ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2014, Vol. 35 ›› Issue (12): 3425-3437.

• Electronics and Control •

### Accurate Data Fitting for Adjustments of Focus Position Coordinates Applied to Cassegrain Antenna's Sub-reflector Compensation

HU Kaiyu1,2, AILI Yusup1, XU Xuelin3, XIANG Binbin1, LIU Qi1

1. 1. National Astronomical Observatories/Xinjiang Observatory, Chinese Academy of Sciences, Urumqi 830011, China;
2. School of Physical Science, University of Chinese Academy of Sciences, Beijing 100190, China;
3. School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
• Received:2013-12-19 Revised:2014-02-17 Online:2014-12-25 Published:2014-02-26
• Supported by:

China Lunar Exploration Project Ⅲ; National Basic Research Program of China (2013CB837900); National Natural Science Foundation of China (11103056,10778703,11153002); "Westen Light" Project of Chinese Academy of Sciences (XBBS201122)

Abstract:

Based on the rapidly progress of the Xinjiang 110 m radio telescope project, Nanshan antenna reform programme and national strategic demand for aerospace development, this paper makes a thorough study for the real-time compensation of the sub-reflector for the deformation of the large antenna's main panel. First, it presents a brief introduction to the theoretical model of sub-reflector compensation and an analysis of adjustments under certain special elevations. Then it realizes high-precision data fit using MATLAB because of its powerful numerical calculation. This paper gives two different data fit methods and model equations and compares the effects of the two fit methods from different aspects by detailed error analysis. When the fit order is 4 and computing to 15 decimal places, it calculates the error of the difference between these two data fit methods: the value is negative and the magnitude is 10-13 mm. Finally, the paper chooses the higher precision fitting method whose absolute error is minuend and uses this method to generate a partial adjustment database in the range of some special angels in order to create conditions for the entire sub-reflector compensation process which satisfies the requirements for astronomical observations and deep-space exploration for data accuracy and system reliability. The specific technology is believed to possess certain general value for applicability.

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