雷达高精度测距相位差改进算法

介绍了基于相位差法的线性调频连续波(LFMCW)雷达测距算法的原理，针对其计算量大和信噪比门限高的问题，提出一种改进相位差测距算法。该算法在快速傅里叶变换(FFT)的基础上先使用线性调频Z变换（CZT）对峰值附近的窄带进行细化，避免误差可能导致的谱线之间的相位差模糊，提高抗噪声性能，再应用相位差算法作距离估计。与经典算法进行仿真对比，结果表明，该方法的测距精度比改进Fitz算法高一个数量级，信噪比门限比补零相位差算法低7dB，且运算量有一倍以上的减少，适用于低信噪比环境下对检测精度要求较高的实时场景,有利于现阶段工程实现和推广。

An Improved Algorithm of High Precision Ranging Phase Difference for LFMCW Radar

The principle of the linear frequency modulation continuous wave (LFMCW) radar ranging algorithm based on the phase difference method is introduced. To solve its problem of large amount of calculation and high signal-to-noise ratio threshold, an improved phase difference ranging algorithm is proposed. On the basis of fast Fourier transform (FFT), this algorithm uses chirp Z transform (CZT) to refine the narrow band near the peak to avoid the phase difference ambiguity between spectral lines caused by errors, so as to improve the anti-noise performance, and then applies the phase difference algorithm to make the distance estimation. Compared with classical algorithms, the simulation results show that the ranging accuracy of the proposed method is an order of magnitude higher than improved Fitz algorithm, the SNR threshold is 7 dB lower than zero-padded phase difference algorithm, and the computation load is reduced by a factor of 2 or more. The method is suitable for the real-time scene with high requirement for detection accuracy under low SNR environment, and is conducive to the project implementation and promotion at the present stage.