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.

Actual reflector antenna always has a deformation which has a serious influence on antenna performance. Establishing the equation of the distorted reflector surface is important for calculating antenna performance and precise control. A new best-fitting method based on least square method is submitted in this paper. This method depart from the ideal parabolic equation, and use the distance between the deformation point and the correspondent fitting point to establish the least square error condition equations, though which the six parameters can be got to determine the geometry position of the deformed parabolic accurately. Matrix operation can make the algorithm easy to realize in computer. Nan-shan 25m antennas finite element model is established in ANSYS program, and its result is analyzed compared with another method, confirmed the operability and accuracy of this algorithm.