# GNSS jamming and spoofing: protecting business operations Protection starts with knowing where operations depend on GNSS, including hidden dependencies such as network time servers. Receivers are then placed and chosen with care, signals are monitored, authenticated Galileo navigation data helps detect spoofing, and an independent backup such as a holdover clock or inertial navigation bridges an outage. ## Why GNSS interference is a business risk GNSS gives position and time to vehicles, vessels, machines, telecom networks and power grids. Its signals reach the ground below the level of ambient noise, so even a weak interference source can disturb a receiver [2]. EASA describes two forms of deliberate interference [1]: - **Jamming**: radio interference that prevents a receiver from locking onto the satellite signals, so the service is lost or degraded. - **Spoofing**: counterfeit satellite signals that make a receiver compute a wrong position, navigation or time. The effects range from reduced accuracy to sudden jumps in time, position or direction. A receiver that keeps reporting can pass hazardously misleading information into the systems that rely on it. Systems that take precise time from GNSS are usually automated and often unattended, which puts them at greater risk [2]. - **Latest EASA bulletin on GNSS interference:** SIB 2022-02R4, 3 July 2026 - **Attempted cyberattacks on shipping since February 2020, incl. GNSS jamming and spoofing:** fourfold increase - **Galileo OSNMA operational since:** 24 July 2025 The figures come from EASA [1], the EUSPA EO and GNSS Market Report 2024, which refers to the maritime sector [4], and EUSPA [3]. EASA reports a notable increase in jamming and spoofing since February 2022 and names the Mediterranean, the Black Sea, the Middle East, the Baltic Sea and the Arctic among the areas affected [1]. ## How protection works Protection works in four layers. None of them is enough alone. 1. **Know the dependence.** Even vigilant operators may not be fully aware of how much they rely on GNSS. Systems that look independent, such as some network time services, can take their time from GNSS receivers. The UK Blackett review therefore recommends that operators of critical infrastructure review their reliance on GNSS, direct or through other systems [2]. 2. **Harden the receiver.** Stationary receivers are more exposed than mobile ones. An antenna with a full view of the sky, mounted away from roads, avoids many cases of interference. Professional receivers check the veracity of signals, while mass-market components easily fall prey to interference [2]. 3. **Detect and authenticate.** Systems that monitor the radio spectrum detect jamming and spoofing and alert users [2]. Galileo OSNMA lets civilian receivers verify that the navigation data is authentic [3]. In aviation, EASA asks operators to cross-check the position with non-GNSS navigation aids and to report spoofing events [1]. 4. **Bridge the outage.** When GNSS is lost, a holdover oscillator, such as a crystal, rubidium or caesium clock, keeps time for a while, and an inertial navigation system keeps estimating the position [2]. The review recommends GNSS-independent backup systems for critical infrastructure [2]. **Figure:** Where the four layers of protection act: layers 1 and 4 (know the dependence, bridge the outage) protect your systems, layer 2 hardens the receiver, and layer 3 (detect and authenticate) covers the signal and the receiver. Jamming and spoofing act on the link between the satellites and the receiver. Schematic drawing. How timing for power grids is designed, including Galileo as a second source next to GPS, is covered under [precise timing for power grids](https://leto.space/use-cases/grid-timing/). Our page on [what GNSS is](https://leto.space/knowledge/gnss/) explains the basics. ## What you get - An inventory of every system that takes position or time from GNSS, including indirect dependencies. - Requirements for accuracy, integrity, availability and continuity per application, as the Blackett review recommends for procurers [2]. - Detection of jamming and spoofing, with alarms that reach the people who act on them. - A fallback for each critical dependency, with the time it has to bridge. ## Limits **Limits** - **Authentication does not stop jamming:** OSNMA confirms that navigation data is authentic \[3]. Jamming can stop a receiver from locking onto the signals at all \[1], so the operation still needs a backup. - **Every backup drifts:** A holdover clock gradually drifts away from GNSS time, and its quality is defined by how long it holds a given accuracy. Inertial navigation accumulates errors over time \[2]. A backup bridges an outage; it does not replace GNSS indefinitely. - **More satellites are not more protection:** Additional constellations such as Galileo reduce the dependence on GPS, but the problems caused by interference remain \[2]. ## How we help We find out where your operations depend on GNSS and what a loss or a false signal would cost in each case. In [requirements and procurement](https://leto.space/consulting/procurement/) we specify receivers, detection and backups and compare providers against them. In [implementation](https://leto.space/consulting/implementation/) we test the fallback before it is needed. To see who offers space-enabled solutions, use [Spacegraph](https://leto.space/spacegraph/), our discovery platform. ## Related use cases - [Precise timing for power grids](https://leto.space/use-cases/grid-timing/): Why grids depend on GNSS time and how to make it resilient. - [Tracking fleets beyond mobile coverage](https://leto.space/use-cases/fleet-tracking/): GNSS positions sent by satellite where mobile networks end. - [Machine guidance and surveying with GNSS](https://leto.space/use-cases/gnss-machine-guidance/): Satellite positioning on construction sites. - [Satellite data in mobility and logistics](https://leto.space/industries/mobility-and-logistics/): All use cases for transport and logistics. ## Frequently asked questions ### What is the difference between jamming and spoofing? Jamming is radio interference that prevents a receiver from locking onto the satellite signals, so position and time are lost or degraded. Spoofing broadcasts counterfeit satellite signals, so the receiver computes a wrong position, navigation or time [1]. A spoofed receiver keeps delivering a position, and the system may not be able to tell that it has been compromised [2]. ### Does Galileo protect against spoofing? Galileo's Open Service Navigation Message Authentication (OSNMA) has been operational since 24 July 2025. It lets civilian receivers check that the navigation data they use is authentic [3]. This helps a receiver detect spoofed signals. It does not help against jamming, so a backup is still needed. ### How do we start? Start with an inventory: which systems take position or time from GNSS, directly or through other systems, and what happens in each of them when the signal is lost or false. From there we define requirements and a fallback for each critical dependency. Our [consulting overview](https://leto.space/consulting/) shows the path from the problem to operation. ## Sources 1. [Global Navigation Satellite System (GNSS) outages and alterations, European Union Aviation Safety Agency (EASA), 2026-07-03](https://www.easa.europa.eu/en/domains/air-operations/global-navigation-satellite-system-outages-and-alterations) 2. [Satellite-derived time and position: a study of critical dependencies (Blackett review), UK Government Office for Science, 2018-01-30](https://www.gov.uk/government/publications/satellite-derived-time-and-position-blackett-review) 3. [From Testing to Operations: Galileo OSNMA Service Now Available to Users, EU Agency for the Space Programme (EUSPA), 2025-09-05](https://www.euspa.europa.eu/newsroom-events/news/testing-operations-galileo-osnma-service-now-available-users) 4. [EUSPA EO and GNSS Market Report, Issue 2, 2024, EU Agency for the Space Programme (EUSPA), 2024](https://www.euspa.europa.eu/sites/default/files/external/publications/euspa_market_report_2024.pdf) Page: