Calibration Techniques for Asymmetric Spatial Heterodyne Interferometers

The detection of wind in the middle and upper atmosphere has important scientific and practical value for the construction of atmospheric models, satellite orbit prediction, communication and navigation support, and space weather disaster prediction. The Doppler shift of airglow radiation obtained by optical interferometer is one of the most important methods for remote sensing of atmosphere wind. Ensuring the accuracy of these measurements necessitates the calibration of the wind measurement performance of optical interferometers. In this paper, we propose the concept of wind measurement sensitivity coefficient through studying the wind measurement principle of asymmetric spatial heterodyne interferometer, providing a solid theoretical foundation for instrument calibration. Two typical calibration systems are designed and implemented to calibrate an asymmetric spatial heterodyne interferometer. By examining both the calibration process and results, we conduct a comprehensive evaluation of the uncertainty and applicability of these two systems. The acousto-optic frequency shift calibration system boasts an uncertainty of less than ±1 m·s^–1, coupled with its compact design and ease of integration, making it an ideal transfer standard for internal calibration within ground wind measurement networks. On the other hand, the reflective wheel calibration system demonstrates wide applicability across various light sources. The findings presented in this paper can serve as a valuable reference for both laboratory and routine field calibration of wind-measuring optical interferometers.