CAJ | 학술논문

目前国内外射电望远镜指向修正大多采用线性修正模型，这种方法未考虑非线性偏差对指向的影响，其修正精度有一定局限，为此提出一种用于大型轮轨式射电望远镜考虑方位轴非线性倾斜偏差的指向修正方法。针对国家天文台密云50 m射电望远镜，对其进行全轨水平度测量，通过有限元建模并仿真计算天线方位轴的非线性倾斜偏差，同时通过实验测量了由于轨道不平度引起的俯仰轴角测量误差并进行了有限元仿真验证。应用天线指向试验数据进行考虑方位轴非线性倾斜偏差指向误差修正，得到新的指向辨识参数及指向残差分布。该修正方法与线性修正模型相比，总的指向精度提高了约0.5783″。
목전국내외사전망원경지향수정대다채용선성수정모형，저충방법미고필비선성편차대지향적영향，기수정정도유일정국한，위차제출일충용우대형륜궤식사전망원경고필방위축비선성경사편차적지향수정방법。침대국가천문태밀운50 m사전망원경，대기진행전궤수평도측량，통과유한원건모병방진계산천선방위축적비선성경사편차，동시통과실험측량료유우궤도불평도인기적부앙축각측량오차병진행료유한원방진험증。응용천선지향시험수거진행고필방위축비선성경사편차지향오차수정，득도신적지향변식삼수급지향잔차분포。해수정방법여선성수정모형상비，총적지향정도제고료약0.5783″。
In most radio-telescope pointing calibrations in China and abroad linear calibration models are used.The linear models do not consider the impact of nonlinear deviations on telescope pointing, and their calibration accuracies are rather limited.In this paper we present a new pointing-calibration method that includes correction for nonlinear deviations of the tilts of the azimuth axis of the antenna of a large-aperture radio telescope movable on a rail.We have applied the method to the Miyun 50m radio telescope of the NAOC. For the 50m radio telescope we measured roughness along its entire rail track and used the finite-element method to simulate nonlinear deviations of the tilts of the azimuth axis of its antenna.We also measured altitude errors of the antenna caused by rail-track roughness.The measurements are consistent with our finite-element simulations based on our new method and our measured rail-track roughness values, and thus verify the new method.We have carried out an experiment of pointing calibration of the 50m radio telescope using our new method.Compared to a conventional linear calibration model, our nonlinear model improves pointing accuracies by 0.5783 arcsecond on average.