VLBI在探月卫星定位中的应用分析

Application Analysis of Lunar Exploration Satellite Positioning by VLBI Technique

中国实施的"嫦娥"探月工程中,探月卫星的定轨测控系统由我国现有的S频段航天测控网(USB)和甚长基线干涉测量(VLBI)系统组成。系统中,VLBI技术主要为绕月卫星定轨提供卫星的角位置。本文分析了在探月项目中,VLBI单点定位的必要性。探讨了VLBI技术用于探月卫星单点定位的基本原理及其实现方法。通过算例对模拟数据进行处理,检验了方法的正确性。对结果进行分析,得出一些结论。

In lunar exploration project of Chinese ＂Chang-E＇, the orbit determination and measurement control system for ＂Chang E-I＂ lunar exploration satellite consist of the existing S band spaceflight measurement control network （Unified S-band USB） and Very Long Baseline Interferometry （VLBI）. The main mission of VLBI in Chinese lunar exploration project is providing the angular position of circumlunar satellite for orbit determination. GPS （Global Positioning System） and SLR （Satellite Laser Ranging） are the two main techniques on satellite precise orbit determination, but GPS is only used in LEO （Low Earth Orbit） satellite orbit determination. For HEO （High Earth Orbit）, the orbit determination precision may be very poor or can not be determinated by GPS. SLR may be used in the orbit determination for this satellite, but it should be amounted by laser reflector, and it is also limited by the height of orbit. Moon is 384 thousand kilometers far away from the Earth. The space geodesy techniques served on earth such as GPS and SLR can not determinate such far distant satellite orbit. While with the capability and predominance of deep space observation, VLBI can be used in lunar exploration satellite orbit determination. In this paper, we present a new method of VLBI point positioning which can be fit for the demand of angular surveying on Chinese lunar exploration project. The necessary of VLBI point positioning on the exploration lunar project is ana- lyzed in this paper. The basic theory and realization method of satellite point positioning using VLBI are discussed. Surveying model is also established in this paper. The correctness of this method is checked by using simulated data, and analyzed the result.