INMARSAT integrity channels for global navigation satellite systems

摘要: It is pointed out that the transmission of integrity information using a signal format compatible with GPS (Global Positioning System) and relayed through geostationary satellite repeater will be critical in achieving high availability global navigation by satellite, along self-contained consistency checking techniques such as receiver autonomous monitoring. The next generation Inmarsat spacecraft, Inmarsat-3, contain repeaters designed to fulfill this function. system channel, use pseudorandom codes same family but distinct from reserved GPS. data basic channel convey user range error for 24 40 satellites. A closed-loop timing compensation technique used at uplinking earth station, make signal's clock carrier Doppler variations identical those would result an on-board source. Therefore, Inmarsat-3 satellites increase number useful available any user, can also function sources precise tuning. There possibility wide-area differential corrections carried on signal. >