When GPS fails, what’s Plan B? For most civilian operators, the answer is uncomfortably vague. But as GPS jamming and spoofing incidents surge into the thousands monthly, alternative Positioning, Navigation, and Timing (PNT) solutions are moving from niche research to operational necessity.
This article examines the leading alternatives to GPS—focusing on eLoran, the terrestrial backup system experiencing a global renaissance—and evaluates their readiness for protecting critical infrastructure.
The PNT Dependency Crisis
What Depends on GPS?
GPS isn’t just for navigation. Critical infrastructure relies on GPS timing for:
- Power grids – Synchronize load flows across thousands of miles
- Telecommunications – Coordinate data packets in cellular networks
- Financial markets – Timestamp transactions to microsecond precision
- Emergency services – Dispatch and locate responders
- Transportation – Coordinate air, sea, and ground traffic
The Single Point of Failure
As GPS World noted (November 2025):
“The protection of critical infrastructure today depends heavily on precise timing and positioning data. Yet this dependency creates a single point of failure that adversaries can exploit.”
The solution? Diversification—multiple independent PNT sources that can back each other up.
eLoran: The Comeback Kid
What Is eLoran?
Enhanced Long-Range Navigation (eLoran) is a terrestrial radio navigation system that:
- Operates at low frequency (90-110 kHz)
- Uses high-power ground-based transmitters (up to 4 megawatts)
- Provides positioning accuracy of 8-20 meters
- Delivers timing accuracy of 1 microsecond
- Covers 1,000+ km range per transmitter
Why eLoran Matters
| Characteristic | GPS | eLoran |
|---|---|---|
| Signal source | Satellite (space) | Terrestrial (ground) |
| Signal strength | -130 dBm (weak) | -70 dBm (strong) |
| Frequency | 1.2-1.6 GHz | 90-110 kHz |
| Jam resistance | Vulnerable | Highly resistant |
| Indoor penetration | Poor | Excellent |
| Infrastructure control | US Space Force | National sovereignty |
The Key Advantage: Signal Power
eLoran signals are 1,000,000 times stronger than GPS signals at Earth’s surface. This means:
- Jammers would need megawatts of power to interfere (vs. watts for GPS)
- Signals penetrate buildings, caves, and underground facilities
- Simple antennas can receive signals (no expensive phased arrays needed)
Global eLoran Renaissance (2025-2026)
United Kingdom: £155 Million Commitment
In November 2025, the UK announced the largest PNT resilience investment in history:
- £71 million for national eLoran program
- 15-year operating license for eLoran service provider
- Regulated utility model – Similar to water or energy
- Cross-departmental governance – Defence, Transport, Energy, Telecom
Inside GNSS reported:
“The UK model creates a regulated timing service—combining public safety, sovereign capability, and commercial sustainability.”
Germany: Mobile eLoran Testing
IABG (German engineering firm) completed Phase 1 of eLoran testing in 2025:
- Mobile eLoran systems – Tactical deployment capability
- Dynamic scenario testing – Real-world operational conditions
- European leadership – First continental European deployment
Results were presented at ION GNSS+ 2025 in Baltimore, gaining international attention.
United States: Ongoing Advocacy
The US has studied eLoran for over a decade:
- 2020 DOT contracts – 11 companies demonstrated backup technologies (2 focused on eLoran)
- PNT Executive Committee – Technical advisers recommending eLoran for 11+ years
- Coast Guard history – Operated Loran-C until 2010 (infrastructure partially preserved)
Industry advocates continue pushing for federal eLoran deployment.
GCC Nations: Regional Roadmap
Gulf Cooperation Council countries are developing eLoran as part of PNT resilience:
- Strategic motivation – Hormuz crisis demonstrated vulnerability
- Regional coverage – Few transmitters can cover entire Gulf
- Oil infrastructure protection – Timing for pipelines and refineries
eLoran Use Cases
1. Critical Infrastructure Timing
Application: Power grids, telecom networks, financial systems
Implementation:
- Install eLoran receivers at substations and data centers
- Use as backup to GPS timing
- Automatic switchover when GPS fails
Real-World Example:
UrsaNav demonstrated eLoran integration with ADVA grandmaster clocks (December 2025):
“Now that UrsaNav has demonstrated the power of our OSA 5420 series to utilize eLoran in the event of outages, we have another very important tool to ensure the quality and availability of time-sensitive services.”
2. Maritime Navigation Backup
Application: Commercial shipping, naval vessels
Implementation:
- Integrate eLoran into bridge navigation systems
- Use for coastal navigation (optimal eLoran coverage)
- Cross-check with GPS for spoofing detection
Real-World Example:
Royal Navy reportedly incorporating eLoran into ship navigation suites.
3. Aviation Backup
Application: Commercial and military aviation
Implementation:
- eLoran receivers in avionics bays
- Integration with FMS (Flight Management Systems)
- Use during GPS outages in conflict zones
Challenge: Certification requirements for aviation equipment
4. Military Operations
Application: Tactical navigation and timing
Implementation:
- Mobile eLoran transmitters (deployable with forces)
- Handheld eLoran receivers for dismounted troops
- Independent PNT in GPS-denied environments
Real-World Example:
Germany testing mobile eLoran for tactical scenarios (2025).
Other Alternative PNT Technologies
1. Low Earth Orbit (LEO) Satellites
Concept: Use communications satellites (Starlink, OneWeb) for PNT
Advantages:
- Stronger signals than GPS (closer to Earth)
- Different frequency bands (harder to jam all simultaneously)
- Existing infrastructure (no new satellites needed)
Challenges:
- Still vulnerable to space-based attacks
- Requires modifications to LEO constellations
- Not sovereign (commercial operators)
2. Atomic Clocks (Holdover)
Concept: High-precision clocks maintain timing during GPS outages
Types:
- Cesium clocks – Accuracy: 1 microsecond for 100+ days
- Rubidium clocks – Accuracy: 1 microsecond for 1-10 days
- Chip-scale atomic clocks – Smaller, cheaper, shorter holdover
Use Case: Telecom networks, power grids, financial systems
Real-World Example:
Safran’s BlackNaute system includes atomic clock for precise timing during GNSS outages.
3. Inertial Navigation Systems (INS)
Concept: Accelerometers and gyroscopes calculate position without external signals
Advantages:
- Completely independent (no external signals)
- Works anywhere (underground, underwater, space)
- High short-term accuracy
Challenges:
- Drift over time (requires periodic GPS reset)
- High-quality INS is expensive
- Size and weight for tactical applications
4. Terrestrial Radio Signals
Concept: Use existing radio broadcasts for positioning
Sources:
- FM radio – Widely available, good penetration
- Digital TV – Precise timing information
- Cellular networks – Tower triangulation
Accuracy: 10-100 meters (varies by source)
5. Visual/Optical Navigation
Concept: Cameras and AI recognize landmarks for positioning
Applications:
- Autonomous vehicles
- Drone navigation
- Urban canyon environments
Challenges:
- Requires detailed maps
- Weather dependent
- Computational intensity
6. Quantum Navigation
Concept: Quantum sensors measure acceleration and rotation with extreme precision
Status: Early development (2025-2026)
Potential:
- Drift-free inertial navigation
- No external signals required
- Revolutionary accuracy
Timeline: 2030+ for widespread deployment
PNT Architecture: Defense in Depth
Layered Approach
No single technology provides complete protection. The solution is layered PNT architecture:
Layer 1: Primary PNT
- Multi-constellation GNSS (GPS + Galileo + BeiDou + GLONASS)
- OSNMA authentication where available
Layer 2: Terrestrial Backup
- eLoran for timing and coarse positioning
- Cellular/WiFi positioning in urban areas
Layer 3: Self-Contained
- Inertial navigation systems
- Atomic clocks for timing holdover
Layer 4: Opportunistic
- LEO satellite signals
- Terrestrial radio (FM, TV)
- Visual/optical navigation
Integration Challenge
The key is sensor fusion—combining multiple sources intelligently:
- Weight each source by reliability
- Detect and reject anomalous inputs
- Smooth transitions between sources
- Maintain continuity during outages
Economic Analysis: Cost of Implementation
eLoran Infrastructure
| Component | Cost | Notes |
|---|---|---|
| Transmitter station | $5-10M | One-time construction |
| $500K-1M | Per station | |
| Receiver unit | $500-2,000 | Volume pricing |
| Coverage (national) | $50-100M | 3-5 stations for medium country |
Critical Infrastructure Hardening
| Sector | Estimated Cost | Timeline |
|---|---|---|
| Power grid (national) | $100-500M | 3-5 years |
| Telecom networks | $50-200M | 2-3 years |
| Financial systems | $10-50M | 1-2 years |
| Maritime fleet | $1,000-5,000/ship | 1-2 years |
Cost of Inaction
Compare to potential losses from GPS disruption:
- 2019 US DOT study – GPS disruption could cost US economy $1B/day
- Hormuz crisis 2026 – Insurance premiums increased 400%
- Power grid failure – Cascading blackouts cost billions per hour
- Financial market disruption – Trading halts cost millions per minute
The question isn’t “Can we afford PNT backup?” but “Can we afford not to?”
Policy and Regulation
UK Model: Regulated Utility
The UK’s approach (November 2025) offers a template:
- Government funding – £71M anchor investment
- Private operation – 15-year license to commercial provider
- User fees – Sustainable revenue model
- Cross-departmental oversight – Defence, Transport, Energy, Telecom
US Model: Market-Driven (So Far)
The US has relied on:
- Industry voluntary adoption
- Research grants and demonstrations
- No federal mandate (yet)
Advocates argue for stronger federal leadership.
International Coordination
eLoran requires international cooperation:
- Frequency allocation – 90-110 kHz protected internationally
- Cross-border coverage – Signals don’t respect national boundaries
- Standards harmonization – Interoperable receivers
Implementation Roadmap
Phase 1: Assessment (Months 1-6)
- Audit GPS dependency across critical systems
- Identify single points of failure
- Prioritize by risk and impact
- Develop business case for investment
Phase 2: Pilot Deployment (Months 6-18)
- Install eLoran receivers at critical sites
- Test integration with existing systems
- Validate switchover procedures
- Train operations staff
Phase 3: Scale-Up (Months 18-36)
- Expand to all critical infrastructure
- Implement automated monitoring
- Establish maintenance procedures
- Conduct regular exercises
Phase 4: Operational Resilience (Ongoing)
- Continuous monitoring and improvement
- Regular testing and validation
- Update procedures based on lessons learned
- Maintain spare capacity and redundancy
Conclusion: The Time to Act Is Now
The eLoran renaissance of 2025-2026 isn’t coincidental. It’s a direct response to the GPS crisis:
- Thousands of jamming incidents monthly
- Real-world disasters (tanker collisions, aviation disruptions)
- Geopolitical tensions showing no signs of abating
- Critical infrastructure vulnerability exposed
Technology is ready:
- ✅ eLoran proven (decades of operational history)
- ✅ Receivers available (commercial off-the-shelf)
- ✅ Integration demonstrated (power grids, telecom, finance)
- ✅ Economics favorable (compared to risk)
What’s needed now is political will and investment.
The UK has committed £155 million. Germany is testing mobile systems. The GCC is developing regional coverage. The question for other nations is: Will you act before a crisis forces your hand, or after?
For critical infrastructure operators, the answer is equally clear: Don’t wait for regulation. The cost of GPS disruption far exceeds the cost of backup systems. Your competitors are already evaluating PNT resilience. The question is whether you’ll be leading or following when the next crisis hits.
The GPS monopoly is over. The age of PNT diversity has begun.
This article is Part 6 of our GNSS Security Technologies series. Previous installments covered the threat landscape (Part 1), signal structure vulnerabilities (Part 2), defensive technologies (Part 3), real-world case studies (Part 4), and GPS warfare (Part 5). Next: The Economics of GNSS Warfare – Cost-Benefit Analysis of Attacks vs. Defenses.
Sources: IABG, GPS World, Inside GNSS, UrsaNav, Resilient Navigation and Timing Foundation, Bridge Connect, Ground Control, Royal Navy, UK Government