Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-26T12:28:05.368Z Has data issue: false hasContentIssue false
  • English
  • Français

Improving Loran Coverage with Low Power Transmitters

Published online by Cambridge University Press:  01 December 2009

Sherman C. Lo ,
Benjamin B. Peterson ,
Tim Hardy  and
Per K. Enge
Sherman C. Lo*
Affiliation:
(Stanford University)
Benjamin B. Peterson
Affiliation:
(Peterson Integrated Geopositioning)
Tim Hardy
Affiliation:
(Nautel)
Per K. Enge
Affiliation:
(Stanford University)
*
(Email: daedalus@stanford.edu)
Get access Rights & Permissions [Opens in a new window]

Abstract

Enhanced Loran (eLoran) is currently being implemented to provide back up to global navigation satellite systems (GNSS) in many critical and essential applications. In order to accomplish this, eLoran needs to provide a high level of availability throughout its desired coverage area. While the current Loran system is generally capable of accomplishing this, worldwide, there remain a number of known areas where improved coverage is desirable or necessary. One example is in the middle of the continental United States where the transmitter density is not adequate for providing the desired availability for applications such as aviation in some parts. This paper examines the use of lower power, existing assets such as differential GPS (DGPS) and Ground Wave Emergency Network (GWEN) stations to enhance coverage and fill these gaps. Two areas covered by the paper are the feasibility and performance benefits of using the antennas at these sites.

Using DGPS, GWEN or other existing low frequency (LF) broadcast towers requires the consideration of several factors. The first is the ability of the transmitting equipment to efficiently broadcast on these antennas, which are significantly shorter than those at a Loran station. Recent tests at the US Coast Guard Loran Support Unit (LSU) demonstrated the performance of a more efficient transmitter. This technology allows for the effective use of smaller antennas at lower power levels. Second is the ability to broadcast a navigation signal that is compatible with the Loran system and the potential DPGS broadcast (when using a DGPS antenna). The paper examines some possibilities for navigation signals. The goal is to develop a suitable low power signal that enhances navigation and is feasible for the transmission system.

The second part of the paper examines the benefits of using these stations. The benefits depend on the location of the stations and the ability seamlessly to integrate them within the existing Loran infrastructure. Analysis of these factors is presented and the coverage benefits are examined.

Keywords

eLoranDGPS antennaGWENLF broadcast towers
Type
Research Article
Information
The Journal of Navigation , Volume 63 , Issue 1 , January 2010 , pp. 23 - 38
Copyright
Copyright © The Royal Institute of Navigation 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]International Loran Association, (2007). Enhanced Loran (eLoran) Definition Document, version 0.1, January 2007Google Scholar
[2]Press Office, U.S. Department of Homeland Security, (2008). Statement from DHS Press Secretary Laura Keehner on the Adoption of National Backup System to GPS, February 7, 2008Google Scholar
[3]FAA report to FAA Vice President for Technical Operations Navigation Services Directorate, (2004). Loran's Capability to Mitigate the Impact of a GPS Outage on GPS Position, Navigation, and Time Applications, March 2004.Google Scholar
[4]General Lighthouse Authorities of the United Kingdom and Ireland, Research and Radionavigation, (2006). The Case for eLoran, Version 1.0, May 2006Google Scholar
[5]Frank, R. L., (1974). Current Developments in Loran-D, Navigation: The Journal of the Institute of Navigation, v. 21, no. 3, Fall 1974, pp. 234–241.CrossRefGoogle Scholar
[6]Celano, T. P., Peterson, B. B., and Schue, C. A., (2004). Low Cost Digitally Enhanced Loran for Tactical Applications (LC DELTA), Proceedings of the International Loran Association 33rd Annual Meeting, Tokyo, Japan, October 2004Google Scholar
[7]Wolfe, D. B., Judy, C. L., Haukkala, E. J. and Godfrey, D. J., (2000). Engineering the World's Largest DGPS Network, Proceedings of the Institute of Navigation Annual Meeting, San Diego, CA, June 2000Google Scholar
[8]Hardy, T., (2008). The Next Generation LF Transmitter Technology for (e)LORAN, Proceedings of the Royal Institute of Navigation NAV08/International Loran Association 37th Annual Meeting, London, UK, October 2008.Google Scholar
[9]Enge, P., Young, D. and Butler, B., (1998). Two-Tone Diversity to Extend the range of DGPS Radiobeacons, Navigation: The Journal of the Institute of Navigation, Vol. 45 No. 3, 1998CrossRefGoogle Scholar
[10]Peterson, B. B., (2007). Feasibility of Increasing Loran Data Capacity using a Modulated Tenth Pulse, Proceedings of the International Loran Association 36th Annual Meeting, Orlando, FL, October 2007Google Scholar
[11]Lo, S., Peterson, B., Boyce, L. and Enge, P., (2007). The Loran Coverage Availability Simulation Tool, Proceedings of the Royal Institute of Navigation NAV08/International Loran Association 37th Annual Meeting, London, UK, October 2008.Google Scholar
[12]Lo, S., Wenzel, R., Morris, P. and Enge, P., (2008). Modeling and Validating Bounds Loran Temporal ASF Bounds for Aviation, Navigation: The Journal of the Institute of Navigation, January 2008Google Scholar
[13]Boyce, C. O. L. Jr.,, (2007). Atmospheric Noise Mitigation for Loran, Ph.D. Dissertation, Stanford University, June 2007Google Scholar