Satellite navigation interference, intercepts and the shadow fleet. Baltic security in summer 2026

GNSS interference covered 11.39 percent of June off the Polish coast. The figure comes from two stations monitoring signal quality and works out at an average of close to two hours and forty minutes a day during which satellite navigation in the area is unreliable. For owners, terminal operators and maritime administration it means planning operations on the assumption that a satellite position may be unavailable or false.

security aviation navy worldwide pomerania west pomerania tricity news army

05 august 2026   |   07:31   |   Source: Gazeta Morska   |   Prepared by: Kamil Kusier   |   Print

fot. Ministerstwo Obrony Narodowej

Interference is one of several elements in the security picture on this sea. Over three weeks Polish air forces intercepted Russian aircraft over the Baltic three times, a Russian Kh-101 cruise missile came down in the Lublin region, and a vessel of the EUNAVFOR MED IRINI operation boarded an EU-sanctioned tanker with support from a Polish patrol aircraft. In the same period the commander-in-chief of the Swedish armed forces called on his population to prepare for an attack.

Monitoring data for June

In June 2026 two Polish stations monitoring GPS and GNSS signal quality detected 18 incidents. Eleven were classified as highly probable events, seven as possible.

The probable events lasted 63 hours in total, or 8.75 percent of the entire month. A single event averaged five hours and 44 minutes. Possible events accounted for a further 19 hours. Together, interference covered 11.39 percent of June.

One of the more serious incidents was recorded during a flight over the Baltic by the British defence secretary.

The data comes from two stations operated by a Polish company, the second of which was designed to shield signals arriving from the north-east. Comparing readings from both units makes it possible to separate deliberate interference from ordinary signal loss.

Jamming and spoofing of the signal

Since the start of Russia's full-scale invasion of Ukraine, thousands of aircraft and ships operating off north-eastern Europe have recorded navigation problems: false position readings, loss of GPS signal, and in some cases route changes or cancelled voyages. The intensity of these events has been rising since 2022.

At sea, jamming and spoofing present two distinct situations.

Jamming removes the position. The receiver stops working, the alarm is immediate, and the navigator falls back on radar, bearings and dead reckoning. It is disruptive but overt.

Spoofing works differently. The receiver still supplies a position, only a false one, and that position feeds onward into the vessel's other systems. It reaches ECDIS, the AIS transponder and radar image stabilisation, so the ship goes where the master takes her while appearing on the bridge display and in the VTS picture several or more miles away. The crew has no reason to suspect anything until the discrepancy emerges on comparison with the radar image or on approach to port.

The most dangerous variant lies in between: a positional offset small enough to raise no doubts, yet sufficient to take a vessel outside the fairway.

Sources of emission

The answer to the question of where the interference originates is not straightforward and has shifted with successive research. In July 2025 Polish experts, including from the Gdynia Maritime University, published analysis identifying specific locations from which interfering signals over the Baltic are emitted, linking them unambiguously to Russian activity in the region.

Later research, reported among others by TradeWinds, indicated that a substantial share of the interference recorded at sea originates from ships. Krasimir Hristov of GPSPatron, quoted in that analysis, noted that all satellite signals are relatively easy to jam, and that the high-power emissions from Kaliningrad are directed principally at aircraft operating at higher altitudes.

The findings are not contradictory. Both high-power shore sources and dispersed sources afloat are active over the Baltic. The latter are considerably harder to locate and effectively impossible to attribute to any particular actor.

Effects on operations

For owners and masters, interference is an operational and a financial problem at once. Every delay, every course alteration and every additional safety procedure costs money, and for vessels working to terminal time windows a delay measured in hours can mean losing the window and waiting at anchor. On a single voyage the sums are small; across months and a whole fleet they become a line in operating accounts.

The documentary burden is growing too. Position discrepancies logged in the deck log and reported to traffic services have to be described, and in disputes over liability they become evidence in proceedings run by underwriters and P&I clubs.

In aviation the effects fall differently. Aircraft are not wholly dependent on GPS and can use conventional instruments, radar and alternative procedures. The difficulty arises on approach, in precision operations, and whenever a crew has to re-establish the aircraft's position quickly.

On the Polish coast this translates into risk in areas of heavy traffic, at port entrances and during manoeuvring, which are the places where the margin for error is smallest.

Timing signal and port systems

Satellite systems provide not only position but a time signal. Satellite timing is used in telecommunications, in the power sector and in port and cargo-handling automation.

Researchers studying Baltic interference note that ports, telecommunications operators and emergency services rely on GNSS for navigation, timing and safety. Without precise ground-level monitoring, interference can go undetected and cause failures across several sectors at once. Jamming can also affect port automation and cargo handling systems.

No monitoring network covering the whole Polish coast currently exists. There are individual stations run by private companies and universities.

R-Mode Baltic as a fallback

Germany, Poland, Sweden, Norway, Finland and Estonia are deploying R-Mode Baltic, a positioning system that uses existing radio infrastructure instead of satellite signal. Work on it began before the current wave of interference, but its significance has grown considerably since 2022.

R-Mode is less accurate than GNSS and will not replace it in routine navigation. It does, however, have one property GNSS currently lacks: it cannot be jammed from space, because it does not use space. It is a fallback intended for situations in which the satellite signal becomes unusable.

Intercepts over the Baltic

On the morning of 3 August, 60 kilometres north-west of Łeba, a Polish quick reaction pair intercepted a Russian Ił-20 reconnaissance aircraft. It was flying in international airspace, without a flight plan and with its transponder switched off. Polish airspace was not violated.

On 31 July an F-16 pair intercepted an Ił-20 forty kilometres north of Kołobrzeg. The circumstances were identical.

On 16 July Polish fighters had three targets in one day. They first intercepted two Russian Su-30s over the Baltic, then were directed to an Ił-20 reconnaissance aircraft. Once it had been identified, Swedish fighters took over the escort. Two days earlier a Polish pair had intercepted an Ił-20 flying some thirty kilometres from Ustka.

Being in international airspace is lawful and constitutes no violation. The problem is the absence of a flight plan and the switched-off transponder. Russian reconnaissance aircraft, and for some time combat aircraft too, fly over the Baltic without either, which makes remote identification impossible. Air traffic control sees an object about which it holds no data, in one of the busiest air and sea corridors in Europe. Each time, this forces a quick reaction launch.

The handover to Swedish fighters in flight matters beyond the incident itself. It shows the Baltic alert system operating as a whole rather than as the sum of national responses. Following Swedish and Finnish accession to NATO, this is a new operational capability in the region.

The missile at Tarnawa-Kolonia

On the night of 29 to 30 July, at 03:40, an unidentified object was detected in Polish airspace. An F-16 was scrambled to identify it. At 03:46 the object disappeared, and its probable point of impact was located near the village of Tarnawa-Kolonia in the Lublin region. A Mi-24 military helicopter found a crater. The missile struck open ground, nobody was hurt and there was no damage.

Examination of the fragments established that it was a Russian Kh-101 cruise missile manufactured in the second quarter of 2026 at a plant near Moscow. Prosecutors confirmed the missile was armed and carried a substantial quantity of explosive. The military refrained from shooting it down because the trajectory indicated it would fall on uninhabited terrain.

The manufacturing date matters for assessing the situation. A missile built in the second quarter of this year entered use within weeks of leaving the plant. The fact that it was armed rules out any suggestion of a decoy.

The decision not to engage followed peacetime procedure. Destroying a missile over built-up terrain means debris falling on people and buildings. Where the trajectory leads to open fields, procedure dictates letting it come down and securing the point of impact.

The Swedish command's position

On 4 August General Michael Claesson, commander-in-chief of the Swedish armed forces, told the newspaper Svenska Dagbladet that Swedes should prepare mentally for a Russian attack. The immediate backdrop was the Russian missile that fell in Poland.

Claesson pointed above all to the risk of sabotage, which he called obvious for every state supporting Ukraine. He did not rule out smaller-scale military operations, for instance involving special forces, but attributed to them a purpose other than seizing ground: observing, measuring and testing reaction patterns, both political and military.

As an extreme scenario he cited the possibility of finding swarms of pre-programmed drones with some form of armament inside a container in the port of Gothenburg. As the more likely scenario he named hybrid warfare: the gradual erosion of the decision-making environment and of trust in European armed forces and political systems, pursued through sabotage and action in the information space.

The container scenario bears directly on ports. A container is a sealed space nobody opens without reason, and its contents are declared by the shipper. Inspections cover a fraction of cargo units and rest on risk analysis rather than physical examination.

Vice Admiral Ewa Skoog Haslum, head of operations in the Swedish armed forces, drew attention to a different problem. In her view the hardest task today is interpreting information. She cited the missile that fell in Poland and the questions to which there was no answer at the time: whether it was a navigational error or a deliberate test of responses, and how to act should it happen again. Skoog Haslum said Sweden has a plan for Russian escalation in the Baltic in connection with a shift in how the shadow fleet is being used.

Tanker boarding with Polish support

On 2 August ITS Thaon di Revel, flagship of the EUNAVFOR MED IRINI operation, carried out a boarding of the tanker Toa Payoh west of Pantelleria. The vessel is under EU sanctions and counted among Russia's shadow fleet.

The master initially declined to cooperate, so an Italian boarding team reached the deck by helicopter. The action was supported by a Greek warship and a Polish patrol aircraft, most likely an M28B 1R Bryza of the Polish Military Contingent Irini, provided by the Polish Naval Aviation Brigade.

The legal basis was Article 110 of the United Nations Convention on the Law of the Sea, which allows a warship to verify a merchant vessel's nationality where there are reasonable grounds for suspicion. It is one of the few instruments available to states against such ships in international waters.

For the Baltic the case is directly relevant. The main export route for Russian crude from Gulf of Finland ports runs through this sea, and vessels of this class pass regularly through the Danish straits. The methods are the same whichever sea is involved: a flag from a register with limited oversight capacity, an irregular voyage pattern, transponders switched off, non-cooperation when challenged, and often insurance of unverified value.

Transponders switched off aboard tankers and GNSS interference are separate phenomena, but they produce the same outcome. The maritime picture available to the authorities ceases to be complete.

Implications for shipping and ports

The Baltic is not a sea at war, but it has ceased to be a sea where instrument readings can be relied on without reservation. That is a change from the position before 2022 and it affects everyone who goes to sea professionally. In practice it means the return of navigation conducted without GNSS: the ability to work on radar, bearings, echo sounder and dead reckoning is no longer a matter of tradition but an operational requirement, in training programmes and in bridge procedures alike.

The second consequence concerns infrastructure. Interference monitoring functions in substance as critical infrastructure, though regulation does not treat it as such, and without a network of ground stations events remain invisible until somebody reports a problem. The same applies to container terminals, where security extends to the contents of cargo and not merely to site access and IT systems.

The third concerns quick reaction forces. Three intercepts in three weeks, including one day with three targets, means steady consumption of a resource that is finite and cannot be increased overnight. The hardest question, however, remains the one raised by the Swedish vice admiral: at the moment a decision has to be taken, it is usually not known whether an event was an error or a test. Grey-zone activity rests on precisely that, and no amount of equipment will resolve it.

Buy us a coffee, and we’ll invest in great maritime journalism! Support Gazeta Morska and help us sail forward – click here!

zakłócenia GNSS nad Bałtykiem przechwycenie rosyjskiego Ił-20 rakieta Ch-101 nad Polską rosyjska flota cieni na Bałtyku bezpieczeństwo żeglugi Morze Bałtyckie

comments

---

enter content

COMMENT

nick

Add the first comment