月球轨道器交会对接同波束VLBI测量差分相时延实时解算

同波束VLBI技术是解决月球轨道交会对接地面高精度引导的重要手段．传统的多频点同波束VLBI实时解算算法成功解算差分相位整周模糊度的概率较低，而事后统计修正求解整周模糊度的算法存在较大的时间滞后，从而直接影响月球轨道交会对接两个航天器地面定轨、定位的精度以及实时性．在此背景下，本文研究了应用于月球交会对接条件下的同波束VLBI差分相时延实时解算算法．首先给出了多频点同波束VLBI解算差分相时延及整周模糊度的原理，根据差分相关相位整周模糊和差分相时延实时及事后解算结果，对整周模糊度产生的原因进行分析通过求解精确差分群时延值、采用匹配搜索算法以及差分相位连接条件对传统实时解算算法进行改进，提出一种新的差分相时延实时解算算法．利用SELENE同波束VLBI观测数据进行实时解算．结果表明该算法成功解算模糊度的准确度达到95．49％，相对于传统解算算法准确度提高了5．45％．

Real-time differential phase delay resolving of same beam VLBI in lunar orbiter rendezvous and docking

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.