为实现近距离目标的准确测量, 充分利用线性调频连续波(LFMCW)信号的优良特性, 基于ARM单片机设计实现了毫米波LFMCW雷达测距系统。该系统采用“ARM+PLL+射频收发器”的结构, 其中,ARM单片机为主控芯片, 控制锁相环(PLL)和77 GHz射频收发器, 完成LFMCW信号的发射和接收, 同时使用ARM内部的ADC对中频回波进行IQ双路差分采样, 并在ARM内部实现快速傅里叶变换(FFT), 提取目标距离信息。当调制信号带宽为3.2 GHz, 调制信号周期为2 ms时, 该雷达系统可实现对2 m内目标的高精度测距, 误差距离控制在0.03 m内。实验结果表明, 系统能够通过发射宽带LFMCW信号, 实现近距离目标的有效探测, 具有探测精度高、通用性强、可靠性好、体积小等优点。

In order to achieve accurate measurement of close range targets and make full use of the excellent characteristics of Linear Frequency Modulated Continuous Wave (LFMCW),a millimeter wave LFMCW radar ranging system is designed based on ARM single chip.The system adopts the structure of “ARM+Phase-Locked Loop (PLL)+RF transceiver”,uses STM32F3 series ARM MCU as the main control chip for controlling the PLL and 77 GHz RF transceiver chip to complete the transmission and reception of the LFMCW signal,and uses the ARM internal ADC to perform IQ dual differential sampling on the intermediate frequency echo.The Fast Fourier Transform (FFT) is implemented inside the ARM to extract the target distance information.When the bandwidth of the modulated signal is 3.2 GHz and the period is 2 ms,the radar system can implement high-precision ranging to the targets within 2 m with an error less than 0.03 m.The experimental results show that the system can effectively detect short-range targets by transmitting broadband LFMCW signals,and has the advantages of high detection accuracy,strong versatility,good reliability and small volume.