Applications of Delta Differential One-way Ranging (ΔDOR) to Lunar Exploration Program

Delta Differential One-way Ranging (ΔDOR) is used for high precision angle measurement in many deep space exploration programs. The fundamentals of ΔDOR are introduced. Also, recommendations about ΔDOR of CCSDS (Consultative Committee for Space Data System) are presented. According to the high precision and real-time navigation requirements, the ΔDOR measurement schemes are designed for China's lunar exploration program whose current object is soft-land on the moon. The angle measurement precisions are analyzed in terms of the current performances of on-board and ground TT&C equipments. The resolution of the cycle ambiguity is presented. Research results show that the angle measurement precision is 25 nrad, which corresponds to about 10m on the moon. Further, the cycle ambiguity of DOR measurements can be resolved correctly.