Bureau of Oceans and International Environmental and Scientific Affairs
August 29, 2006
U.S. Global Positioning System (GPS)
The Global Positioning System (GPS), managed and operated by the U.S. Government, is used for a wide array of economic, scientific, and military applications. GPS consists of a constellation of 24 satellites and associated ground support facilities. The satellites send signals that can be converted into precise positioning, navigation, and timing information anywhere in the world.
Available Free to the Public Worldwide
The civil GPS signals are available in the United States and abroad at no charge, free of direct user fees. The United States also makes available without restriction the technical specifications for the civil GPS signals—enabling businesses, scientific institutions, and government entities anywhere in the world to develop products, services, and research tools on an equal basis. These policies have helped spur rapid growth in the global market for GPS goods and services. The United States is committed to providing reliable, uninterrupted service to civil users of GPS around the world.
Over the past decade, GPS has grown into a global utility whose multi-use services are integral to U.S. national security, economic growth, transportation safety, and homeland security, and are an essential element of the worldwide economic infrastructure.
GPS technology can be found in everything from cars and planes to cell phones and wristwatches. It is being used to improve productivity in areas as diverse as farming, mining, construction, surveying, taxicab management, and package delivery. It is enhancing public safety by preventing transportation accidents and by reducing the response times of ambulances, firefighters, and other emergency services. GPS is also furthering scientific aims such as weather forecasting, earthquake prediction, and environmental protection. Furthermore, the precise GPS time signal, derived from atomic clocks, is being applied to critical economic activities such as synchronizing communication networks, managing power grids, and authenticating electronic transactions. This same technology, whether designed for military capabilities or not, provides inherent capabilities that can be used by adversaries, including enemy forces and terrorist groups. As such, the United States is committed to developing a range of capabilities to prevent potential hostile use of GPS services while protecting access to U.S./Allied national security services and preserving peaceful use of civil services outside an area of conflict.
Looking Ahead: GPS Modernization
GPS currently provides positioning data with accuracy within 10 meters or less. Advanced techniques and augmentations allow users to obtain positioning accuracy in the millimeter range. The U.S. Government began fielding new civil signals into the GPS constellation in 2005, and will continue upgrading the system with new capabilities over the coming years. When fully operational, these added signals will increase the robustness of the civil service and improve basic accuracy to within 3-5 meters. Additional upgrades being planned for the next generation of satellites, known as GPS III, are designed to ensure that GPS remains a state-of-the-art system for the civil user community. More information on GPS can be found at the following websites: www.pnt.gov, www.navcen.uscg.gov, gps.losangeles.af.mil, and gps.faa.gov.
GPS and Europe’s Galileo System
The European Union (EU) plans to build its own global navigation satellite system called Galileo, currently projected to become operational in the 2010-2012 timeframe. Galileo is slated to be a civil system that will be operated by a commercial Galileo concessionaire. In June 2004, the United States and the EU reached an agreement covering their satellite navigation services. The historic agreement protects Allied security interests, while paving the way for an eventual doubling of satellites that will broadcast a common civil signal worldwide, thereby promoting better and more comprehensive service for all users. The agreement ensures that Galileo's signals will not harm the navigation warfare capabilities of the United States and NATO military forces, ensures that both the United States and the EU can address individual and mutual security concerns, and calls for non-discrimination and open markets in terms of trade in civil satellite navigation-related goods and services. The additional availability, precision, and robustness that will be provided by dual GPS-Galileo receivers lays the foundation for a new generation of satellite-based applications and services, promoting research, development, and investment that will benefit business, science, governments, and recreational users alike.