Interface verification and satellite-ground testing of high-precision time comparison system between LEO satellites and Beidou satellites

In recent years, LEO satellite systems have become a research hotspot for scholars both domestically and internationally, and their applications in military and mobile communication have rapidly developed. The Chinese space station also belongs to the LEO satellite system and has been fully built and entering the stage of application and development. The Chinese space station is equipped with a high-precision time and frequency system that includes hydrogen atomic clocks, microwave clocks, and optical clocks. The system outputs 100MHz and 1pps signals as inputs, and an inter-satellite test payload is configured on the Chinese space station to perform two-way time comparison and synchronization with the Beidou satellite, thus achieving high-precision time comparison between LEO spacecraft and medium to high orbit satellites. In this article, firstly, a ground testing environment is established to verify the interface of the high-precision time comparison system between LEO spacecraft and medium to high orbit satellites. The test results show that the information interface of the comparison system remains consistent. Then, a satellite to ground test system is constructed to achieve high-precision time comparison between LEO spacecraft and medium to high orbit satellites. Analysis of ranging data shows that the comparison accuracy is better than 0.3ns.