双向相干测距测速体制是最常用的航天器测量体制,是一种闭环体制。与之相比较,开环测距测速可以在信号更微弱的情况下获取到观测量,在深空任务中有着独特的意义。然而,开环测距也面临棘手的技术难题——高精度航天器定时技术。针对该难题,在保持现有航天器信号体制的基础上,阐述了基于遥测信号和测距侧音信号(差分单向测距DOR信号可看作侧音信号)间相频约束的航天器定时原理,研究了侧音频率最优化设计方法,给出了“器上发射—测站接收”的初步实现方案,为后续开展工程应用奠定了基础。 Bi-directional coherent distance measuring system is the most commonly used spacecraft measurement system is a closed-loop system. In contrast, open-loop Ranging and Velocimetry can obtain the observed data in the case of a weaker signal, which is of special significance in deep space missions. However, open-loop ranging is also faced with a difficult technical problem - high-precision spacecraft timing technology. In view of this problem, based on the existing spacecraft signal system, the spacecraft timing based on the phase-frequency constraint between the telemetry signal and the ranging sidetone signal (the differential unidirectional ranging DOR signal can be regarded as the sidetone signal) Principle, the optimization design method of sidetone frequency is studied, and the initial implementation scheme of “transmitter on the device - receiving station” is given, which lays the foundation for the subsequent application of engineering.