GPS support centers team up

Military and civilian users of the Global Positioning System can now visit

a single online support center to check the status of the 28-satellite system,

request help with the system and report interference problems.

The U.S. Space Command is taking the lead in creating the Joint GPS

User Support Center, a World Wide Web site that consolidates GPS-related

information from several agencies.

Federal agencies began to explore ways to centralize GPS operational information

after civil users of GPS expressed concern last year when they were not

given advance notice of Defense Department GPS signal tests that restricted

service in certain regions. GPS provides accurate positioning and timing

information to receivers on the ground, in the air or in space.

"To find out what was going on with GPS, we went to a number of different

sources," said Mike Shaw, senior team leader on the Transportation Department's

radionavigation and positioning staff. The joint center is not a replacement

for those sources but rather a consolidated data center, he said.

To build the center, Spacecom is integrating three key GPS support

operations:

* The databases and support provided by its own GPS support center for military

users.

* The U.S. Coast Guard Navigation Center's Navigation Information Service.

* The Federal Aviation Administration's Spectrum Management and National

Operations Control Center.

The Joint GPS User Support Center will help civil and military users report

problems and get data from a single point of contact, said Hank Skalski,

DOT liaison at the U.S. Air Force Space Command, Colorado Springs, Colo.

Skalski spoke at a March 28 meeting of the Coast Guard-sponsored Civil GPS

Service Interface Committee in Fairfax, Va.

"We're talking about optimizing what we have today — bringing the resources

together," he said. "Different groups have different jobs. We're not changing

the jobs. We're just looking for a more efficient way to do the job."

The joint center also is building a GPS User Advisory and Reference

Database that will bring together space weather data and NASA Jet Propulsion

Laboratory International GPS Service data in addition to the other three

sources of information, Skalski said. Although most of the systems are compatible,

the complicated part will be dealing with portions of DOD databases that

are classified, he said.

Another challenge, Skalski said, is figuring out the best way to disseminate

the data — which is used to ensure the safety of aviators and mariners,

to maintain the critical infrastructure protection of systems that rely

on GPS and to support service providers such as the telecommunications industry

that use GPS for precision call hand-offs.

To accomplish that, the GPS Interagency Notification Team was formed in

March to identify the GPS user base, determine user needs, rank priorities

and develop an information dissemination process, he said. That work also

will be extended to international users of the global system.

Currently, the different GPS support centers carry out a variety of tasks:

* DOD's GPS support center provides continuous monitoring of the GPS

constellation operated by DOD. It also provides users with information about

what satellites are visible, satellites' accuracy and future performance

predictions.

* The FAA provides a notice to pilots about disruptions to the GPS signal,

performance data about GPS augmentation systems used for aviation, spectrum

protection information, interference mitigation and GPS test coordination.

* The Coast Guard's Navigation Information Service also provides the

notice to pilots and gathers, processes and disseminates data about GPS,

Differential GPS and ground-based navigational aid Loran-C. The Coast Guard

maintains a 24-hour telephone watch, Internet Web and FTP sites, an e-mail

response system, an e-mail listserv, online forms and a document database.

The Coast Guard also wants to implement a forum for online discussion of

GPS issues, said Lt. Cornell Thompson, chief of the Navigation Information

Service.

Although it is not a top priority, Skalski said he hopes to consolidate

all the GPS Web sites maintained by the government.

"Why are there half a dozen or more government GPS sites?" he asked.

By reducing the redundancy, it will be clear to users where to turn for

GPS information as well as save the government money on Web service time

and personnel to operate the sites, he said.