基于加速度信号的TMT三镜镜面jitter测量

为了更好地对于TMT三镜镜面jitter进行评价,基于镜面方向的加速度信号,通过传递函数以及功率谱的方法,获得了镜面jitter的频域分布与数值特征。首先,对于梯形积分、辛普森积分以及3/8辛普森积分的基本性质进行推导,之后基于功率谱的思想,提出利用白噪声填满数据全部频域以及结合数值方法得到传递函数;最后对于实际测量得到的加速度信号,得到了米级口径望远镜镜面jitter的数值以及频域分布,同时证明了利用文中方法对TMT三镜镜面jitter进行评价的可行性。文中的方法对于同类的大口径望远镜的jitter测量也有一定的借鉴意义。

TMT tertiary mirror jitter measurement with acceleration signal

To evaluate the jitter of the Thirty Meter Telescope tertiary mirror, the acceleration signal collected from the tertiary mirror should be integrated into displacement signal and to be analyzed. The first and foremost, the acceleration of the mirror along the normal line was achieved. Then, the trapezoidal, Simpson, 3/8 Simpson numerical integration method were analyzed to show the basic property of the integration method; after that, using the transfer function and spectrum method, the jitter property of a large telescope at one meter scale was analyzed in both value and frequency domain and the jitter after adaptive optical adjustment was 6 m RMS. At the same time, this verifies the testing process plan for the jitter of the TMT M3. In this paper, the basic procedure for mirror jitter analysis was presented, and the conclusion can be draw that the method is adequate to fit the requirement proposed by TMT project. This work will give guidance to the jitter testing in the similar large aperture system.