Tag Archives: acoustic fingerprints

Hearing the Naked Truth: Earth Observation

In the middle of last year, Ecuadorians watched with concern as 340 foreign boats, most of them Chinese, fished just outside the Exclusive Economic Zone (EEZ) around their country’s westernmost province, the Galapagos Islands. The law of the sea requires such vessels to carry GPS-based automatic identification systems (AIS) that broadcast where they are, and to keep those systems switched on. Some boats, however, failed to comply. There were more than 550 instances of vessels not transmitting their locations for over a day. This regular radio silence stoked fears that the boats concerned were sneaking into Ecuador’s waters to plunder its fish.

Both local officials and China’s ambassador to Ecuador denied this, and said all the boats were sticking to the rules. In October 2020, however, HawkEye 360, a satellite operator based in Virginia, announced it had detected vessels inside Ecuador’s EEZ on 14 occasions when the boats in question were not transmitting AIS. HawkEye’s satellites could pinpoint these renegades by listening for faint signals emanating from their navigation radars and radio communications.

HawkEye’s satellites are so-called smallsats, about the size of a large microwave oven. They are therefore cheap to build and launch. HawkEye deployed its first cluster, of three of them, in 2018. They are now in an orbit that takes them over both of Earth’s poles. This means that, as the planet revolves beneath them, every point on its surface can be monitored at regular intervals…Unlike spy satellites fitted with optical cameras, RF satellites can see through clouds. Their receivers are not sensitive enough to detect standard mobile phones. But they can pick up satellite phones, walkie-talkies and all manner of radar. And, while vessels can and do illicitly disable their AIS, switching off their communications gear and the radar they use for navigation and collision-avoidance is another matter entirely. “Even pirates don’t turn those things off,” says John Beckner, boss of Horizon Technologies….

RF data are also cheap to collect. Satellites fitted with robotic high-resolution cameras are costly. Flying microwave ovens that capture and timestamp radio signals are not. America’s National Geospatial-Intelligence Agency (NGA), one of that country’s numerous spying operations, is a big user of RF intelligence. It employs HawkEye’s data to find guerrilla camps and mobile missile-launchers, and to track both conventional warships and unconventional ones, like the weaponised speedboats sometimes deployed by Iran. Robert Cardillo, a former director of the agency who now advises HawkEye, says dozens of navies, Russia’s included, spoof AIS signals to make warships appear to be in places which they are not. RF intelligence is not fooled by this. Mr Cardillo says, too, that the tininess of RF satellites makes them hard for an enemy to destroy.

Beside matters military, the NGA also uses RFdata to unearth illicit economic activity—of which unauthorised fishing is merely one instance. Outright piracy is another. And the technique also works on land. In 2019, for example, it led to the discovery of an illegal gold mine being run by a Chinese company in a jungle in Gabon. And in 2020 the managers of Garamba National Park in the Democratic Republic of Congo began using HawkEye data to spot elephant poachers and dispatch rangers to deal with them…

Horizon also plans to compile a library of unique radar-pulse “fingerprints” of the world’s vessels, for the tiny differences in componentry that exist even between examples of the same make and model of equipment mean that signals can often be linked to a specific device. It will thus be able to determine not merely that a vessel of some sort is in a certain place, but which vessel it is, and where else it has been…

Excerpt from Espionage: Ears in the Sky, Economist, Mar. 20, 2021

Biometrics Run Amok: Your Heartbeat ID, please

Before pulling the trigger, a sniper planning to assassinate an enemy operative must be sure the right person is in the cross-hairs. Western forces commonly use software that compares a suspect’s facial features or gait with those recorded in libraries of biometric data compiled by police and intelligence agencies. Such technology can, however, be foiled by a disguise, head-covering or even an affected limp. For this reason America’s Special Operations Command (SOC), which oversees the units responsible for such operations in the various arms of America’s forces, has long wanted extra ways to confirm a potential target’s identity. Responding to a request from soc, the Combating Terrorism Technical Support Office (CTTSO), an agency of the defence department, has now developed a new tool for the job.

This system, dubbed Jetson, is able to measure, from up to 200 metres away, the minute vibrations induced in clothing by someone’s heartbeat. Since hearts differ in both shape and contraction pattern, the details of heartbeats differ, too. The effect of this on the fabric of garments produces what Ideal Innovations, a firm involved in the Jetson project, calls a “heartprint”—a pattern reckoned sufficiently distinctive to confirm someone’s identity.

To measure heartprints remotely Jetson employs gadgets called laser vibrometers. These work by detecting minute variations in a laser beam that has been reflected off an object of interest. They have been used for decades to study things like bridges, aircraft bodies, warship cannons and wind turbines—searching for otherwise-invisible cracks, air pockets and other dangerous defects in materials. However, only in the past five years or so has laser vibrometry become good enough to distinguish the vibrations induced in fabric by heartprints….

Candice Tresch, a spokeswoman for the cttso…. cannot discuss the process by which heartprint libraries might be built up in the first place. One starting point, presumably, would be to catalogue the heartbeats of detainees in the way that fingerprints and dna samples are now taken routinely.

Excerpts from Personal identificationPeople can now be identified at a distance by their heartbeat, Economist, Jan 23, 2020

Fiber Optic Cables and Surveillance

[T]he technology known as distributed acoustic sensing (DAS)… allows underground fibre-optic cables, like those used by telecoms companies, to be turned into a giant string of microphones. They can then be used to monitor all sorts of sensitive locations, from oil and gas pipelines to railway tracks, military bases and international borders. In its latest guise, DAS is even being used to help make hydraulic fracturing, or “fracking” as it is known, more efficient at releasing natural gas and oil trapped in rocks.

There are some limitations to the technology. Its powers of hearing are not sufficiently acute to pick up a conversation, for example. And since the cables inside buildings are typically a tangle of short lengths interrupted by junction-boxes, it is unlikely to work there. However, a long cable buried outdoors can provide the equivalent of a microphone every ten metres.  Algorithms are used to establish acoustic “fingerprints” for the sounds that are detected; and depending where and when they occur, each is assigned a level of risk, says Magnus McEwen-King, OptaSense’s managing director. Footsteps around a guarded facility at midday may not be unusual, but at 2am they would be.

OptaSense is also using the system to monitor sounds coming from below ground, in particular those produced by the water, sand and chemicals pumped under high pressure to fracture rock during fracking. There is concern about exactly what is going on underground, and in particular if the process might contaminate aquifers. Various seismic sensors can be used to monitor the fracking process, sometimes from test bores drilled nearby. But it is a costly and tricky process.

Shell and other oil companies are using a DAS system, which OptaSense calls vertical seismic profiling, to monitor their fracking. It uses a fibre-optic cable inserted into a well bore to build up an acoustic picture of the fracking fluid going into the rock at multiple levels. This means that potential problems, such as blockages, or leaks from one layer of rock to another, can be spotted before they become serious. And by having a clearer idea of how much fluid is going where, the fracking process can be constantly adjusted so that it runs in the most efficient way.

Listening for intruders and monitoring the efficiency of fracking are just two of the potentially lucrative applications of DAS technology. No doubt there will be others in the pipeline.

Acoustic sensing: The ear underground, Economist,  January 4, 2014, at 62