X-Band TT&C Design in Launch and Early Orbit Phase for Chang’ E-5

Abstract

Due to advantage of high measurement accuracy and less interfere. X band TT&C had been the main frequency band in lunar and deepspace exploration. Chang’E-5 used X band TT&C in launch phase first time. Compared with S band, X band had the shortage of wider target dynamic range、narrower antenna beam，and shorter system acquisition time. Furthermore Long March 5 rocket used narrow window multi-orbit launch plan. Both of them asked for higher requirements in launch phase quick acquisition, TT&C ship position determination，first acquisition of ground station after separation. In view of the difficulties of narrower ground antenna beam, wider frequency dynamic range and wider receiver bandwidth of explorer in the launch and early orbit phase for Chang’E-5， an overall plan of the X-band was designed by using such methods as analyzing ship position covered by feature points，Doppler preset fast scan capture and cooperated backup of deep-space stations between ESA (European Space Agency) and Kuru，which effectively reduced the risk of implementation and ensured the success of the mission. Chang’E-5 mission has laid a foundation for the overall design and construction planning of the future lunar and deep space TT&C mission.

Keywords

Chang’E-5 / launch and early orbit phase / two-way acquisition / TT&C general design