Abstract: A satellite communication system by which information of afflicted areas can be collected rapidly and accurately at the time of disaster such as an earthquake or the like, and which is easy to introduce. In the system, a center station accommodates a plurality of extensions of a private branch exchange. Portable terrestrial stations are made to one-to-one correspond to the extensions accommodated in the private branch exchange and the center station connects the extensions to the corresponding portable terrestrial stations. The respective frequency bands of a communication satellite to be used for the transmission from each of the portable terrestrial stations to the center station and for the transmission from the center station of each of the portable terrestrial stations corresponding to the one extension are stationarily secured. Each portable terrestrial station is small-sized so as to be portable by a person or by a motorcycle.

Abstract: A satellite communications system and method capable of bidirectional satellite communications between earth stations via a satellite, whereby communications by a plurality of signals sharing the same frequency band become possible while partially or wholly superposing respective signal frequencies. Each earth station including: a transmission circuit for transmitting a local transmission signal toward the satellite; a reception circuit for receiving a remote transmission signal transmitted from a remote earth station and a return signal, the return signal being part of the local transmission signal transmitted from the local earth station toward the satellite and partially returned from the satellite and received at the local earth station; and a cancelling circuit being supplied with part of the local transmission signal and the received return signal, for cancelling the received return signal by part of the local transmission signal.