基于改进协方差法的风廓线雷达谱分析

The Wind Profile Radar Spectrum Analysis Based on the Improved Covariance Method

针对风廓线雷达回波信号较弱的问题,介绍了一种基于改进协方差的风廓线雷达谱分析方法。该方法利用使前、后向预测误差之和为最小而建立起协方差方程,并通过一种递归运算快速求解,得到回波信号功率谱。对比改进协方差法和现有FFT法分别在仿真与雷达实际数据两种情况下的谱分析效果,结果表明在信噪比较大时,两种谱分析方法都能辨别回波信号谱峰,但改进协方差法分析得到谱峰更尖锐;而当回波信噪比较弱时,FFT谱分析法无法识别出回波谱峰,在改进协方差谱分析中却能清晰辨别,且还具有噪声抑制效果。该方法可用于改善风廓线雷达弱信号的谱分析及谱矩估计性能。

Aiming at the weak echo signal of wind profiler radar, we introduced a spectral analysis method based on the improvement of covariance. This method made use of the covariance equation of making the sum of the forward and backward prediction error minimum, and used a recursive algorithm to get the echo signal power spectrum. Then we compared the spectrum analysis effects of the improved covariance method with the existing FFT method under the condition of the simulation data and the actual radar data. The results showed that two methods can both identify echo signal spectrum peak under the condition of high SNR （signal to noise ratio）, while only improved covariance method can show a sharper spectral peak under a low SNR. The improved covariance method can also suppress noise effectively. This method can be used to improve the weak signal spectrum analysis for wind profile radar and spectral estimation performance.