eLoran Initial Operational Capability – Providing Resilient PNT to Mariners

Erik Johannessen, Gerard Offermans, Stephen Bartlett, Andrei Grebnev, Martin Bransby, Paul Williams, Chris Hargreaves

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 dissimilar 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. All existing and currently planned GNSS systems are based on the same satellite technology occupying the same space and frequencies, and consequently suffer the same failure modes. This disqualifies two or more GNSS systems to be independent and dissimilar for e-Navigation. For many years now, eLoran has been identified as the most suitable complementary radio system to provide resilience and back-up for positioning, navigation and timing applications. This view has been supported by stakeholders in all layers of the navigation community and is slowly catching up at decision making levels. The General Lighthouse Authorities of the UK and Ireland are implementing an Initial Operational Capability (IOC) eLoran system along the east coast of the Scotland and England. UrsaNav provides Differential eLoran Reference Station and Integrity Monitoring technology, which will be installed in spring. The system is expected to be operational in fall of 2014. Differential eLoran Stations are installed at seven harbors (two in Scotland and five in England), which provide corrections to the users over the Loran Data Channel of the Anthorn eLoran station. Users will apply the corrections to their eLoran measurements to determine their position with a typical accuracy of 10 meters meeting IMO’s accuracy requirement for future GNSS systems. The Republic of Korea (ROK) announced their plans to deploy an IOC eLoran system on their territory, consisting of three eLoran transmitters (one new and two upgrades from Loran-C), new monitor and control, two Differential eLoran sites, and ASF measurement equipment. At the time of the ION GNSS conference ROK has selected a vendor for award of a contract for the deployment of the system. The paper describes the Initial Operational Capability eLoran system in the UK, consisting of Differential eLoran RSIMs covering seven major harbors in England and Scotland. ASF maps for the harbor and harbor approaches are published by the GLA for integration into maritime user equipment. The objectives and further steps towards full operating capabilities will be highlighted. The paper further describes UrsaNav’s Differential eLoran Reference Station and Integrity Monitoring technology, interacting with existing eLoran stations for broadcast of differential corrections over the Loran Data Channel. We will conclude with measurement results from the system’s verification surveys during and after commissioning.
Published in:	Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014) September 8 - 12, 2014 Tampa Convention Center Tampa, Florida
Pages:	3101 - 3112
Cite this article:	Johannessen, Erik, Offermans, Gerard, Bartlett, Stephen, Grebnev, Andrei, Bransby, Martin, Williams, Paul, Hargreaves, Chris, "eLoran Initial Operational Capability – Providing Resilient PNT to Mariners," Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014), Tampa, Florida, September 2014, pp. 3101-3112.
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