OPTICAL COMMUNICATION SYSTEM

摘要

An optical communications system for enabling short- range communication between two stations, which may be relatively movable stations such as helicopters, comprises on each helicopter 10 (Fig. 2) a directional optical transmitter 11 coupled to a sight 10' steerable in azimuth by an operator and an array of (e.g. eight) optical receivers (12) arrayed about the helicopter in housings 15-18 and having fields of view defining communication sectors, the adjacent sectors being contiguous or slightly overlapping in azimuth. The receivers are connected to sector selection means 26 (Fig. 4) for determining on a continuous basis the sector containing the strongest signal, identifying the sector to the sight operator and passing the signal from that sector to a speech (or other) decoder. The communication link is established by a first helicopter transmitting a coded signal to a second identified by the sight operator. The receiving helicopter determines in which of its communication sectors the signal is received and a verification code is transmitted into that sector, the first helicopter on receipt of this verifying the connection and permitting messages to be passed. The transmitter may alternatively take the form of a plurality of fixed transmitters housed with the receivers enabling transmission into one or more sectors by choice of transmitter rather than physical rotation of a single transmitter.