Surface accuracy of main reflector of a radio telescope is a key factor affecting performance of large radio telescopes.
In order to ensure good performance of the radio telescope, deformation error of antenna surface of the radio telescope is required at a low magnitude compared to the wavelength. The change of environmental load (gravity, temperature, wind load) has a significant impact on the accuracy of main reflective surface because of size of main reflector (ten or even hundred of meters) for large radio telescopes. It is a huge challenge to maintain surface accuracy of the huge main reflector during observation. Li Guoping team of Nanjing Institute of Astronomy and Optical Technology (NIAOT) and Wang Na team of Xinjiang Astronomical Observatory put forward a set of technical schemes to meet surface accuracy requirements of the main reflector for Xinjiang Qitai 110-meter radio telescope. Important progress was made as follows:
1: development of high-precision displacement actuator with displacement greater than 50mm and positioning accuracy better than 15μm. 2: development of new edge sensor based on light spot centroid extraction algorithm using three-dimension arctan function fitting proposed by Li Guoping team with angular measurement accuracy better than 0.2 ". 3: development of active real-time surface maintenance system based on above two technology which can maintain closed-loop surface accuracy better than 0.2mm for the main reflector of Xinjiang Qitai 110 m radio telescope through a real-time closed-loop algorithm. Above research results supported by the National Key Basic Research Development Program (973), National Natural Science Foundation of China and the LAMOST project were published in the Publication of the Astronomical Society of the Pacific (PASP) in January 2022.
active real-time surface maintenance system for main reflector
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