CAJ | 학술논문

在微型SAR实时成像样机的设计中,对雷达回波在中频进行采样,然后采用数字下变频技术实现正交解调,可以减少系统的复杂性,提高雷达的数字化程度和性能.该文针对微型SAR方案中数字下变频设计中的难点,即采样频率高达2 Gsps,带宽900 MHz,实时处理的难度很大,根据具体设计参数优化了数字下变频的实现结构,重点比较了并行FIR滤波器和快行FIR滤波器的差别,然后在FPGA中编程实现了数字下变频模块,给出资源占用情况、运行速度和量化噪声影响,最后给出在微型SAR技术项目中的实际应用结果,理想的成像结果表明了该设计的正确性.
재미형SAR실시성상양궤적설계중,대뢰체회파재중빈진행채양,연후채용수자하변빈기술실현정교해조,가이감소계통적복잡성,제고뢰체적수자화정도화성능.해문침대미형SAR방안중수자하변빈설계중적난점,즉채양빈솔고체2 Gsps,대관900 MHz,실시처리적난도흔대,근거구체설계삼수우화료수자하변빈적실현결구,중점비교료병행FIR려파기화쾌행FIR려파기적차별,연후재FPGA중편정실현료수자하변빈모괴,급출자원점용정황、운행속도화양화조성영향,최후급출재미형SAR기술항목중적실제응용결과,이상적성상결과표명료해설계적정학성.
In the designation of the real-time imaging machine of Mini SAR, the radar return signal is sampled in the intermediate frequency, then Digital Down Converter(DDC) is used to realize quadrature demodulate, which can reduce system complexity and improve radar's performance. The difficulty in the design of the DDC of Mini SAR is firstly given in this paper, i.e. the sampling frequency is as high as 2Gsps and the bandwidth is 900MHz, which leads large difficulty in real-time processing. The optimal architecture of DDC based on real design parameters is given in the next, with the emphasis on the difference of the parallel FIR filter and fast FIR filter. Then the implementation of the DDC module using parallel processing with optimized structure in FPGA is given, the resource usage, running speed and quantity noise influence are given. Finally, the result of Mini SAR is given, which confirms the validity of the design.