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1 INTRODUCTION

This paper aims to identify potential effective

regulatory instruments for preventing spoofing—one

form of cyber-attack—by clarifying the current legal

structures for the regulations on Global Positioning

System (GPS) spoofing. Then the current safety and

security measures for prevention of GPS spoofing will

be examined through case studies.

GPS, the US form of Global Navigation Satellite

System (GNSS), is a constellation of satellites providing

signals from space that transmit positioning,

navigational and timing (PNT) data to GPS receivers

on the Earth [1]. These receivers are then able to

determine their location from this data. Four global

constellations: the US’s GPS Navigation System with

Time and Ranging Global Positioning Satellite (GPS

NAVSTAR), the EU’s Galileo, Russia’s Global'naya

Navigatsionnaya Sputnikovaya Sistema (GLONASS)

and China’s Beidou are providing global coverage

services. Also the following regional satellite-based

augmentation systems (SBAS) are in operation: Japan’s

Quasi-Zenith Satellite System (QZSS), India’s

GAGAN, the US’s Galaxy 15 and the UK’s Inmarsat 3-

F2 and 4-F3 [2]. What would be indispensable to

drawing up clear blueprints for the use of GNSS, or

even future cyber warfare, should be an accurate

understanding of not only the major GPS players but

also states embarking on space activities, such as Iran.

Among these GPS services, errors in signals that

inform vessels and aircraft of their locations and

navigation routes have the potential to cause accidents.

GPS spoofing is an act of deliberate conduct that sends

false signals that may cause navigational hazards and

danger. For example, ultra-large crude carriers (ULCC)

that carry up to 500,000 tons of crude oil, navigate

safely by GPS through narrow straits. Drill ships that

extricate oil and gas from the ultra-deep seabed use

GPS Jamming and Spoofing – Countermeasures

for Safety and Security

M. Okochi

& M. Haberfeld

Tokyo University of Marine Science and Technology, Tokyo, Japan

City University of New York, John Jay College of Criminal Justice, New York, USA

ABSTRACT: This paper aims to clarify the legal status of Global Positioning System (GPS) jamming and spoofing,

which have a dichotomous nature of countermeasures and cyber-attacks. GPS is an indispensable tool to enable

ships, aircraft, and weapons to navigate to a predetermined destination. The jamming and spoofing of these

signals apparently hinder safe navigation through Sea Lines of Communication (SLOCs). At the same time,

jamming has been positively employed to prevent the triggering of explosives and to conceal communications

between terrorists during critical operations. In light of these positive uses of jamming, international legal

structures have not been established to prohibit jamming and spoofing. In order to find essential factors to help

legalise or criminalise jamming, this research analyses cases of GPS jamming. Both Ben Gurion International

Airport in Israel and the Black Sea have often been disrupted by intentional interference with GPS, such as

jamming and spoofing.

http://www.transnav.eu

the International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 19

Number 3

September 2025

DOI: 10.12716/1001.19.03.26

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Dynamic Positioning System (DPS) depending on GPS

signals to hold their positions. Naval fleets and

unmanned aerial vehicles (UAV) know their and their

targets’ exact positions. On the other hand, authorities

can use jamming to hinder precision-guided missiles,

UAVs and the triggering of remote-controlled

improvised explosive devices (RC-IEDs) [3].

Different parties’ various activities, such as

shipping, controlling air traffic, and engaging in

military operations, can be done safely with the signals

that notify these parties of their locations. Thus, GPS

has become an indispensable infrastructure for

individuals, private companies and sovereign states,

along with their military and police forces [4].

While these activities require the accuracy and

continuity of GPS signals, ‘jamming’, i.e., intentional

radio frequency interference prevents receivers from

locking onto satellite signals, rendering the system

ineffective or degraded. Also, ‘spoofing’ involves

broadcasting counterfeit satellite signals to deceive

GNSS receivers, causing them to compute incorrect

position, navigation, and timing (PNT) data [5]. Since

spoofing is a newly emerging technological issue, in

general, ‘jamming’ is often described as the

impediment of satellite signals, such as broadcasting

and communications jamming, electronic interference

and any other form of cyber-attacks. Also, ‘meaconing’

is the transmission of original but delayed signals to

confuse a GPS receiver. Lastly, spoofing is the

stealthiest activity to make users misunderstand their

location without their noticing. In a broad sense,

jamming is an umbrella term that broadly means

interference and covers spoofing, meaconing and non-

intentional interference.

The actual situation of GPS spoofing, including

Automatic Identification System (AIS) spoofing, is a

threat to be eliminated; they can disrupt maritime

traffic. Especially ports and chokepoints on

international corridors are considered potential targets

and high risk infrastructure [6]. If receivers catch and

follow signals from multiple satellite constellations, the

risk of spoofing might be reduced. However this

robustness depends on the performance of receivers.

Therefore, considering the key role of GPS in safe

navigation and prevention of spoofing, international

technical standards in the design and construction of

vessels are developed under the auspices of the

International Maritime Organization (IMO), which is

the international organisation in charge of the safe

operation of ships [7]. Following these standards,

many vessels are equipped with one or two

standardised DPSs. DPS is an integrated control

system that implements GPS signals to automatically

hold the vessel’s position via multiple thruster pods

[8]. When a vessel is operating in the ocean, GPS

signals from satellites to her DPS are critical for safe

navigation.

In comparison to these concrete technical standards

for safe navigation, no branch of international law,

such as the Law of War, Maritime Law, Law of the Sea

and Space Law, had either prepared for or solved this

problem single-handedly. In addition to these legal

instruments, the regulations of specialised

international organisations and sovereign states

overlap and are fragmented with respect to their issue-

oriented approaches. In terms of the distribution of

radio wavebands, the International

Telecommunications Union (ITU) is an authoritative

agency that has provided a common service since its

founding in 1865. Regarding maritime safety, the IMO

and its specialised committees are in charge of

international legislation and technical standards in

detail, as mentioned above. As an example of this

fragmented nature, each state determines their rules of

engagement during military operations and combat as

circumstances require.

Thus, legal structures for the security of GPS signals

- especially for the prevention of GPS spoofing - are not

sufficiently discussed or established, even though

spoofing can have serious consequences [9]. GPS is

indispensable infrastructure that enables states to

safely conduct operations such as counter-terrorism

and counter-insurgency (COIN), military operations or

offshore energy exploitation. In this regard, troubles

with NATO's fleet in the Black Sea, the landing of the

US drone in Iran and GPS spoofing in the areas

surrounding Ben Gurion International Airport in Israel

are one step ahead of the current regulatory

frameworks. Consequently, it is essential to examine

these cases from a legal standpoint to establish safety

and security measures against GPS spoofing.

2 CASES AND MATERIALS OF GPS SPOOFING

GPS spoofing is progressing rapidly in all fields of GPS

use and serious disturbances have arisen as a result.

This disruption and interference has not been

determined to be illegal since the legal instruments and

concrete regulations that prohibit it do not exist yet. In

addition to the legal characteristics, the activity is not

defined as wrongdoing since it is also useful for

protecting national security by preventing drone

attacks on vital infrastructure such as military facilities,

nuclear power plants and airports, as occasionally

mentioned in cases of jamming carried out by certain

governments.

In consequence, some cases should be given as

examples which demonstrate the harmfulness of GPS

spoofing to national security.

2.1 The Black Sea Case

The Black Sea is of critical concern to the international

community as a shipping route and a seabed rich in

energy resources. It is located between the

Mediterranean Sea, connected by the Dardanelles-

Bosphorus straits, and the Azov Sea, connected by the

Kerch strait in the east of the Crimean Peninsula. It is

422,000 km

in area, and consists of high seas except for

the territorial waters of the six coastal states; of Russia,

Ukraine, Romania, Bulgaria, Turkey and Georgia. The

principle of freedom of navigation is applied to the

high seas area of the Black Sea.

Long before recent technological incidents relating

to GPS, the Black Sea has historically been the focus of

two types of dispute [11]. One is the freedom of

navigation within this strategic half-closed sea, which

essentially depends on the rights of passage through

the Dardanelles-Bosphorus straits. The straits are

under the governance of Turkey, in accordance with

the Montreux Convention Regarding the Regime of the

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Straits of 1936 (the Montreux Convention). The other is

maritime delimitation between coastal states, which

may determine the possession of seabed natural

resources, namely oil and gas in the Black Sea.

Figure 1. The Black Sea and Ukraine. Source: US Department

of Defense [10]

These two issues concerning freedom of navigation

and sovereign rights to natural resources within the

seabed are fundamental to the six coastal states of the

Black Sea. Consequently, Ukraine has some disputes

with the other coastal states with regards to the

delimitation of the Black Sea.

Each of the six Black Sea states has its own interests

in the solution to these two issues. In addition to that,

not only these coastal states, but also other interested

states, including EU members and the US, deploy their

fleets to establish freedom of navigation even in

peacetime. As a prime example, the Black Sea is one

focus of the US Freedom of Navigation (FON) Program

[12]. The Black Sea incident of 12 February 1988

occurred when two U.S. naval vessels entered the

Soviet territorial sea in the Black Sea during the FON

Program. This case illustrates the importance of the

Black Sea as a strategic point in the region [13].

In addition to the issue of the freedom of

navigation, Romania filed an application in 2004 with

the International Court of Justice against Ukraine with

respect to a maritime boundary in the Black Sea

between the two states [14]. The case concerned the

delimitation of the continental shelf and exclusive

economic zones (EEZ) between them. As a further

example, an arbitral case between Ukraine and Russia

concerning coastal state rights in the Black Sea, Sea of

Azov, and Kerch Strait has been pending before the

Permanent Court of Arbitration since 2016 [15].

Thus, the Black Sea is a locus of interests and

conflicts between states. Freedom of navigation is a

critical issue which relates to the safety of life and

stability of global order.

2.1.1 Freedom of Navigation in the Black Sea

First, an important feature of the Black Sea is that it

is a half-closed sea. Its exit to the High Seas, namely the

Mediterranean Sea, is limited to the Dardanelles-

Bosphorus straits. The Black Sea or to be more specific,

the Dardanelles-Bosphorus straits are essential to

enabling the five coastal states except Turkey to exit to

the High Seas.

As well as the issue about seabed natural resources

and maritime delimitation, the Black Sea has the core

value of transit corridor to the Mediterranean Sea for

the coastal states with no ports or sufficient winter

ports other than ports in the Black Sea. Thus,

Dardanelles-Bosphorus Straits are characterised as the

international straits, which are used as international

routes between high seas according to geographical

conditions provided by Article 37 of the UN

Convention on the Law of the Sea (UNCLOS) of 1982.

At the same time, the straits are Turkey’s territorial

sea, where its sovereignty extends. As a result, the

straits are controlled by the Montreux Convention in

order to balance the interests between Turkey’s

sovereignty and other states’ freedom of navigation.

For instance, the convention provides Turkey the rights

to control over the straits by prohibiting the passage of

belligerent states’ fleets in times of wars on the one

hand, on the other hand, Article 19 of the Montreux

Convention allows military vessels to return to their

home ports.

As a prime example, the Russian fleet may return to

their port, e.g., the Sevastopol Naval Base in Crimea

although Turkey announced that belligerents' fleets

may not pass the straits during the Ukraine war in

2022.

Thus, the Black Sea has been drawing attention

under the Montreux Convention, especially since the

invasion of the Crimean Peninsula of Ukraine by

Russia in 2014 and a GPS spoofing case against the

NATO fleet mooring at Odessa in Ukraine occurred in

2021.

According to the AIS and GPS plotter, the two naval

warships HMS Defender (IMO 4907878) and HNLMS

Evertsen (MMSI 244942000), were identified leaving

and navigating from Odessa to Sevastopol, the port of

the Russian Black Sea fleet in Crimea, on 18 June [16].

However, satellite imagery confirmed the two

warships had stayed in Odessa. This case shows

vessels and their crews rely upon GPS signals to

identify their and other ships’ locations, and moreover,

false signals can be wrongly interpreted and given as

correct by the vessel’s GPS plotter.

This case illustrates that GPS spoofing may have a

harmful influence upon international relations

between unfriendly states who are not necessarily

outright belligerents. Thus, the more ships that depend

on GPS signal for navigation, the more GPS becomes

the locus of offence and defence. As a result, manifold

measures to keep ships navigating safely and

accurately are being taken by various actors.

As another example, Russia placed radio-jamming

equipment on a gas rig in the Black Sea after seizing it

in 2015, thus blocking Ukraine from using

telecommunications in the area. According to the

Defense Intelligence of the Ministry of Defense of

Ukraine, Ukraine retook the field from Russia on 11

September 2023. Now this field can not only extract

natural resources but also act as a forward deployment

base [17].

In preparing a response to the emerging threat of

jamming and spoofing, US authorities have devoted

themselves to countering GPS jamming. The Maritime

Administration of the US Department of

Transportation has reported AIS manipulation and

jamming in the Black Sea since February 2022 [18].

These cases are available as part of the GPS Problem

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Report Status, coordinated by the Navigation Center of

the US Coast Guard [19].

Also, the US and its allies developed a concept

called SLOC. SLOC recognises that one of the principal

missions of the military is protecting SLOC and

merchant vessels navigating sea lanes. GPS disruption

is a threat that must be removed from these lanes.

Besides measures taken by the sovereign states such

as the US, an international organisation, IMO adopted

Resolution A.1106 (29) on 2 December 2015, which

provides a Revised Guidelines for the Onboard

Operational Use of Shipborne AIS [21]. The resolution

warns that information provided by AIS may not be

giving a complete or correct picture of shipping traffic

in their vicinity.

Thus, the disputes concerning rights of coastal

states potentially impede free and safe navigation in

the Black Sea. These obstacles to safe navigation,

especially GPS jamming and maritime disputes, need

to be removed in order to achieve free and safe

navigation. While the settlement of disputes and

implementing countermeasures to GPS jamming in the

Black Sea are imperative, the Black Sea is undergoing

interruption of maritime traffic after the Russian

invasion of Ukraine.

Therefore, safety and freedom of navigation

guaranteed by GPS during wartime will be discussed

in the next section.

2.1.2 The Grain Export Initiative through the Black Sea

Since the Russian invasion, the export of grains and

iron ore, Ukraine’s main export goods, could not be

transported to and loaded at ports along the Black Sea.

For example, seaborne exports from three main ports

on the coast of the Black Sea, namely Odessa,

Pivdennyi and Ismail, could not be used any longer.

Commercial disruption—‘guerre de course’—around

Black Sea ports was implemented by Russia as a long-

distance blockade.

Yet according to the traditional Law of War, Law of

Neutrality and International Customary Law, which

regulate freedom of navigation, protection of

commercial cargo vessels, and safety of

communications under the circumstances of wartime,

are blockade must be effectuated with a naval fleet and

set closely around the enemy state’s ports. These two

requirements are called ‘effectiveness’ and ‘proximity’

respectively [22].

In light of these requirements recognised by

theories and state practise of the Law of War, Russia

does not have the right to set a long-distance blockade

in order to block commercial cargo vessels or the naval

fleets that escort these vessels.

At the same time, freedom of navigation in the

Black Sea is indispensable to continuing the export of

goods such as iron ore, wheat, and sunflower oil from

Ukraine and the import of essential materials into the

country by stabilising international cargo

transportation in the region. Without ports that

provide Ukraine exits to the Black Sea, it becomes a

land-locked state, which will have limited supply

routes. From that strategic viewpoint, Russia has been

imposing blockades around the Black Sea and the

shipping routes going through international and

Ukrainian territorial waters in order to disrupt

Ukraine’s seaborne trade.

Consequently, the states supporting Ukraine

commonly consider that establishing a new supply

chain and strengthening logistical capacity in and

around Ukraine while roads and railways to ports and

sea routes are blocked by the Russian military and

navy is to be the stimulus for Ukraine’s full recovery

from severe war damage.

The EU Council penned a document on May 31 that

demanded Russia stop attacking Ukrainian transport

infrastructure and lift the blockade of the Black Sea

ports, especially Odessa, to allow the export of grains.

The EU Commission announced on May 12, 2022, the

establishment of the ‘Solidarity Lanes’ that enable

essential humanitarian aid and materials to be

imported into Ukraine.

Within the framework of the Solidarity Lane, key

players in and around Ukraine’s logistics are Romania,

Poland and Hungary. Romania is repairing the railway

from the port city of Galati to the Moldovan border at

Giurgiu. It will connect the port of Reni in the south of

Odessa with other Danube ports. This railway line will

allow the transport of goods to and from Ukraine via

Moldova and the port of Galati. As a result of efforts to

support Ukraine’s export capabilities, 35,000 tonnes of

Ukrainian iron ore at the Black Sea port of Constanta

were loaded by a Romanian company in April. Also

80,000 tonnes of grains have been sent to Constanta

since the start of the invasion.

In addition to the regional cooperation, the UN

brokered an agreement between Ukraine, Russia and

Turkey on resuming grain exports from Ukraine

through Black Sea ports. The four parties finally

reached an agreement - the Black Sea Grain Initiative -

on July 22, 2022, not to attack vessels and infrastructure

engaged in this transportation. The agreement means

the lifting of the Russian de facto blockade in the Black

Sea. At the same time, this agreement needs effective

implementation through inspection at designated

ports.

The agreement guarantees the maximum safety to

vessels which transport grains from Ukraine in

accordance with this agreement. Indeed, the Initiative

allows for commercial food exports from the Ukrainian

ports of Odessa, Chornomorsk and Yuzhny in the

Black Sea after inspection by the monitoring team of

the Joint Coordination Centre, Istanbul, at checkpoints

set up at the ports on the Dardanelles-Bosphorus

straits. The Centre consists of representatives of

Ukraine, Russia and Turkey to check whether cargoes

and crews are permitted to sail under the Initiative.

Russia objected to this scheme on October 29, 2022,

alleging that the Russian fleet had been attacked at

Sevastopol port, but later retracted their objection on

November 2. Russia, however, also asserted they

required the ability to export fertiliser to developing

countries in order to stabilise agriculture. The

agreement was extended on November 17, 2022, for an

additional 120 days, as no party had announced its

intention to end or amend the agreement. Finally,

Russia decided to leave the Agreement on 17 July 2023.

Thus, the intentness of the EU’s regional efforts and

Grain Export Initiative illustrate how free and safe

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navigation is critically essential for the maintenance of

maritime transport even during an armed conflict. The

halting or continuing of maritime transport via the

Black Sea may influence regional stability and the

outcome of the conflict.

While the issue of GPS jamming is not directly

involved in the Grain Export Initiative, it is often used

as a weapon for non-kinetic or cyber-based attacks to

disrupt seaborne trade. Conflict concerning control of

the Black Sea is inseparable from the issue of GPS

signal accuracy as a precondition for free and safe

navigation.

2.2 Interferences in Israel

Israel is, due to its location, one of several states that

are influenced by GPS jamming. As a result, the

country’s cybersecurity policy is progressively and

practically implemented by its authorities [23]. Cases

and materials in Israel are worthy to be examined as a

prime example.

2.2.1 GPS Spoofing Cases and Countermeasures in Israel

A disruption of GPS signals at Ben Gurion

International Airport in Tel Aviv, Israel, was detected

in 2019. The International Federation of Airline Pilots’

Associations (IFALPA) issued a Notice to Airmen

(NOTAM), which warned crews landing at the airport

that the Association had received many reports from

pilots of loss of GPS signals or erroneous positioning of

several miles in the vicinity of the airport. The airport

again experienced disruptions to their GPS signals in

February 2022.

According to Kan News, a division of the Israeli

Public Broadcasting Corporation, the Israel Defence

Forces - specifically the Spectrum Warfare Center -

identified that the GPS jamming signals emanated

from Khmeimim Air Base, built by Russia in 2015 on

the western coast of Syria. These signals caused GPS

disruptions to nearby aircraft but were concluded to

not be intentional. Russia asserted that she was

attacked by drones in 2018 and used jamming as a

defensive measure to protect their soldiers around the

air base.

Israel’s cybersecurity strategy has been in

development since 2002, when the National

Information Security Authority (NISA) was

established. NISA focused on protecting vital

computer systems in some critical fields of the period.

Having gained experience in building robustness in

cybersecurity, the government, via Resolution 2444,

authorised the establishment of the National Cyber

Security Authority (NCSA) in 2015 [24].

This continuation in the cyber security strategy of

Israel can be outlined with two characteristics. The first

is a theoretical and conceptual framework which is

built to be flexibly applied. This framework consists of

three layers. The efforts within the broadest layer target

and improve the cyber-readiness capabilities of the

civil and private sectors by setting standards for critical

infrastructure. Then, more concrete measures within

the second layer establish the sharing of information,

the development of technologies, and the enhancement

of education and training, all based on a supply and

demand system between the government and private

sector. Lastly, law enforcement and military

organisations prepare for and respond to incidents

through successfully battle-testing cyber defences

against persistent cyber-attacks and intentional

interferences.

The second is international cooperation. Israel has

concluded cyber defence cooperation agreements with

friendly states and organisations, and is actively

participating in multilateral platforms. The country

works to share its experience and lessons, and seeks to

harness its advantages in cyber to promote global cyber

resilience and cooperation based on shared values and

trust.

However, as Israel itself indicates, the risk of cyber-

attacks is intensifying. Offensive cyber tools are

becoming stealthier and more sophisticated. They are

available to a diverse range of actors as they become

more accessible by growing smaller and more

affordable. The technological landscape is becoming

more interconnected and embedded in all areas of

national security and people's lives.

The harsh environment of national and

international cybersecurity requires clearly targeted

threats, such as GPS spoofing, be examined and

countered on a case-by-case basis.

Although difficult, the intent and result of spoofing

can be used to determine the legitimacy and legality of

individual instances of the activity. Therefore, the

differentiation between every single incidence of

spoofing should be examined according to their intent

and result [25].

2.2.2 Interferences to Leviathan Gas Field

A recent example is the Israeli gas field ‘Leviathan’,

discovered in 2010, 125 km west from Haifa, near the

disputed border with Lebanon. It contains 33 Tcf of

natural gas resources in place (22 Tcf recoverable). The

offshore natural gas field was opened in 2019.

Operations at the Leviathan gas field are ongoing.

Another gas field, ‘Tamar’, discovered in 2009 and

brought online in 2013, is 23 km (14 miles) off the coast

of Ashkelon, a city in northern Israel.

Oil and gas rigs are primarily vulnerable to waves,

winds and technical troubles even though states and

contractors adhere to authoritative international

technical standards. Furthermore, offshore support

vessels carrying personnel and heavy modules

between rigs and coast depend on GPS due to their

proximity to condensate pipelines transporting

extracted high-pressure gas to onshore facilities. While

safe navigation and resource exploitation are secured

by the accuracy and continuity of GPS, they can be

hindered by the loss of GPS signals. According to

accident reports distributed by the International

Maritime Contractors Association (IMCA), collisions

between a vessel and facility occur when the vessel

comes alongside the rig or performs maintenance on a

wellhead and the vessel experiences an unexpected

movement due to a dysfunction in its DPS [26].

In addition to the primary vulnerabilities of oil and

gas exploitation, if oil and gas fields are situated within

areas disputed by adjacent or opposite coastal states,

each state vehemently criticises the exploration and

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exploitation of resources, as well as the entire operation

of the other state [27].

Figure 2. Oil and Gas Fields in the Eastern Mediterranean

Region. Source: US Energy Information Administration [28]

Indeed, contests over the ownership of Leviathan

have been aggravating the border delimitation dispute

between Israel and Lebanon, which has been

unresolved for several decades [29]. Lebanon is under

the control of the Hezbollah political party, which

plans to import gas from Iran and does not have

diplomatic relations with Israel.

In fact, the region has the potential to become a

pipeline hub of energy security in the Middle East, if

an arrangement for the delivery of natural gas from

Israel to Egypt, Jordan and Syria can be planned and

agreed upon with the construction of new pipelines.

However, the current situation in the region has

aggravated the instability of the relationships between

the states interested in energy security that requires the

involvement of Israel.

Since such regional challenges and geopolitical

risks have not been solved, the most major concern and

focus for Israel is Hezbollah’s Precision Guided Missile

Project, which can bring significant threats to Israel’s

infrastructure via attack with GPS-guided missiles [30].

Figure 3. Leviathan and its export routes. Source: NewMed

Energy [31]

The Precision Project depends on GPS guidance

kits. The project consists of cruise missiles and UAV,

among others. The Israeli Defense Forces believe the

attacks are guided by GPS and each UAV is capable of

delivering some 5 kilograms of explosives and each

missile can carry 300 kilograms. Such weapons could

be directed against targets both out at sea and along

Israel’s coastline. Indeed, the Karish gas platform,

along with the Leviathan gas reservoir, has already

experienced attacks by UAVs [32]. Indeed, the missile

attack on Saudi Arabia’s Abqaiq oil facility in

September 2018 proved the capabilities of this GPS-

guided weaponry.

The Israeli Navy and IDF assume that explosive-

carrying UAVs or submarines guided by GPS could be

directed against the country’s offshore energy

infrastructure, such as Tamar and Leviathan. In this

case, GPS jamming will be a key countermeasure.

Meanwhile, Israel’s Iron Dome defence system uses

Tamir rockets to intercept Hezbollah missiles. The

rockets are guided by onboard GPS receivers and

electro-optical sensors, which enable the rockets to

adjust their course to track down missiles.

The phenomenon of both sides depending on GPS

is symbolic of how the technology is critical on the

modern battlefield. GPS systems are simultaneously

employed to attack and defend against other states.

Indeed, immediately preceding their attack on the

Iranian embassy in Syria in April 2024, Israel prepared

for Iranian counterattacks by jamming GPS signals

within Israeli territory, although civil life was affected.

Jamming is a measure with two sides to its character.

On the one hand, it is quite effective in preventing GPS-

guided missile attacks, while on the other hand, Israeli

defences are at a disadvantage without GPS signals

within its territory. Thus, hostilities employing GPS

between Israel and Iran demonstrated the critical

necessity of GPS and its jamming after the Hamas

attack in October 2023 aggravated the Israel-Palestine

conflict [33].

3 LEGAL STRUCTURES OF REGULATIONS

AGAINST GPS JAMMING

The regulation or prohibition of GPS jamming and

spoofing is apparently beneficial to the safe operation

of critical infrastructures; those functions are reliant

upon GPS.

At the same time, jamming was characterised in the

beginning as a justifiable reprisal in response to illegal

acts previously committed by foreign governments,

such as an intentional unauthorised, often political,

broadcast. A territorial state receiving those illegal

broadcasts needs to send stronger signals to jam them.

It is also useful to jam the frequency for explosives,

such as RC-IED, within unstable regions such as Iraq

and Afghanistan. Thus, it is used as a protective

measure as well as a tool of wrongdoing.

Consequently, jamming had not been defined as an

illegal act or terrorism. Defining GPS jamming is the

most difficult part of the codification process.

3.1 Historical Status of GPS Jamming in International

Law

An international legal basis for the regulation of

jamming was firstly constructed within the framework

of ITU’s frequency allocations. The ITU is charged with

extending international cooperation and promoting

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development of technical facilities. To achieve this, the

ITU assigns bands of radio frequencies so that

unintentional harmful interference will be less likely

between different states [34]. Thus, the ITU contributes

to efficiency of telecommunication services and

prevents accidental entanglement—multiple signals

sharing one frequency—but does not specialise in

controlling intentional illegal jamming. The ITU

conferences discussed the legal status and regulation of

jamming in the context of freedom of information but

did not reach an international agreement [35].

In addition to the regulations of the ITU, the Law of

the Sea and maritime law are also able to partially

regulate spoofing, since the safe operation of

navigation depends highly upon the AIS, which is a

system where signals transmitted from vessels show

their position by GPS. The IMO is an authoritative

entity that controls the safety of navigation and ship

operation by preventing collisions via AIS.

The Law of War has slowly and historically

developed its forms and contents. First, state practices

with respect to the means and methods used in combat

have accumulated and been recognised as fragmented

and unwritten customary rules. Among them, some

rules were codified as multilateral conventions to the

extent that states explicitly agree. The miscellaneous

rules thus established are basically characterised in two

categories; regulations on the means of combat, such as

the prohibition of chemical weapons and on the

methods of combat, such as the prohibition of attacks

on nuclear power plants.

In contrast to this classical law, which has a long

history and is still often called jus in bello in Latin, GPS

and its interferences is one of the latest combat

techniques. Therefore, GPS spoofing or, more

generally, cyber-attacks, are not simply or directly

regulated by the classical legal instrument, the Law of

War.

The issue of how the laws of the sea and war - in

other words, rules of naval engagement - regulate

spoofing in light of the traditional principles of

freedom of navigation and the safety at sea should be

immediately clarified.

Thus, considering the historical context, a complete

prohibition of spoofing is not feasible. Meanwhile,

limits to justifiable jamming and the prohibition of

harmful jamming against the safety of life must be

established.

In light of the necessity of jamming as a legitimate

countermeasure against illegal broadcasts, regulations

for jamming are not sufficient when compared to the

detailed international technical standards for the

design of facilities and equipment that enable GPS

receivers to detect and exclude fake signals and ensure

safe operation.

Technical standards in international law are mainly

codified through the IMO’s Maritime Safety

Committees. Filters are required to be built into DPSs

to avoid and exclude false signals. Some particular

types of vessel must have a backup DPS to provide

redundancy and resiliency in case of malfunction in the

main system. Mandatory regulations have not yet been

established to manoeuvre DPSs by certified DP

operators but are intended. All these regulations and

standards aim to prevent accidents caused by DPSs

that depend on GPS signals.

The issue, therefore, is finding concrete methods to

prohibit and prevent hazardous jamming, while

tolerating justifiable jamming as countermeasures

against terrorism.

3.2 Jamming as Countermeasures and a Cyber-attack

A dichotomous characteristic of GPS jamming is that

legitimate countermeasures and illegal cyber-attacks

coexist in the sphere of jamming. As a result, this

causes difficulties in defining the legal status and

prohibition of jamming and spoofing.

Indeed, the Center for Advanced Defense Studies

(C4ADS) published a report in 2019 which detected

9,883 instances of GPS spoofing across the entire

Russian Federation, its occupied territories, and

overseas military facilities that affected 1,311 civilian

vessel navigation systems since February 2016 [36].

According to the report, this spoofing was considered

a serious threat to global security, but was also being

used as a defence mechanism to protect people and

locations from drone attacks.

3.2.1 Targeted Killing

Targeted killing is one of the most controversial acts

that is supported and realised by GPS technologies.

They are defined as "the use of lethal force attributable

to a subject of international law with the intent,

premeditation and deliberation to kill individually

selected persons who are not in the custody of those

targeting them." [37] Targeted killing itself is not

necessarily a new phenomenon, and state-sponsored

killing has been practised throughout history, in the

form of assassination as a countermeasure or self-

defence.

In the modern era, UAVs enable user states to

control remotely, to acquire visually and to ultimately

attack targets without casualties of their own. The

public has become more aware of targeted killing by

UAVs since the beginning of the Russian invasion of

Ukraine in 2022 and the current Israel-Palestine

conflict.

After the September 11th terrorist attack against the

US in 2001, the US and international community

became more tolerant of targeted killing than they had

ever been before. At a glance, targeted killing was

practised by governments, but criticised and discussed

by various groups in the US, including the New York

South District Court, and finally accepted to some

extent by international law.

The most complicated argument regarding targeted

killing is whether it should be categorised as self-

defence in wartime or as law enforcement against

crime. If it is the former, international humanitarian

law and the law of war will be applied. Under this legal

scheme, enemy combatants can be targeted and killed

when they commit hostile activities against civilians or

military allies.

On the other hand, in the case of the latter, terrorists

should be brought to court and judged as criminals

with due process in accordance with the national

constitution of that country. Additionally, law

924

enforcement jurisdiction is based on the territorial

principle in contrast to the more extensive realm of

UAVs’ flight range.

The territorial principle is the most fundamental

basis on which to exercise jurisdictions. Under this

principle, each state restrains from exercising such

rights within other states’ territories so that multiple

states’ jurisdictions do not overlap or conflict with each

other. From this standpoint, as extraterritorial search,

seizure, investigation, interrogation, and arrest

activities are problematic, targeted killing is also an

issue.

Indeed, the Parliamentary Assembly of the Council

of Europe adopted Resolution 2051 in 2015, in which

the use of armed drones for targeted killings raises

serious questions in terms of human rights and other

branches of international law [38].

Since there are many intricate issues to solve single-

handedly, it is imperative to analyse each case

individually. Targeted killings have been carried out to

neutralise terrorists, such as Al-Qaeda operatives. In

this case, one of the issues is whether the ‘war on

terror’, ‘special military operations’, or other armed

conflicts are categorised as a war or a form of law

enforcement. Also, it is questionable whether the law

of war or domestic laws legally allow a government to

kill terrorists.

A recent concern in the US is whether American

citizens can be targeted if or when they were members

of Al-Qaeda. Not only for combatting such terrorist

organisations, drones are also used to search for drug

traffickers around the southern US border with

Mexico. This is clearly a domestic use of UAVs

supported by GPS.

Discussing targeted killing is, therefore, to

distinguish the subject, object, purpose, and location

before determining its legality. While anti-terrorism

measures are a positive aspect of GPS use, jamming

will simultaneously be worthwhile in preventing

illegal attacks that use GPS and drones. In this regard,

the focus of discussion on the precise legal justification

or illegal use of GPS and targeted killings are parallel.

The US administration concluded that it is lawful for

US government employees or contractors to target

persons for killing, including US citizens, who are

suspected of ties to Al-Qaeda or other terrorist groups.

This created a foundation, such as the right to self-

defence, for the legality of the use of GPS jamming as a

countermeasure or cyber-attack.

3.2.2 The Right to Self-Defence

From the broader framework of the right to self-

defence rather than targeted killings, Article 51 of the

UN Charter stipulates that the right to self-defence

arises if an armed attack occurs. According to this

provision, three requirements must be satisfied for the

justification of the use of force as an exercise of the right

of self-defence. First, an armed attack must occur to

enable the victim state to legally use force as an exercise

of the right of self-defence. This condition relates to the

prohibition of anticipatory self-defence. Second, the

preceding use of force must fall into the scope or range

of an armed attack, which is the most serious category

of the use of force. Third, a balanced use of force to

defend the state from a pressing illegal armed attack is

required.

Besides kinetic attacks—typically destructive,

direct-ascent anti-satellite (ASAT) missiles—non-

kinetic attacks, such as GPS interference against vessels

navigating within narrow international straits, are

serious threats to safe navigation and often detected by

the US Coast Guard Navigation Center (NAVCEN).

Having considered these conditions provided by

Article 51, traditional international law theory defines

the right of self-defence as the inherent right of a state

to use force in response to an armed attack. This is an

exception to the prohibition of the use of force in

Article 2, paragraph 4 of the UN Charter.

Based on the legal framework of the right to self-

defence, safety and protection of merchant vessels in

strategic water courses such as the Hormuz Strait, the

Black Sea or Taiwan Strait, the concept of armed attack

and the time of occurrence of the armed attack are

interconnected issues. Merchant vessels are located far

from their flag states and they are private actors.

Therefore, even if a vessel is attacked, it cannot

necessarily be identified as an armed attack against its

flag state. In addition to this, the scale of the armed

attack should be examined and discussed to decide

whether the attack—even on a single merchant

vessel— can still be categorised as a most serious use

of force against the flag state.

The issue of the scale of attack on merchant vessels

influences the issue of the level of armed attack on

satellites. Jamming the uplink between the control

segment and satellites, and the downlink between

satellites and receivers cannot be unconditionally

categorised as an armed attack that legitimises the right

to self-defence. On the other hand, sending stronger

radio signals to override jamming can be considered a

legally accepted countermeasure.

In a recent case, the Israel Defence Forces and its

home front command division use specific radio

frequencies around Tel Aviv and Haifa to jam GPS-

guided missiles launched from the southern part of

Lebanon. At the same time, it affects Israeli civilians,

who receive information regarding the likely landing

point of missiles on their mobile phones. Jamming

confuses the information of location, navigation, and

communication systems. The IDF invented and

introduced a new method to alert civilians by sending

messages via cellular towers instead of GPS

frequencies [39].

Having considered cases related to targeted killings

and the right to self-defence, it is clear that GPS can be

used as a tool of targeted killings, justifiable or not, and

legitimate defence. In other words, GPS and its

jamming have a dichotomous nature.

4 LEGAL FOUNDATION OF JAMMING IN THE

LAW OF WAR

GPS, the latest technology that is not involved within

the traditional scope of law of the sea and war, needs

its legal status to be clarified. This chapter will examine

the significant meaning of the basic legal scheme of the

925

sea for safe navigation and shipping during naval

battles with respect to GPS.

4.1 Historical Development of the Use of the Sea and the

Law of War

At this moment, when the Coronavirus pandemic is

disrupting the global supply chain, the significance of

borders that exclude external threats from entering

territories has been revisited. In this regard, quarantine

functioned to prevent the intrusion of emerging

infectious diseases. In much the same way, blockades

are one of the most effective methods to destroy an

enemies’ maritime trade during wartime.

At the same time, the continuation of maritime

commerce between neutral states and belligerents, as

well as freedom of navigation of neutral states are

guaranteed by the Law of War. Consequently,

equilibrium of stringent conditions between

belligerents waging war and neutral states continuing

maritime commerce was historically sought, adjusted

and settled on in order to legalise blockades.

As a prime example, in the 1987 case of Amerada

Hess Shipping v. Argentine Republic, the US court

judged that international conventions recognise the

right of a neutral ship to free passage on the high seas

[40].

During the Falklands War, both belligerent states—

the UK and Argentina—declared 200 nautical miles

around the islands as ‘exclusion zones’ and would

attack foreign ships entering these zones. Therefore, on

June 3, the United States Maritime Administration sent

a list of US flagged vessels and US interest Liberian

tankers, including Hercules, to both the UK and

Argentina to ensure that these neutral vessels would

not be attacked.

Amerada Hess used Hercules to carry oil from

Alaska, around the southern tip of South America, to

its refinery in the US Virgin Islands. On May 25, 1982,

Hercules embarked from the Virgin Islands, fueled but

without cargo, headed for Alaska. On June 8, the ship

was navigating about 300 nautical miles off the

Argentine coast and 200 nautical miles from the

Falkland Islands, in international waters outside the

exclusion zones, when it was attacked without

warning by Argentine aircraft.

International recognition of the rights and

protection of ships bearing the flag of a neutral state

can be found in paragraphs three and four of the

Declaration Respecting Maritime Law of 1856 (the

‘Paris Declaration’). Paragraph three declares that,

“neutral goods, with the exception of contraband of

war, are not liable to capture under enemy's flag”.

Paragraph four continues that, “blockades, in order to

be binding, must be effective, that is to say, maintained

by a force sufficient really to prevent access to the coast

of the enemy.” [41]

Thus, in order to be effective, a blockade must be

enforced by vessels being in physical proximity to the

enemy port(s). However, under paragraph three, trade

and navigation by neutral ships will not be

unnecessarily deterred or hindered by the blockade.

This is an exact point of equilibrium between

belligerents and neutral states. In disregard of these

rights, an oil tanker used by Amerada Hess was

attacked on the high seas by Argentine military aircraft

in 1982.

The court referred in the judgement to a

contemporary statement of international concern and

accord on the protection of neutral ships. It upheld the

Geneva Convention on the High Seas of 1958 (the High

Seas Convention), in which the rights of neutral ships

are considered established by international law, and to

which the US and Argentina were signatories. The

High Seas Convention codified the practice of nations

with respect to the rights of neutral ships in time of

war. Article 22 of the High Seas Convention provides

that a warship encountering a foreign merchant ship

on the high seas may not board her without suitable

grounds for suspecting piracy, slave trading or use of

false flags. Even when there are grounds for suspicion,

proper procedure is not to attack, but rather investigate

by sending a party to inspect the ship and her

documents. If an inspection fails to support the

suspicions, the merchant ship shall “be compensated

for any loss or damage that may have been sustained.”

This conflict and adjustment of interests is not

unique to sea battles, but common to other ocean

management and schemes as well. The ocean is a

potential battleground for the extraction and

ownership of natural resources as well as the right to

free navigation. In terms of the rights of coastal states

to explore continental shelves, Article 77, paragraph 1

of UNCLOS says that these states may exercise their

sovereign rights over their continental shelf for the

purpose of exploring it and exploiting its natural

resources. Their exclusive rights stretch at least 200

nautical miles from their coastline as a natural

extension of their land territories.

Thus, the Law of the Sea allocates the sovereign

rights to natural resources to the state in whose

territorial jurisdiction they are discovered.

Consequently, maritime delimitation disputes can

occur in order to obtain those resources. As a result,

rights to freedom of navigation to other states can be

threatened. In this regard, Ukraine had some claims

about the delimitation of the Black Sea, similar to the

border dispute between Israel and Lebanon around the

Leviathan gas field.

A case concerning the limits of the EEZ between

Romania and Ukraine was submitted to the

International Court of Justice (ICJ) by Romania.

Romania and Ukraine agreed a treaty on Good

Neighbourliness and Co-operation and the Additional

Agreement in 1997, which has a provision to negotiate

the delimitation of their EEZ and continental shelves.

According to paragraph 4 of the Additional

Agreement, the parties may submit cases to the ICJ if

negotiations fail. Consequently, Romania brought a

case against Ukraine before the ICJ in 2004. In this case,

Ukraine asserted some special circumstances to

achieve equitable delimitation. For example, the fact

that it has already given oil concessions to petroleum

companies within the waters being disputed. Although

the ICJ refused to adjust the delimitation line by oil

concessions, a discovery of natural resources can be a

cause of maritime delimitation disputes. As a result,

the Olimpiskoye gas field is exploited by Romania, to

whom the area belongs.

Ukraine had another dispute with regard to the

Black Sea. In 2016, it served on Russia a Notification

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and Statement of Claim under Annex VII to UNCLOS,

referring to a dispute concerning coastal state rights in

the Black Sea, Sea of Azov and Kerch Strait [42].

Ukraine presented its position before the Permanent

Court of Arbitration (PCA) in October 2024. Ukraine

asserted that the PCA must order Russia to remove the

Kerch Bridge to restore passage for the vessels of all

states following UNCLOS. During this war, the Law of

the Sea can be referred to in court as a foundation for

the use of the sea.

Furthermore, a newly emerging dispute is a 135

billion cubic metre (bcm) natural gas reserve that

Turkey found in 2020 at a depth of 2,100 metres in

Sakarya field, within its EEZ. The field is located in the

southwestern part of the Black Sea, 100 nautical miles

from the Zonguldak province of Turkey. This case

might have an impact on the area near the intersection

of Romanian, Bulgarian, and Turkish waters [43].

From the standpoint of the Law of the Sea, the

management of the sea and seabed has experienced a

period of transition from complete “dominion” to

functional jurisdiction. Developing countries demand

“fair distribution” of the benefits from these activities

because they have had their continental shelves and

their natural resources plundered by foreign entities

even though, according to UNCLOS, they are

protected under the sovereign rights of producing

countries. The point is that the developed countries,

which contribute to the techniques for exploration and

exploitation of the seabed, are required to share the

revenue from development of the seabed based on

their physical and financial risks of seabed

exploitation.

Therefore, this sort of confrontation for resources

can not immediately reach an agreement on the fair

sharing of revenue among the global community.

However, identifying common interests and

constructing real partnerships with neighbouring

countries materialise the core and common value of

safe navigation.

Due to an insufficiency in enforceability, the Law of

the Sea is limited in its ability to eliminate GPS

jamming at present. However, states know that none

can deal with or solve global issues such as freedom of

navigation on the high seas and safety of shipping by

acting alone. Thus, states need to discuss, negotiate,

and agree on these issues which are emerging in the

global arena. The Law of the Sea often provides useful

frameworks and a common ground for sovereign states

to build robust foundations of a new legal order for the

use of GPS to be applied to the ocean and space. This

would be a breakthrough for a transition in the legal

status of GPS jamming within the framework of the

freedom of navigation, which is an established

principle.

4.2 Law of War and Diplomatic Protection

From the viewpoint of international law, state

responsibility will become an issue to solve newly

emerging problems regarding GPS jamming in both

military and civilian contexts. Industry and the

military are increasingly reliant on GPS. Since it has

both offensive and defensive functions, legal schemes

are required that allow the legitimate use of GPS while

prohibiting illegal attacks.

However a common understanding regarding the

illegality of jamming GPS cannot be agreed upon

between sovereign states, which strongly insist on

maintaining their right to use force against belligerents.

As a result, GPS jamming is not yet regulated by the

Law of War. The concepts of C4ISR (command, control,

communication, computer, intelligence, surveillance,

reconnaissance) and C5ISR (C4ISR plus ‘cyber’) are

now focusing on making the military more effective in

the context of martial evolution [44]. From this

standpoint, the stability and integrity of GPS is a

critical factor. To operate and control UAVs, and—vice

versa—to prevent incoming GPS-guided missiles, GPS

has an indispensable role in offensive and defensive

operations.

In addition to military activities, international law

has a number of important established principles for

industry, one of them being the diplomatic protection

of nationals. This principle often becomes an issue

because not only do people have a nationality, but

vessels have one as well, i.e., the flag it raises.

However, the ocean is an international crossroads and

indeed a single vessel is an international complex

which consists of its flag state, owner, consigner,

nationality of the crew, etc. The principle of diplomatic

protection, established as a customary international

law, has two issues concerning strict conditions for the

application of diplomatic protection.

The first one is the nationality rule, which is

generally stated as follows: from the time of the

incident(s) until the ruling, the claim must belong to

persons having the nationality of the claimant state and

not the defendant state. In other words, states may

exercise diplomatic protection only for their nationals.

Therefore, in the case of I’m Alone, the

Commissioners were concerned with the ship’s

owners, whose nationality was not Canadian (the

claimant), but American (the defendant). As a result,

the arbitral ruling decided that the Canadian

government could not claim that the US was

responsible for the sinking of I’m Alone.

The right to diplomatic protection allows a state to

present an international claim against a wrongdoing

state on behalf of its national, when the national is

injured, or their property is confiscated without

compensation, in breach of due diligence towards the

treatment of foreign nationals. In other words,

international law requires states to treat foreign

nationals and their property properly. If they do not,

the victim’s country may be entitled to exercise

diplomatic protection.

In fact, the cases brought before the ICJ and other

international proceedings are not limited to ones of

individuals, but also corporations. When a ship is hit

and sunk because of the exercise of force during hot

pursuit, such as the case of I’m Alone, the flag state can

bring an international claim against the state

undertaking the hot pursuit [45].

Therefore, diplomatic protection is problematic

where a ship flying a foreign flag is actually hired by

nationals whose nationalities are identical to the state

which caused damage to the ship and cargo. Since the

vessel can be considered to have the nationality of the

foreign state and be treated as its own national,

nationals should obtain satisfaction through ordinary

927

domestic procedures. This was the case of the arbitral

sentence in the case of Amerada Hess and the case of

I’m Alone.

I’m Alone was a British vessel, registered in Canada,

used for running rum to the USA in breach of the

Volstead Act, which had prohibited the production

and import of alcoholic beverages in the 1920s. She was

sunk on the high seas on March 22, 1929 by the US

revenue cutter Dexter.

In this case, one of the issues that should have been

resolved was the implication of ownership and control

of the vessel, and the shares of the corporation owning

the vessel. Answering this question, the

Commissioners decided that I’m Alone, a British ship of

Canadian registry, was de facto owned and controlled

by US citizens for illegal purposes, contravening US

law. In conclusion, the Commissioners denied the

necessity of compensation by the US to His Majesty’s

Canadian Government for the loss of the ship and

cargo.

This case thus raised the issue of whether the formal

nationality might be of no importance but the de facto

ownership might be more significant for the claimant

of indemnity or compensation. The complexity of

nationalities of ships is the cause of the ambiguous

nature of state responsibility regarding damage of

ships through GPS jamming.

Recently, private multinational enterprises’

activities cross territorial borders, so the traditional

principles of international law, such as diplomatic

protection, should adapt their approach to fit the swift

movement of people and finances. As a result, not only

states and militaries, but also private industries, such

as maritime shipping companies, must be protected

against GPS jamming and illegal attacks on the sea.

5 CONCLUSION

This paper examined cases of GPS interference and the

past and current discussions concerning the safety and

security measures used to build a legal order to

regulate GPS jamming for safe navigation. GPS

jamming has been classified as both a legal

countermeasure and illegal activity, as discussed by

the ITU member states. As a result, even though GPS

jamming is critically dangerous to the safety of life at

sea and, in a broader context, social economy, these

acts are not formally prohibited by international

agreement in current legal structures.

Indeed, the cases in the Black Sea ports in Ukraine

and Ben Gurion International Airport in Israel

illustrate how easily entities depending on GPS signals

are interfered with. At the same time, the targeted

killings, even though they are controversial, were

successfully executed depending on the accuracy of

GPS. Preventing UAVs’ attacks are also a positive

outcome of GPS jamming.

Such opacity and versatility of the role and legal

status of GPS jamming is depicted in this paper

through the analysis of cases and legal instruments.

One of these instruments—the Law of the Sea—

provides a legitimate order to guarantee the right of

freedom of navigation, which can potentially provide a

legal basis against illegal GPS jamming. Secondly, the

Law of War also strictly requires the preconditions of

armed attack, necessity and balanced counterattack to

legitimise self-defence.

Based on these two fundamental legal instruments,

this paper has tried to clarify the legal and technical

issues related to the use of GPS in both peacetime and

wartime. It compared the positive aspects of GPS

jamming as a defensive measure or neutralising other

states’ defence systems with the negative aspects of

wrongdoing. Although GPS and its jamming have an

indispensable function on the battlefield, legal

definition of GPS jamming is not yet fully developed

due to its dichotomous nature.

In comparison, the recent nature of armed conflict

has been evolving. UAVs steered by GPS have

demonstrated their capabilities as weapons. Their

remarkable results in military operations are closely

tied to GPS. This is an example of how constant efforts

in developing defence technologies bring success.

GPS jamming and spoofing on a massive scale is

generally not committed by civilians due to the large

and expensive equipment necessary for such activities.

Rather, armed forces depend on GPS and its jamming

to defend essential infrastructure from GPS-guided

UAVs and missile attacks.

As a result, countries that make use of GPS jamming

did not agree with its prohibition. But frequent

jamming instances have made governments aware of

how influential it can be in preventing attacks. Thus,

governments are beginning to recognise that other

states are committing GPS jamming or spoofing. The

analysis of practices and establishment of legal theories

concerning due diligence of states who should prevent

GPS jamming and spoofing, will be a leitmotif in the

near future [46].

From the law of war, to be successful in the optimal

management and use of GPS, it is worthwhile to

establish legal and technical standards with

neighbouring countries during peacetime. In wartime,

while belligerents adhere to established norms that

protect neutral states’ interests, they must also achieve

their own military goals.

It is no exaggeration to say that, since ancient times,

states and individuals who control navigation,

shipping and logistics control the world. The earliest

example is the Egyptian civilisation, which has

benefited greatly from navigation since 2500 B.C. In

those days, a stable current and winds allowed them to

manage the shipping of goods and people along the

Nile River. The same civilization left records dating to

around 1500 B.C., which depict a large sea-going three-

masted ship.

Thus, waterborne transport was the earliest and the

most efficient means of commerce. Consequently, legal

disputes have inevitably emerged as the result of

conflicts of interest. In light of the necessity of dispute

settlement for the continuation of safe navigation and

stable trade, mechanisms, procedures, and rules for the

fair demarcation and burden of damages were

developed in each coastal area. These rules gave rise to

what is now known as Maritime Law.

The Law of the Sea, which originated with maritime

law and merchant customs, is now facing a world

928

where the legitimacy of the rule of law is questionable

both de jure and de facto in contrast with its origin.

From a broader and more long-term perspective, there

is a need to establish legal norms to control and

regulate GPS technologies—including jamming and its

countermeasures—and ensure that these laws have

adapted to and caught up with technical progress. It is

imperative to attach greater importance to the

consideration for the safety of navigation as well as the

right to jamming.

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Federation), Permanent Court of Arbitration, Case

Number 2017-06.

[16] R. Pedrozo: Russia-Ukraine Conflict: The War at Sea,

International Law Studies, Vol. 100. 2023, p. 14; H. I.

Sutton, Positions of Two NATO Ships were Falsified near

Russian Black Sea Naval Base, US Naval Institute News,

2021. https://news.usni.org/2021/06/21/positions-of-

twonato-ships-were-falsified-near-russian-black-sea-

naval-base. (2024.11.10).

[17] Ministry of Defense of Ukraine: Ukraine Returned under

Control «Boyko Towers», 11 September 2023.

https://gur.gov.ua/en/content/ukraina-povernula-pid-

kontrol-t-zv-vyshkamy-boika.html. (2024.11.20); M.

Bugriy: The Cost to Ukraine of Crimea’s Annexation,

Jamestown Foundation, Eurasia Daily Monitor, Vol. 11,

Issue 70, 2014.

[18] US Department of Transportation: 2022-005-Various-

GPS Interference & AIS Spoofing.

https://www.maritime.dot.gov/msci/2022-005-various-

gps-interference-ais-spoofing; ibid., Maritime

Administration, MSCI Advisory, at

https://www.maritime.dot.gov/msci/2022-003-persian-

gulf-strait-hormuz-gulf-oman-arabian-sea-gulf-aden-

bab-al-mandeb-strait-red. (2024.11.6).

[19] Navigation Center, US Coast Guard: GPS Problem

Status. https://navcen.uscg.gov/gps-problem-report-

status. (2024.3.20).

[20] R. B. Peele: Maritime Chokepoints: Key Sea Lines of

Communication (SLOCs) and Strategy, US Army War

College, Strategy Research Project, 1997, p. 19.

[21] IMO: A 29/Res. 1106, p. 3, para. 3.

[22] S. C. Neff: The Rights and Duties of Neutrals, a general

history, Manchester University Press, 2000, p. 98.

[23] State of Israel, Prime Minister’s Office, National Cyber

Directorate: Israel National Cyber Security Strategy in

Brief, September 2017.

https://cyber.haifa.ac.il/images/pdf/cyber_english_A5_fi

nal.pdf. (2024.11.10).

[24] The Government Secretary of Israel: Government

Resolution No. 2444 of February 15, 2015, Advancing the

National Preparedness for Cyber Security, p. 1, para. 3.

https://nsarchive.gwu.edu/sites/default/files/documents/

5989653/National-Security-Archive-Israeli-

Government.pdf. (2024.11.10).

[25] M. N. Schmitt: Cyber Operations and the Jus Ad Bellum

Revisited, Villanova Law Review, Vol. 56, 2011, p. 575.

[26] International Maritime Contractors Association, GPS

systems – Warning of interference. https://www.imca-

int.com/information-notes/gps-systems-warning-of-

interference/. (2024.11.10).

[27] The case between Guyana and Suriname is symbolic. A

private contractor hired by Guyana was exploring the

continental shelf in the disputed area with permission

from the Guyanese government. Patrol vessels from

Suriname requested, under threat of use of force, that the

contractor leave the area. An arbitral tribunal based on

UNCLOS held that this action verged on threats of

military action, as defined by paragraph 4 of Article 2 of

the UN Charter, rather than law enforcement activities.

Guyana and Suriname, Arbitral Award.

[28] US Energy Information Agency,

https://www.eia.gov/todayinenergy/detail.php?id=12611

[29] O. Mizrahi and O. Eran: The Negotiations between Israel

and Lebanon on the Maritime Border, Institute for

National Security Studies, INSS Insight, No. 1180, June 24,

2019, p. 4.

[30] C. Bauer, H. Ghaddar and A. Orion: Iran’s Precision

Missile Project Moves to Lebanon, Washington Institute

for Near East Policy, Policy Note, Vol. 56, 2018, p. 2; S.

Henderson: The Obstacles Still Facing Israel’s Leviathan

Gas Field, Policy Alert, Washington Institute for Near

East Policy, 2019.

[31] NewMed Energy, Operations of Leviathan.

https://newmedenergy.com/operations/leviathan/.

(2024.11.20).

[32] I. Klotsman: Iran’s Threat to Attack Israel’s Gas

Platforms, Times of Israel, August 8, 2024; Y. Lappin, Z.

Haimovich and S. Shohat: Can Israel Defeat Iran’s

Precision Guided Missile Threat? Commentary, Mir Yam

Institute, 2022.

929

[33] See also, S. Peterson and P. Faramarzi: Exclusive: Iran

hijacked US drone, says Iranian engineer, Christian

Science Monitor, 2011.

[34] P. Sands and P. Klein: Bowett’s Law of International

Institutions, 6th ed., Sweet & Maxwell, 2009, p. 105.

[35] L’institut de droit international: Annuaire de l’institut de

droit international, Tome 50-I, 1963, p. 413.

[36] Center for Advanced Defense Studies: Above Us Only

Stars, Exposing GPS Spoofing in Russia and Syria, 2019,

p. 24.

[37] T. B. Hunter: Targeted Killing, Self-defense, preemption,

and the War on Terrorism, booksurge, 2009, p. 33.

[38] Parliamentary Assembly of the Council of Europe:

Drones and targeted killings: the need to uphold human

rights and international law, 2015.

[39] Israel Defense Forces: Home Front Command’s

Guidelines; B. Diakun: War zone GPS jamming sees more

ships show up at airports, Lloyd’s List, 2024.

[40] Amerada Hess is a US oil company, which registered an

office in Liberia and entered a long-term time-charter

agreement with United Carriers (UC) in 1977 for use of

the oil tanker Hercules. The ship was registered in Liberia

and flew a Liberian flag.

[41] Amerada Hess Shipping v. Argentine Republic, 830 F.2d

421, 428-29 (2d Cir. 1987).

[42] Dispute Concerning Coastal State Rights in the Black

Sea, Sea of Azov, and Kerch Strait (Ukraine v. the Russian

Federation).

[43] W. C. Ackerman: Turkey: A new emerging gas player

with resources and infrastructure, Middle East Institute,

15 June 2022.

[44] US Army Combat Capabilities Development Command:

C5ISR. https://c5isrcenter.devcom.army.mil/activities/.

(2024.12.6).

[45] S. S. I’m Alone (Canada v. United States), Reports of

International Arbitral Awards, 30 June 1933 and 5

January 1935, Vol. III, pp. 1609-1618.

[46] M. N. Schmitt: In Defense of Due Diligence in

Cyberspace, Yale Law Journal Forum, Vol. 125, 2015; S.

Besson: La due diligence en droit international, Martinus

Nijhoff, 2021, p. 269.