Inter-Satellite Time Transfer: Techniques and Applications
Abstract
The role of the NASA Tracking and Data Relay Satellite System (TDRSS) is to increase the volume and frequency of communication between an orbiting spacecraft and the Earth, while at the same time providing command and tracking functions with extended coverage via a network of orbiting satellites and one or more ground stations. The same concept is currently being studied and is planned by the European Space Agency (ESA) under the name of Data Relay Satellite System (DRSS). TDRSS is an answer to the increasing complexity of new satellites and space missions that, especially in the field of scientific and application satellites, are placing increasing requirements in terms of mission support. New satellites, designed for scientific missions, such as astronomical observatories, or earth applications, for remote sensing, geodesy and precise navigation, are relying on precise onboard clocks to accomplish their missions. All these spaceborne clocks require precise synchronization to some external ground reference, synchronization that must be provided as a part of the standard mission support. Since mission support is the primary role for the TDRS systems, synchronization must be provided through the same links used for telemetry, command and data acquisition. There have been many time transfer experiments, and the techniques are well known and established throughout the years. A number of experiments have evolved into operational services now available worldwide and, in the case of the GPS, even to satellites in low earth orbit. However, the requirement to provide timing support as a part of the standard support to the space missions, has resulted in NASA providing timing services to user spacecraft directly via the TDRSS. The same service is being considered for the new Advanced TDRSS (ATDRSS) and the ESA Data Relay Satellites (DRS).
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1990
- Accession Number
- ADA519911
Entities
People
- E. Detoma
- S. C. Wardrip