What "whizzy new tools" in space are America and its allies using to track China’s military activity and illegal fishing? (The Economist) [closed]

Question

Background and evidence of research effort

The non-paywalled part of the Economist's August 15, 2023 Keeping tabs on China’s murky maritime manoeuvres; America and its allies are using whizzy new tools to track China’s military activity and illegal fishing begins:

In January 2021 a fleet of Chinese fishing vessels approached the coast of Oman, apparently searching for squid. According to the ships’ automatic identification transponders, they stayed just outside Oman’s Exclusive Economic Zone (EEZ), which grants it control of fishing rights up to 200 nautical miles (370km) from its shores. But radio signals from the ships, detected by commercial satellites, told a different story. They indicated that the ships were operating within Oman’s EEZ in a suspected illegal raid on its valuable squid stocks.

That was an early demonstration of a new tool being used by America and its allies to help expose illegal or aggressive Chinese activity at sea. They are contracting private companies to provide governments across the Indo-Pacific region with near-real-time data, gathered from space, to help them monitor coastal waters and to use their limited naval and coastguard resources more effectively.

Maritime Automatic identification system is an (apparently optional) self-identification and self-reporting system. A device on a ship receives GNSS signals (e.g., GPS) signals, calculates speed and direction, adds a user-entered (or at least user-hackable) identification code, and sends the information out as a radio signal that can be picked up by other ships and by satellites. There are maritime websites (analogous to FR24 but for ships) that aggregate and display the information, but it's still a presentation of self-reported, good-faith data.

It is widely reported that fishing vessels as well as clandestine military supply ships just turn the damn thing off when they don't want to be tracked.

Since alas, I no longer have a subscription to The Economist, I'd like to ask:

Question:

What "whizzy new tools" in space are America and its allies are using to track China’s military activity and illegal fishing?

Satellite imagery from low Earth orbit (LEO) is spotty because it requires a recent pass of a satellite - Planet Lab has a constellation of ~10 cm aperture cameras in cubesats and smallsats but these are insufficient to identify specific ships and not ideal to spot a ship at sea if you don't already have a good idea where to look.

Using Synthetic Aperture Radar ships at sea stand out like bright stars in a dark night sky, (cf. Star-shaped artifacts in SAR images of the "Suez Canal traffic jam seen from space") (and works through cloud cover, day and night) but the satellites are (currently) few and far between so again, coverage is spotty.

So I'm really interested to find out what these "whizzy new tools" are that are based on data from private companies that provide "near-real-time data, gathered from space."

Answer 1

The new and improved technology is "radio frequency data acquisition, an application of military signals intelligence for the maritime world." ^[1] Even with their AIS turned off or "spoofed" there are other radio frequencies emitted from the ships that act as a signature for tracking.

Three companies: Unseen Labs, Kleos Space, and Spire Global, use the technology.

Using satellite receivers, companies like Unseen Labs, Kleos Space and Spire Global monitor a wide swath of the RF spectrum for all kinds of radio emissions. Their satellites can geolocate the source of a radio frequency transmission from a ship - for example, its radio communications.

According to Unseen Labs, the "fingerprint" of each ship's unique RF signature is much harder to spoof or turn off than the AIS transciever on the bridge. When the crew of a suspect vessel shuts off their AIS, their "dark" vessel is still emitting on other frequencies, so it is just as visible to RF tracking satellites as it was before. The concept works in all conditions, day or night, fair weather or foul. Combined with synthetic aperture radar or visual imaging for confirmation, it can be a useful tool for tracking ships that do not want to be tracked.

The U.S. Navy has partnered with Kleos Space. ^[2] Kleos uses many orbiting clusters, each with four satellites, for accurate triangulation of each ship's position.