Synthetic Aperture Radar(SAR)can achieve images of remote targets by making use of synthetic aperture theory and pulse compression technology.Compared with realaperture radar,SAR attains higher spatial resolution.Being different from SAR which detects the target with microwave band,Synthetic Aperture Ladar(SAL)uses light wave band which has lower wave length to detect the target.And the lower wave length means the better resolution.Therefore,SAL has been applied to many fields of military and civilian more and more widely.Besides,real-time signal processing is the key point to realize radar engineering.In this background,with support of the national major project “Research of ×××× Imaging Algorithm and Atmospheric Effect” and “Research of SAL Tecniques”,this paper conducts a design of the real-time signal processing board for airborne SAL with high performance and a study of imaging algorithm realizing.In this paper,the main research work are carried out as follows:1.The fundamentals of SAR is described in this dissertation,which also applies to SAL.And on this basis,the imaging algorithm,the range-doppler algorithm(RDA)is described in this thesis.Because that SAL generates pulse signal by adopting the way of galvanometer scanning which is non-linear to provide quadratic phase,range compression can not be realized by RDA directly.Therefore echo data is interpolated firstly in this project,and the interpolation algorithm is introduced and the imaging algorithm which is appropriate for this real-time signal processing board is put forward in this thesis.2.The hardware which is mature and can be applied to SAL is analyzed and compared in this paper.According to the performance requirements of SAL of this project,the hardware architecture based on FPGA and DSP is chose to set up the real-time signal processing board.The hardware design of the signal processing board is developed further.First,the procedure of the selection of the core chips of the board is introduced.And the design of communication interface modules between FPGA and DSP and between DSP and upper computer is dicussed mainly.SRIO and Gigabit Ethernet is employed in the two modules respectively,and the transmission speed of them can reach 6.25 Gpbs and 200 Mbps respectively.Then,the design of peripherals and configuration and loading mode of FPGA and DSP are also introduced in detail.Lastly,the physical board got through the hardware design is given.3.The task assignment of imaging algorithm in signal processing board is described in detail,of which FPGA is responsible for the interpolation and compression of the data of range and the match-filtering of the data of azimuth,and the matrix transposition of echo data is in charge of DSP.The ultimate imaging result can be displayed on PC through Gigabit Ethernet after importing the simulation data to the board.Compared with the image which is obtained by algorithm simulation of MATLAB,the feasibility of the realization of the imaging algorithm in signal processing board is verified.Furthermore,as a result of analysis of the time-consuming of each module,the board is proved to meet the request of real-time of SAL.This thesis realizes the hardware design and algorithm implementation et al of the realtime signal processing board for SAL based on FPGA and DSP.The board possesses extremely capacity to handle data and can meet performance requirements of SAL of the project and has a certain engineering value.