The Use of the AOA TTR-4P GPS Receiver in Operation at the BIPM for Real-Time Restitution of GPS Time,
Abstract
The Global Positioning System is an outstanding tool for the dissemination of time. Using mono-channel C/A-code GPS time receivers, the restitution of GPS time through the satellite constellation presents a peak-to-peak discrepancy of several tens of nanoseconds without SA but may be as high as several hundreds of nanoseconds with SA. As a consequence, civil users are more and more interested in implementary hardware and software methods for efficient restitution of GPS time, especially in the framework of the project of a real-time prediction of UTC, UTCp, which could be available in the form of time differences UTCp - GPS time. Previous work, for improving the real-time restitution of GPS time with SA, to the level obtained without SA, focused an the implementation of a Kalman filtering based on past data and updated at each new observation. An alternative solution relies upon the statistical features of the noise brought about by SA: it has already been shown that the SA noise is efficiently reduced by averaging data from numerous satellites observed simultaneously over a sufficiently long time. This method has been successfully applied to data from a GPS time receiver, model AOA TTR4P, connected to the caesium clock kept at the BIPM. This device, a multi-channel, dual-frequency, P-code GPS time receiver, is one of the first TTR-4P units in operation in a civil laboratory. Preliminary comparative studies of this new equipment with conventional GPS time receivers are described in this paper.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 02, 1993
- Accession Number
- ADP009105
Entities
People
- Claudine Thomas
Organizations
- National Aeronautics and Space Administration