Deformation measurement and modeling analysis for the 25m antenna

The pointing of an antenna always exists deviation due to track deformation, gravity and thermal influence. Through long time observation, we find that sunlight also has some influence on antenna structure. In order to get the antenna pointing deviation in the effects of the sunlight of 25m antenna in Urumqi, we use the frame-typed level and thermometer to make a week's measurement about the temperature around the antenna and the antenna tilt. The measured data was analyzed and combined with the track deformation data, and the pointing error fixed model as well as the thermal load deformation model were built. The measured data was fitted by the two models, and the result shows that the model can well reflect the pointing error and thermal load error, thus can give a better understanding of the antenna deformation, and also can give some good reference to antenna pointing calibration and the antenna's reconstruction.