Global ship-shore satellite data transmission system for connecting digital data processors

This paper describes a global data transmission system, currently being implemented by the US Navy, for connecting ship-board data processors to shore stations. This system which uses the Defense Satellite Communication System (DSCS), serves the Atlantic, Pacific, and Indian Ocean regions. The transmissions from the ships are grouped in relatively narrowband adjacent channels which are processed by a single down-converter in the satellite ground facility. Transmissions from the shore are broadcast using a time-division multiplexing arrangement to preserve satellite repeater power. Special equipment, including the modem and the multiplexer, has been developed and tailored to the system's requirements. For on shore circuit extensions new standardized Navy equipment will be used. To verify the system design and develop operations procedures the system has been tested over an extended time period. As a result a robust system has been developed which, despite of its complexity, is expected to perform its task to an operational availability of 95 percent.