射电天线指向改正模型中轴系误差的完全表达式

为了提高射电天线的目标跟踪精度,采用直接法推导了射电天线轴系误差对指向的影响,并给出轴系误差指向改正模型的完全表达式,明确了指向改正模型中各轴系参数的定义,传统分项以及球谐函数所推导的轴系误差项为该模型的简化形式.基于此,评估得出基本参数改正模型中,因忽略轴系误差高次谐项而引起的指向精度损失可能达到1′′量级,具体需结合轴系误差大小而定;同时明确了基本参数改正模型(如22项指向模型)中与轴系误差有关的部分高次谐项系数的物理意义.为高精度轴系误差指向改正模型的建立提供了理论依据.

The Complete Expression of the Axes Related Errors for the Pointing Calibration Model of the Radio Telescope

In order to improve the target tracking accuracy of radio telescope, the impact of axis related errors (ARE) on the pointing of the radio telescope is derived directly, and the complete expression of the ARE pointing correction model is given. The definition of the axis parameters in the pointing correction model is clarified. The items of ARE derived from the traditional splitting item and spherical harmonic function are the exactly simplified form of our model. Thus, the evaluation results show that the pointing accuracy loss due to neglecting high order ARE terms in the basic parameter correction model is sim$1''$, which depends on the magnitude of the ARE. At the same time, the physical meanings of some high order harmonic coefficients regarding to ARE in the basic parameter correction model, e.g. the 22-item model, are also clarified. It provides a theoretical basis for the establishment of the model of high precision ARE pointing correction.