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Automatic Identification Systems (AIS)

What is an Automatic Identification System (AIS)?


AIS, or Automatic Identification Systems, provide a ship's location, speed, heading, and other identification data to maritime authorities and other ships using AIS transponders, which can be employed to trace and track a ship's past and current activity.


AIS systems were first created as a collision avoidance measure for vessels at sea. However, they are now used for monitoring and intelligence purposes, helping maritime authorities regulate shipping and trade activities. 

Today, almost all maritime vessels are equipped with AIS transponders. AIS systems help ensure sanctions compliance, legal and sustainable fishing operations, and many other things related to maritime activity. 

Although most operable vessels use AIS, the tracking systems can easily be turned off or manipulated - creating an opportunity for nefarious individuals to achieve unlawful goals by altering or hiding their AIS position and operating undetected. While some AIS circumvention methods are complex and require detailed planning, turning off an AIS transponder (Dark Shipping) is extremely simple and easy to execute. 

The above image displays an example of an "AIS Darkness" event. The solid black lines represent the locations where the ship was transmitting its position on AIS, while the red line indicates gaps in AIS transmission. 

Why Would a Ship Turn Off its AIS Transponder?


While there are some legitimate and lawful reasons for turning off a ship's AIS, think ship maintenance or inactivity, it is unlikely that there is a valid reason for doing so while in transit. Most incidences of AIS darkness at sea are a sign of foul play - most commonly used to avoid sanctions enforcement or pass through prohibited waters. By circumventing sanctioned waters, ships like large oil tankers can make massive profits by loading or offloading cheap sanctioned crude from places like Venezuela or Iran and passing it off as legitimate, unsanctioned cargo. 

How Can We Track a Vessel When it Goes AIS Dark?


Tracking a vessel with no AIS data can be challenging, depending on the length of an AIS Darkness event. The longer the outage, the more possibilities there are for where the ship could have traveled. However, a few methods can yield positive results when tracking dark ships. Depending on the time, location, and proximity to landmarks when a ship goes dark, we can use open-source information, satellite imagery, and radar emissions (doppler data) to confirm whether the vessel made a call to port in a sanctioned country during the outage. This multi-faceted approach allows authorities to reach a more defined conclusion about a darkness event, as multiple resources confirm a ship's position or activity. 

It is also important to note that AIS data is not the only type of data emitted by a ship. Vessels operating at sea also emit Radio Frequency (RF) data. While monitoring RF data is a less common method for tracking and investigating ships, more tracking platforms are beginning to incorporate the technology into their processes. 

What Other Methods are Used to Obscure a Ship's AIS Position?


While deliberate periods of AIS darkness remain the most common method to conduct illicit activity, other methods are evolving and becoming more commonplace. 

One of the more complex methods used is referred to as "AIS Spoofing." AIS spoofing involves using additional equipment to manipulate a ship's AIS tracks - continuously plotting points in identical positions or manufacturing fake transits altogether. It is worth noting that periods of AIS spoofing may also involve periods of AIS outages, as each method of AIS manipulation is not exclusive and is often used in conjunction with one another. 





The above image displays two obvious examples of a ship attempting to manipulate its AIS position. 

If a ship were anchored and not moving, you would expect to see a circle or semi-circle pattern, with only slight changes in speed as the wind and waves impact the ship. In the images above, the ships record consistent speeds with almost no variation - a telltale sign of AIS manipulation. 


The above image displays two examples of a ship's AIS position while at anchor. 

The left image is an example of legitimate AIS data from an anchor position, while the image on the right displays an AIS spoofing attempt. We can immediately see that the legitimate anchor position has subsequent AIS tracks in a natural flow, with the wind and waves slowly pushing the ship from side to side. The spoofed position, however, has no natural effects present - with AIS data plotted on opposite sides of the anchor position. 

Looking to the Future with AIS


As long as ships are tracked with AIS data, certain groups and individuals will continue implementing AIS manipulation techniques to hide their actions. Due to the ease and accessibility of AIS manipulation methods, going AIS dark will likely remain the "go-to" way of obscuring a ship's position. Fortunately, we can counter these efforts by incorporating additional datasets, open-source information, and satellite imagery to accurately track a ship's past and current movements.  

Map displaying a ship's AIS data during an AIS manipulation event
What manipulated AIS data looks like with data points
Legitimate AIS data from a ship rotating at anchor
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