The upcoming World Radiocommunication Conference (WRC) in Geneva will address key issues for the increasingly important Global Positioning System (GPS) and other satellite navigation systems.

The U.S. government-operated GPS is used widely by people throughout the world to fix their positions, navigate ships and planes, and perform a host of other functions. The planned launch of the European Galileo satellite navigation system and proposed upgrades to the Russian government’s GLONASS satellite system highlight the growing significance of such services.

At the same time, the GPS community is coordinating spectrum use with other positioning systems and services. GPS representatives want to ensure its spectrum is protected from potential interference. The upcoming WRC may well help the cause.

“There should be spectrum available for each system to operate successfully and without interference,” said Raul Rodriguez, a partner with the law firm Leventhal Senter & Lerman.

The International Telecommunication Union’s WRC, scheduled to be held from June 9 to July 4, gives the positioning industry an opportunity to ensure the services it offers have sufficient, unencumbered spectrum and protection from interference by other spectrum users.

A number of issues that affect GPS will be addressed, said Rodriquez, who is counsel to the U.S. GPS Industry Council. The main issues revolve around use of GPS spectrum bands: L-2 (1215-1300 MHz) and L-5 (1164-1215 MHz). Those issues are a carry-over from the last WRC, he said.

Proposals affecting GPS have been accepted by CITEL, the Inter-American telecommunications committee that is part of the Organization of American States (OAS). The United States is among the CITEL member countries that support the proposals aimed at avoiding interference problems.

FCC Woes

The GPS industry has experienced difficulty in trying to ensure it has adequate access to interference-free spectrum, both before international bodies and at the Federal Communications Commission (FCC).

“One problem faced by GPS is that it not a natural constituent of the FCC,” Rodriguez said. The GPS industry “cannot look to the International Bureau for support and guidance to fight for its interests within the commission. During the ultra-wideband proceeding, GPS lacked a base of support within any of the FCC’s bureaus. There is no one group that looks after this sector of the telecomm community,” he added.

The GPS interests are looked after by parts of the U.S. government but coordination of those efforts among federal agencies is a challenge, Rodriguez said.

“The FCC is an independent regulatory agency that receives guidance from the NTIA [National Telecommunications & Information Administration] with respect to the U.S. government’s spectrum priorities. However, other entities can offer input to the FCC that may run counter to the NTIA’s position. It is not always the case that NTIA’s views prevail with the agency, especially if constituents of the agency — companies it licenses and regulates — take issue with the NTIA position.

“Every time a spectrum issue affects GPS, other commercial interests tend to have more say at the FCC than the GPS user community,” Rodriguez said. “Yet, the FCC is making the ultimate decisions that affect all [commercial] users of spectrum – including the GPS user community.”

And that problem will only intensify as GPS applications multiply.

“GPS has become pervasive in location-based commercial applications,” said Kevin Leclaire, an associate with the Reston, Va.-based venture capital firm SpaceVest. “GPS can be found in cell phones, PDAs, cars, trucks, tractors, mining and construction equipment, airplanes and so on.”

As these applications mature, the presence of GPS is becoming more transparent to the end user, Leclaire explained. Consumers are enjoying GPS-enabled applications that integrate layers of map and position-related data to provide relevant information such as turn-by-turn directions or listings of the nearest restaurants and services. One potentially life-saving application is emergency roadside assistance, he added.

“Enterprises are similarly taking advantage of systems that use GPS to track shipments and assets, control vehicles and machinery, and survey and manage resources,” Leclaire said.

GPS Limitations

However, GPS has limitations. “GPS is limited by the number of satellites visible to the receiver, accuracy, and strength of signal,” Leclaire said.

Differential GPS (DGPS) providing greater accuracy, GPS system upgrades and competitive satellite systems, such as Galileo, could help to overcome GPS shortcomings, Leclaire said. Also, terrestrial systems, such as spinning lasers, can provide higher precision over a smaller area, while determining position with wireless signal information assisting GPS (AGPS). Such AGPS capabilities have been demonstrated to allow indoor use of GPS to a certain extent, Leclaire said.

The GPS system itself is going to be upgraded. Mike Swiek, executive director of the U.S. GPS Industry Council, said the existing GPS system operated by the U.S. government has 24 IIA and IIR satellites in orbit, along with three spares, that will be followed by the launch of IIF replacement spacecraft.

The needs of GPS for up to the next 20 years are addressed by ongoing planning for GPS 3, Swiek said. The existing GPS system has been a reliable and accurate source of positioning information, he added.

“For that reason, there has not been a lot of pressure from the user manufacturer community to dramatically change what is up there,” Swiek said. “I think the plans out there for GPS modernization and GPS 3 are well thought out and will be welcome when they appear. The plan to bring in new capabilities is a good thing.”

Matt Jones, manager of GPS programs in the Washington office of Boeing [NYSE: BA], said the civil goals for modernizing GSP include:

• Significant gain in system accuracy;
• Assured and improved level of stand-alone integrity;
• Backward compatibility with existing receivers; and
• Flexibility to respond to evolving requirements with limited programmatic impacts.

One military application of GPS that was showcased during the recent war in Iraq included the use precision-guided bombs that hit their designated targets with as little collateral damage as possible, Jones said.

–Paul Dykewicz

(Raul Rodriguez, Leventhal Senter & Lerman, 202/416-6760; Kevin Leclaire, SpaceVest, 703/904-9800; Mike Swiek, United States GPS Industry Council, 202/739-0128; Matt Jones, Boeing Co., 703/465-3339)

GPS At A Glance:

• Consists of 24 satellites in medium-Earth-orbit (MEO) operated by the U.S. Air Force
• Uses four atomic clocks per satellite
• Broadcasts signals on L-band frequencies
• Enables receivers to establish latitude and longitude, as well as elevation

Source: Boeing