Space-based RF detection reports hidden vessel activity in disputed waters

Space maritime surveillance company Unseenlabs has announced the results of two campaigns that exposed major blind spots in maritime visibility. The company found that 92% of vessel activity near the Spratly Islands in the West Philippine Sea went unreported by the existing AIS (automatic identification system), including a Chinese Coast Guard ship that went dark.

In the case of the Chinese Coast Guard vessel, Unseenlabs’ analysts found its AIS signal went dark for 45 minutes; however, RF emissions continued throughout the blackout, allowing its movement to be followed from space.

These results highlight the scale of unmonitored activity in one of the world’s most contested maritime zones, and how independent RF detection can reveal what conventional maritime surveillance systems miss.

What Unseenlabs found was:

• 80 RF data collections over 31 days revealed 16,261 RF detections (7% without AIS).
• 71 RF data collections over another 15 days gave 9332 detections (6% without AIS).
• 92% of maritime traffic in the ‘Dangerous Ground’ went unreported by AIS.
• A Chinese Coast Guard vessel near the Spratlys turned off its AIS for about 45 minutes, but space RF detection maintained tracking and the vessel was attributed via a stable RF fingerprint, enabling continuity before, during and after the blackout.
   

The West Philippine Sea, within the Philippines’ Exclusive Economic Zone, lies at the centre of competing territorial claims and strategic rivalry in the South China Sea, a corridor that carries one-third of global maritime trade. Here, Chinese Coast Guard and militia vessels frequently patrol, while commercial and fishing activity overlaps in dense and politically sensitive waters.

Conventional tracking systems like AIS often fail, either through technical gaps or deliberate silence. Unseenlabs says its space-based RF detection offers an independent means of observation, providing verifiable data even when cooperative signals stop.

Each Unseenlabs satellite operates autonomously, without the need for triangulation or satellite clusters, and every new unit launched increases revisit frequency over areas of interest. The data from Unseenlabs supports governments, NGOs and private-sector organisations seeking to improve maritime transparency, identify non-reporting vessels, reduce uncertainty in contested regions, and fight against illegal activity at sea.

A full report of the campaign results can be found here.

Image credit: Unseenlabs