A novel two-layered optical satellite network of LEO/MEO with zero phase factor

Optical satellite communication has advantages over the RF satellite communication in capacity, speed, secrecy and anti-interference. Space information superhighway composed of GEO/MEO/LEO satellites which are linked by optical inter-satellite links (OISL) would play important roles in communication, navigation, martial recon, remote sensing and deep space exploration. A novel LEO/MEO two-layered optical satellite network with global coverage is designed with the street-of-coverage technique. The layer of LEO satellites is the walker-delta constellation with zero phase factor and has the quasi-stable logical structure of Mesh. Equatorial and polar orbit satellites constitute the layer of MEO satellite, which can cover LEO layer effectively. Rising satellites of the system can provide 99.9% of coverage for the whole globe and 100% for China averagely. The network can provide a minimum elevation angle at 21A degrees with single-satellite visibility for China, and at 16A degrees with the dual-satellite visibility. Simulation results of the inter-satellite links show LEO constellation of zero phase factor outperforms non-zero phase factor constellations in azimuth angle, elevation angle and distance, which is very fit for the OISL. Simulation results of the communication performance indicate a little difference between short wave band and long wave band at low communication speed (several Gbit/s); however, the wave band at 1550 nm is a better choice at high communication speed (100 Gbit/s).