两点求星历表的计算方法

A Computational Method of Using Two Position Data to Make Ephemeris

利用三站同步测距资料就能算出同步卫星位置。如果已经算出了同步卫星在两个不同时刻的位置,采用本文所提供的计算方法就能建立同步卫星星历表。本文所采用的计算方法,适合于在计算机上编程,从而构成同步卫星星历表计算的—个实用软件。

Adams-Cowell method is one of the most efficient numerical methods for making ephemeris of small eccentricity orbit. If the position vector and velocity vector of the celestial body at the same time have been obtained, the ephemeris of the celestial body can be made by means of Adams-Cowell method. This is the way which had been used befor. In this paper, the way of using position data of the celestial body at two different time to make the ephemeris is suggested. The principle is explained and the formulae are listted. By the use of the way it is eaay to form a practical software for making ephemeris with the aid of computer. The simulation computation of using circular orbit (Table 1 and Table 2 )shows the way suggested in thes paper to be efficient. In many cases the way suggested in this paper is convenient to be used. For example, measuring distance is a very important means for determining orbit of satellites. The position of satellite can be computed by using three stations. If the positions of satellite at two different time have been obtained, by using the way, we can make the ephemeris of the satellite easily. The error derivred Iron the way also is analysed. If the interval between the two different time corresponding to two different position of the celestial body. respectively is too short or too long, the way will cease to be efficient. To attain higher accuracy, the interval between the two time will be asked to be moderate. The simulation computation with cicular orbit (Table 3)has shown it.