APPLICATION ANALYSIS OF LUNAR EXPLORATION SATELLITE POSITIONING BY VLBI TECHNIQUE

Abstract

In lunar exploration project of Chinese "Chang-E", the orbit determination and measurement control system for "Chang E-1" 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 analyzed 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.