A Backtracking Method Based on Frame Synchronization for Deep Space Super Low Bit Rate Data

Due to the super low telemetry bit rate and limited transmitting time for deep space mission, the total received telemetry data is precious; it is necessary to obtain as much telemetry data as possible, and decrease overhead and increase the efficiency of data receiving. A backtracking method（BTM）for deep space super low bit rate frame synchronization data was proposed in this paper for the data loss in the process of three-state transfer in traditional frame synchronization. The data frames in the process of three-state transfer in frame synchronization were backtracked, and multiple valid telemetry data frames were obtained by using the valid frame synchronization information. The method was successfully applied to the super low telemetry data receiving for orbiter and rover in Tianwen-1 Mars exploration mission. The result shows that 2~4 more valid data frames were obtained with the method proposed compared with the traditional method, and transfer efficiency was improved by 13%~40%. More valid data frames and higher transfer efficiency could be obtained by using the method. The method proposed in this paper can be particularly useful for deep space super low bit rate telemetry data receiving, and could be used in the further exploration of asteroids, Jupiter and the boundary of the solar system.