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多普勒非对称空间外差干涉仪可用来探测氧气大气带气辉谱线的多普勒频移,进而反演中高层大气的风速。由风速变化引起的干涉条纹相位频移十分微小,而由系统误差导致的绝对相位漂移会严重影响风速反演精度。双臂式干涉仪与单臂式不同,除受扩视场棱镜和光栅影响之外,用于产生光程差的空气隔片的热膨胀也会影响干涉图的绝对相位。通过实测和仿真计算不同温度下的绝对相位漂移,分析了绝对相位漂移的原因。在此基础上,提出了一种绝对相位漂移校正方法,通过求零风速和某一给定风速下两条线性相位拟合曲线之间的距离,校正温度引起的绝对相位漂移,从而准确反演风速。结果表明,仿真分析与实测的绝对相位漂移具有较好的一致性。校正绝对相位漂移后反演的风速误差为3.5m/s,与校正前相比风速反演误差得到了极大的改善。
Doppler asymmetric space heterodyne interferometer can be used to detect the Doppler shift of oxygen gas with gas chromatogram, and then reverse the wind speed in the middle and upper atmosphere. The frequency shift of the interference fringes caused by the change of wind speed is very small, while the absolute phase shift caused by system error will seriously affect the accuracy of wind speed inversion. The two-arm interferometer is different from the one-armed and, in addition to being affected by the field prism and grating, the thermal expansion of the air spacers used to create the optical path difference also affects the absolute phase of the interference pattern. By measuring and simulating the absolute phase shift at different temperatures, the reason for the absolute phase shift is analyzed. On this basis, an absolute phase shift correction method is proposed, which can correct the absolute phase shift caused by temperature by correcting the distance between the two linear phase fitting curves at zero wind speed and given wind speed Wind speed. The results show that there is a good agreement between the simulation analysis and the measured absolute phase shift. The corrected wind speed error of absolute phase drift is 3.5m / s, and the error of wind speed inversion has been greatly improved compared with that before correction.