DOD, DOT explore next-gen satellite systems

The Defense and Transportation departments are working with government agencies and private-sector organizations to assess the capabilities that users want in the next-generation Positioning, Navigation and Timing (PNT) architecture, planned for 2025.

The Global Positioning Satellite system is the core of today’s National Space-Based PNT architecture. GPS provides positioning and navigation information with accuracy of about 50 feet and precise timing information. Twenty-nine GPS satellites are in orbit, according to a presentation by Mike Shaw, director of the National Space-Based PNT Coordination Office, at the ITS World Congress earlier this month.

The departments will include GPS in their PNT plan. They must consider other global navigation satellite systems, including the European Union’s Galileo system and Russia’s GNSS, said Karen Van Dyke, eastern region vice president of DOT’s Volpe Center, during a presentation at a September meeting of the Civil GPS Service Interface Committee. In addition to those systems, China plans to build a regional navigation satellite system to upgrade its Beidou satellite systems, said Chuang Shi, an engineer at the Chinese National GNSS Engineering Center, at the meeting.

DOT and DOD should also work with other countries that are developing regional systems, such as Japan and India, Shaw said.

India plans to develop a seven-satellite regional system in the next five to six years, said Madhavan Nair, chairman of the Indian Space Research Organisation, at an industry conference in Bangalore in July. Japan plans to launch the first satellite in its three-satellite regional system in 2009.

Developing the next-generation PNT will also require developing the right mix of space-based and terrestrial systems, Van Dyke said. For example, the Federal Aviation Administration’s Wide Area Augmentation System uses satellites to transmit GPS connections from 25 ground-based reference stations. The Coast Guard’s Nationwide Differential GPS network, a terrestrial system, has 35 operational sites, and the Coast Guard plans to add another six by the end of this year, according to its Navigation Center.

PNT planning will also require an assessment of regional augmentation systems, according to DOD and DOT briefing documents. Shaw said 50 countries operate differential GPS networks, while India and Canada plan satellite augmentation systems.

To help plan the PNT, the National Security Space Office and DOT’s Research and Innovative Technology Administration have issued a request for information to government agencies and commercial users. In addition to the RFI, the agencies are holding a series of meetings -- one today in California and others Nov. 7 and 8 in Fairfax, Va. -- to help assess PNT capabilities that national security, civil and commercial organizations use, plan or propose. RITA officials said they are particularly interested in innovative practices, concepts, standards, technologies and associated commercial architectures as they develop the new PNT architecture.

The RFI also asks government and industry to identify useful technologies. It wants respondents to indicate which capabilities the government should provide and which ones commercial entities should provide. To help coordinate PNT planning, DOD and DOT have set up a central Web site.

A PNT reference paper signed by John Grimes, assistant secretary of Defense for networks and information integration, and Jeffrey Shane, DOT’s undersecretary for policy, states that development of a next-generation PNT is a high-stakes process.

“PNT touches almost every aspect of American life today,” the paper states, adding that PNT is an essential element of DOD network-centric operations. In the commercial and civil sectors, it is “improving efficiency, increasing safety and making America more productive,” the reference paper states.

“Absence of a coordinated PNT architecture may result in operational risks, uncoordinated research efforts, lack of clear deployment paths, potentially wasteful procurements, inefficient deployment of PNT resources and possible impacts to architectures or other systems dependent on PNT,” the paper states.