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GPS/Loran-C interoperability for time and frequency applications: A survey of the times of arrival of Loran-C transmissions via GPS common mode/common view satellite observationsThe results from this survey clearly indicate that the Global Positioning System (GPS) time transfer capability is superior to that of the Loran-C system for absolute timing accuracy, and that even with the most careful calibration of the Loran-C receiver delay and propagation path, inexplicable time of arrival (TOA) biases remain which are larger than the variations across all of the transmitters. Much more data covering years would be needed to show that these biases were stable enough to be removed with a one time site calibration. The synchronization of the transmissions is excellent, all showing low parts in 10(exp 13) offsets versus the United States Naval Observatory (USNO) master clock. With the exception of the Searchlight transmitter, all of the transmissions exhibit timing stabilities over the entire period of less than 300 ns RMS which is at the observed levels of GPS under selective availability (SA). The Loran-C phase instabilities take place over a much greater time interval than those being forced onto the GPS signals under SA, providing for better medium to short term frequency stability. Data show that all but the most distant transmitters offer better than three parts in 10(exp 11) stability at this averaging time. It is in the frequency control area where GPS/Loran-C interoperation will offer some synergistic advantages over GPS alone under SA.
Document ID
19910016489
Document Type
Conference Paper
Authors
Penrod, Bruce (AUSTRON, Inc. Austin, TX, United States)
Funderburk, Richard (AUSTRON, Inc. Austin, TX, United States)
Dana, Peter (AUSTRON, Inc. Austin, TX, United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1990
Publication Information
Publication: JPL, The 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting
Subject Category
AIRCRAFT COMMUNICATIONS AND NAVIGATION
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.