Ramon Lopez/WASHINGTON DC
A study conducted by the Johns Hopkins University Applied Physics Laboratory concludes that risks associated with jamming of the global positioning system (GPS) signal can be managed. This can be achieved if steps are taken to minimise the prospects of intentional and unintentional interference, says a US aviation industry source familiar with the contents of the closely held report.
The $500,000 six-month study, sponsored by the US Federal Aviation Administration, the Aircraft Owners and Pilots Association and the US Air Transport Association, is not due to be released before the end of January. It is understood to endorse the FAA's plan to replace all forms of ground-based civil aviation navigation aids with the GPS, a satellite-based system. The report is said to conclude that the GPS, and the associated Wide Area Augmentation System and Local Area Augmentation System, can be the only navigation service needed to guide civil aircraft. Critics have demanded that a back-up system, such as Loran C, be retained as an insurance against jamming. A Russian firm is already marketing a portable GPS jammer.
FAA Administrator Jane Garvey said in December that the GPS will probably be the primary, rather than sole, means of navigation. Without seeing the report, she felt that the USA will require "some form of back-up system for the foreseeable future".
There have been at least three instances where the GPS system has been accidentally jammed. In one case, a Continental Airlines aircraft suffered a GPS failure while flying over France.
The independent risk assessment is not the first to address the jamming issue, with a White House task force, the US Coast Guard and the FAA also considering the threat. The FAA has previously said that "-interference is a major concern that must be addressed-lightweight, hand-held, battery-powered jammers could interfere with GPS signal reception, as could malfunctioning satellite-based cellular phones".
A recently released US Defense Science Board report says: "GPS receivers employing adaptive nulling antennas and highly integrated, closely coupled inertial measurement units are just beginning to address the issue of deliberate or self-induced jamming-a well-funded programme should pursue a wide menu of high pay off anti-jamming technologies."
Source: Flight International
