Accession Number : ADP001547

Title :   Optimal Time and Frequency Transfer Using GPS Signals,

Corporate Author : NATIONAL BUREAU OF STANDARDS BOULDER CO TIME AND FREQUENCY DIV

Personal Author(s) : Allan,David W. ; Barnes,James A.

Report Date : 1982

Pagination or Media Count : 10

Abstract : The advent of the GPS satellite constellation makes atomic clocks available to any one who has a receiver. Proper characteristics of both the clocks and user links is essential for optimal extraction of time and frequency (T/F) information. In this paper we will consider both optimum T/F extraction from a set of GPS data, and also some near optimum and simple data processing techniques. We consider three simple cases: case A is what we call the 'common-view' approach; case B is the direct viewing of a single satellite for sample times ranging from a few seconds to a few hours; and case C is viewing a single satellite for a few minutes each day for several successive days. The common-view approach has been studied elsewhere (1-3), and the results will be reviewed as they related to the common-mode cancellation of errors which occur when two user sites view the same satellite for the same several minutes each day, and then subtract their results to get the time difference between the two receiving sites. If one of the two receiving sites is a primary T/F reference standard, then state-of-the-art calibrations are possible. Case B allows one to use the GPS signals as a short-term T/F reference to UTC (NBS) or UTC (USNO)--thus allowing one to calibrate against a primary reference standard.

Descriptors :   *Frequency, *Control, *Symposia, *Atomic clocks, *Global positioning system, Time signals, Signal processing, Communication satellites, Global communications, Frequency shift, Data links, Sampling

Distribution Statement : APPROVED FOR PUBLIC RELEASE