DOD charts GPS path

The Defense Department is in the early stages of setting a new course for

its satellite-based Global Positioning System, DOD officials said last week.

And the Transportation Department and other civilian GPS users are asking

for more of a say in the process.

DOD is gathering system architecture requirements for what it calls

GPS 3, a 30-year modernization project of the system that provides accurate

positioning and timing information used by military and civilian organizations

for navigation and other applications.

GPS currently operates with a minimum of 24 satellites. The study could

lead to new configurations of the satellites, an increase in the number

of satellites or modifications to the signals they broadcast. The changes

would provide users with increased positioning accuracy, more access to

the signals and higher signal power.

"We are on the fast track to GPS requirements," said Ray Swider, assistant

for GPS, positioning and navigation at DOD, at a meeting of the U.S. Coast

Guard-sponsored Civil GPS Service Interface Committee last week in Fairfax,

Va.

Earlier this year, the Air Force indicated it would not exercise options

with Boeing Co. for up to 33 new GPS Block 2F satellites, which were designed

to add two new signals for use by civilian agencies, as well as new military

signals. Six of those satellites already have been purchased.

"One of the reasons for entertaining GPS 3 rather than continuing Block

2F was to give time to assess future needs," Swider said. "We want to use

a clean sheet of paper to look at the architecture."

DOD plans to award three study contracts in 2001. The studies will assess

satellite architecture, ground infrastructure, ways to optimize the constellation,

augmentation systems and other platforms for navigation payloads, said Lt.

Col. Bill Kaneshiro, chief of systems architecture and engineering at the

GPS Joint Program Office at Los Angeles Air Force Base. They also will look

at ways to upgrade the satellites in orbit.

"We want to fly satellites that allow technological changes and evolve

to meet user needs," Kaneshiro said.

DOD, which originally created GPS, is the lead agency on GPS 3, but

civilian users of satellite navigation want to ensure their needs are accounted

for as DOD defines its requirements, which should be complete next summer,

Swider said.

DOT and other civilian agencies are concerned because DOD controls the

funding available to upgrade the GPS system. DOT failed to secure $17 million

in its 2000 budget request to upgrade those GPS satellites that provide

signals available to nonmilitary users. For fiscal 2001, the Clinton administration

chose to include the civilian modernization in DOD's budget request.

But the administration shares the civilian agencies' concerns. The Office

of Management and Budget has asked DOD to sign a "memorandum of understanding"

with DOT. The memo, which should be complete in about three weeks, is the

mechanism for ensuring civilian requirements are included in the GPS 3 studies,

Swider said. Also, the Interagency GPS Executive Board, sponsored by the

Commerce Department, is responsible for articulating the civilian community's

future requirements for GPS.