Accession Number:

ADA503345

Title:

AF/NGA GPS Monitor Station High-Performance Cesium Frequency Standard Stability 2007/2008: From NGA Kalman Filter Clock Estimates

Descriptive Note:

Conference paper

Corporate Author:

NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY ARNOLD MO TECHNICAL TRANSLATIONS

Report Date:

2008-12-01

Pagination or Media Count:

15.0

Abstract:

The National Geospatial-Intelligence Agency NGA and the United States Air Force USAFAF operate a worldwide network of GPS monitoring stations. The NGA and USAF monitor stations utilize high-performance cesium frequency standards CFS and geodetic quality GPS receivers. Products derived from the NGA Monitor Station Network MSN include the postprocessed GPS satellite ephemerides, and GPS broadcast ephemeris and clock parameters. The NGA monitor stations are unmanned and operate in non-laboratory environments. As such, the NGA stations must be monitored frequently to ensure data integrity. The Monitor Station Network Control Center in St. Louis monitors all NGA stations on a 247 basis. The USAF operates their stations in a similar manner, with the USAF GPS Operational Control Segment OCS at Schriever AFB incorporating data from ten NGA monitor stations in their Kalman filter process. This paper summarizes USAF and NGA MSN clock stability for 2007 and 2008, using the Kalman filter clock estimate data computed daily at NGA St. Louis. The clock stability of six USAF and ten NGA monitor stations is presented. Also presented are site-specific observations, along with an overview of station configuration and planned upgrades. Results show that the USAFNGA station clock estimates generally meet or exceed specifications for high-performance cesiums, providing accurate, stable, and reliable clocks in support of the GPS program.

Subject Categories:

  • Test Facilities, Equipment and Methods
  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE