On Navigation of Lunar Orbiter by Utilizing GPS

Abstract

The purpose of this paper is to discuss the method and accuracy of position determination of a spacecraft at a long distance from the earth like a lunar orbiter. Several very long base-lines which start at a main radio station, spread out in any directions and end at several subordinate radio stations are used to measure differences in the time of arrival of the radio signal transmitted from the spacecraft. Precise measurements of positions and clock offsets of subordinate stations relative to the main station are required to achieve the accurate position determination. The method and the accuracy of the position and clock offset determination of radio stations by using GPS satellites as radio sources of the interferometry measurements are investigated and the following accuracy of the space navigation is shown by simple equations.