Global Positioning System

GIS planet: Navigator 1.0.1

2010-02-23T10:59:00.000-08:00

First Multimedia Community Portal for GPS Users Launched

2008-12-05T02:57:00.000-08:00

After a complete re-vamp of it's website, GPS Software Hub has officially launched a multimedia community portal for global GPS users. GPS Software Hub Community, the first of its kind, has come up with many interactive features for GPS users, such as image gallery, video gallery, user blogs, live news and a dedicated forum.

“There are websites on GPS, but this community portal is different in many ways.” an official claimed, “The number of GPS users around the globe is growing very fast and support from OEMs takes long time. People are looking for a place where they can come together and try to help each other and we have created this platform for the same”. The site has a User Blog section where users share there thoughts on GPS units, software or maps. They also can create own photo gallery and share videos.

“We have carefully designed the image and video gallery sections with categories, such as video tutorial, trails, geocaching, automotive GPS, cell phone GPS, GPS tracking and more. Users can view, vote, comment and create their own photo gallery. “ said a product manager at GPS Software Hub. The new portal also host a dedicated discussion board on GPS navigators, software and maps. The forum also has a classified section where users can post their GPS Buy-Sell ads.

“We wanted to create a common platform for both the end users and businesses. GPS companies can also use this platform to blog about their products or submit videos and pictures to educate users. We are also planning to launch a GPS company directory soon. The bottom line is whatever we do, it' should benefit the users and that's our ultimate aim”, said an official at GPS Software Hub.

GPS in Recreation

2007-12-28T00:08:00.000-08:00

The Global Positioning System (GPS) has eliminated many of the hazards associated with common recreational activities by providing a capability to determine a precise location. GPS receivers have also broadened the scope and enjoyment of outdoor activities by simplifying many of the traditional problems, such as staying on the “correct trail” or returning to the best fishing spot.

Outdoor exploration carries with it many intrinsic dangers, one of the most important of which is the potential for getting lost in unfamiliar or unsafe territory. Hikers, bicyclists, and outdoor adventurers are increasingly relying on GPS instead of traditional paper maps, compasses, or landmarks. Paper maps are often outdated, and compasses and landmarks may not provide the precise location information necessary to avoid venturing into unfamiliar areas. In addition, darkness and adverse weather conditions may also contribute to imprecise navigation results.

GPS technology coupled with electronic mapping has helped to overcome much of the traditional hardships associated with unbounded exploration. GPS handsets allow users to safely traverse trails with the confidence of knowing precisely where they are at all times, as well as how to return to their starting point. One of the benefits is the ability to record and return to waypoints. Similarly, fishermen typically use GPS signals as a means to continually stay apprised of location, heading, bearing, speed, distance-to-go, time-to-go, chart plotting functions, and most importantly, returning to a location where the fish are plentiful.

An advantage in newer GPS receivers is the capability to transfer data to and from a computer. Outdoor enthusiasts can download waypoints from an exciting adventure and share them. An example of this is a web site based in Malaysia dedicated to GPS for mountain biking enthusiasts. Riders post waypoint files marking their favorite rides allowing other riders to try out the trails.

Golfers use GPS to measure precise distances within the course and improve their game. Other applications include skiing, as well as recreational aviation and boating.

GPS technology has generated entirely new sports and outdoor activities. An example of this is geocaching, a sport which rolls a pleasurable day’s outing and a treasure hunt into one. Another new sport is geodashing, a cross-country race to a predefined GPS coordinate.

GPS modernization efforts, designed to enhance more serious applications than recreation have provided direct and indirect benefits to the user. Various GPS augmentation systems that were developed in several countries for commerce and transportation are also being widely used by outdoor enthusiasts for recreational purposes. Modernization plans for GPS will result in even greater reliability and availability for all users, such as under a denser forest cover -- just the environment in which many adventurers most need this capability.

Source:gps.gov

GPS in Surveying and Mapping

2007-12-28T00:05:00.000-08:00

As technology evolves and expands throughout the world, the surveying and mapping community is steadily redefining the tools required to increase productivity and obtain highly accurate data.

Using the near pinpoint accuracy provided by the Global Positioning System (GPS) with ground augmentations, highly accurate surveying and mapping results can be rapidly obtained, thereby significantly reducing the amount of equipment and labor hours that are normally required of other conventional surveying and mapping techniques. Today it is possible for a single surveyor to accomplish in one day what used to take weeks with an entire team. GPS is unaffected by rain, wind, or reduced sunlight, and is rapidly being adopted by professional surveyors and mapping personnel throughout the world.

GPS provides accurate three-dimensional positioning information for natural and artificial features that can be displayed on maps and models of everything in the world - mountains, rivers, forests, endangered animals, precious minerals and many other resources. GPS position information for these features serves as a prime input to geographic information systems (GIS), that assemble, store, manipulate, and display geographically referenced information.

GPS has played a vital role in relief efforts for global disasters such as the tsunami that struck in the Indian Ocean region in 2004, Hurricanes Katrina and Rita that wreaked havoc in the Gulf of Mexico in 2005, and the Pakistan-India earthquake in 2005. Search and rescue teams used GPS position information to create maps of the disaster areas for rescue and aid operations, as well as to help assess damage.

Throughout the world, government agencies, scientific organizations, and commercial operations are using the surveys and maps deriving from GPS and GIS for timely decision-making and wiser use of resources. Any organization or agency that requires accurate location information can benefit from the efficiency and productivity provided by the positioning capability of GPS.

Unlike traditional techniques, GPS surveying is not bound by constraints such as line-of-sight visibility between reference stations. Also, the spacing between stations can be increased. The increased flexibility of GPS also permits survey stations to be established at easily accessible sites rather than being confined to hilltops as previously required.

Remote GPS systems may be carried by one person in a backpack, mounted on the roof of an automobile, or fastened atop an all-terrain vehicle to permit rapid and accurate field data collection. With a GPS radio communication link, real-time, continuous centimeter-level accuracy makes possible a productivity level that is virtually unattainable using optical survey instruments.

With the modernization of GPS even further enhancements are in the works. In addition to the current GPS civilian service, the United States is committed to implementing two additional civilian signals. The extra signals will, for example, provide a means for correcting errors caused by the ionosphere, thus improving positioning accuracy. The new signals will also improve the availability and overall integrity of the system for all users.

Source:gps.gov

GPS in Public Safety and Disaster Relief

2007-12-28T00:02:00.000-08:00

A critical component of any successful rescue operation is time. Knowing the precise location of landmarks, streets, buildings, emergency service resources, and disaster relief sites reduces that time -- and saves lives. This information is critical to disaster relief teams and public safety personnel in order to protect life and reduce property loss. The Global Positioning System (GPS) serves as a facilitating technology in addressing these needs.

GPS has played a vital role in relief efforts for global disasters such as the tsunami that struck in the Indian Ocean region in 2004, Hurricanes Katrina and Rita that wreaked havoc in the Gulf of Mexico in 2005, and the Pakistan-India earthquake in 2005. Search and rescue teams used GPS, geographic information system (GIS), and remote sensing technology to create maps of the disaster areas for rescue and aid operations, as well as to assess damage.

Another important area of disaster relief is in the management of wildfires. To contain and manage forest fires, aircraft combine GPS with infrared scanners to identify fire boundaries and “hot spots.” Within minutes, fire maps are transmitted to a portable field computer at the firefighters’ camp. Armed with this information, firefighters have a greater chance of winning the battle against the blaze.

In earthquake prone areas such as the Pacific Rim, GPS is playing an increasingly prominent role in helping scientists to anticipate earthquakes. Using the precise position information provided by GPS, scientists can study how strain builds up slowly over time in an attempt to characterize, and in the future perhaps anticipate, earthquakes.

Meteorologists responsible for storm tracking and flood prediction also rely on GPS. They can assess water vapor content by analyzing transmissions of GPS data through the atmosphere.
GPS has become an integral part of modern emergency response systems -- whether helping stranded motorists find assistance or guiding emergency vehicles.

As the international industry positioning standard for use by emergency and other specialty vehicle fleets, GPS has given managers a quantum leap forward in efficient operation of their emergency response teams. The ability to effectively identify and view the location of police, fire, rescue, and individual vehicles or boats, and how their location relates to an entire network of transportation systems in a geographic area, has resulted in a whole new way of doing business. Location information provided by GPS, coupled with automation, reduces delay in the dispatch of emergency services.

Incorporation of GPS in mobile phones places an emergency location capability in the hands of everyday users. Today’s widespread placement of GPS location systems in passenger cars provides another leap in developing a comprehensive safety net. Today, many ground and maritime vehicles are equipped with autonomous crash sensors and GPS. This information, when coupled with automatic communication systems, enables a call for help even when occupants are unable to do so.

The modernization of GPS will further facilitate disaster relief and public safety services. The addition of new civil signals will increase accuracy and reliability all over the world. In short, GPS modernization translates to more lives saved and faster recovery for victims of global tragedies.

Source:gps.gov

GPS in Environment

2007-12-27T23:59:00.000-08:00

To sustain the Earth’s environment while balancing human needs requires better decision making with more up-to-date information. Gathering accurate and timely information has been one of the greatest challenges facing both government and private organizations that must make these decisions. The Global Positioning System (GPS) helps to address that need.

Data collection systems provide decision makers with descriptive information and accurate positional data about items that are spread across many kilometers of terrain. By connecting position information with other types of data, it is possible to analyze many environmental problems from a new perspective. Position data collected through GPS can be imported into geographic information system (GIS) software, allowing spatial aspects to be analyzed with other information to create a far more complete understanding of a particular situation than might be possible through conventional means.

Aerial studies of some of the world’s most impenetrable wilderness are conducted with the aid of GPS technology to evaluate an area’s wildlife, terrain, and human infrastructure. By tagging imagery with GPS coordinates it is possible to evaluate conservation efforts and assist in strategy planning.

Some nations collect and use mapping information to manage their regulatory programs such as the control of royalties from mining operations, delineation of borders, and the management of logging in their forests.

GPS technology supports efforts to understand and forecast changes in the environment. By integrating GPS measurements into operational methods used by meteorologists, the atmosphere’s water content can be determined, improving the accuracy of weather forecasts. In addition, the proliferation of GPS tidal tracking sites, and improvement in estimating the vertical component of a site’s position from GPS measurements, present a unique opportunity to directly observe the effects of ocean tides.

GPS receivers mounted on buoys track the movement and spread of oil spills. Helicopters use GPS to map the perimeter of forest fires and allow efficient use of fire fighting resources.
The migratory patterns of endangered species, such as the mountain gorillas of Rwanda, are tracked and mapped using GPS, helping to preserve and enhance declining populations.

Another benefit to using GPS is timeliness with which critical products can be generated. Because GPS data are in a digital form available at all times and in all parts of the world, they can be captured and analyzed very quickly. This means that it is possible for analysis to be completed in hours or days rather than weeks or months, thus ensuring that the final product is timelier. With the rapid pace of change in the world today, these savings in time can be critical.

The modernization of GPS will further enhance the support of GPS technology to the study and management of the world’s environment. The United States is committed to implementing two additional civilian signals that will provide ecological and conservation applications with increased accuracy, availability, and reliability. Tropical rain forest ecology, for example, will benefit from the increased availability of GPS within heavy foliage areas and the reduction of spatial error in fine-scale vegetation mapping.

Source:gps.gov

GPS in Rail systems

2007-12-27T23:57:00.000-08:00

Rail systems in many parts of the world use the Global Positioning System (GPS) in combination with various sensors, computers, and communication systems to improve safety, security, and operational effectiveness. These technologies help to reduce accidents, delays, operating costs, and dangerous emissions, while increasing track capacity, customer satisfaction, and cost effectiveness. Integral to the efficient operation of rail systems is the requirement for accurate, real-time position information of locomotives, rail cars, maintenance-of-way vehicles, and wayside equipment.

Ensuring high levels of safety, improving the efficiency of rail operations, and expanding system capacity are all key objectives of today’s railroad industry. Unlike most other modes of transportation, there is little flexibility in managing rail traffic. Most rail systems are comprised of long stretches of a single set of tracks. Trains bound for thousands of destinations must simultaneously share the use of these single line tracks.

Precise knowledge of where a train is located is essential to prevent collisions, maintain smooth flow of traffic, and minimize costly delays due to waiting for clearance for track use. Only the skill of the crews, accurate timing, a dynamic dispatching capability, and a critical array of “meet and passes” locations on short stretches of parallel tracks, allow rail dispatchers to guide their trains safely through. It is therefore critical for safety and efficiency reasons to know the position and performance of these trains both individually and system-wide.

GPS also contributes to dependable scheduling through train location awareness, enhancing connectivity with other modes of transportation, such as rail station to airport transfers.

An enhancement to the basic GPS signal known as Differential GPS (DGPS) improves accuracy and safety within its coverage areas. The enhanced position information enables the dispatcher to determine on which of two parallel tracks a train is located. When coupled with other location and navigation devices to account for time in tunnels, behind hills, and other obstructions, DGPS can provide a reliable and accurate position-locating capability for rail traffic management systems.

Differential GPS is an essential element of the Positive Train Control (PTC) concept being adopted in many parts of the world. This concept involves providing precise railroad position information to sophisticated command and control systems to produce the best operating plan to include varying train speed, re-routing traffic, and safely moving maintenance crews onto and off tracks.

A PTC system can track the location and speed of a train more accurately than was previously possible, providing train movement information to rail management personnel who can then enforce speeds and limits of authority, as necessary. By providing better tracking of train location and speed, PTC increases operational efficiency, allows higher track capacity, enhances crew, passenger, and cargo safety, and also results in a safer environment for personnel working on the track.

Differential GPS can also aid in surveying and mapping track structure for maintenance and future system planning. By using DGPS, one can precisely locate mileposts, signal masts, switch points, bridges, road crossings, signal equipment, etc. GPS can satisfy the high level of accuracy needed for operation in terminal areas and rail yards, where dozens of tracks may run in parallel.

Finally, with the modernization of GPS, rail operators can look forward to providing better service. In addition to the current GPS civilian service, the United States is committed to implementing two additional civilian signals. Access to the new signals will mean increased accuracy, more availability, and better integrity for all users.

Source:gps.gov

GPS in Marine

2007-12-27T23:54:00.000-08:00

The Global Positioning System (GPS) has changed the way the world operates. This is especially true for marine operations, including search and rescue. GPS provides the fastest and most accurate method for mariners to navigate, measure speed, and determine location. This enables increased levels of safety and efficiency for mariners worldwide.

It is important in marine navigation for the ship's officer to know the vessel's position while in open sea and also in congested harbors and waterways. While at sea, accurate position, speed, and heading are needed to ensure the vessel reaches its destination in the safest, most economical and timely fashion that conditions will permit. The need for accurate position information becomes even more critical as the vessel departs from or arrives in port. Vessel traffic and other waterway hazards make maneuvering more difficult, and the risk of accidents becomes greater.

Mariners and oceanographers are increasingly using GPS data for underwater surveying, buoy placement, and navigational hazard location and mapping. Commercial fishing fleets use GPS to navigate to optimum fishing locations, track fish migrations, and ensure compliance with regulations.

An enhancement to the basic GPS signal known as Differential GPS (DGPS) provides much higher precision and increased safety in its coverage areas for maritime operations. Many nations use DGPS for operations such as buoy positioning, sweeping, and dredging. This enhancement improves harbor navigation.

Governments and industrial organizations around the world are working together to develop performance standards for Electronic Chart Display and Information Systems, which use GPS and/or DGPS for positioning information. These systems are revolutionizing marine navigation and are leading to the replacement of paper nautical charts. With DGPS, position and radar information can be integrated and displayed on an electronic chart, forming the basis of the Integrated Bridge System which is being installed on commercial vessels of all types.

GPS is playing an increasingly important role in the management of maritime port facilities. GPS technology, coupled with geographic information system (GIS) software, is key to the efficient management and operation of automated container placement in the world's largest port facilities. GPS facilitates the automation of the pick-up, transfer, and placement process of containers by tracking them from port entry to exit. With millions of container shipments being placed in port terminals annually, GPS has greatly reduced the number of lost or misdirected containers and lowered associated operation costs.

GPS information is embedded within a system known as the Automatic Identification System (AIS) transmission. The AIS, which is endorsed by the International Maritime Organization, is used for vessel traffic control around busy seaways. This service is not only vital for navigation, but is increasingly used to bolster the security of ports and waterways by providing governments with greater situational awareness of commercial vessels and their cargo.

AIS uses a transponder system that operates in the VHF maritime band and is capable of communicating ship to ship as well as ship to shore, transmitting information relating to ship identification, geographic location, vessel type, and cargo information -- all on a real-time, wholly automated basis. Because the ship's GPS position is embedded in these transmissions, all essential information about vessel movements and contents can be uploaded automatically to electronic charts. The safety and security of vessels using this system is significantly enhanced.

Finally, with the modernization of GPS, mariners can look forward to even better service. In addition to the current GPS civilian service, the United States is committed to implementing two additional civilian signals. Access to the new signals will mean increased accuracy, more availability, and better integrity for all users.

Source:gps.gov

GPS in Agriculture

2007-12-27T23:43:00.000-08:00

The development and implementation of precision agriculture or site-specific farming has been made possible by combining the Global Positioning System (GPS) and geographic information systems (GIS). These technologies enable the coupling of real-time data collection with accurate position information, leading to the efficient manipulation and analysis of large amounts of geospatial data. GPS-based applications in precision farming are being used for farm planning, field mapping, soil sampling, tractor guidance, crop scouting, variable rate applications, and yield mapping. GPS allows farmers to work during low visibility field conditions such as rain, dust, fog, and darkness.

In the past, it was difficult for farmers to correlate production techniques and crop yields with land variability. This limited their ability to develop the most effective soil/plant treatment strategies that could have enhanced their production. Today, more precise application of pesticides, herbicides, and fertilizers, and better control of the dispersion of those chemicals are possible through precision agriculture, thus reducing expenses, producing a higher yield, and creating a more environmentally friendly farm.

Precision agriculture is now changing the way farmers and agribusinesses view the land from which they reap their profits. Precision agriculture is about collecting timely geospatial information on soil-plant-animal requirements and prescribing and applying site-specific treatments to increase agricultural production and protect the environment. Where farmers may have once treated their fields uniformly, they are now seeing benefits from micromanaging their fields. Precision agriculture is gaining in popularity largely due to the introduction of high technology tools into the agricultural community that are more accurate, cost effective, and user friendly. Many of the new innovations rely on the integration of on-board computers, data collection sensors, and GPS time and position reference systems.

Many believe that the benefits of precision agriculture can only be realized on large farms with huge capital investments and experience with information technologies. Such is not the case. There are inexpensive and easy-to-use methods and techniques that can be developed for use by all farmers. Through the use of GPS, GIS, and remote sensing, information needed for improving land and water use can be collected. Farmers can achieve additional benefits by combining better utilization of fertilizers and other soil amendments, determining the economic threshold for treating pest and weed infestations, and protecting the natural resources for future use.

GPS equipment manufacturers have developed several tools to help farmers and agribusinesses become more productive and efficient in their precision farming activities. Today, many farmers use GPS-derived products to enhance operations in their farming businesses. Location information is collected by GPS receivers for mapping field boundaries, roads, irrigation systems, and problem areas in crops such as weeds or disease. The accuracy of GPS allows farmers to create farm maps with precise acreage for field areas, road locations and distances between points of interest. GPS allows farmers to accurately navigate to specific locations in the field, year after year, to collect soil samples or monitor crop conditions.

Crop advisors use rugged data collection devices with GPS for accurate positioning to map pest, insect, and weed infestations in the field. Pest problem areas in crops can be pinpointed and mapped for future management decisions and input recommendations. The same field data can also be used by aircraft sprayers, enabling accurate swathing of fields without use of human “flaggers” to guide them. Crop dusters equipped with GPS are able to fly accurate swaths over the field, applying chemicals only where needed, minimizing chemical drift, reducing the amount of chemicals needed, thereby benefiting the environment. GPS also allows pilots to provide farmers with accurate maps.

Farmers and agriculture service providers can expect even further improvements as GPS continues to modernize. In addition to the current civilian service provided by GPS, the United States is committed to implementing a second and a third civil signal on GPS satellites. The first satellite with the second civilian signal was launched in 2005. The new signals will enhance both the quality and efficiency of agricultural operations in the future.

Source:gps.gov

GPS in Aviation

2007-12-27T23:39:00.000-08:00

Aviators throughout the world use the Global Positioning System (GPS) to increase the safety and efficiency of flight. With its accurate, continuous, and global capabilities, GPS offers seamless satellite navigation services that satisfy many of the requirements for aviation users. Space-based position and navigation enables three-dimensional position determination for all phases of flight from departure, en route, and arrival, to airport surface navigation.

The trend toward an Area Navigation concept means a greater role for GPS. Area Navigation allows aircraft to fly user-preferred routes from waypoint to waypoint, where waypoints do not depend on ground infrastructure. Procedures have been expanded to use GPS and augmented services for all phases of flight. This has been especially true in areas that lack suitable ground based navigation aids or surveillance equipment.

New and more efficient air routes made possible by GPS are continuing to expand. Vast savings in time and money are being realized. In many cases, aircraft flying over data-sparse areas such as oceans have been able to safely reduce their separation between one another, allowing more aircraft to fly more favorable and efficient routes, saving time, fuel, and increasing cargo revenue.

Improved approaches to airports, which significantly increase operational benefits and safety, are now being implemented even at remote locations where traditional ground-based services are unavailable. In some regions of the world, satellite signals are augmented, or improved for special aviation applications, such as landing planes during poor visibility conditions. In those cases, even greater precision operations are possible.

The good news for the aviation community is that GPS is being constantly improved and modernized. A main component of the ongoing civilian modernization effort is the addition of two new signals. These signals complement the existing civilian service. The first of these new signals is for general use in non-safety critical applications. The second new signal will be internationally protected for aviation navigational purposes. This additional safety-of-life civilian signal will make GPS an even more robust navigation service for many aviation applications.

The second safety-of-life signal will enable significant benefits above and beyond the capabilities of the current GPS services. The availability of this signal offers increased instrument approach opportunity throughout the world by making the use of dual-frequency avionics possible. Dual frequency means that errors that occur in the signals due to disturbances in the ionosphere can be significantly reduced through the simultaneous use of two signals. This will improve the overall system robustness, to include accuracy, availability, and integrity, and will allow a precise approach capability with little or no ground infrastructure investment.

Reliance on GPS as the foundation for today and tomorrow's air traffic management system is a major part of many national plans. Those aviation authorities that are moving forward with GPS have observed and documented reductions in flight time, workload, and operating costs for both the airspace user and service provider. GPS also serves as an essential component for many other aviation systems, such as the Enhanced Ground Proximity Warning System (EGPWS) that has proven successful in reducing the risk of Controlled Flight into Terrain, a major cause of many aircraft accidents.

Source:gps.gov

GPS in Space

2007-12-27T23:34:00.000-08:00

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:

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.

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

GPS in Roads and Highways

2007-12-27T23:27:00.000-08:00

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.

Source:gps.gov

GPS Augmentations

2007-12-27T22:58:00.000-08:00

To meet the specific user requirements for positioning, navigation, and timing (PNT), a number of augmentations to the Global Positioning System (GPS) are available. An augmentation is any system that aids GPS by providing accuracy, integrity, reliability, availability, or any other improvement to positioning, navigation, and timing that is not inherently part of GPS itself. Such augmentations include, but are not limited to:

Nationwide Differential GPS System (NDGPS): The NDGPS is a ground-based augmentation system operated and maintained by the Federal Railroad Administration, U.S. Coast Guard, and Federal Highway Administration, that provides increased accuracy and integrity of the GPS to users on land and water. Modernization efforts include the High Accuracy NDGPS (HA-NDGPS) system, currently under development, to enhance the performance and provide 10 to 15 centimeter accuracy throughout the coverage area. NDGPS is built to international standards, and over 50 countries around the world have implemented similar systems.

Wide Area Augmentation System (WAAS): The WAAS, a satellite-based augmentation system operated by the U.S. Federal Aviation Administration (FAA), provides aircraft navigation for all phases of flight. Today, these capabilities are broadly used in other applications because their GPS-like signals can be processed by simple receivers without additional equipment. Using International Civil Aviation Organization (ICAO) standards, the FAA continues to work with other States to provide seamless services to all users in any region. Other ICAO standard space-based augmentation systems include: Europe's European Geostationary Navigation Overlay System (EGNOS), India's GPS and Geo-Augmented Navigation System (GAGAN), and Japan's Multifunction Transport Satellite (MTSAT) Satellite Augmentation System (MSAS). All of these international implementations are based on GPS. The FAA will improve the WAAS to take advantage of the future GPS safety-of-life signal and provide better performance and promote global adoption of these new capabilities.

Continuously Operating Reference Station (CORS): The U.S. CORS network, which is managed by the National Oceanic & Atmospheric Administration, archives and distributes GPS data for precision positioning and atmospheric modeling applications mainly through post-processing. CORS is being modernized to support real-time users.

Global Differential GPS (GDGPS): GDGPS is a high accuracy GPS augmentation system, developed by the Jet Propulsion Laboratory (JPL) to support the real-time positioning, timing, and orbit determination requirements of the U.S. National Aeronautics and Space Administration (NASA) science missions. Future NASA plans include using the Tracking and Data Relay Satellite System (TDRSS) to disseminate via satellite a real-time differential correction message. This system is referred to as the TDRSS Augmentation Service Satellites (TASS).

International GNSS Service (IGS): IGS is a network of over 350 GPS monitoring stations from 200 contributing organizations in 80 countries. Its mission is to provide the highest quality data and products as the standard for Global Navigation Satellite Systems (GNSS) in support of Earth science research, multidisciplinary applications, and education, as well as to facilitate other applications benefiting society. Approximately 100 IGS stations transmit their tracking data within one hour of collection.

There are other augmentation systems available worldwide, both government and commercial. These systems use differential, static, or real-time techniques.

U.S. Policy on International Cooperation

The U.S. Space-Based Positioning, Navigation, and Timing Policy underscores the importance that all global navigation satellite systems and their augmentations be compatible with GPS.

The agreement in 2004 between the United States and the European Union (E.U.) on GPS and Galileo recognized the benefits of interoperable systems. The parties agreed to pursue a common, open, civil signal on both Galileo and future GPS satellites, in addition to ongoing cooperation on the GPS-based EGNOS augmentation system.

The United States has a long cooperative relationship with Japan on GPS. In addition to the Multifunction Transport Satellite (MTSAT) Satellite Augmentation System (MSAS), the parties are working towards developing a GPS-compatible regional satellite "mini-" constellation known as the Quasi Zenith Satellite System (QZSS).

The United States is also consulting closely with India on its development of its GAGAN space-based augmentation system, and with the Russian Federation on compatibility and interoperability between GPS and Russia's satellite navigation system, GLONASS.

The U.S. Department of Defense also cooperates with numerous countries to ensure that GPS provides military space-based PNT service and interoperable user equipment to its coalition partners around the world.

Space-based PNT services must serve global users with transparent interfaces and standards. The U.S. policy is to provide space-based PNT services on a continuous worldwide basis, freely available to all for civil, commercial, and scientific uses, and provide open, free access, to information necessary to develop and build equipment to use these services.

Source:gps.gov

GPS Services and the Future of GPS

2007-12-27T22:49:00.000-08:00

What is GPS?

The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. This system consists of three segments: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments.

The space segment consists of a nominal constellation of 24 operating satellites that transmit one-way signals that give the current GPS satellite position and time.

The control segment consists of worldwide monitor and control stations that maintain the satellites in their proper orbits through occasional command maneuvers, and adjust the satellite clocks. It tracks the GPS satellites, uploads updated navigational data, and maintains health and status of the satellite constellation.

The user segment consists of the GPS receiver equipment, which receives the signals from the GPS satellites and uses the transmitted information to calculate the user’s three-dimensional position and time.

GPS Services

GPS satellites provide service to civilian and military users. The civilian service is freely available to all users on a continuous, worldwide basis. The military service is available to U.S. and allied armed forces as well as approved Government agencies.

A variety of GPS augmentation systems and techniques are available to enhance system performance to meet specific user requirements. These improve signal availability, accuracy, and integrity, allowing even better performance than is possible using the basic GPS civilian service.

The outstanding performance of GPS over many years has earned the confidence of millions of civil users worldwide. It has proven its dependability in the past and promises to be of benefit to users, throughout the world, far into the future.

The Future of GPS

The United States is committed to an extensive modernization program, including the implementation of a second and a third civil signal on GPS satellites. The second civil signal will improve the accuracy of the civilian service and supports some safety-of-life applications. The third signal will further enhance civilian capability and is primarily designed for safety-of-life applications, such as aviation.

The figure on the right depicts the improvement of the quality of service with the additional civilian signals.

Positioning, Navigation, and Timing Policy

U.S. law and policy on GPS emphasize continuity of service, open access to civil signals, and technological leadership. In 1996, the United States issued a national policy statement on the management and use of space-based positioning, navigation and timing services, which include GPS and augmentations. It underscored the dual use (civilian-military) nature of GPS and established a joint civil-military national management structure to oversee its operation.

U.S. policy was expanded in 2004 in response to changing international conditions and the incredible growth in the types and complexities of GPS applications. This policy reaffirms the United States commitment to provide reliable civil space-based positioning, navigation, and timing services through GPS on a continuous, worldwide basis -- freely available to all. The policy also calls for improving the performance of GPS and cooperating with other nations.

Source:gps.gov