North Korean GPS jamming shows vulnerability of Army radios

North Korea’s jamming of Global Positioning System signals on the Korean Peninsula this week illustrates a “life-threatening” vulnerability of the Army’s Rifleman Radio, which is equipped with a nonmilitary GPS chip, a former top Defense Department official told Nextgov. The Army plans to test the hand-held radio this month at its semiannual Network Integration Evaluation exercise at White Sands Missile Range, N.M., which began Tuesday.

GPS satellites broadcast jam-resistant military signals as well as civil signals susceptible to blocking. Jules McNeff, who spent 20 years in the Air Force working on GPS, said the Army evidently decided to use a chip that receives only civil GPS signals as a “cheap and expedient” way to incorporate location information into the Rifleman Radio.

McNeff, now vice president for strategies and programs at Overlook Systems Technologies Inc., a GPS engineering firm in Vienna, Va., said any time a jamming incident occurs, “it calls into question why we are using [civil chips] in the Rifleman Radio.”

The Army plans to field 5,900 short range Rifleman Radios to infantry squads in seven brigade combat teams over the next year.

Army Lt. Gen. Ronald Burgess Jr., director of the Defense Intelligence Agency, told lawmakers on the Senate Armed Services Committee in February that North Korea has mounted high-powered Russian-made jamming devices on vehicles near the border -- 40 miles north of Seoul, the South Korean capital -- which can disrupt GPS signals within a 30-to-60 mile range. He added North Korea has started to develop its own GPS jammer with a greater range.

John Merrill, position, navigation and timing program manager for the Homeland Security Department, said small, inexpensive GPS jammers widely sold on the Web have proved difficult to locate. In a presentation to attendees at a National Institute of Standards conference in March, Merrill said it took DHS, the Federal Communications Commission and the Federal Aviation Administration from November 2009 to April 2011 to locate one GPS jammer in a truck traveling the New Jersey Turnpike and knocking out GPS signals at the Newark, N.J., airport.

The Army has billed the Network Integration Evaluation, which runs through June, as a “real-world” exercise and McNeff said the service should include “navigation warfare” maneuvers to test the vulnerability of the Rifleman Radio and other systems to jamming.

Paul Mehney, a spokesman for the Army's System of Systems Integration Directorate, which manages the NIE, declined to comment on whether the exercise will include GPS jamming for security reasons.

The Coast Guard Navigation Center, which coordinates and manages the Civil GPS Service Interface Committee as part of the Department of Transportation's program to respond to the needs of civil GPS users, maintains a list of military tests that could interfere with GPS. It has posted a notice that GPS signals could be unreliable within 180 miles of White Sands through May 25.