USA's GPS-enabled devices in danger of compromise
by Dorie Cox, The Triton on 3 Aug 2011

If GPS were compromised it would affect every GPS-dependent piece of equipment Garmin
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GPS-enabled devices could be compromised if a plan to expand the United States’ broadband system goes forward, writes Dorie Cox of www.triton.com!The_Triton.
But maritime industry sources say they are confident the U.S. government will ensure the plan protects the government-operated GPS system.
The U.S. National Broadband Plan, mandated by Congress in early 2009, directed the Federal Communications Commission (FCC) to develop a plan to ensure every American has 'access to broadband capability,' especially in rural and under-served areas.
The government gave Virginia-based LightSquared conditional approval in January to do just that. The private company, using $14 billion of private capital, proposed a plan to expand its nationwide 4G-LTE wireless broadband network integrated with satellite coverage.
Since then, groups representing GPS consumers, including those in maritime, aviation, military and smart phone applications, have presented concerns that the proximity and strengths of LightSquared’s signals might overpower the relatively weak GPS satellite signals.
'Although LightSquared will operate in its own radio band, that band is so close to the GPS signals that most GPS devices pick up the stronger LightSquared signal and become overloaded or jammed,' according to the U.S. government organization Space-Based Positioning, Navigation, and Timing (PNT), a group established for matters concerning GPS and related systems.
'The frequencies are very close, which leaves little margin for error,' said Derik J. Wagner managing director of yacht services at MTN Satellite Communications. 'Many devices can malfunction or be misused, many times emitting frequencies outside of the range they are intended or licensed for.'
'If you needed a comparison, it would be similar to the old days of FM radio when one station would bleed into another one,' said Peter Prowant, SE regional manager of Furuno USA, which sells marine navigational equipment.
Aeronautical tests showed that receivers on transport-category aircraft would be unable to track GPS satellites in certain regions near land-based towers. LightSquared’s plan includes 400,000 towers.
Several megayacht industry sources note that less than 1 percent of GPS devices are likely to be impacted, predominantly older units without filters that protect from interference and high precision level GPS use.
'Precision frequencies are different than the ones most maritime operations use,' Prowant said.
Navigation along the coastal United States and its inland waterways may be more affected by signal interference than high seas operations, he said.
Possible solutions:
The three factions -- Lightsquared, GPS-users and the U.S. government -- are negotiating to resolve potential problems through testing and analysis. LightSquared has offered to operate in the section furthest away from the GPS signal.
But according to the company's site, www.lightsquared.com, some of the problem rests with GPS-enabled device manufacturers that have not actively protected the GPS signal from interference.
The FCC may require actions from either or both LightSquared or GPS manufacturers and users, Wagner said.
'They could require that LightSquared purchase more bandwidth with frequencies further from those used by GPS today, like the L-band they acquired from Inmarsat,' he said.
Or the FCC could require older GPS devices to be upgraded or replaced in order to work properly. GPS manufacturers may be required to install filters to prevent interference, possibly through a recall or with regulations for future equipment, he said.
In the meantime, if there is an accident because a boater could not receive the proper GPS signal, the issues of responsibility and liability are only the beginning.
'Then whose fault would an accident be?' said Jeff Erdmann, president of Bollman Yachts and chairman of the legislative affairs committee of the Florida Yacht Brokers Association.
'For long periods of time, people were told not to rely on GPS, that the government could degrade the signal at any time,' he said. 'But, instead, we have become very reliant on it.'
The government accepted comments until July 30, after which the FCC will determine whether to let LightSquared begin commercial operations.
'In general, the FCC is strong on this and will not allow GPS to be compromised,' Wagner said. 'There is too much at risk.'
For more information, visit www.pnt.gov and www.gps.gov.
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