月球轨道器交会对接同波束VLBI测量差分相时延实时解算

Abstract

Same beam VLBI is an important mean for the high precision ground-based navigation in lunar orbit rendezvous and docking. The probability of calculating the differential cycle ambiguity successfully by conventional real time resolving algorithms of multi-frequency same beam VLBI is low. However, the time delay is very long if the differential phase delay is calculated by post-processing method. The precision and the time delay of ground based navigation for two spacecrafts in lunar orbit rendezvous and docking will be affected. Under this background, a real time differential phase delay resolving algorithms of same beam VLBI which is applicable for lunar orbit rendezvous and docking is studied. The differential phase delay and cycle ambiguity resolving principles of multi-frequency same beam VLBI are introduced. The cause of cycle ambiguity error is analyzed according to the real-time and post-processing results of differential phase cycle ambiguity and differential phase delay. Some improvements are achieved by calculating accurate differential group delay and using matching searching method and continuity of differential phase, and a novel real time differential phase delay resolving algorithm is put forward. The result, calculated by using same beam VLBI observation data of SELENE mission, shows that the probability of getting the right cycle ambiguity is up to 95.49%, which is 5.45% higher than the conventional method.