New eLoran Receiver and Antenna Technology for Integrated GPS/Loran Systems

G. Linn Roth, Paul Schick, Chad Schweitzer, James Jacoby, Dean Gervasi and Richard Ferrier

Abstract:	As the evolution to enhanced or eLoran continues, improvements to eLoran technology will become more commonplace and facilitate integration with GPS to provide robust navigation and timing performance under demanding conditions. Over the last year, several new features have been added to the core Locus SatMate 1030 eLoran system in order to provide better dynamic performance and more general utility within various marine, aviation, terrestrial, and timing applications. These features include the ability to generate and apply additional secondary factor (ASF) corrections in realtime, the addition of a single axis gyroscope (SAG), a revised H-field antenna, and a new receiver front end. The SatMate 1030 now has three operational modes to utilize ASF corrections in real time. First, the receiver can apply ASFs that have been loaded manually by the user or through a batch file. Second, the user can input the latitude and longitude of a fixed datum, and the SatMate 1030 can derive ASFs from that point. Third, the SatMate 1030 can import GPS NEMA $GPGGA messages from a GPS receiver, and then generate and apply ASF corrections in real time. Additional hardware and software for a SAG has also been developed for the 1030 system that significantly improves antenna performance in dynamic applications. Work on this feature has included investigation of filter parameters to optimize performance in different dynamic conditions and software compensation to enable an operational temperature range of -25º to +60º C. A new iteration of Locus’ H-field antenna has also been recently completed. This new version has substantially better balance between antenna poles, better noise characteristics, reduced power consumption, and much improved manufacturability. These improvements are beneficial for virtually all applications where GPS and eLoran can be integrated, and will help reduce costs for combined GPS/Loran antennas. Finally, a new receiver front end has been developed for both e and H-field antennas. This front end reduces power consumption 2.7 watts and improves overall system thermal properties while providing the same level of performance as the previous design. In addition, further improvements may be possible as a result of the new design. This paper will review these new receiver and antenna features and include test data illustrating the performance improvements for this next generation eLoran system.
Published in:	Proceedings of the 2005 National Technical Meeting of The Institute of Navigation January 24 - 26, 2005 The Catamaran Resort Hotel San Diego, CA
Pages:	255 - 261
Cite this article:	Roth, G. Linn, Schick, Paul, Schweitzer, Chad, Jacoby, James, Gervasi, Dean, Ferrier, Richard, "New eLoran Receiver and Antenna Technology for Integrated GPS/Loran Systems," Proceedings of the 2005 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2005, pp. 255-261.
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