RADIO HOLOGRAPHIC METROLOGY WITH BEST-FIT PANEL MODEL OF THE NOBEYAMA45-M TELESCOPE

A best-fit panel model in the radio holographic metrology taking into account locations and sizes of actual surface panels in a large reflec tor antenna is presented. A displacement and tilt of each panel can be estimated by introducing the best-fit panel model. It was confirmed b y simulations that the distinction can be drawn between a continuous s urface 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 128 x 128 map is optimum for the 45-m telescope. The reliability of the measurements using this model was examined by exper iments with panel displacements. Panel adjustments using the best-fit panel model successfully improved the surface accuracy of the antenna from 138 mum rms to 84 mum rms (epsilon/D = 2 x 10(-6).