eLoran for e-Navigation – The Requisite Co-Primary Source for Position, Navigation, Time and Data

G. Offermans, E. Johannessen, C. Schue, A. Grebnev, S. Bartlett

Abstract:	e-Navigation is the concept being developed by the International Maritime Organization (IMO) to increase maritime safety and security via means of electronic navigation. The concept identifies the need for (at least) two independent sources of positioning and time in the system to make it robust and fail-safe. Demonstrations by the General Lighthouse Authorities of the UK and Ireland jamming GPS in a controlled environment showed the ever-increasing dependency on, and pervasiveness of, GNSS technology. The General Lighthouse Authorities of the UK and Ireland have started the deployment of equipment for an Initial Operating Capability eLoran system with typical accuracy of 10 meters along the east coast of the UK and the Republic of Korea announced their plans to deploy a full eLoran system on their territory. UrsaNav has been developing eLoran systems and receiver technology to support these efforts. Additionally, accurate timing and frequency is becoming increasingly important in many applications that influence our daily life. In the US, fifteen out of eighteen sectors of the Critical Infrastructure and Key Resources (CIKR) identified by the Department of Homeland Security (DHS) use GPS for timing and for eleven it is deemed essential. More and more systems have become solely dependent on GPS or other GNSS for their precise position, timing, and frequency information, especially as additional multi-constellation GNSS, i.e. Galileo, Compass, and GLONASS, and Regional Navigation Satellite Systems (RNSS) become fully operational and “fill the world’s skies.” The explosive growth of systems and applications based on GNSS has resulted in an increasing awareness of GNSS vulnerabilities including interference, jamming, and spoofing. UrsaNav is under a Cooperative Research and Development Agreement (CRADA) with the US Government, which allows us to use existing and former Loran infrastructure to broadcast signals in the spectrum between 90-110 kHz in the USA. eLoran signal measurements are made on a regular basis from a USCG broadcast site in Wildwood, NJ, using a 400 kW transmitter. Monitor receivers are set-up in locations in Virginia, Washington, DC, and Massachusetts to monitor the transmissions and analyze timing performance against GPS disciplined Cesium clocks or better. One such monitor is installed at the US Naval Observatory and is compared directly to the USNO master clock. Additional tests are underway to evaluate eLoran as a co-primary system in synchrophasors and other smart grid devices. The paper will discuss our latest developments and test results. The paper will describe the transmitter and monitor receiver set-up, as well as technology improvements to increase timing and position accuracy.
Published in:	Proceedings of the 2014 International Technical Meeting of The Institute of Navigation January 27 - 29, 2014 Catamaran Resort Hotel San Diego, California
Pages:	574 - 582
Cite this article:	Offermans, G., Johannessen, E., Schue, C., Grebnev, A., Bartlett, S., "eLoran for e-Navigation – The Requisite Co-Primary Source for Position, Navigation, Time and Data," Proceedings of the 2014 International Technical Meeting of The Institute of Navigation, San Diego, California, January 2014, pp. 574-582.
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