LFMCW雷达测距中的自适应频率校正

Adaptive Frequency Correction in LFMCW Radar Ranging

信号的频率落在两个量化频点之间时会产生估计误差,所以需要校正快速傅里叶变换(FFT)后估计的频率。结合Rife算法和抛物线插值法的特点,提出了一种自适应频率校正算法。该算法依据不同的频率自适应地选择不同的频率校正算法,克服了Rife算法在信号的频率落在FFT量化频点周围的情况下容易产生插值方向错误的缺点,同时避免了抛物线插值法在信号频率落在相邻两个量化频点的中心附近时估计均方误差会急剧增加的缺点。仿真结果验证了所提算法的有效性。此外,相比于单一的Rife算法和抛物线插值法,所提算法在频率估计精度以及抗噪声能力方面都有显著提升。

When the real frequency of signal is within two frequency resolution values,estimation error will occur. Therefore,it is necessary to correct the estimated frequency after fast Fourier transform（ FFT） . By combining the advantages of Rife algorithm and parabola interpolation method,an adaptive frequency cor-rection algorithm is proposed. The proposed algorithm can adaptively select frequency correction algorithm according to different frequency,which can not only overcome interpolation error with direction of Rife algo-rithm when the signal frequency is near the FFT quantization frequencies,but also decrease the error of the parabola interpolation method when the signal frequency is near the medium of two adjacent quantization frequencies. The simulation results verify the validity of the algorithm and show that it can perform more ef-ficiently in frequency estimation accuracy and anti-noise ability compared with single Rife or parabolic in-terpolation method.