用于风场探测的非对称空间外差干涉数据处理方法研究

Data Processing Method of Asymmetric Spatial Heterodyne Interferogram for Wind Measurement

利用非对称空间外差光谱技术和多普勒效应,通过测量中高层大气气辉谱线的干涉图,采用傅里叶变换的方法求解相位,获得大气的风速信息。分析了干涉数据的处理方法,并针对干涉相位的求解进行推导。相比于传统观空间外差数据处理,不仅要考虑噪声和系统误差,而且要考虑用于光谱隔离的窗函数引入的相位误差。通过软件模拟了窗函数的类型和窗长度对干涉数据和风速误差曲线的影响;在此基础上选择合适的窗函数模拟了对干涉图添加噪声和平场因子情况下的风速反演误差。结果说明,虽然窗函数造成了干涉图和相位的畸变,但是使用汉宁窗在合适的光程差处能够使其引入的误差低于5%;同时,噪声的仿真说明,风速误差随着系统噪声的增加而增大,在实验过程中控制噪声以及实验数据预处理对于控制风速精度的必要性。数据处理方法的研究和相关的仿真,对于提高空间外差风速测量精度及系统设计提供了理论参考,具有一定的指导意义。

By using doppler asymmetric spatial heterodyne spectroscopy and doppler effect,the wind speed can be achieved through detecting the interferogram of airglow in the upper atmosphere.This paper mainly analyses the data processing method of the interferogram and then derive the interferometer phase in order to get the wind speed.Comparing with the traditional spa-tial heterodyne spectroscopy,not only the noise and error of the system should be taken into consideration,but the window func-tion that used to isolate the spectrum has a great influence during the data processing.Then the effect of window type and win-dow width on phase difference of interferogram and the wind error curve are simulated through software.On basis of this the wind error curve under the noise of system and flat field factor are simulated by choosing appropriate window function.The win-dow function simulation indicates that although the joining of window leads to a distortion of the interferogam and phase,the wind speed error can be less than 0.5% with Hanning window in the appropriate optical path difference.The noise of the system simulation indicates that the wind speed error increases with the noise,so it is necessary to control the system noise and prepro-cess the sampling data.The research on data processing method has great theoretical significance and practical value for desig-ning the system parameter and improving the precision of spatial heterodyne wind detection.