An Evaluation of VLBI Observations for the Deep Space Tracking of the Interplanetary Spacecrafts

摘要

We performed more than 30 VLBI experiments for the two Japanese spacecraft NOZOMI and HAYABUSA from September 2002 until June 2003 using nine VLBI antennas in Japan. Algonquin 46-m of Natural Resources Canada also participate in several experiments. The final group delay products obtained from the VLBI experiments were available with approximately 30 hours latency. These group delays are consistent with the NOZOMI orbit using range and range rate observables. However, the rms scatter between them are relatively large up to several tens of nanoseconds due to the low signal to noise ratio of the NOZOMI signals. We also perform another VLBI experiments for HAYABUSA in order to establish the positioning technology for the interplanetary spacecrafts in realtime.