Federal radio navigation plan relies on GPS, with no backup

The federal government intends to rely on the Global Positioning System for precision navigation, location and timing services for the foreseeable future, with no defined backup, according to a key planning document released Thursday by the Defense, Homeland Security and Transportation departments.

The 2010 Federal Radio Navigation Plan also envisions decommissioning key ground band navigation aids maintained by the Federal Aviation Administration as it moves to its GPS-based Next-Generation Air Transportation System.

Homeland Security approved the 219-page plan in March and Transportation last December. Defense Secretary Robert Gates signed it on April 15, three weeks after Deputy Secretary of Defense William J. Lynn III and Deputy Secretary of Transportation John Porcari blasted plans by startup cellular carrier LightSquared to operate in a frequency band that could interfere with GPS receivers.

Last November the National Space-Based Position, Navigation and Timing (PNT) Advisory Board, chaired by former Defense Secretary James Schlesinger, warned that the proliferation of inexpensive GPS jammers widely available for purchase over the Web made development of a backup system for GPS a national imperative.

Despite this warning and the potential of interference from LightSquared, the latest radio navigation plan did not identify a specific backup system for GPS. The plan said Homeland Security "is determining whether alternative backups or contingency plans exist." But, the plan added, "An initial survey of the federal critical infrastructure partners indicated wide variance in backup system requirements ... DHS is working with federal partners to clarify the operational requirements."

The PNT advisory board recommended using a system called eLORAN as a GPS backup, but President Obama zeroed out funding for LORAN (LOng RAnge Navigation) project in his 2010 budget, and the U.S. Coast Guard started shutting down the system and blowing up its towers last April.

The advisory board said FAA is exploring an alternative ground-based navigation system, but the earliest it would be capable of operation is 2025. In the meantime, FAA intends to divest to private operators or decommission ground-based navigation systems, the plan said. FAA operates 1,200 instrument landing systems to aid precision approaches, and the plan said FAA may shut some of these down, once GPS augmentation systems become operational. FAA has also targeted for eventual closure another 1,000 ground-based systems that provide heading information to pilots.

The plan also calls for Homeland Security to develop systems to mitigate the effect of jammers on GPS, but does not detail any specific systems.

This March the Royal Institute of Navigation in the United Kingdom released a report that warned that "Society may already be dangerously overreliant on satellite radio navigation systems like GPS ... The range of applications using the technology is now so broad that, without adequate independent backup, signal failure or interference could potentially affect safety systems and other critical parts of the economy."

David Last, a consultant to the General Lighthouse Authorities of the United Kingdom and Ireland, which operates aids to navigation systems in those countries, said, "It is difficult for international observers to see consistency in U.S. radio navigation policy."

While the PNT advisory board called for development of GPS backup systems, the radio navigation plan abandons that "in the hope that detection and mitigation of interference will save the day" Last said. He found it odd that the plan did not include any GPS backup, even as Defense and Transportation raised serious concerns about the potential of interference to GPS by LightSquared.