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中国物理学会期刊

基于全局拟合的多普勒差分干涉仪成像漂移检测方法

CSTR: 32037.14.aps.74.20250027

A method of monitoring image shift based on global fitting Doppler heterodyne interferometer

CSTR: 32037.14.aps.74.20250027
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  • 大气风场在全球气候研究和空间探测中具有重要作用, 多普勒差分干涉仪作为新型被动测风干涉仪, 其通过测量大气气辉谱线的多普勒频移引起的相位变化量来反演大气风速, 但环境温度波动会导致像面相对于干涉仪发生漂移, 从而影响风场测量结果. 本文提出一种在光栅上刻蚀周期性刻槽, 并对其成像图案进行建模与全局拟合以实现高精度成像漂移检测的方法. 对刻槽图像的信噪比及模型参数拟合误差对检测结果的影响进行仿真分析, 结果表明, 图像信噪比、刻槽数量拟合精度与刻槽宽度拟合精度是影响检测精度的关键因素, 而刻槽图像边缘的平滑度的拟合精度对检测结果影响较小. 在近红外多普勒差分干涉仪的热稳定实验中, 通过对实验所测数据人为施加漂移量, 并进行成像漂移监测, 结果表明该方法能够实现9.96 nm的检测精度. 此外, 经成像漂移校正后的干涉图相位的局部振荡显著减弱, 表明该方法能有效检测与校正成像漂移, 显著提升干涉图像相位稳定性, 为高精度风速测量提供了可靠保障.

     

    Accurate atmospheric wind field measurements are critical for understanding global climate dynamics and facilitating space exploration. Doppler asymmetric spatial heterodyne interferometer (DASH) is used to measure atmospheric wind speed through detecting the phase changes in interferograms induced by Doppler shifts of airglow emission lines. However, environmental temperature fluctuations and mechanical vibrations often cause imaging plane to shift, thereby introducing phase deviations, and degrading the measurement accuracy. In this study, a novel method of monitoring global fitting-based imaging shift is proposed. By etching periodic notches on the diffraction grating surface, the method models and fits the notch patterns formed on the detector plane to achieve precise imaging shift detection and correction. The optimization of notch signal modeling significantly reduces the number of fitting parameters, thus improving computational efficiency and detection precision. Through extensive simulations, the influences of signal-to-noise ratio (SNR) and model parameter variation on detection accuracy are analyzed. The results indicate that when the SNR exceeds 11, the detection uncertainty is still below 6.5 nm. Sensitivity analysis reveals that the detection error stays within acceptable limits when the variations of notch number and notch width are controlled within 40% and 0.7%, respectively, while the influence of edge smoothness parameter of notch pattern is negligible. To validate the performance of the method, the thermal stability is tested by using a near-infrared DASH prototype. The experimental results demonstrate a strong correlation between interferogram phase shifts, imaging plane shifts, and environmental temperature variations. After applying the proposed correction method, local phase fluctuations in the interferogram are significantly reduced, thus the phase stability is improved. Further, artificially applied imaging shifts are accurately detected with errors consistently below 9.96 nm, thereby confirming the reliability and precision of this method. All in all, the proposed method effectively detects and corrects the imaging plane shifts caused by temperature variations, enhancing interferogram phase stability and ensuring high-precision wind speed measurements. This method provides a robust and computationally efficient solution for reducing imaging shifts in DASH systems, and has great potential applications in atmospheric wind field measurement and space-based observation.

     

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