摘 要：FMCW 雷达通过发送和接收信号的差频信号进行测距，因此，差频信号的频率估计精度将直接影响到测距精度。本文通过进行详细的数学推导，提出了一种基于三个DFT 采样值的新型频率估计方法，用于提高调频连续波（FMCW）雷达的测距精度。仿真证明，新方法无论在无噪声条件下还是在高斯噪声影响下，相比传统频率估计方法均有性能提升。同时由于新方法只需要三个DFT 采样值，而且无须进行数据加窗处理，在计算复杂度上相比传统方法也有明显改善。
关键词：频率估计；离散傅里叶变换（DFT）；测距精度
中图分类号：TN958.1 文献标识码：A 文章编号：2096-4706（2019）13-0059-04
A Novel Frequency Estimator Based on Three DFT Samples
CHEN Hao1，LEI Yi2
（1.Aperture Array and Space Exploration Key Laboratory of Anhui Province，The 38th Research Institute of China Electronics Technology Group Corporation，Hefei 230088，China；2.School of Computer Science and Information Engineering，Hefei University of Technology，Hefei 230601，China）
Abstract：To determining distance，frequency-modulated continuous-wave （FMCW） radars need to estimate the frequency difference between the transmitted signal and the received echo signal. Therefore，the accuracy of the estimated frequency will have a direct impact on the range accuracy. In this paper，a new frequency estimation method based on three DFT sampled values is proposed to improve the ranging accuracy of FMCW radar through detailed mathematical derivation. The simulation results show that，compared to conventional methods，the performance of the proposed estimator has been improved in both noiseless scenario and Gaussian white noise scenario. Because it only needs three DFT samples and doesn’t need windowing technique，comparing with traditional methods，the computational complexity is also improved significantly.
Keywords：frequency estimation；discrete fourier transform（DFT）；range accuracy
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作者简介：
陈皓（1989.01-），男，汉族，安徽颍上人，工程师，博士，研究方向：雷达系统设计；
雷艺（1990.12-），女，汉族，重庆忠县人，讲师，博士，研究方向：光纤无线融合、MIMO、信道编码。