同波束VLBI技术对嫦娥三号巡视器的高精度相对定位

Precisely Relative Positioning of Chang'E 3 Rover with SBI Delta VLBI Delay Measurements

基于中国VLBI网的同波束技术对嫦娥三号着陆器和巡视器进行了跟踪测量,依据探测器的数传和遥测信标特征分别获得差分群时延和相时延两类测量量。由于两探测器所处地势平缓,采用了运动学统计和高程固定的约束方法相结合的定位模式,基于同波束差分群时延和相时延分别获得100m和1m的相对定位精度。对未来探月三期探测器返回时的目标分离、对接等过程及其他未来深空探测项目中的相对定位具有重要借鉴意义。

Based on Chinese VLBI Network,the Chang＇E 3lander and rover are traced with the same beam interferometry（SBI）method.The SBI delta group delay and phase delay measurements are obtained respectively from the digital signal and telemetry signals of the onboard detectors.The two detectors are close to each other in the flat region of Mare Imbrium on the moon.We present the kinematically combined or statistical relative positioning of the rover with respect to the lander in two dimensions with lunar height constrained to the lander.Relative position accuracy was better than 100 m with SBI delta group observations,while the accuracy reached 1mwith SBI delta phase delay measurements.Our positioning method will play an important role in relative positioning during the course of separation and locking of spacecrafts in the future Phase III of Chinese lunar project and other future deep space projects.