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One giant leap for vessel-tracking

Giving AIS a satellite platform will greatly expand its range - from the coasts onto the oceans

When shuttle astronauts Michael Foreman and Randolph Bresnik flew to the International Space Station during Thanksgiving last year, they attached an Automatic Identification System antenna to the Columbus laboratory so the European Space Agency could begin testing a pair of AIS receivers for use in tracking global maritime traffic from space.

An AIS antenna was installed on the International Space Station late last year to test vessel tracking from space.

Designed to pick up signals from standard shipboard AIS transponders, satellite-based AIS promises to add a new dimension to maritime security and vessel tracking by extending ship-to-shore AIS coverage from the coast to the oceans.

"I think this is a great case study of a technology and system being established for one reason and then finding multiple other applications," says Dana Goward, director of the Coast Guard's assessment, integration and risk management office, and the man who oversees the agency's vessel-tracking capabilities.

Limited range

AIS was developed for collision avoidance and vessel-traffic management in busy ports and along coastal shipping routes, and until recently, it was terrestrial-based only. Ship transponders send VHF signals ship to ship and from ships to coastal towers and buoys, their range limited to line of sight - typically 20 to 40 nautical miles, depending on antenna height.

A boat's AIS transponder sends out a continuous stream of messages giving such information as the boat's position, course, speed, heading and identity. With AIS, skippers can see one another on their chart plotters or navigation computers and have information on hand about each other. And traffic managers can "see" ships arriving and leaving - and information about them - on their electronic displays.

Satellite-based AIS is feasible because VHF signals can travel the 400 or so miles into space to reach a low-Earth-orbiting satellite. The satellite receives the signal, then forwards it to a ground station. From orbit, an AIS receiver has a range of more than 1,000 nautical miles in any direction to the Earth's horizon.

By regulation of the International Maritime Organization, some 60,000 to 80,000 international vessels must carry AIS - mainly ships over 300 gross tons, passenger vessels and, in the United States, commercial vessels over 65 feet and many of the higher-powered towing vessels over 26 feet.

Goward says the Coast Guard already is using satellite-based AIS to collect information about vessels around the world, though the coverage is neither continuous nor worldwide. The Coast Guard buys its coverage from Orbcomm of Fort Lee, N.J., the only commercial provider of satellite-based AIS, with two AIS-equipped satellites in orbit. That soon will change.

Between now and 2012, Orbcomm plans to launch 18 more satellites with VHF data communication capabilities, including receiving and forwarding AIS. Com Dev, a Canadian satellite company, and exactEarth, its data services subsidiary, has scheduled three AIS satellite launches in 2010-11. The European Union also is working on satellite AIS and expects its first launches in 2011-12.

A work in progress

Right now, AIS is the "only way" to track large numbers of ships far from the nation's coasts, says Jorge Arroyo, the Coast Guard's AIS regulatory project officer. The technology still is in development. The best systems can get information to users within two hours of capturing it. The goal is to develop a real-time system that delivers information within six minutes. Scientists also are grappling with how to capture thousands of signals simultaneously and separate them without losing any in the process.

"That's the technological challenge that the satellite companies are having to deal with," Arroyo says.

Orbcomm's satellites circle the globe every 100 minutes. Once its constellation of 18 AIS satellites is in place, the company will be able to deliver AIS reports from a particular ship every 15 minutes, says Orbcomm CEO Marc Eisenberg. Eisenberg, who has 500,000 subscribers for his other satellite-based VHF data communication services, says AIS has many applications.

"It's a good way for people who have stuff on ships to know where the ships are on a real-time basis," he says. For instance, an oil company can route and schedule its tankers for off-loading based on where they are and how many ships are lined up at the docks - information it can get from AIS. It also can use AIS to track both its ships and those of competitors, and use that data to negotiate shipping contracts and reroute ships while they are at sea.

"There are lots of uses for it," Eisenberg says.

Goward says the Coast Guard uses satellite-based AIS to look for water-borne terrorists and others involved in criminal activity. "The bad guys aren't going to be broadcasting on AIS," he says. "But if someone is supposed to be broadcasting on AIS and they're not, there's a very high probability they're engaged in illicit activity. It calls it to our attention."

But that's not all AIS is good for. Goward says he can use space-based AIS to enforce anti-piracy rules for ships traversing the pirate-infested Gulf of Aden, track down a ship responsible for an oil spill, locate a ship in distress, find the tanker that ran over a sailboat or see a ship that is drifting dangerously at anchor.

"We see a lot of Coast Guard and public safety missions for it," he says.

'See and share'

Goward says his agency uses information from terrestrial- and space-based AIS along with reports from ships' Long Range Identification and Tracking systems, which send their position and identification every six hours via satellite; the Vessel Monitoring System, which requires fishing vessels to report in via satellite while they fish; port radars; and a variety of intelligence sources to get a picture of what's going on in and around U.S. waters.

He says his department's charge is to "see, understand and share" that information - and report any suspicious anomalies. Satellite-based AIS helps put the picture together.

Satellite AIS faces some political challenges. The General Accounting Office released a March 2009 report that said satellite AIS duplicates information that will be available as more LRIT systems come online, but Arroyo says the difference between receiving a continuous stream of real-time information about ships and information every six hours is huge. He is excited about putting satellite AIS to work in search and rescue once the service is available on a real-time basis.

"That opens the door to a whole new set of possibilities," he says.

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This article originally appearred in the April 2010 issue.