Inmarsat for maritime telecommunications to aeronautical service

Current capabilities of the maritime Inmarsat satellite system are described along with plans for expanding the service. Inmarsat is composed of three segments: coast and shipboard receiving stations and satellites. Transponders are leased from Comsat, ESA, and Intelsat. Circuits on Marecs-A, Marisat, and Intelsat spacecraft are used for navigational coverage of the Atlantic, Indian, and Pacific oceans with 6/4 GHz uplink and downlink frequencies, respectively. Transmission capabilities include telephony, telex, facsimiles, data, and TV signals. Nine spacecraft are planned for operational status in 1988 to furnish 125 telephone channels per satellite and L-band data transmission. Commercial aircraft equipped with appropriate apparatus will then have access to the services.