engleski

AIS intentional interference from the military security aspect

Automatic Identification System (AIS) is a shipborne broadcast transponder which continually transmits vessel’s identifiable and dynamic information. AIS usage increases vessels’ vulnerability in terms of AIS signal denial, vessels’ information being deliberately altered or interfered. This threat is most prominent in transition through high risk areas (HRA). Global Positioning System (GPS) transmissions can be jammed both by intentional and unintentional sources. Attackers can, for example, move military ships to within the jurisdiction of the adversarial nations, causing political tensions. There are two approaches an adversary can take in an effort to jam the system: noise jamming and smart jamming (spoofing), latter being complex and more severe action. Transmitted signals attempt to duplicate features of real GPS navigation signals, causing the receiver to track false signals. The weapon or user can then be led off-course or crashed into the ground. Jammers can be deployed on airborne platforms, thus being more effective than ground-based jammers ; their altitude allows them to jam a much larger area than ground-based jammers, especially against low-altitude targets. Moreover, an airborne jammer’s signal will approach a receiver from the same direction as GPS Space Vehicles (SV) ; thus, it will be much harder to block out such signals using physical obstacles. It has been recorded that in past spoofing cases some cargo vessels altered their transponders to transmit false information. These vessels, usually under sanctions by United Nations Security Council (UNSC) resolutions, were carrying illegal contraband, or were just trying to evade patrolling warships. Changing their identifiable information (e.g. name or call sign) they were able to hide in busy shipping lanes, and unless tracked by other means (visual or radar, for instance) their identity verification was disabled. Most military vessels do not transmit AIS data unless it is required for navigational safety, for example in narrow channels or major traffic separation schemes. The paper presents current state of intentional AIS interference activities as interpreted from the military security aspect, with emphasis on software based interference. Two main system abuses are described along with their features: i) intentional interference of other vessels and ii) false transmission of own data. Misuse of the system refers to potentially hazardous operational areas where certain perils can be expected, coming from pirates and/or various terrorist groups. From the military security aspect, sharpened analysis should be made when receiving information and messages from online providers in order to identify source of data and updates. Relation with NSC is outlined together with discussion on developing directives and recommendations on cyber security and on-board AIS status. Guidelines for possible future system security improvement and for definition of AIS security policy are presented, aiming at proper response to emerging threats.

intentional interference, automatic identification system, smart jamming, military security aspect

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