Radio Holographic Metrology with Best-Fit Panel Model of the Nobeyama 45-m Telescope

Hiroyuki DEGUCHI  Masanori MASUDA  Takashi EBISUI  Yutaka SHIMAWAKI  Nobuharu UKITA  Katsunori M. SHIBATA  Masato ISHIGURO  

IEICE TRANSACTIONS on Communications   Vol.E76-B   No.12   pp.1492-1499
Publication Date: 1993/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on 1992 Internatioal Symposium on Antennas and Propagation)
antennas and propagation,  surface accuracy,  holography,  

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A best-fit panel model in the radio holographic metrology taking into account locations and sizes of actual surface panels in a large reflector antenna is presented. A displacement and tilt of each panel can be estimated by introducing the best-fit panel model. It was confirmed by simulations that the distinction can be drawn between a continuous surface error and a discontinuous one. Errors due to truncation of the radiation pattern were calculated by simulations. It was found that a measurement of a 128128 map is optimum for the 45-m telescope. The reliability of the measurements using this model was examined by experiments with panel displacements. Panel adjustments using the best-fit panel model successfully improved the surface accuracy of the antenna from 138µm rms to 84µm rms (/D=210-6).