Accession Number:

ADA495334

Title:

Performance of Global Positioning System Block II/IIA/IIR On-Orbit Navstar Clocks

Descriptive Note:

Conference paper

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

• McCaskill, Thomas B.
• Oaks, Orville J.
• Largay, Marie M.
• Reid, Wilson G.
• Warren, Hugh E.
• Buisson, James A.

Report Date:

1999-12-01

Pagination or Media Count:

16.0

Abstract:

Analysis of the performance of all on-orbit Navstar space vehicle clocks and Global Positioning System GPS monitor station reference clocks is performed by the Naval Research Laboratory NRL, in cooperation with the GPS Master Control Station, under the sponsorship of the GPS Joint Program Office. The measurements are collected by multi-channel GPS receivers located at the Air Force and National Imagery and Mapping Agency NIMA monitor stations. The offset of each Navstar clock, computed every 15 minutes, is referenced to the Department of Defense Master Clock. The resultant Navstar clock offsets are then used to compute frequency offset, drift offset, frequency stability profiles, and frequency stability histories. The beginning-of-life, steady state, and end-of-life performance of selected cesium and rubidium atomic clocks is presented. Frequency stability results are presented using sample times that vary from 15 minutes to several days. The stability for sample times of less than one day characterizes the measurement noise, while the stability for sample times in excess of one day characterizes both the periodic effects in the on-orbit data and the long-term performance of the Navstar atomic clocks.

Descriptors:

• *ATOMIC CLOCKS
• *NAVIGATION SATELLITES
• *GLOBAL POSITIONING SYSTEM
• PERFORMANCE(ENGINEERING)
• DRIFT
• RUBIDIUM
• SYMPOSIA
• STABILITY
• FREQUENCY
• CESIUM

Subject Categories:

• Test Facilities, Equipment and Methods
• Unmanned Spacecraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE