An Imperative Case for eLoran

Imagine a liquefied natural gas (LNG) or an oil tanker transiting some of the world's most strategically important waterways while relying on civil Global Navigation Satellite System (GNSS) that may be spoofed, jammed or denied, leaving navigators uncertain about the safety and security of their ships. Thousands of vessels are dealing with this situation in the Persian Gulf and Red Sea today. This is one of today's most widespread Positioning, Navigation and Timing (PNT) challenges facing commercial shipping.

Even before the U.S. and Israel launched airstrikes against Iran in late February 2026, there was already widespread GNSS jamming and spoofing throughout the Persian Gulf, the Strait of Hormuz, Red Sea, and Gulf of Oman making civil GNSS unreliable or unusable. In May 2025, GPS interference was blamed in the 304-metre container ship MSC ANTONIA running aground near the port of Jeddah in the Red Sea, and then a month later the tanker FRONT EAGLE, carrying approximately 2 million barrels of crude oil, collided with the ADALYNN, a 900-foot tanker in the Gulf of Oman.

The Joint Maritime Information Center (JMIC) under a 47-nation naval partnership under the Combined Maritime Forces (CMF) monitors this situation and disseminates warnings. The CMF covers about 3.2 million square miles of international waters which encompasses some of the world's most important shipping lanes. JMIC was established in February 2024 to share accurate and timely information on attacks on merchant vessels with stakeholders. JMIC's threat information is posted on the internet by the United Kingdom Maritime Trade Operations (UKMTO) Centre. JMIC's May 2026 report (see Figure 1) summarizes the incidents and Electro-Magnetic Interference (EMI) in both the Persian Gulf and Red Sea from November 2025 through April 2026.

Extracted from JMIC Monthly Statistics, May 2026

Similar situations exist in the North Sea and Baltic regions and in the western Pacific Ocean area due to intermittent episodes of jamming and spoofing of GNSS signals in those areas. Regional conflicts and use of EMI against GNSS as demonstrations of national intent can cause disruptions to GNSS-dependent maritime and aviation commerce at any time and without warning. In all such cases, on-board availability of a reliable source of alternative PNT represented by enhanced Loran (eLoran) would be a valuable risk mitigation solution. eLoran has been demonstrated as a viable, robust complement to GNSS for situations where GNSS signals are unreliable or unavailable.

PNT in the Commercial Maritime Shipping Industry

PNT is deeply embedded in the maritime shipping systems, but getting any alternate PNT on a ship, including an eLoran receiver, is not as simple as duct-taping an eLoran receiver onto a ship's bridge. The U.S. Navy introduced consolidated bridge systems in the 1970s to reduce crew sizes while improving command, control, and situational awareness. Various navigational tools such as radar, Electronic Chart Display and Information Systems (ECDIS), Automatic Identification Systems (AIS), GNSS, gyro, etc. are now part of a ship's Integrated Bridge System (IBS) in conjunction with the autopilot, propulsion system controls, monitors, alarms, etc.

The United Nations' International Maritime Organization (IMO) administers more than 50 international treaties governing global shipping. These treaties establish the regulatory framework and standards covering the maritime industry on safety, environmental protection, legal compliance and technical performance. IMO's standards also are a baseline in obtaining initial certification, annual/intermediate verifications, and renewals for ship surveys, certification/permitting, and insurance in conjunction with the Safety of Life at Sea (SOLAS). eLoran can be integrated into the ship's systems recognizing a ship is certified based on an as-installed and tested system configuration.

While IMO recognizes eLoran as a PNT sensor, there is no modern IMO performance standard for eLoran receivers. In contrast, IMO's existing GNSS performance standards were all written years ago, before GNSS jamming and spoofing became common. Integrity requirements are defined in the GNSS standards, but the criterion was written in a previous era where worldwide interference-free GNSS was taken for granted and before today's fact-of-life situation where many sea areas are routinely jammed or spoofed. Performance standards are needed for eLoran and GNSS receivers recognizing outage or interference conditions.

The maritime industry has adopted new navigation technologies when risks justify action. The 1990 US Oil Pollution Act became law because of the 1989 Exxon Valdez oil spill. It mandated a dependent surveillance system as a carriage requirement to monitor tankers navigating to and from Valdez, Alaska. The US Coast Guard in 1993 developed Automated Dependent Surveillance Shipboard Equipment (ADSSE) paving the way for Automatic Identification System (AIS) eventually becoming an IMO mandated SOLAS convention carriage requirement.

A similar path could follow for eLoran. As GNSS interference continues to threaten maritime navigation and safety, a standardized and resilient terrestrial PNT source like eLoran can mitigate risks for vessels operating around the world.

eLoran Performance and Interference Resistance

eLoran positioning accuracy can be better than 10 meters. eLoran is most often transmitted from fixed, high-power ground-based stations at a low frequency (100 kHz). A receiver needs to receive signals from at least three stations to get a two-dimensional position fix. However, positioning can be achieved using signals from two stations when the receiver has access to a precise time source synchronized to the same time reference as the eLoran stations. For precise timing and frequency purposes, eLoran has demonstrated synchronizing to within 50 nanoseconds of Coordinated Universal Time (UTC) from one or more stations.

Further, the eLoran high-power low-frequency signal can reach out over 1,000 miles (1,600 km) from a station as powerful as 1 megawatt. The signal can penetrate buildings, dense foliage, and below ground or water where satellite signals are challenged. Overpowering a high-power eLoran station with a jammer or spoofer is very difficult, while at the same time it's not simple for a bad actor to operate and hide a comparable high-power-level jammer or spoofer.

eLoran Receiver Availability

Commercial Off The Shelf (COTS) maritime civil and military eLoran receivers are already available from at least three vendors, usually with a GNSS receiver:

- UrsaNav, LLC: provides Loran-C, eLoran, and Chayka receivers in several form factors including maritime receivers. Integrations with GNSS and/or IMUs are available.
- Reelektronika: LORADD-SP is a GPS / eLoran receiver tailored for the civil maritime market. Their manual discusses how it would be integrated into ship systems.
- SkyDec: 06Series is a military Multi-GNSS navigation host system that includes options for GPS M-code/SAASM and eLoran receivers. SkyDec cites this system as being used for many      years in surface ships and submarines with various navies.

Recent Developments

The UK, South Korea, and Saudi Arabia are committed key investors in eLoran stations to make eLoran signals available. Additionally, China also completed a national eLoran network in 2024 to provide a backup and operate independently of satellite navigation timing, while Russia has also had a version of Loran since WWII. These active coverage areas lay the groundwork to make installing eLoran in commercial shipping a solution to mitigate GNSS disruptions in the mid-East, Northern European and Western Pacific Ocean waters.

United Kingdom

The UK launched the Chain Odyssey eLoran programme as a sovereign terrestrial backup for critical infrastructure with six eLoran transmission sites in Northern Ireland, the Shetlands, Outer Hebrides, East Anglia/Dover, and Southwest Cornwall. The UK has also engaged the IMO to further formalize eLoran into the IMO's regulatory and standards framework (IMO NCSR 13/INF.22, UK, "eLORAN Service and Resilient PNT Strategic Opportunity," April 2026). In May 2026, the UK Ministry of Defence launched Urgent Compass, a two-year programme developing eLoran technology and supply chain including highly miniaturized eLoran receivers and antennas along with transportable deployable stations.

Maritime accuracy coverage contours of UK-based eLoran. Blue = 10 m, green = 20 m, red = 30 m. Source: MarRINav Executive Summary Report, 25 March 2020

South Korea

The South Korean Ministry of Oceans and Fisheries has several eLoran stations to mitigate North Korean GNSS interference. South Korea also is the world's second-largest shipbuilder, focusing primarily on LNG carriers while also building petroleum tankers and container ships. These shipyards could easily add eLoran into ships being built while defining a streamlined retrofit template on ships they already built. Although South Korea is planning eLoran for Arctic shipping, security, and fisheries sectors, it would not be surprising if South Korea mandates eLoran for maritime shipping to protect its economic and security interests because it depends on imported oil and maritime trade.

South Korean eLoran coverage. Source: "South Korea Relaunches Its eLoran Program," Inside GNSS, January 2015

Saudi Arabia

Saudi Arabia operates four eLoran stations recently upgraded from Loran-C to support maritime police and first responders. These 1-megawatt stations are some of the most powerful in the world. The desert and sea geography around these stations would maximize signal propagation out more than 1,000 miles in all directions covering wide areas of the Persian Gulf, Red Sea, and Gulf of Oman, although verified coverage maps for Saudi Arabia's eLoran chain have not been published. Additional strategically located stations could be added to further improve coverage while adding redundancy. Saudi Arabia's station locations are:

- Ash Shaykh Humayd
- Afif
- Salva
- Al Muswassam

Saudi Arabia eLoran station ranges

Saudi Arabia is investing in eLoran infrastructure initially for maritime police and first responders. It would not be surprising if Saudi Arabia chooses to expand coverage and establish a carriage requirement for eLoran for maritime shipping operating in Saudi Arabian waters to protect its economic and security interests given the ongoing EMI situation in both the Persian Gulf and Red Sea.

Insurance

Marine insurance covers basic ship physical loss or damage while other insurance covers:

- War risk: General hull insurance does not cover the risks of a vessel sailing into a war zone. The war risk areas are generally established by the London-based Joint War Committee.
- Cargo: This insurance depends on the value and risk associated with cargo such as perishable foods or bulk commodities such as fuel and ore.

In principle, eLoran carriage could be factored into risk calculations in obtaining certification by a ship classification society to obtain marine and war risk insurance. Ships equipped with eLoran and operating in future GNSS-vulnerable areas, such as the Persian Gulf and Red Sea, as well as in contested regions of other waters, could conceivably obtain more advantageous marine insurance terms. The risk calculus for ships operating in the Persian Gulf and Red Sea with mined areas and the potential for further conflict also justifies the minimal cost to add eLoran to a ship's IBS to mitigate navigation risks in GNSS-disrupted environments.

Action

Ship owners have a risk management dilemma between continuing operations in this hazardous environment or sustaining costs to not operate. eLoran is hiding in plain sight as an immediate solution as a backup and alternative to GNSS for LNG carriers, tankers and other ships needing to navigate through the Strait of Hormuz, Persian Gulf, Red Sea or other troubled waters. The three noted national investors in eLoran enable this opportunity:

- Saudi Arabia already provides eLoran signals covering the Strait of Hormuz, Persian Gulf, and Red Sea that can be augmented as needed.
- The UK is jump-starting additional eLoran signal availability as well as receiver options and production, in addition to the COTS eLoran-capable maritime receivers already being produced.
- South Korea already provides eLoran signals, and its shipbuilders can incorporate eLoran into ships being built and provide retrofit solutions to ships already built at a minimal impact if it chooses.

Essentially, everything is available to leverage eLoran as a speed-to-delivery solution for maritime users operating in worldwide GNSS interference areas that can be implemented in months rather than years. This could potentially be accelerated even faster in a coordinated effort between government agencies, industry stakeholders and international standards organizations.

Victor Tasiemski is a principal systems engineer for Overlook Systems Technologies. He is the primary staff engineer monitoring, technically evaluating and assessing Positioning, Navigation, and Timing (PNT) programs including Global Positioning System (GPS), alternatives, and complements, cybersecurity and Navwar imperatives for the Department of Defense/War Chief Information Office (CIO).

References:

1. GNSS Interference in Ship Collision, Fires, Grounding, https://rntfnd.org/2025/06/27/gnss-interference-in-ship-collision-fires-grounding-inside-gnss/

2. Joint Maritime Information Center (JMIC), https://combinedmaritimeforces.com/combined-task-forces/joint-maritime-information-center/

3. UKMTO Products, https://www.ukmto.org/ukmto-products

4. IMO, https://www.imo.org/

5. List of IMO Conventions, https://www.imo.org/en/about/conventions/pages/listofconventions.aspx

6. USCG, Office of Navigation Systems, Providing Navigation Safety Information for America's Waterways briefing, https://www.navcen.uscg.gov/sites/default/files/pdf/AIS/[email protected]

7. The Automatic Identification System, U.S. Coast Guard Office of Navigation Systems, Electronic Navigation Division, USCG Proceedings Spring 2011, https://apps.dtic.mil/sti/tr/pdf/ADA551029.pdf

8. Enhanced Loran, Stanford University, https://web.stanford.edu/group/scpnt/jse_website/documents/Enhanced_Loran_rv2-short.pdf

9. Reelektronika LORADD-SP series, https://www.reelektronika.nl/products/eloran-receivers-loradd-sp-series/

10. Skydec 06SERIES, https://www.skydec.com/brochures/06SERIES-Brochure-eLOran_extension.pdf

11. China completes national eLoran network, https://www.gpsworld.com/china-completes-national-eloran-network/

12. United Kingdom Resilient PNT Programme, Nov 19, 2025, https://www.navnin.nl/new/wp-content/uploads/2025/11/251119_NINsymposiumPNT_Mark-Brammer_Amsterdam_UK_PNT-SOS_BRIEF-Official.pdf

13. IMO NCSR 13/INF.22, 17 UK, eLORAN Service and Resilient PNT Strategic Opportunity, April 2026

14. UK MOD Press release, UK Armed Forces better protected with new jamming-proof navigation tech, https://www.gov.uk/government/news/uk-armed-forces-better-protected-with-new-jamming-proof-navigation-tech

15. MarRINav – Maritime Resilience and Integrity in Navigation, Executive Summary Report, 25th March 2020, MarRINav – 4000126063/18/NL/MP – 2020-03-25, https://marrinav.com/wp-content/uploads/2020/04/20-03-25-Executive-Summary-Report-MarRINav-v1.0.pdf

16. South Korea unveils five-year maritime agenda – resilient PNT foundational, https://rntfnd.org/2025/09/22/south-korea-unveils-five-year-agenda-for-arctic-shipping-security-and-fisheries-sectors-baird-maritime/

17. Stimson South Korean Shipbuilding Capacity 2025, https://www.stimson.org/2025/south-korean-shipbuilding-capacity/

18. South Korea Relaunches Its eLoran Program, Inside GNSS, January 2015, https://insidegnss.com/south-korea-relaunches-its-eloran-program/

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19. Saudi Arabia eLoran, https://rntfnd.org/2023/06/09/saudi-arabia-upgrading-to-eloran/

20. Marine Insurance, https://en.wikipedia.org/wiki/Marine_insurance