The Department of Transportation (DOT) and the Department of
Defense (DOD) today announced an agreement assuring civil users
of the satellite-based Global Positioning System (GPS) the
availability of a second frequency. A second frequency is
essential for critical civilian uses of GPS. The White House
Commission on Aviation Safety and Security, chaired by Vice
President Al Gore, called for the establishment of a second civil
frequency as part of a broader program to maintain U.S.
leadership in aviation and satellite technology.
DOD agreed to assure civil users uninterrupted access to a
portion of its military signal, known as the "carrier phase."
The uninterrupted access to L2 carrier phase for civilian uses
will be reflected in the upcoming publication of the Federal
Radionavigation Plan, jointly published by both departments.
Guaranteed availability of the L2 carrier phase will support
the accelerated implementation of the Federal Aviation
Administration's (FAA) Wide Area Augmentation System (WAAS).
WAAS is the centerpiece of FAA's transition to a satellite based
air traffic control system. WAAS enhances the capabilities of
GPS signals by providing the accuracy, integrity, and reliability
needed to allow the system to be used by civilian pilots as a
primary means of navigation.
In addition, the DOT and DOD agreed to develop a plan for
providing a second frequency with course acquisition code and
navigation message for civil use. This will enhance worldwide
GPS capability and allow each department to most effectively meet
its responsibilities as laid out in the President's GPS Policy
issued in 1996. The addition of a second civil frequency will
result in an upgrading of the next generation satellites, known
as the Block IIF. The detailed plan for providing this coded
second civil frequency will be announced within one year.
Dr. Paul Kaminski, Under Secretary of Defense for
Acquisition and Technology, and Frank Kruesi, Assistant Secretary
for Transportation Policy, met on February 22 to review the
frequencies specified in the Block IIF contract for possible use
as the second civil frequency, referred to as L5. Although none
of the candidate frequencies was considered mutually acceptable
to all federal agencies with an interest in GPS, DOT and DOD
reaffirmed their commitment to providing the second coded
frequency for civil use.
As a first step, DOD's GPS Joint Program Office will request
a proposal from Boeing North American, the Block IIF contractor,
for an alternative design for providing the second civil
frequency. Also, the DOD intends to investigate increasing the
robustness of GPS for military use by supplementing the current
system with an enhanced military capability at a yet to be
These planned changes reflect the commitment in the
President's GPS Policy that the U.S. will provide the most
capable and reliable satellite navigation system for use by all
the nations of the world well into the next century.
The DOT and DOD also announced the signing of the charter
for the Interagency GPS Executive Board (IGEB). The charter was
signed by Secretary of Defense William Cohen and Secretary of
Transportation Federico Pena before he left office. This board,
established by the President's GPS Policy, will provide
interagency management of the GPS and U.S. augmentations to the
GPS, and policy guidance for U.S. efforts to assure global
acceptance of GPS technology.