messages back to the ground station, and another satellite capable of relaying inbound messages from the users to the ground station. Depending on the spot beams, a minimal system can serve a small geographical area, or can serve nearly one-fifth of the globe. Six satellites with wide-area coverage, and three ground stations, are sufficient to provide all services world-wide, excluding only the extreme polar latitudes (Fig. 1). That number provides instantaneous recovery against the failure of the transmit capability of any single satellite. It might be noted also that several Geostar-like systems could coexist using the same frequency bands. FREQUENCY CHANGES PROPOSED In September of 1984, the U.S. Federal Communications Commission (FCC) issued a Notice of Proposed Rulemaking proposing the allocation of frequency bands in the microwave region in the United States for a new service, to be called the Radio Determination Satellite Service (RDSS). Because the Notice was the FCC’s reply to the application of a single company, the Geostar Corporation, the term “Geostar System” will be used hereafter. The Commission proposed in the Notice that the technical specifications submitted by our firm become the standards for the RDSS. The Commission also submitted to the International Telecommunication Union an Advanced Notification of the RDSS orbital locations and satellite characteristics for the United States, and these were published by the International Frequency Registration Board on 9 October 1984 under the names “USRDSS East, Central and West.”
RkJQdWJsaXNoZXIy MTU5NjU0Mg==