Bustelo, Richard A.; Harris Corporation (International Foundation for Telemetering, 1986-10)
      The Global Positioning System Ground Antenna is an unmanned earth terminal providing TT&C functions for the constellation of GPS satellites. This paper describes the design of the GPS/GA, with emphasis on those design issues unique to unmanned terminals. The primary contribution of trained operators is contingency management and mission flexibility. The real challenge in design of an unmanned terminal is not automating the processes, but providing the ability to handle off-nominal situations, equipment failures, and new mission scenarios. Design philosophy of the architectural, communications and contingency management features of the GPS/GA are discussed. System performance and mission flexibility in off-nominal situations are related to operational aspects of a typical manned terminal. Operational experience with the GPS/GA provides further insight into the critical design issues of unmanned terminals.