Using RF Data to Identify and Track Dark Vessels

The moment Russia invaded Ukraine in early 2022, economists around the world knew there would be trouble. Russia is one of the world’s largest oil and natural gas exporters, and its invasion of Ukraine has been seen as anything but positive. Because of this (among other things), nations across the globe have slapped numerous sanctions on Russian trade, causing global energy costs to soar. And, while you would assume this is hurting Russia economically, the truth is that in April of 2023, Russian oil exports reached and surpassed pre-invasion levels.

So, even with fewer buyers, Russia continues to find ways to ship its oil around the world. But how?

One of the keys to this success is the growing global dark fleet moving Russian oil to all corners of the globe. According to Windward, the global dark fleet moving Russian oil consists of around 600 ships - many of which are masked with mysterious ownership, flags of convenience, and false documentation. 

While these ships use different tactics to hide their cargo's origin, one thing remains true for all of them. They operate “in the dark,” - meaning they commonly and repeatedly turn off or manipulate their AIS position in order to move sanctioned Russian oil. 

What's worse is that some of the oil that ends up in places like India gets refined and eventually reaches locations like the EU and the US - both of which have restrictions on importing Russian energy. 

But with AIS being so easy to manipulate and the global dark fleet growing daily, how can maritime authorities begin to identify and track the dark vessels moving Russian oil in order to ensure places like the US don’t unintentionally buy Russian crude?

Numerous strategies can be employed to help identify and track dark vessels, but one of the most useful and efficient strategies is using satellites to collect and analyze Synthetic Aperture Radar (SAR) and Radio Frequency (RF) data in the absence of AIS. 

While AIS can be easily manipulated, SAR and RF technologies offer a more certain view of how ships operate at sea - regardless of weather conditions, day/night, etc. 

Below, we look at a few case studies performed by some of the prominent companies offering space-based RF services to identify and track dark ships without legitimate AIS data present. 

Unseen Labs: Identifying IUU Fishing in the North Arabian Sea

In one instance, Unseen Labs monitored a fishing fleet in the north Arabian Sea using RF data collection. The area is well-known for its open-water fishing activity and has been identified as an area commonly containing dark fishing vessels. 

The data collection was simple. They started by identifying all of the RF signals in the northern Arabian Sea. Once the data was collected, they analyzed how many of the ships with RF signals were also broadcasting AIS data. Once the analysis was complete, Unseen Labs found that around 65% of the vessels identified with RF data were also transmitting AIS data. That means that around 35% of the vessels in the area were operating “in the dark.” 

It’s clear from the data that without RF signal collection, maritime authorities would not have a clear and accurate picture of all the vessels operating in the area. 

Of the ships identified as dark vessels, several groups were clustered together right on the edge of the Omani and Indian EEZs. While not 100% certain, the clustered groups of dark vessels indicate that they are likely part of an illegal fishing operation. 

Several of the vessels were identified because they turned off their AIS systems during the period Unseen Labs was monitoring the area, unintentionally providing Unseen Labs with vessel names and identifiable characteristics of each ship. 

One vessel, in particular, was a Chinese fishing vessel that switched its AIS system off as it ventured into the Indian EEZ - a clear sign of data manipulation that is all too common for illegal fishing vessels. The ship went dark for a period of just over 40 hours in the Indian EEZ, turning its AIS system back on once it exited the territory. After exiting the Indian EEZ, the vessel met with another ship in open water, a commonly used tactic to offload illegal fishing cargo. 

While this is just one simple instance of how RF data can be used to validate or invalidate a vessel's position or actions while operating in the dark, it outlines the challenges of efficient and effective maritime monitoring solely using technologies like AIS. 

Another plausible method to build on this type of monitoring strategy would be introducing SAR or other visual monitoring into the mix. In instances of uncertainty or times when 100% clarity is needed before action can be taken against a suspected vessel, SAR would provide the data needed for definite action. 

HawkEye 360: Dark Ship Detection in he Mediterranean 

HawkEye 360 offers RF geolocation services to help analyze AIS gaps for ships at sea, providing important information regarding the actions or whereabouts of vessels while their AIS systems are turned off. 

On November 18th, 2021, a cargo vessel flying the flag of Honduras exited the port of Yazici in Turkey, heading south through the Gulf of Alexandretta. 3 days into the voyage, just west of Al Ladhiqiyah, the ship stopped transmitting AIS data for approximately 7 days. On November 25th, the vessel once again began transmitting AIS data near the coastal waters of Cyprus. 

The week-long AIS gap raised eyebrows, to say the least, creating questions regarding the ship's path, potential visits to coastal ports, or the possibility of open-water meetups with other vessels. 

HawkEye 360 decided to use RF signal data to understand more about why the vessel may have stopped transmitting its AIS position for an entire week. Their satellites were able to pick up a VHF signal from the ship, which provided far more precise insights into the vessel’s journey and activity during the period of darkness.

The RF data revealed that during the period of darkness, the ship stopped at Tartus Port in Syria before returning to its original route, where the AIS transmissions stopped. The RF data provided HawkEye 360 with a clear picture, establishing a cause for the week-long AIS outage and allowing maritime authorities to better prepare for these scenarios in the future. With the right approach, the vessel can be monitored more closely for similar instances moving forward. 

Spire Global: Identifying Vessels Trading Sanctioned Venezuelan Oil 

On July 15th, 2022, Spire Global identified the Symphony Freedom on AIS, passing the southern tip of South Africa and heading north up the coast. However, Spire concluded using RF data that the ship was manipulating its AIS positions using a tactic called “spoofing.” 

Rather than heading north up the coast of Africa, the ship was actually heading northwest on a course to an oil terminal in Port Jose, Venezuela - likely to break sanctions by loading sanctioned crude. 

According to Spire’s database, approximately 250 other vessels had taken the same route in just 7 days, highlighting a clear correlation between AIS manipulation and illegal trade of sanctioned oil. 

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In a similar instance, Spire was able to track the Roza, a Cameroon-flagged oil tanker, making a suspiciously similar journey. 

Like the Symphony Freedom, the Roza passed the southern tip of Africa and began tracking north up the coast on AIS. However, during this period, several irregularities were identified on AIS. The ship displayed multiple AIS positions in each location, recorded multiple AIS outages, and showed fixed speeds over prolonged periods - raising suspicions and prompting further investigation. 

To make things more suspicious, the Roza has a history of trading sanctioned Venezuelan crude. Knowing this, Spire used the vessel’s history and compared it to current RF data and satellite imagery. RF data allowed Spire to locate the moment the Roza deviated from its apparent AIS course and began moving through the Atlantic Ocean on track toward Venezuela. 

To confirm these suspicions, Spire analyzed satellite imagery at Port Jose in Venezuela during the suspected time of arrival - ultimately identifying a vessel matching the description of the Roza alongside the port. 

The two instances described above are just a few examples of how RF data can be used to validate or invalidate a vessel's AIS positions - especially when a ship has numerous irregularities throughout a journey. 

To learn more about how space-based strategies can help enhance your maritime domain awareness, visit our solutions page HERE.