基于色散条纹传感技术的拼接镜共相方法

Method of Segmented Mirror Co-Phasing Based on Dispersed Fringe Sensing Technology

针对拼接型望远镜共相难的问题,提出了一种基于色散条纹传感技术的共相误差检测方法。根据色散条纹传感技术的探测原理,给出了色散条纹传感器的光学成像模型,并利用计算机进行模拟研究。为解决色散条纹检测技术在接近共相时失效的问题,提出一种辅助检测方案,即色散哈特曼检测法,并通过仿真验证了该方法的可行性。结合两种方法,色散条纹传感器在可见光范围内能准确检测±60μm以下的活塞误差,检测精度可达λ/10。同时,对一系列影响检测精度的因素进行了定量分析,提出了条纹开窗、多路采集、提高波长标定精度等解决方法,还针对算法提出新的改进方案,降低了标定误差影响。结果表明,该方法可以有效地完成对活塞误差的大量程、无盲区、高精度检测,在空间和地基拼接型望远镜的粗共相标定和相位控制领域有广阔的应用前景。

Aimed at the difficult problem of segmented telescope co-phasing, a method of co-phasing error measurement based on dispersed fringe sensing technology is proposed. According to the detecting principle of the dispersed fringe sensing technology, an optical imaging model of dispersed fringe sensor is introduced. The simulation study is carried out on the computer. An auxiliary scheme called dispersed Hartmann measurement is brought out to solve the problem that dispersed fringe sensing algorithm loses efficiency under the near co-phasing condition. Simulations are also made to verify the feasibility of this method. By combining the two methods, dispersed fringe sensor can detect piston error under the range of ±60μm in the visible waveband, and the detecting accuracy can achieve λ/10. Besides, the impacts of various factors on the detection accuracy have been analyzed in quantity. And solutions such as the fringe windowing, multi-trace and enhancing wavelength calibration accuracy are put forward to improve the dispersed fringe sensing technology performance. An advanced algorithm is also presented to make the method less sensitive to calibration errors. The results show that the proposed method can effectively detect piston error with high precision, no blind area and extremely wide range. It can be widely applied in the coarse co phasing calibration and phasing control for space and ground based segmented mirror telescopes.