International Two-Way Satellite Time Transfers Using INTELSAT Space Segment and Small Earth Stations

The satellite system operated by the International Telecommunications Satellite Organization INTELSAT provides new and unique capabilities for the coordination of international time scales on a world wide basis using the two-way technique. A network of coordinated clocks using small satellite earth stations collocated with the time scales is possible. Antennas as small as 1.8 m at K-band and 3 m at C-band transmitting powers of less than 1 W will provide signals with timing jitters of less than 1 ns wing existing spread spectrum modems. One way time broadcasting is also possible, under the INTELSAT INTELNET system, possibly using existing international data distribution press and financial systems that are already operating spread spectrum systems. The technical details of the satellite and requirements on satellite earth stations are given. The resources required for a regular operational international time transfer service is analyzed with respect to the existing international digital service offerings of the INTELSAT Business Service IBS and INTELNET. Coverage areas, typical link budgets, and a summary of previous domestic and international work using this technique are provided. Administrative procedures for gaining access to the space segment are outlined. Contact information for local INTELSAT signatories is listed.