GPS signal disruption and STS operations pose a threat to shipping, including Baltic ports
By Windward recently detected numerous incidents of GPS jamming at a new location in the port of Nakhodka. This represents a 30% increase in deliberate disruptions of ship navigation systems across the region in August. Two areas in the Baltic Sea have been identified where GPS jamming redirects ship position information towards land. This is most common around the port of Kaliningrad and near Primorsk.
The Group of Seven (G7) price cap of $60 per barrel for Russian crude oil, combined with sanctions on financial institutions such as Gazprombank, has limited Moscow’s revenue from energy exports. Despite these restrictions, Russia continues to generate revenue from oil sales. For example, in July, it achieved $9.8 billion from oil and gas exports. In July, Russia’s monthly revenue from fossil fuel exports fell by 3% month-on-month, reaching as much as €585 million per day, according to CREA analysts.
“The five largest importers of Russian fossil fuels in the EU paid Russia a combined €1.1 billion for fossil fuel purchases,” reports Petras Katinas, an expert at CREA. It’s important to note that gas imports from Russia by operators from EU countries are fully legal. The EU has not imposed sanctions on natural gas from Russia, which accounts for over 67% of global imports.
In July, Russia exported 25.3 million tons of crude oil by sea. More than half (55%) of these oil exports were transported by tankers owned by operators operating in G7+ countries or insured in G7+ countries. Since January, the G7+ share of Russian crude oil transport has increased from 36% to 55%, according to CREA.
It has been calculated that a price cap of $30 per barrel would reduce Russia’s oil export revenues by 40% (€150 billion) from the start of EU sanctions in December 2022 to the end of July 2025. In July alone, a price cap of $30 per barrel would reduce Russia’s revenues by 36% (€3.84 billion).
Legal operators of shadow fleets and tanker fleets are fully prepared for such actions. STS operations, including the disabling of AIS signals, vessel renaming, and false vessel registrations, are used to covertly move cargo.
Russia continues to export most of its oil to China and India. Some of these transactions comply with the G7 price cap, while others are the result of sanctions evasion techniques. In the words of Russia’s Deputy Trade Commissioner, “a very, very special mechanism” is used to settle Russian oil with Indian buyers.
GPS Jamming and AIS Manipulations. Source: Windward AIShadow Vessels in STS Operations
Mats E. Sæther, CEO and shipping lawyer at Nordisk, analyzed one of several STS operations. He conducted an in-depth analysis of the changes in vessel data during a ship-to-ship transfer operation, as recorded by CBS operators.
The first identified STS operation involves an oil transfer between the tankers Eon (IMO 93125509) and Alpy. The name Alpy is false, as is the flag of St. Maarten, which is not listed in the administration’s inventory. This vessel is Nova (IMO 9283801), which Mats E. Sæther identified by its distinctive superstructure. The colors of the shipowner Embiricos are also visible on the funnel. The vessel has had many names—both real and fake—since it was sold in 2022.
“Note that the information on the stern, displayed on the metal plates suspended from the ropes, is also false,” Sæther points out. Eon (IMO 93125509) was also a new ship on the market at the time of the CBS crew’s documenting. Previously, the ship sailed as Atlantic Loyalty in Sinokor colors. The former name can be seen beneath the fresh paint,” Sæther points out.
During the STS operation filmed by the CBS crew, the tanker Lafit (IMO 9379698, former Advantage Virtue) still had the labels in Advantage Tankers colors. The blue ship moored alongside was Stellar Oracle (IMO 9194127), formerly Young Yong and originally Maran Castor until the end of 2021, Sæther explains.
He emphasizes that “another operator is disguising the vessel under a number of different names, including Full Wood, King Plus, and the zombie name EM Longevity, which is a “darling of the dark fleet.”
AIS Manipulations in the Far East
“From August 5th to 18th, the automatic identification (AIS) signals of 112 vessels were transmitted ashore in the port of Nakhodka. This is the first time GPS jamming has been detected in these waters,” Windward observers report. GPS jamming occurred on the other side of the bay. AI-based tracking of vessel positions was used to record changes in the approaches to Transneft’s export terminal at the Kozmino fuel terminal. Export crude oil from the East Siberian Pacific Ocean (ESPO) pipeline is delivered here.
“This is the third major Russian oil hub to be affected by deliberate signal jamming. Similar GPS signal disruptions have been reported for an extended period in the Baltic Sea near Ust-Luga and Primorysk, as well as in Novorossiysk on the Black Sea,” Windward reports.
Significant disruption of tanker AIS signals related to GNSS manipulation was observed near Kozmino well before GPS jamming was detected near the port of Nakhodka. In addition to the 112 vessels observed in the GPS jamming areas, another 154 vessels in the eastern region were manipulated or disrupted in the first 18 days of August.
Vessels with disabled identification signals off the eastern coast of Russia have been observed previously. Captains have been manipulating GNSS signals on a large scale since the beginning of 2022. This activity is intended to conceal the timing and location of loading at fuel terminals and ship-to-ship transfers. GPS jamming, or blocking ships’ AIS satellite signals, is a common tactic attributed to vessels (primarily tankers) operating in the gray zone.
Windward first identified GPS jamming in the waters around Nakhodka on August 6, 2025. The company’s research showed that the combined GPS jamming and location manipulation (GNSS) activity in Kozmino in August was 30% higher compared to the first 18 days of July. The emergence of the maritime areas around Kozmino as a GPS jamming area is a signal that this terminal is being used for increased oil exports.
Zakłócenia sygnałów GPS i AIS w rejonach Primorska i Wyborga. GPS przekierowuje sygnały w pobliże Finlandii. Źródło: Windward AI
Interference in the Baltic, Black, and Red Seas
Since 2022, GPS jamming has been widespread in the Baltic and Black Seas. Two areas in the Baltic Sea have been noted where GPS jamming directs ships’ AIS signals towards land, according to Windward. This is happening around the port of Kaliningrad and near Primorsk.
Such activity poses a serious navigational hazard. It is particularly prevalent in areas where significant numbers of ships gather on maritime routes, such as the waterways leading to Gdańsk, Gdynia, and Świnoujście. Vessels transiting the Danish Straits or maneuvering at their entrances are particularly vulnerable to collision.
DW journalists also found that gray fleet vessels also anchor near the terminals in the port of Ust-Luga. Only by approaching an anchored tanker can it be truly identified, as AIS signals from vessels calling at Ust-Luga and Primorsk indicate that the tankers have entered waters off the coast of Finland.
Disruptions throughout the Black Sea have become widespread since Russia’s invasion of Ukraine in 2022. Since May of this year, the Red Sea has experienced significant disruptions to navigation due to GPS jamming and AIS shutdowns, coordinated with the intensification of attacks on commercial maritime traffic by the Houthis. Windward’s analysis indicates that GPS jamming affects nearly 1,000 vessels per month in the Red Sea. In August of this year alone, approximately 600 vessels lost their GPS signal.
GPS jamming has been found to be particularly intense in the Red Sea off the coast of Sudan. Over the past 30 days, GPS jamming has affected nearly 2,000 vessels in four key regions identified by Windward. The largest area of interference was in the Red Sea off the coast of Sudan (824 vessels), followed by the Black Sea (471 vessels), the Baltic Sea (460 vessels), and Nakhodka-Kozmino (112 vessels).
However, the number of GPS jamming incidents in the Strait of Hormuz and the Persian Gulf has decreased. At the height of the conflict with Iran, nearly 1,000 vessels per day experienced interference. Currently, the number of threats to vessels has decreased dramatically. In August of this year, fewer than a dozen instances of satellite signal jamming were detected.
Ships conducting STS operations or waiting at anchor to load in Russian ports often disable their identification systems. DW Documentary journalists have produced an extensive report on this. The film also highlights the anchorages and passages of shadow ships in the Baltic Sea.