FMCW雷达相位测量误差分析及抑制方法

Analysis and Treatment of Errors in Phase Measurement of FMCW Radar

FMCW雷达利用回波信号的频率和相位信息测量目标的距离，相位测量精度直接影响到距离测量精度．由于频谱泄漏造成的镜像干扰，近距离处相位测量出现非线性误差．本文推导了相位误差的计算公式，与实测结果完全吻合，并介绍利用窗函数对采样信号进行加权处理抑制相位误差的方法。实际测量结果表明该方法有效地抑制了相位误差，保证了系统的距离测量精度。

The FMCW radar measures target range from the frequency and phase of the echo signal.Range measurement accuracy depends on the accuracy in phase measuremetn.Due to the spectra leakage from the side lobes of the spectra component located at the negative half side of the frequency axis at near range,the phase of the spectra appears to be a nonlinear function of range and thus causes singificant errons in range measurement.The analytic relation between phase and range is derived first in this paper,which fits well with measured data. Then the use of the weignting window function on the sampled data before FFT is applied on them is introduced.Experimental results show that phase measurement errors can be effectively suppressed by a suitable weighting window.