欠采样全相位FFT鉴相方法仿真与实现  

Simulation and implementation of undersampling all-phase FFT phase discrimination method

作　　者：朱雅庆 纪荣祎 董登峰 周维虎 Zhu Yaqing;Ji Rongyi;Dong Dengfeng;Zhou Weihu(Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院微电子研究所,北京100029 [2]中国科学院大学,北京100049

出　　处：《红外与激光工程》2023年第11期215-225,共11页Infrared and Laser Engineering

基　　金：国家重点研发计划项目(2019YFB1310100)。

摘　　要：测距精度是相位式激光测距系统的重要指标之一。为了提高测距精度,采用欠采样方法和全相位FFT(all-phase FFT, apFFT)算法设计了鉴相电路,使用卡尔曼(Kalman)滤波提高了测量数据的稳定性。根据欠采样谱分析鉴相原理,仿真分析了在不同采样频率和不同信号频率下的鉴相精度,对比了基于欠采样的FFT鉴相法和apFFT鉴相法在高斯白噪声、频率偏移等因素影响下的鉴相性能。仿真结果表明,欠采样不会影响鉴相精度,并且欠采样apFFT鉴相法的鉴相精度优于欠采样FFT鉴相法。进行了鉴相性能的实验验证,实验数据表明,当采样频率为100 MHz、信号调制频率为201 MHz时,apFFT鉴相精度为0.134°,卡尔曼滤波后鉴相精度优于0.023°,测距精度可达0.20 mm。因此,基于Kalman滤波的欠采样apFFT鉴相法具有精度高、抗干扰能力强等优点,在相位式激光测距系统中具有重要的应用价值。Objective The ranging accuracy is one of the important indicators that characterize the performance of phasebased laser ranging systems.The improvement of ranging accuracy is mainly achieved by improving modulation frequency and phase discrimination accuracy.If the modulation frequency is too high,meeting the high sampling frequency required for Nyquist sampling will result in high requirements for ADC hardware and increase system design costs.The traditional differential frequency phase detection method has complex circuit design,which can easily lead to the loss of signal frequency,phase and other information during the mixing process.Due to direct sampling of high-frequency signals,undersampling technology can maximize the retention of the original phase information of the signal,with simple circuit design and low hardware costs.In digital phase detection,spectrum leakage is a prominent drawback of traditional spectrum analysis,and the degree of spectrum leakage directly affects the accuracy of phase detection.All-phase FFT(apFFT)has"phase invariance",which can effectively suppress spectrum leakage and improve phase detection accuracy.In the actual measurement process,it is unavoidable to produce Gaussian white noise that affects the stability of the measurement results.Kalman filtering algorithm is a recursive time-domain filtering algorithm that meets the minimum mean square error estimation,and can effectively remove the Gaussian white noise generated in the measurement process.In order to improve the ranging accuracy,this paper proposes an undersampling all-phase FFT phase detection method based on Kalman filtering.Methods This paper first introduces the principle of phase laser ranging(Fig.1)and the principle of undersampling apFFT phase detection based on Kalman filter(Fig.3),and analyzes the phase detection performance under different sampling frequencies and signal frequencies(Fig.5)through simulation,as well as the phase detection performance under the influence of Gaussian white noise,frequency shift

关 键 词：相位式激光测距 数字鉴相 欠采样 全相位FFT 卡尔曼滤波 

分 类 号：TN249[电子电信—物理电子学] TH711[机械工程—测试计量技术及仪器]