Aspects of GPS applications in the ENSEMBLE UHP timing system

There are several unique system level design considerations and a number of specific engineering issues associated with the synchronization and syntonization of globally distributed timing systems using the Precise Positioning Service (PPS) of the Global Positioning System (GPS). The development, evaluation and deployment of an operational US Department of Defense (DoD) `ultra-high-precision´ (UHP) timing system known as ENSEMBLE was undertaken to provide the necessary long term stability to support: mission level UHP synchronization and syntonization requirements; and the long term monitoring of GPS time transfer performance. The planned use of GPS at the extremes of its passive one-way time transfer operating capability in ENSEMBLE posed a number of challenges associated with the access and application of PPS GPS