GLOBAL POSITIONING SYSTEM

Home Applications Roads & Highways

Roads & Highways

The promise of GPS technology for increasing safety and security, reducing congestion, and improving efficiency are limitless. Quite simply, GPS has become the enabling technology for transportation.

Jeffrey N. Shane, Under Secretary for Policy, U.S. Department of Transportation

Benefits

Higher levels of safety and mobility for all surface transportation system users.

More accurate position determination to provide greater passenger information

More effective monitoring to ensure schedule adherence, creating a transit system more responsive to transportation users needs.

Better location information with electronic maps to provide in-vehicle navigation systems for both commercial and private users.

Increased efficiencies and reduced costs in surveying roads.

It is estimated that delays from congestion on highways, streets, and transit systems throughout the world result in productivity losses in the hundreds of billions of dollars annually. Other negative effects of congestion include property damage, personal injuries, increased air pollution, and inefficient fuel consumption.

The availability and accuracy of the Global Positioning System (GPS) offers increased efficiencies and safety for vehicles using highways, streets, and mass transit systems. Many of the problems associated with the routing and dispatch of commercial vehicles is significantly reduced or eliminated with the help of GPS. This is also true for the management of mass transit systems, road maintenance crews, and emergency vehicles,

GPS enables automatic vehicle location and in-vehicle navigation systems that are widely used throughout the world today. By combining GPS position technology with systems that can display geographic information or with systems that can automatically transmit data to display screens or computers, a new dimension in surface transportation is realized.

A geographic information system (GIS) stores, analyzes, and displays geographically referenced information provided in large part by GPS. Today GIS is used to monitor vehicle location, making possible effective strategies that can keep transit vehicles on schedule and inform passengers of precise arrival times. Mass transit systems use this capability to track rail, bus, and other services to improve on-time performance.

Many new capabilities are made possible with the help of GPS. Instant car pools are feasible since people desiring a ride can be instantly matched with a vehicle in a nearby area.

Using GPS technology to help track and forecast the movement of freight has made a logistical revolution, including an application known as time-definite delivery. In time-definite delivery, trucking companies use GPS for tracking to guarantee delivery and pickup at the time promised, whether over short distances or across time zones. When an order comes in, a dispatcher punches a computer function, and a list of trucks appears on the screen, displaying a full array of detailed information on the status of each of them. If a truck is running late or strays off route, an alert is sent to the dispatcher.

Many nations use GPS to help survey their road and highway networks, by identifying the location of features on, near, or adjacent to the road networks. These include service stations, maintenance and emergency services and supplies, entry and exit ramps, damage to the road system, etc. The information serves as an input to the GIS data gathering process. This database of knowledge helps transportation agencies to reduce maintenance and service costs and enhances the safety of drivers using the roads.

Research is underway to provide warnings to drivers of potential critical situations, such as traffic violations or crashes. Additional research is being conducted to examine the potential for minimal vehicle control when there is a clear need for action, such as the pre-deployment of air bags. The position information provided by GPS is an integral part of this research.

GPS is an essential element in the future of Intelligent Transportation Systems (ITS). ITS encompasses a broad range of communications-based information and electronics technologies. Research is being conducted in the area of advanced driver assistance systems, which include road departure and lane change collision avoidance systems. These systems need to estimate the position of a vehicle relative to lane and road edge with an accuracy of 10 centimeters.

With the continuous modernization of GPS, one can expect even more effective systems for crash prevention, distress alerts and position notification, electronic mapping, and in-vehicle navigation with audible instructions.

For additional information about the use of GPS on roads and highways, visit any of the following websites:

U.S. Federal Highway Administration (FHWA) Nationwide Differential GPS Homepage

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GLOBAL POSITIONING SYSTEM

Home Applications Space

Space

GPS is transforming the way nations operate in space -- from guidance systems for the International Space Stations return vehicle to the control of communication satellites to entirely new forms of Earth remote sensing. When all is said and done, the power and compass of this new tool will surely surpass what we can imagine now.

Dr. Tom Yunck, Jet Propulsion Laboratory, California, USA

Benefits

Providing high precision positioning with minimum ground control.

Replacing high cost, and high mass, on-board sensors.

Earth Orbit

The Global Positioning System (GPS) is revolutionizing and revitalizing the way nations operate in space, from guidance systems for crewed vehicles to the management, tracking, and control of communication satellite constellations, to monitoring the Earth from space. Benefits of using GPS include:

Jason-1 Ocean Surface Topography Mission (includes a GPS receiver and a laser reflectometer for high precision orbit determination)

Navigation solutions -- providing high precision orbit determination, and minimum ground control crews, with existing space-qualified GPS units.

Attitude solutions -- replacing high cost on-board attitude sensors with low-cost multiple GPS antennae and specialized algorithms.

Timing solutions -- replacing expensive spacecraft atomic clocks with low-cost, precise time GPS receivers.

Constellation control -- providing single point-of-contact to control for the orbit maintenance of large numbers of space vehicles such as telecommunication satellites.

Formation flying -- allowing precision satellite formations with minimal intervention from ground crews.

Virtual platforms -- providing automatic "station-keeping" and relative position services for advanced science tracking maneuvers such as interferometry.

Launch vehicle tracking -- replacing or augmenting tracking radars with higher precision, lower-cost GPS units for range safety and autonomous flight termination.

The Moon, Mars, and Beyond

The U.S. vision for space exploration, being implemented by the National Aeronautics and Space Administration (NASA), includes developing innovative technologies, knowledge, and infrastructures for returning to the Moon and preparing the way for future human missions to Mars and beyond. The vision will stimulate new research that will literally become the final frontier in navigation. Drawing on the experience with GPS, one could imagine creating a GPS-like network of satellites around the Moon and Mars. A Lunar or Martian network could provide an integrated communications and navigation infrastructure to support exploration and science missions both in lunar orbit and on the surface of the Moon and Mars.

NASA is also studying the utility of placing GPS-like beacons on satellites destined for the Sun-Earth Lagrangian points. Geodetic reference points could be established at these locations to support the future exploration of the Solar System.

Concept Martian Communications & Navigation Network

The figure on the right depicts a Martian communication and navigation concept of two satellites in areostationary orbit (equivalent of geostationary orbit in Mars).

For additional information about the use of GPS in space, visit any of the following websites:

NASA Global Differential GPS System Applications

The Navigator GPS Receiver

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This U.S. Government website has been developed by the National Space-Based Positioning, Navigation, and Timing Coordination Office. It is hosted by the U.S. Coast Guard Navigation Center. Disclaimer & privacy policy. Webmaster.

GLOBAL POSITIONING SYSTEM

Home Applications Aviation

Aviation

Ten of the major airports here in the Democratic Republic of the Congo now have the added capability of GPS approaches and departures. The satellite-based navigation system we are using is not dependent on expensive ground-based navigational aides, and it increases the safety and efficiency of our operations.

Chris O'Brien, Deputy Chief of Aviation, MONUC/ICAO Project, Democratic Republic of the Congo

Benefits

Continuous, reliable, and accurate positioning information for all phases of flight on a global basis, freely available to all.