DOD to step up defense of GPS

The Defense Department plans to add a new set of military antijam frequencies to the next series of military Global Positioning System (GPS) satellites, to prevent the loss of critical positioning information during a battle, a top DOD official said today.

ALEXANDRIA, Va.—The Defense Department plans to add a new set of military anti-jam frequencies to the next series of military Global Positioning System (GPS) satellites, to prevent the loss of critical positioning information during a battle, a top DOD official said today.

New generations of precision munitions as well as U.S. attack aircraft can tap into highly precise military signals broadcast by the existing GPS constellation. But the Pentagon has serious concerns about the vulnerability of those signals to jamming by an enemy who views such efforts as an inexpensive way to render U.S. "smart" weapons less smart, said Mike Shaw, assistant for GPS, positioning and navigation in the Office of the Assistant Secretary of Defense.

If the present constellation of 24 GPS satellites has one weakness, "it is their anti-jam capabilities," Shaw said at the Coast Guard-sponsored Civil GPS Service Interface Committee meeting here. "It would not surprise me" if potential U.S. adversaries possessed GPS jamming systems, Shaw said.