雷达成像系统中采用CORDIC算法的IQ实时解调与FPGA实现  

CORDIC algorithm for IQ real-time demodulation and FPGA implementation in radar imaging system

作　　者：宋超凡 李鑫宇 简彦澎 尚双丽 郑其斌 Song Chaofan;Li Xinyu;Jian Yanpeng;Shang Shuangli;Zheng Qibin(Institute of Biomedical Engineering,Shanghai University of Technology and Science,Shanghai 200093,China;School of Medical Instrument and Food Engineering,Shanghai University of Technology and Science,Shanghai 200093,China;Shanghai Radio Equipment Research Institute Shanghai 201109,China)

机构地区：[1]上海理工大学生物医学工程研究所,上海200093 [2]上海理工大学医疗器械与食品学院,上海200093 [3]上海无线电设备研究所,上海201109

出　　处：《电子测量技术》2020年第18期136-140,共5页Electronic Measurement Technology

基　　金：科技部国家重点研发计划(3018302819)项目资助。

摘　　要：针对雷达成像系统中频信号数字解调的需求,提出一种基于坐标旋转数字计算法(CORDIC)的IQ实时解调方法,对传统的模拟IQ解调和基于查找表法的IQ解调法进行了改进,可在雷达系统中实现高精度、实时且占用硬件资源少的中频信号IQ解调。采用CORDIC算法和查找表法在FPGA中设计数字控制振荡器(NCO)并完成IQ解调,对比了两种方法消耗的硬件资源量。设计结果表明,在同等精度下,CORDIC算法实现IQ解调消耗的硬件资源量优于查找表法,随着精度要求的提高,CORDIC算法节约资源的优势更显著。最后,通过建立雷达二维成像MATLAB仿真系统验证本方法的可行性,在基于迭代16次CORDIC算法(CORDIC-16)实现IQ解调的情景下,成像结果较好;目标的峰值旁瓣比(PSLR)好于-13 dB,可满足绝大多数雷达成像系统的需求。Aiming at the requirement of IF signal digital demodulation in radar imaging system, a real-time IQ demodulation method based on coordinate rotation digital computing(CORDIC) is proposed. This method overcomes the shortcomings of traditional analog IQ demodulation and look-up table based IQ demodulation, and realize IQ demodulation with high-precision, real-time and less hardware resources. Two kinds of digital controlled oscillator(NCO) were implemented in FPGA to realize IQ demodulation base on CORDIC or look-up table. The results show that IQ demodulation based on CORDIC algorithm cost less FPGA resources than that base on look-up table under the same accuracy. As the accuracy requirements increase, the CORDIC method has more significant advantages in saving resources. Besides, a two-dimensional radar imaging MATLAB simulation system was set up to verify the feasibility of this method. In the case of IQ demodulation based on CORDIC with 16 iterations(CORDIC-16), the radar imaging was good and a PLSR better than-13 dB was achieved that met the needs of most radar imaging systems.

关 键 词：FPGA NCO CORDIC IQ解调 雷达成像系统 

分 类 号：TN911.7[电子电信—通信与信息系统]