Design of Layered Aerospace Time Synchronization Architecture and Time Synchronization Links Budget Comparison

The rapid development of various kinds of aerospace application systems requires the appropriate high-accuracy time and frequency standard. In order to establish suitable time and frequency standard in aerospace, based on the establishment of aerospace satellite visual model, we simulate the satellite visual time of 3-layer satellite constellation, including GEO satellite(Geostationary Earth Orbit), IGSO (Inclined GeoSynchronous Orbit)satellites and MEO(Medium Earth Orbit) satellites. The visual features of this satellite constellation have been gained. Combining with the major influencing factors of satellite clock offset error, we study the layered aerospace time synchronization architecture and give the advantage of the architecture and the choice of time synchronization method. Starting from the establishment of the time synchronization link demand, we simulate the variation range of intersatellite distance of the layered aerospace time synchronization architecture, and give budget results of GEO-GEO link in laser band and GEO-IGSO and GEO-MEO links in S-band and Kuband. The results show that GEO-GEO link can achieve to more than 3Gb/s data transmission rate on condition that the transmitting power is 0.5W, the antenna diameter is only 20cm; if the S-band transmission rate is in excess of 2Mb/s, when the antenna is 1m in diameter, the transmitting power needed is about 50W. In the Ka-band, 1m antennas only need 1W transmitting power to provide an intersatellite data transmission rate higher than 2Mb/s. Research results serves as reference for the establishment of layered aerospace time synchronization architecture and improvement of time synchronization precision.