DOT studying threats to GPS

The Transportation Department is investigating the vulnerability of its

Global Positioning System-based infrastructure in response to a presidential

directive.

Following a recommendation from the President's Commission on Critical

Infrastructure Protection and Presidential Decision Directive 63, DOT charged

the Volpe National Transportation System Center with studying threats to

the GPS signal received from the Defense Department's 28-satellite constellation,

said Joseph Canny, deputy assistant secretary for navigation systems policy

at DOT. Canny spoke at the Coast Guard-sponsored Civil GPS Service Interface

Committee meeting Tuesday in Fairfax, Va.

Volpe completed the first phase of the study in July 1999 by documenting

the threats of interference to GPS systems for railroad, maritime, aviation

and intelligent transportation system users, Canny said.

The second phase, expected to be complete this summer, will look at

how to overcome those threats. The solution includes FAA's decision to scale

back ground-based navigational aids to a basic backup network rather than

phasing them out altogether, he said.

The study will be a "guide to future policy development and decision-making

on retention of other navigation systems and the development of [GPS] augmentation

systems," Canny said.