Over 24,000 vessels were affected by GPS/ GNSS jamming and spoofing in 2025. The number is growing every quarter. State actors, criminal networks and shadow fleet operators routinely manipulate the signals that commercial vessels depend on for positioning, timing and situational awareness. Jamming blocks the signal entirely. Spoofing replaces it with a false one – and the bridge never knows it is happening.
The consequences are severe: vessels navigating on incorrect position data, appearing in sanctioned waters, transmitting false distress positions, or sailing into dangerous areas without warning. In the Strait of Hormuz alone, over 1,100 vessels were affected within 24 hours following escalation in early 2026
GPS/GNSS interference includes jamming and spoofing — deliberate disruption or manipulation of satellite signals that vessels rely on for position, navigation and timing. It affects far more than the chart plotter: GMDSS, AIS and other SOLAS-mandated systems can all be compromised. Understanding how it works is the first step to defending against it.
PntGuard Maritime combines GPS/GNSS monitoring with resilient APNT technology, built on NAL Technologies’ Iridium-based signal architecture — roughly 1,000× stronger than conventional GNSS. Cryptographically authenticated and validated under active interference, it delivers a stable position signal the crew can trust, even when GNSS cannot.
Stay on course with PntGuard
Protect your vessel, your crew, and your trusted position.
This is a crew welfare and safety issue, not only a navigation one. Industry surveys show that roughly 4 in 5 mariners have personally experienced GNSS/GPS interference at sea. Reported consequences include physical harm to personnel, property damage and environmental damage, and more than 1 in 10 mariners say interference has led them into an unsafe or unlawful situation. GNSS/GPS interference exposes vulnerabilities in GMDSS and other SOLAS mandated safety systems that depend on satellite timing and position — systems most crews assume are independent of GNSS/GPS.
What was once concentrated in the Baltic and Middle East has spread into new hotspots worldwide. GNSS/GPS interference is no longer a regional anomaly — it is a global operational reality. The Middle East Gulf accounted for 57% of global jamming events before the 2026 escalation, rising to 98% in Q1 2026, while the Black Sea alone made up close to 20% of Q4 2025 events.
New jamming and spoofing activity has emerged at Russias eastern port of Nakhodka, in Venezuelan waters, and across the Mediterranean, Red Sea and Arctic. Interference now recurs across the Baltic, Black Sea, Eastern Mediterranean, Red Sea and Arabian Gulf — events that are no longer isolated or short in duration, and that can affect multiple vessels simultaneously.
GPS (Global Positioning System)
GPS is the satellite navigation system operated by the United States. It is the most widely recognized positioning system, but it is only one of several Global Navigation Satellite Systems (GNSS) used worldwide.
GNSS (Global Navigation Satellite System)
GNSS is the collective term for all global satellite navigation systems, including:
Modern maritime receivers typically use signals from several GNSS constellations simultaneously to improve availability and accuracy.
The key point: Regardless of which constellation is used, all GNSS signals share the same fundamental vulnerability. They are transmitted from satellites approximately 20,000 km above Earth, making them extremely weak when they reach the receiver. A nearby transmitter can therefore jam or spoof these signals with relatively little power.
APNT
APNT (Assured Position, Navigation and Timing) provides a trusted source of positioning and timing when GNSS signals become unreliable or unavailable. Unlike conventional GNSS receivers that simply calculate position from satellite signals, PntGuard continuously verifies whether those signals can be trusted. When interference is detected, A-PNT provides an authenticated and resilient position solution that enables safe navigation even during jamming or spoofing events.
PntGuard combines continuous GNSS monitoring with Iridium Satellite Time and Location (STL) with NAL Technologies receiver, this delivers an authenticated positioning source that remains available even when conventional GNSS signals are compromised.
APNT Technology
PntGuard continuously monitors all available GNSS signals for signs of interference while independently validating vessel position using resilient APNT technology.
Built on NAL Technologies third generation receiver that receive’ Iridium® STL (Satellite Time and Location) architecture, the system utilizes authenticated low-Earth-orbit satellite signals that are approximately 1,000 times stronger at the Earth’s surface than conventional GNSS signals. When GNSS interference is detected, PntGuard provides an independent, trusted position solution, giving crews continuous situational awareness even in contested environments.
GNSS Interference
GNSS interference includes jamming and spoofing—the deliberate disruption or manipulation of satellite navigation signals used for positioning, navigation and timing (PNT).
The effects extend far beyond the vessel’s electronic chart display. Systems including AIS, GMDSS, radar overlays, dynamic positioning (DP), voyage data recorders (VDR), ECDIS, and many other SOLAS-mandated systems rely directly or indirectly on GNSS-derived position and timing. Understanding how interference works is the first step toward protecting your vessel.
Jamming
Jamming is the deliberate transmission of radio-frequency noise on GNSS frequencies to overwhelm legitimate satellite signals. The receiver can no longer calculate its position and typically generates a warning or loses its position fix entirely.
Spoofing
Spoofing is a more sophisticated attack in which counterfeit satellite signals are transmitted to imitate legitimate GNSS signals. Rather than losing position, the receiver calculates a false—but seemingly valid—position, course, or time without alerting the crew. This makes spoofing significantly more difficult to detect and potentially far more dangerous.
Meaconing
Meaconing is a sophisticated form of signal manipulation in which legitimate GNSS signals are captured, delayed, and rebroadcast from another location. Unlike spoofing, the attacker does not generate counterfeit satellite signals—they retransmit genuine ones with a controlled delay.
Because the signals remain authentic, traditional GNSS receivers often accept them as valid. The result is an incorrect position or timing solution that can be difficult to detect without an independent verification source.
For commercial vessels, meaconing can cause gradual position offsets, navigation errors, and degraded situational awareness while appearing to operate normally.
Jamming denies navigation. Spoofing deceives navigation.
Both attacks also affect AIS broadcasts, GMDSS functions, and numerous other maritime systems that rely on GNSS-derived position and timing. Without an independent source of Assured Position, Navigation and Timing (A-PNT), crews may have no reliable way to determine whether their reported position can be trusted.
Stay on course with PntGuard
Protect your vessel, your crew, and your trusted position.
