| Radar signal processing module is the core component of a radar system,which has important effect to the performance of radar.In recent years,with the development of electronic technology and the programmable logic devices,radar signal processing has changed from analog signal to digital signal.Many scientific institutes have put a lot of manpower,material resources to research digital signal processing.By analysing the demand of radar signal digital processing module on the market,the civilian radar has usually the poor bearing resolution,hard to meet the requirements of some users.Therefore,it is need to design a civilian radar with high resolution,portable,light weight and small volume.On basic of understanding the concept and theory of radar digital signal processing,the existing module design of radar signal processing are analyzed by MATLAB simulation,analysis and comparison.Then a new hardware and software design based on the ZYNQ radar digital signal processing module are proposed by consulting to experts and combining with the laboratory condition.By analysis of the demand of radar signal digital processing module,this paper puts forward the practical hardware and software design in detail.In the process of software design,the following six aspects are emphatically studied.(1)The use of serial D/A conversion chip is studed.Delivery module with 204 B is built in serial d/a conversion chip.The parallel data are converted into serial data.And the serial data should be convered to parallel data again by the corresponding 204 B receiving module at the receiving end.The receiver and receiver need to be synchronized by transmitting synchronous code before the data transmission.(2)Polyphase filter is analyzed.The intermediate frequency used in this paper is 600 MHz.According to the sampling theorem,the sampling frequency greater than 1.2 GHz will make the following data processing difficult.Therefore,in this paper,polyphase filter is used to reduce the data rate so as to make subsequent processing more convenient.(3)The DDR3 data storage is studied.DDR3 memory chips added makes up the defect of the insufficient On-chip RAM resources.Due to the disadvantage of long time of DDR3cross-region reading,column processing is considered when phase coherent accumulation.PRI data was transposed through on-chip RAM,so as to realize the continuous address reading and improve the storage efficiency of DDR3.(4)The approximate computation of modulus value is studied.The modular calculation method of nonlinear operation occupies more resources,but the approximate computation method takes up less resources.So in this paper,the software implementation for the approximate calculation method is introduced.(5)The AXI bus data transmission is studied.AXI data transmission bus is the data transfer bus from PS end to PL end of the ZYNQ chip,which can transmit data in each module for PL end,suitable for low speed data.(6)The data collection after digital down converter is studied.Data of digital down converter transmits to acquisition device through the optical fibers.Then the data is analyzed by MATLAB.The implementation of system verifies the algorithms.In this paper,the scheme of hardware design is put forward in the second chapter,software program is designed detailly in the third chapter,and software performance test is executed on software development board in the fourth chapter.Results show that the system reaches the design requirement and features stable and reliable performance.The radar digital signal processing module,disigned by the new device and method can modify software repeatedly.The system algorithm is easy to upgrade.And it have a potential application prospect in engineering fields.In this paper,the popular FPGA + DSP scheme are used as the design of radar signal digital processing module,with the advantages of the reduced processor chip,the simple design in the PCB,the decreased area and the low cost.Meanwhile,it improves integration,stability and reliability. |
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