The United Nations has sounded the alarm: interference and spoofing targeting the Global Navigation Satellite System (GNSS) are accelerating their spread, revealing treacherous hidden reefs for the shipping industry. Statistics show that in July 2024, complaints of ships “losing contact” occurred only once every two weeks. By mid-July 2025, a year later, this number skyrocketed to 150 cases in a single day, with Global Positioning System (GPS) signals collectively failing instantaneously in critical choke points. Course deviations, collision risks, and port paralysis followed one after another, turning hundred-thousand-ton vessels into “blindfolded bulls” in an instant. As forged coordinates rewrite tracks more easily than the sea breeze, the industry and the IMO are pinning their hopes on intelligent defense lines, using smart technology to re-anchor safety coordinates within the electronic fog.
Risk Escalation
Against the backdrop of the shipping industry’s intelligent development, the challenges and threats faced by the Global Navigation Satellite System are intensifying, mainly manifested in interference and spoofing. On one hand, technical means such as high-frequency electromagnetic interference and signal jamming are continuously evolving, potentially causing inaccurate ship positioning, route deviations, and even triggering collision accidents. On the other hand, malicious actors implement “spoofing attacks” by forging navigation signals, causing ships to misjudge their own position and subsequently enter sensitive or dangerous waters, seriously threatening shipping safety and the stability of international trade. Furthermore, as smart ships become increasingly reliant on navigation systems, once these systems are attacked, the consequences will inevitably trigger a domino effect, posing risks not only to the vessel itself but also to other systems reliant on geolocation and precise satellite timing, and even the entire waterborne transportation network. Therefore, enhancing the anti-jamming and anti-spoofing capabilities of navigation systems has become a critical issue for ensuring global shipping safety.
2017 was an extraordinary year when an alert issued by the US Maritime Administration drew significant attention: the GPS of 24 ships in the Black Sea malfunctioned, causing these vessels to remain within the vicinity of Grenzdyk Airport for several days. In July 2023, the NATO Shipping Centre also reported that navigation systems in the Eastern Mediterranean region were still frequently experiencing failures.
Even so, few could predict the impending major outbreak. According to data from Lloyd’s List Intelligence, on April 4, 2024, alone, 227 cargo ships in the Black Sea were reported located at multiple inland locations, and 117 cargo ships in the Mediterranean were reported located at Rafic Hariri International Airport.
Data provided by Windward AI shows that in the second quarter of 2025, 890 vessels experienced interference off the coast of Sudan, up from 180 incidents in the first quarter (zero in Q4 2024). A similar trend emerged in the Baltic Sea, with the number of affected vessels rising from 1,225 in Q1 2025 to over 5,800 in Q2 2025. Windward AI also reported that over a 4-day period in June, an average of 970 vessels per day experienced GPS interference in the Arabian Gulf and the Strait of Hormuz.
A recent report from a satellite service provider indicated that in July 2024, reports of ships being unable to use GPS were received about once every two weeks, whereas by mid-July 2025, over 150 reports were received in a single day.
“GPS spoofing and jamming is now widespread and has a huge impact on the safety of busy shipping lanes,” said Ralf Magner, Director of Product & System Business at Sperry Marine. “Navigation systems are increasingly integrated today, so incorrect heading information can not only mislead the officer on watch (providing them with inaccurate speed and course data) but also prevent collision warnings from being triggered normally, subsequently affecting autonomous navigation systems and Automatic Radar Plotting Aids (ARPA). This sophisticated spoofing can interfere with navigation systems undetected, leading ships unknowingly towards areas with pirates or other hostile forces.”
Incorrect GPS and Automatic Identification System (AIS) position information not only troubles highly automated navigation systems but also creates more uncertainty for vessels relying on manual position input in Electronic Chart Display and Information Systems (ECDIS) and radar systems. According to Windward AI research data, when the AIS system malfunctions, the average “jump” distance of vessels increases tenfold—rising from 600 km in Q4 2024 to 6,300 km in Q1 2025.
Elevated to an International Security Issue
Currently, concerns about GNSS interference and spoofing risks have escalated from a specialized shipping domain to an international security issue, drawing high-level attention from UN agencies such as the International Telecommunication Union (ITU), the International Civil Aviation Organization (ICAO), and the IMO.
In a joint statement issued this March, these UN agencies stated that with the increasing incidents of interference affecting aviation, maritime, and other satellite communication services, countries urgently need to strengthen the protection of this critical frequency band. These harmful interference behaviors, manifesting as jamming and spoofing, disrupt the GNSS operating in the frequency bands allocated to the Radionavigation-Satellite Service (RNSS).
“The safety of seafarers and shipping depends on the resilience of systems supporting safe navigation and communication. Interfering with GNSS poses a serious threat to shipping activities, potentially leading to ship collisions or groundings. I urge all Member States to take action to protect these vital systems,” said IMO Secretary-General Arsenio Dominguez.
Ships and ports rely on GNSS for various applications related to position, speed, and precise global and local time. These applications are primarily used for navigation purposes, and most critically, they are part of the Global Maritime Distress and Safety System (GMDSS).
Chapter V, Regulation 19.2.1.6 of the International Convention for the Safety of Life at Sea (SOLAS), 1974, requires all ships, irrespective of size, to have a GNSS receiver or a terrestrial radionavigation receiver, or other means, usable at all times throughout the intended voyage, to establish and update the ship’s position automatically.
According to IMO’s Maritime Safety Committee /Circ.1644, Member States are urged to take necessary measures, as required by the ITU Radio Regulations, to minimize interference emanating from their territories; it is recommended that States issue warning notices or reminders to seafarers, clearly indicating the known time periods and sea areas affected by interference, to minimize its negative impact on maritime navigation; simultaneously, it is recommended that States develop relevant measures to prevent unauthorized signal transmissions on recognized satellite navigation system frequencies.
According to ITU Radio Regulations Article 4.10, Member States of the International Telecommunication Union recognize the need for special measures to address the safety aspects of radionavigation and other safety services to protect them from harmful interference. Therefore, this factor must be fully considered in frequency allocation and use.
ITU Secretary-General Doreen Bogdan-Martin stated: “GNSS is essential for our safety on land, at sea, and in the air. Member States should ensure the continuous operation of these systems to safeguard everyone’s safety and maintain the stability of the critical services our daily lives depend on.”
Addressing this issue, the joint statement signed by the three UN specialized agencies identifies five key actions that Member States need to take. First, protect radionavigation systems from harmful interference to reduce risks to the reliability of signals used for civil and humanitarian operations, including signal loss or misleading information. Second, enhance the resilience of systems that rely on the Radionavigation-Satellite Service for navigation, positioning, and timing functions. Third, maintain sufficient traditional navigation infrastructure to provide backup support in case of RNSS failure or reception of incorrect signals; concurrently, research countermeasures for service disruptions. Fourth, strengthen cooperation among radio regulatory authorities, civil aviation authorities, maritime authorities, defense departments, and law enforcement agencies. Fifth, establish comprehensive interference reporting mechanisms, reporting cases of harmful interference to RNSS to the respective telecommunications, aviation, and maritime regulatory authorities, as well as to the ITU Radiocommunication Bureau, for comprehensive monitoring of these interference activities.
Intelligent Solutions
When GNSS signals are jammed and coordinates are “dragged” into false trajectories, the shipping industry is moving the response battlefield to the intelligent track, attempting to rebuild coordinates within the spoofing fog and continue safe navigation through intelligent technologies such as multi-system integrated navigation, quantum navigation, multi-source fusion and intelligent algorithms, and interference detection and localization systems.
Multi-system integrated navigation refers to the parallel acquisition, tracking, and computation of ranging signals from multiple independent global satellite navigation constellations on a single receiver platform. Through joint adjustment and selective weight filtering, it achieves redundant complementarity at the signal layer, observation layer, and positioning layer, thereby significantly mitigating the risk of service interruption caused by poor geometric configuration, local signal blockage, or intentional jamming of a single constellation. The system core typically employs multi-frequency, multi-system baseband chips, supporting frequency bands such as GPS, BeiDou, Galileo, and GLONASS, and incorporates chip-level anti-continuous wave and anti-wideband interference algorithms. On the data processing side, using an extended Kalman filter or factor graph optimization as the framework, it uniformly models pseudorange, carrier phase, and Doppler measurements from each system to estimate receiver position, velocity, clock bias, and tropospheric delay in real-time. Furthermore, it adaptively adjusts the weights of abnormal observations through a weighting matrix, ensuring high accuracy is maintained even when some frequency bands are spoofed or experience sudden power drops.
Quantum navigation technology provides the shipping industry with a “starless” positioning solution that operates independently of satellites, requires no external base stations, and functions in all weather conditions. Its core includes quantum-enhanced inertial navigation systems, where laser-cooled atomic clouds are used as ultra-sensitive gyroscopes and accelerometers capable of detecting minute changes in the Earth’s rotation rate and the vessel’s own micro-accelerations. The dead reckoning error is reduced from several kilometers with traditional inertial navigation to tens of meters, sufficient for navigating narrow channels in port areas and for automated docking. Additionally, it includes magnetic field navigation, where quantum magnetometers measure geomagnetic anomalies on the seabed and coast in real-time, matching the 3D magnetic “fingerprint” with a digital geomagnetic map to provide passive position corrections every few hours. After fusion of these two technologies, even when entering areas where GNSS is jammed, spoofed, or satellite signals are weak (such as polar regions), a vessel can still maintain meter-level positioning and sub-degree heading accuracy for several days using a quantum sensing suite the size of a cabinet. This provides an “invisible compass” that does not rely on external signals for intelligent route planning, dynamic positioning, and unmanned navigation, significantly enhancing shipping safety and resilience.
Multi-source fusion and intelligent algorithms involve integrating satellite, sonar, radar, visual, AIS, wheel speedometer, wind /speed sensors, and even shore-based 5G time delay data into a unified spatiotemporal framework. Distributed filtering and deep learning models perform second-level weight reassignment: if GNSS is blocked, visual anchors take over; if radar detects abnormal echoes, AIS intent comparison is triggered; if wheel speed conflicts with Doppler measurements, the system automatically downgrades the weight and switches to sonar bottom tracking. The algorithm layer employs factor graph optimization and LSTM networks in parallel, preserving the real-time performance of the classic Kalman filter while leveraging the nonlinear fitting capability of neural networks for pattern recognition of “false flag” AIS, forged GPS, and spoofed Galileo signals, enabling the output of spoofing probability and corrected tracks in a very short time. This solution provides a continuous, trustworthy, and spoofing-resistant spatiotemporal foundation for intelligent collision avoidance, automated docking, and formation sailing.
Interference detection and localization systems will act as “electronic sentinels” for vessel safety navigation. This solution centers on multi-band monitoring antennas and chip-level spectrum analyzers, continuously scanning from VHF to L-band, and providing second-level alarms for signals with abnormal power, sudden bandwidth changes, or mismatched modulation characteristics. Simultaneously, it utilizes ship-shore-satellite distributed Time Difference of Arrival (TDOA) and Angle of Arrival (AOA) fusion algorithms to mark the bearing and distance of interference sources on electronic charts in real-time, with an error smaller than the vessel’s length. The system has a built-in AI model that can cross-verify target identity using radar echoes and optical images when AIS is off or spoofed, avoiding misjudgment. All data is processed by an onboard edge computing box with a power consumption of less than 80 watts, requiring no additional cooling.
