平均风作用对天马望远镜面形精度和指指向精度的影响

天马望远镜的最高工作频段为43 GHz。为保证高质量的观测结果,需要研究风载荷对天线精度的影响。首先对观测站实测的风速风向数据做了统计分析,结果显示:10 m高度处10min时距平均风速小于4 m·s^-1的占比超过80%,主导风向为北-西北方向。然后,通过将倾斜仪实测结果与有限元模拟结果进行对比,验证了模拟的有效性,并进一步分析了在不同迎风姿态、不同风速下天线结构的平均风荷载响应,以及天线面形精度和指向精度的变化。结果表明,平均风荷载对天线指向精度,尤其是俯仰角指向精度的影响较大,对面形精度的影响较小;在弹性范围内,天线面形精度和指向精度与风速间均为二次关系。研究结果可为天线面形精度和指向精度的评估提供参考。

The Effect of Mean Wind Power on Antenna Surface Accuracy and Pointing Accuracy of the Tian Ma Telescope

The highest working frequency band of the Tian Ma Telescope(TM65m)is 43 GHz.To ensure high-quality observations,it is necessary to study the influence of wind load on the antenna accuracy.Firstly,the wind speed and direction data measured at the observation station were statistically analyzed.The results show that the wind speed below 4 m·s^-1 account for more than 80%of the wind speed at 10 m height,and the dominant wind direction is north-northwest.Then,by comparing the measured data of the inclinometer and the finite element simulation results,the effectiveness of the simulation is verified.Furthermore,the average wind load response of the antenna structure under different windward attitudes and different wind speeds is analyzed,as well as the antenna surface accuracy and pointing accuracy.The results show that the average wind load has a greater influence on the pointing accuracy of the antenna,in particular the pitching pointing accuracy,and has little effect on the accuracy of the surface shape;within the elastic range,the relationship between the antenna surface shape accuracy and the wind speed is a quadratic relationship,so is pointing accuracy and wind speed’s relationship.These results can provide reference for the evaluation of antenna surface accuracy and pointing accuracy.