Testing of Luch-5V Begins Using PRN 140
The L-band SBAS transponder on the third Luch Multifunctional Space Relay System geostationary satellite, Luch-5V (“v” is the third letter of the Russian alphabet), launched on April 28, has started test transmissions using PRN code 140.
The satellite is positioned at 95° east longitude and completes the Russian three-satellite SBAS constelltion for the System for Differential Corrections and Monitoring. Stations in the IGS tracking network first noticed the signals on July 15, but it wasn’t clear where they were coming from. This is because the satellite is not yet transmitting its position and PRN 140 has also been used by the first Luch satellite, Luch-5A, although it hasn’t been heard from recently. It was expected that Luch-5V would use PRN 141, also assigned for the Luch satellites by the GPS Systems Directorate.
By using the pseudorange measurements recorded by the IGS stations and the orbit positions of both the Luch-5A and Luch-5V satellites derived from NORAD 2-line element sets, it was confirmed that the PRN 140 signals were indeed coming from Luch-5V.
The Luch-5V signals have been noted on a few subsequent days but with a very large clock offset from GPS System Time.
About the Author: Richard B. Langley
Richard B. Langley is a professor in the Department of Geodesy and Geomatics Engineering at the University of New Brunswick (UNB) in Fredericton, Canada, where he has been teaching and conducting research since 1981. He has a B.Sc. in applied physics from the University of Waterloo and a Ph.D. in experimental space science from York University, Toronto. He spent two years at MIT as a postdoctoral fellow, researching geodetic applications of lunar laser ranging and VLBI. For work in VLBI, he shared two NASA Group Achievement Awards. Professor Langley has worked extensively with the Global Positioning System. He has been active in the development of GPS error models since the early 1980s and is a co-author of the venerable “Guide to GPS Positioning” and a columnist and contributing editor of GPS World magazine. His research team is currently working on a number of GPS-related projects, including the study of atmospheric effects on wide-area augmentation systems, the adaptation of techniques for spaceborne GPS, and the development of GPS-based systems for machine control and deformation monitoring. Professor Langley is a collaborator in UNB’s Canadian High Arctic Ionospheric Network project and is the principal investigator for the GPS instrument on the Canadian CASSIOPE research satellite now in orbit. Professor Langley is a fellow of The Institute of Navigation (ION), the Royal Institute of Navigation, and the International Association of Geodesy. He shared the ION 2003 Burka Award with Don Kim and received the ION’s Johannes Kepler Award in 2007.
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