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1950s Technology Provides Viable Option to Unreliable GPS Signal in English Channel

Satellite Technology

Satellite Technology Feature Article

January 21, 2013

1950s Technology Provides Viable Option to Unreliable GPS Signal in English Channel

By Ed Silverstein, TMCnet Contributor

GPS signals are easy to jam and can be unreliable, but there is at least one option that was just put into use in parts of the English coastline: eLoran.

Those with a long memory will recall that Loran was used in the 1950s – so it may not be cutting edge. Decades ago it was used by the British Royal Navy and the U.S. Navy for shipping navigation.

But consider, however, how weak satellite signals are from the more modern GPS. On top of that, modern applications are very dependent on GPS for locations and its accurate time signal. GPS transmitters are mounted on satellites and if the satellite signal goes out, so does the GPS.

Enhanced Loran, called “eLoran,” employs “high-power, low-frequency, radio transmitters,” according to a report from The Wall Street Journal. There are nine transmitters now in Europe. The signal comes from radio towers with an impressive range of up to 900 miles. It is therefore an interesting backup or alternative to GPS or even Galileo.

"When a sat nav goes out, it matters a lot to have something secure to fall back on," David Last, special adviser to the General Lighthouse Authorities of the United Kingdom and Ireland (GLA) was quoted by TMCnet. "It (eLoran) is an almost perfect back-up."

eLoran is now available along the East Coast of the United Kingdom as far as Dover (the city known for its white cliffs.)

The GLA said vessels in Dover, its approaches and part of the Dover Strait can use eLoran, according to a recent report from Tanker Operator. And six other eLoran installations will be located on the East Coast of England.

“The Thames Estuary and approaches as far as Tilbury, the Humber Estuary and approaches, plus the ports of Middlesbrough, Grangemouth and Aberdeen (News - Alert) will all benefit from new installations, while the prototype service at Harwich and Felixstowe will be upgraded,” Tanker Operator said.

In addition, P&O Ferries has installed an eLoran receiver on its new Spirit of Britain. Captain Simon Richardson (News - Alert), head of Safety Management at P&O Ferries, told The Telegraph newspaper, “Satellite navigation systems are vulnerable to degradation of signal strength and our ships have also experienced occasional loss of signal.”

“Our primary concern at the GLA is for the safety of mariners,” Capt. Ian McNaught, Trinity House CEO, added in the Tanker Operator report. “But signals from eLoran transmitters could also provide essential backup to telecommunications, smart grid and high frequency trading systems vulnerable to jamming by natural or deliberate means. We encourage ship owners and mariners to assess eLoran in this region and provide feedback to the GLA on its performance.”

In fact, The Telegraph reported there are “growing fears that there could be a major disaster in the [English] Channel.” The English Channel is used by 400 or 500 vessels a day, and there could be environmental hazards or heavy damage from even a single collision between two ships. Also, Dover is considered the world’s busiest shipping lane.

One problem is that GPS is sometimes jammed by criminals who use “the devices to stop stolen cars and lorries being tracked by their legitimate owners.” The jammers are in use near ports and sometimes stolen vehicles “are smuggled onto ferries,” The Telegraph said.

There is also a risk of terrorism. “We do know terrorists have been arrested in the U.S. with GPS jamming equipment," Last said. "So GPS is very vulnerable."

So it’s back to the 1950s for a more secure communication option to deal with very contemporary risks.

Edited by Carlos Olivera

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