U.S. preps GPS defense
- By Paula Shaki Trimble
- Apr 24, 2000
The United States is gearing up to protect its turf at the upcoming World
Radiocommunication Conference next month. At the last conference in 1997,
it nearly lost hold of the radio spectrum used for satellite navigation
A proposal was submitted three years ago to allow mobile satellite services
to transmit signals using the same bands reserved for radionavigation systems
such as the Global Positioning System. In response, U.S. government officials
launched a full-fledged effort to study interference issues and prepare
its defense of exclusive use of that portion of the spectrum for radionavigation
systems when the issue is reconsidered next month.
"I think we've won this one," said James Vorhies, an electronics engineer
in the Office of Spectrum Management at the National Telecommunications
and Information Administration, speaking at a GPS conference late last month.
Already, Inmarsat, a provider of satellite services to users of mobile
communications devices, has scrapped plans to transmit in a portion of the
spectrum used by GPS. However, "some countries want to keep this alive,"
Other industry and government officials stressed that the issue is not
closed and that European countries may cling to the proposal at the WRC
2000 meeting — to be held May 1 to June 2 in Istanbul, Turkey — for future
negotiations that could have nothing to do with GPS.
"Anything can happen during WRC," said F. Michael Swiek, executive director
of the U.S. GPS Industry Council. "As long as the proposal is out there,
the proposal is still on the table."
Despite support from Latin American and Asia-Pacific organizations to
help the United States suppress the resolution, European representatives
are unlikely to give up easily on their request for territory that could
have future uses, he said.
GPS, a satellite system that provides accurate positioning and timing
signals to receivers on the ground, in the air or in space, is widely used
for military and civilian aircraft navigation and defense command and control
Because of the critical nature of these applications, the Defense Department
and aviation industry are determined that nothing interfere with the accuracy
or availability of GPS signals. Therefore, the United States intends to
block any proposal that involves using the spectrum presently dedicated
to radio-navigation services.
While spectrum protection is an area of mutual interest for the United
States and Europe, both of which have existing and proposed radionavigation
satellite systems, the European delegation to the WRC needs to take into
account the views of its member states, said Lt. Col. Julie Karner, assistant
director for space and multilateral cooperation at the State Department.
Karner has been working with European officials to negotiate agreements
on GPS and the Galileo satellite navigation system being developed by Europe.
The meeting also will consider a space-to-space allocation for GPS.
Currently, the GPS spectrum is protected only for transmission from GPS
satellites to receivers on earth or in the air. However, growing use of
GPS by NASA and DOD to navigate the orbit of satellites has prompted a request
to extend that protection to include transmissions to receivers on orbiting
Decisions about the modernization of GPS signals for civilian users
and a new navigation system being developed by the European Union have brought
new issues that will require attention at WRC.
The United States is requesting a radio spectrum for GPS that can be
used by the aviation industry to navigate and land aircraft in low visibility.
However, European countries already use that same spectrum for aviation-related
distance measuring equipment, which could interfere with the GPS signal
at high altitudes, Vorhies said. The United States would like that equipment
moved elsewhere, but Europe plans to increase its use in the next few years.
Vorhies said he does not foresee a problem, though.