Global Navigation Satellite Interference at Sea (GIAS)

WHY

Global Navigation Satellite Systems (GNSS) are central to positioning and timing in offshore operations. Recent military activity in the Baltic Sea has sharply increased both jamming and spoofing, creating a growing threat to vessels and equipment that rely on accurate location data. Jamming blocks legitimate satellite signals, while spoofing transmits false ones. Both can cause vessels or installation equipment to receive misleading or missing positional information. In offshore wind construction, even small accuracy losses can trigger unintended movements. This may raise the risk of structural damage, misaligned foundations, costly rework, or complete loss of assets. These technical failures can also cascade into wider operational delays, vessel downtime, and reduced installation efficiency across the project.

A 2025 study by GPSPATRON and Gdynia Maritime University provides the first systematic assessment of GNSS interference in the Baltic Sea. It shows that disturbance events are often periodic and mobile, frequently linked to nearby vessels, and may last from several hours to more than twenty. Under severe jamming, positioning accuracy can deteriorate by up to thirty‑five metres as signal quality collapses. The research also highlights that most interference originates from line‑of‑sight jammers, whose impact is limited to situations where vessels are within direct radio visibility, as the curvature of the Earth prevents long‑range obstruction at sea.

Despite these insights, current industry responses remain fragmented and largely confined to individual vessels. Upgrading GNSS hardware or relying on system redundancy can improve local resilience, but does not address broader operational vulnerabilities. There is limited integration of alternative or complementary positioning technologies, and no shared framework exists for assessing or mitigating GNSS‑related risks across the offshore wind supply chain. Strengthening resilience therefore requires a shift from monitoring alone towards coordinated mitigation, operational continuity, and decision support, enabling the sector to maintain safe and efficient operations even when GNSS performance is compromised.

WHAT

In this project, we aim to create a shared, cross‑industry understanding of how GNSS interference affects offshore vessels and the execution of offshore wind projects. Rather than treating interference as a vessel‑specific technical issue, the project seeks to establish a system‑level perspective that spans contractors and operational domains. By doing so, we intend to support a more coordinated approach to evaluating complementary and alternative positioning technologies, examining not only their technical performance but also their practical suitability for offshore wind logistics, where accuracy, reliability, and continuity are essential.

The purpose is to build a fundamental understanding of the causes and mechanisms of positioning disturbances and to explore alternative methods that could reduce associated risks. In addition to identifying viable technical pathways, the project will outline the steps required for further development, supporting future innovation, testing, and implementation across the sector.

The project follows a collaborative approach in which user perspectives from contractors, suppliers, and other operational stakeholders are gathered and synthesised into a shared best‑practice report by TNO and TU Delft. The full programme runs for eleven months and is structured to combine technical analysis with practical, experience‑based insights from across the offshore wind value chain.

In the project, TNO and TU Delft contribute independent research expertise, technical assessment, and analytical capability. The industry partners, including Van Oord, Boskalis, HMC, Ampelmann, Huisman, and Fugro, provide operational knowledge, real‑world use cases, and user‑driven perspectives that ensure the study reflects actual challenges encountered during offshore wind installation and vessel operations.

EXPECTED RESULTS

The project will first consolidate knowledge on operational vulnerabilities, identifying where GNSS degradation most significantly affects vessel control, installation precision, and project timelines. This includes mapping current mitigation practices to understand what measures are already in place and where gaps persist. It will then provide a comparative assessment of alternative vessel positioning solutions, enabling operators and contractors to judge which technologies can strengthen resilience under real offshore conditions. A shared framework for risk assessment and operational decision‑making will also be developed, offering structured guidance for planning and executing operations when GNSS performance is compromised. Finally, the study will outline common priorities and actionable next steps to steer future research, pilot projects, and procurement strategies across the sector.

Collectively, these outcomes are intended to help the offshore industry shift from reactive responses to GNSS disturbances towards proactive, resilient, and innovation‑driven operational strategies. By bringing together Dutch research groups and key industry partners, the project also reinforces the Netherlands’ position as a leader in resilient offshore operations. Its findings can be applied directly in upcoming wind farm campaigns and hold strong export potential, particularly as GNSS interference becomes an increasingly global challenge.