Edge sensor based real-time calculation method for active panel position of QTT

Abstract

QiTai Telescope (QTT), the world’s biggest full-steerable telescope, will be constructed in Xinjiang, China. Its extra high operating frequency (115 GHz) imposes strict requirements on the accuracy of the reflector, while its large aperture (110 m) increases the impact of antenna weight and environment on surface accuracy. However, the panels of reflector will deform under the influence of gravity and the environment. Therefore, to compensate for the performance degradation caused by this deformation, a technique called active surface adjustment has been proposed. The existing adjustment methods cannot detect the deformation caused by environment of the reflector surface in real time, which can result in a delay in the compensation. Consequently, it is difficult to achieve an optimal compensating result. To solve this problem, a real-time method to estimate the large-aperture reflector antenna surface by calculating the antenna panel position based on edge sensors is proposed in this paper. In the proposed method, a panel coordinate transfer matrix has been formulated and the data measured from these edge sensors can then be treated as input for the proposed transfer matrix to calculate the actual position of the antenna panel in real time. A numerical simulation has been carried out in the QTT model and the results obtained show that the proposed real-time method is a promising tool to estimate the large reflector surface position in real time. It is believed that this active surface adjustment method has laid the foundation for new methods that will be developed to compensate for the reflector electrical performance.