基于频谱重构的相干激光测风雷达风切变检测算法

Wind shear detection algorithm for coherent lidar based on spectral reconstruction

为了提高相干激光测风雷达风切变的检测率,本文提出了一种在频域检测风切变的新方法。首先,截取激光雷达目标探测距离处的回波信号进行傅里叶变换。其次,通过对回波信号的频率分量按其幅值大小加权进行频谱重构。然后,对重构后的频谱进行平滑并估计峰值频率,计算局部频率差,与风切变阈值进行比较,进而在频域判别风切变。采用旋转电机实验数据对该算法误差进行评估,得到该算法频谱估计误差为0.64 MHz。设计基于小型飞机的激光雷达风切变检测实验对算法检测率进行验证,以小型飞机飞行报告作为风切变判定标准,对激光雷达检测结果进行判别。通过朝阳机场实验得到该算法风切变检测率为84.62%,表明该算法对提高激光雷达风切变检测率具有重要价值。

In order to improve the detection rate of wind shear in coherent lidar, a new method to detect wind shear in frequency domain is proposed in this paper. Firstly,the Fourier transform is carried out by intercepting the echo signal at the detection range of the lidar target. Secondly,the frequency component of the echo signal is weighted by its magnitude and the spectrum is reconstructed with the data. Thirdly, the peak frequency is estimated on the basis of the smoothed reconstructed spectrum. Then,in order to identify the wind shear in the frequency domain,the local frequency difference is calculated and compared with the wind shear threshold. The error of wind shear detection algorithm is evaluated by using the ex- perimental data of rotating machine, and the spectral estimation error of the algorithm is 0. 64 MHz. The lidar wind shear detection experiment based on small aircraft was designed to verify the detection rate of the algorithm,and the small aircraft flight report was used as the wind shear criterion to judge the lidar detection results. Through the Chaoyang Airport experiment, the wind shear detection rate is 84. 62%, which shows that the algorithm is of great value to improve the lidar wind shear detection rate.