The inter-satellite link is realized through a radio frequency transmission and reception device, using the corresponding frequency and communication system, to achieve relative measurement and data exchange between constellation satellites. The relative measurement process within the constellation is composed of a series of relative distance measurements and communication processes between two satellites, mainly to complete the precise measurement of inter-satellite pseudorange and clock time difference. High-precision inter-satellite distance and time difference measurement is the basis for navigation constellation orbit determination and time synchronization, and inter-satellite bi-directional measurement is currently the most commonly used and highest precision method (Jing Yi et al. in Rev Sci Inst 89(6):06,450 (2018)).