Performance Analysis of the GPS Monitor Station Timing Subsystem Enhancement Program at the Naval Research Laboratory

The U.S. Naval Research Laboratory designed, developed, and installed hardware and software for the GPS Monitor Station Timing Subsystem Enhancement MSTSE at the GPS Monitor Station MS located at the Kaena Point Satellite Tracking Station, Hawaii. From December 1995 to the present as part of the evaluation of the system, the U.S. Naval Observatory USNO has been performing time transfers through the Two Way Satellite Time Transfer portion of the MSTSE. It will be shown that the new cesium-beam frequency standard CFS HP5071 has been disciplined to the DoD Master Clock by the MSTSE during this period to within plus or minus 3 pp 10E14. The phase measurement subsystem of the MSTSE has, for the first time, allowed independent measurement of the two operational GPS Monitor Station HP5061 CFSs. During June 1996 a modification was made to the MSTSE to reflect improvements in the system architecture developed during the initial evaluation period. This modification has increased system performance, improved reliability, and facilitated easy integration with future GPS Monitor Station improvements. This paper describes the equipment configuration and the test data collected after the installation of the MSTSE. Results are presented from data collected from June 1996 through October 1996.