Performance of a satellite-aided maritime distress alerting system

A maritime distress alerting system whose signals are to be transmitted by commercial (geostationary) maritime communication satellites is described. The name of the concept is the Satellite-Aided Maritime Search and Rescue System. A distinctive feature of this system is that spread spectrum signaling is used to provide multiple access and interference resistance. Tests carried out in 1979 demonstrated the feasibility of operating a reliable, long-range, low-power maritime spread spectrum distress alerting system through a commercial maritime communications satellite under a variety of high level terrestrial interference. Also demonstrated was an absence of interference to existing public correspondence communications resulting from the presence of a large number of spread spectrum signals.