Applications Of Global Positioning System - Online Article

Timing

"Timing is rapidly becoming a critical element for many industries. As the need for precise timing grows, more and more users are turning to GPS technology."

Dennis L. Workman, VP and General Manager, Trimble Component Technologies Division.

Benefits

  • Widespread availability of atomic clock time, without the atomic clocks.
  • Precise synchronization of communications systems, power grids, financial networks, and other critical infrastructure.
  • More efficient use of limited radio spectrum by wireless networks.
  • Improved network management and optimization, making traceable time tags possible for financial transactions and billing.
  • Communication of high-precision time among national laboratories using "common view" techniques.

In addition to longitude, latitude, and altitude, the Global Positioning System (GPS) provides a critical fourth dimension - time. Each GPS satellite contains multiple atomic clocks that contribute very precise time data to the GPS signals. GPS receivers decode these signals, effectively synchronizing each receiver to the atomic clocks. This enables users to determine the time to within 100 billionths of a second, without the cost of owning and operating atomic clocks.

Precise time is crucial to a variety of economic activities around the world. Communication systems, electrical power grids, and financial networks all rely on precision timing for synchronization and operational efficiency. The free availability of GPS time has enabled cost savings for companies that depend on precise time and has led to significant advances in capability.

For example, wireless telephone and data networks use GPS time to keep all of their base stations in perfect synchronization. This allows mobile handsets to share limited radio spectrum more efficiently. Similarly, digital broadcast radio services use GPS time to ensure that the bits from all radio stations arrive at receivers in lockstep. This allows listeners to tune between stations with a minimum of delay.

Companies worldwide use GPS to time-stamp business transactions, providing a consistent and accurate way to maintain records and ensure their traceability. Major investment banks use GPS to synchronize their network computers located around the world. Large and small businesses are turning to automated systems that can track, update, and manage multiple transactions made by a global network of customers, and these require accurate timing information available through GPS.

The U.S. Federal Aviation Administration (FAA) uses GPS to synchronize reporting of hazardous weather from its 45 Terminal Doppler Weather Radars located throughout the United States.

Instrumentation is another application that requires precise timing. Distributed networks of instruments that must work together to precisely measure common events require timing sources that can guarantee accuracy at several points. GPS-based timing works exceptionally well for any application in which precise timing is required by devices that are dispersed over wide geographic areas. For example, integration of GPS time into seismic monitoring networks enables researchers to quickly locate the epicenters of earthquakes and other seismic events.

Power companies and utilities have fundamental requirements for time and frequency to enable efficient power transmission and distribution. Repeated power blackouts have demonstrated to power companies the need for improved time synchronization throughout the power grid. Analyses of these blackouts have led many companies to place GPS-based time synchronization devices in power plants and substations. By analyzing the precise timing of an electrical anomaly as it propagates through a grid, engineers can trace back the exact location of a power line break.

Some users, such as national laboratories, require the time at a higher level of precision than GPS provides. These users routinely use GPS satellites not for direct time acquisition, but for communication of high-precision time over long distances. By simultaneously receiving the same GPS signal in two places and comparing the results, the atomic clock time at one location can be communicated to the other. National laboratories around the world use this "common view" technique to compare their time scales and establish Coordinated Universal Time (UTC). They use the same technique to disseminate their time scales to their own nations.

New applications of GPS timing technology appear every day. Hollywood studios are incorporating GPS in their movie slates, allowing for unparalleled control of audio and video data, as well as multi-camera sequencing. The ultimate applications for GPS, like the time it measures, are limitless.

As GPS becomes modernized, further benefits await users. The addition of the second and third civilian GPS signals will increase the accuracy and reliability of GPS time, which will remain free and available to the entire world.

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.

Space

"GPS is transforming the way nations operate in space -- from guidance systems for the International Space Station's 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.

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.
  • Safe, flexible, and fuel-efficient routes for airspace service providers and airspace users.
  • Potential decommissioning and reduction of expensive ground based navigation facilities, systems, and services.
  • Increased safety for surface movement operations made possible by situational awareness.
  • Reduced aircraft delays due to increased capacity made possible through reduced separation minimums and more efficient air traffic management, particularly during inclement weather.
  • Increased safety-of-life capabilities such as Enhanced Ground Proximity Warning System (EGPWS). 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.

Agriculture

"We started using more digital technology in the last 10 years. We have gone to GPS (Global Positioning System) for a handful of different operations from cultivating to planting. By using GPS on the tractors, the entire process from leveling the field to planting the seed to irrigating the crop has been much more efficient than in the past. GPS is used in a lot of applications throughout most aspects of agriculture."

John Boelts, Vice President of the Yuma County Farm Bureau, Yuma County, Arizona, USA

Benefits

  • Precision soil sampling, data collection, and data analysis, enable localized variation of chemical applications and planting density to suit specific areas of the field.
  • Accurate field navigation minimizes redundant applications and skipped areas, and enables maximum ground coverage in the shortest possible time.
  • Ability to work through low visibility field conditions such as rain, dust, fog and darkness increases productivity.
  • Accurately monitored yield data enables future site-specific field preparation.
  • Elimination of the need for human "flaggers" increases spray efficiency and minimizes over-spray.

Marine

"We implemented a GPS based container management system three months ago and have already seen direct benefits to our business. We have documented a 4-8% decrease in costs and a 5-10% increase in efficiency."

LingSen Xue, General Manager, Tianjin port Container Terminals (TCT), China

Benefits

  • Enhanced levels of safety.
  • Increased capacity and efficiency for all rail users.
  • Dependable schedule and equipment location awareness.
  • Improved track, traffic, and train sensor information that flows together and produces a constantly updated plan to manage operations.
  • Increased situational awareness for improved safety of trains and maintenance crews.

Environment

"Until the advent of GPS tracking, it was practically impossible to record elephant movements with sufficient temporal resolution to give a full picture of movement patterns. The presence of elephants in Kenya is a key indicator of the health of the environment."

Honorable Dr. Newton Kulundu, Minister for Environment, Natural Resources, and Wildlife, Kenya

Benefits

  • GPS data collection systems complemented with GIS packages provide a means for comprehensive analysis of environmental concerns.
  • Environmental patterns and trends can be efficiently recognized with GPS/GIS data collection systems, and thematic maps can be easily created.
  • GPS data can be quickly analyzed without the preliminary requirement for field data transcription into a digitized form.
  • Accurate tracking of environmental disasters such as fires and oil spills can be conducted more efficiently.
  • Precise positional data from GPS can assist scientists in crustal and seismic monitoring.
  • Monitoring and preservation of endangered species can be facilitated through GPS tracking and mapping.

Public Safety & Disaster Relief

"The data from the Southern California Integrated GPS Network will allow us to anticipate future earthquakes with more accuracy, as well as to study in much greater detail the fundamental processes of crustal deformation that are the root causes of earthquakes."

Dr. Thomas Jordan, Director Designate, Southern California Earthquake Center

Benefits

  • Deliver disaster relief to areas in a more timely and accurate manner, saving lives and restoring critical infrastructure.
  • Provide position information for mapping of disaster regions where little or no mapping information is available.
  • Enhance capability for flood prediction and monitoring of seismic precursors and events.
  • Provide positional information about individuals with mobile phones and in vehicles in case of emergency.

Surveying & Mapping

"The most effective way to achieve a robust and globally consistent continental reference system is through the technology of the Global Positioning System (GPS). The explosive growth of GPS applications and the economics of GPS make it the technique of choice for sustainable geodetic operations within Africa."

Claude Boucher, Chairman, International Association of Geodesy (IAG), Commission X on Global and Regional Geodetic Networks

Benefits

  • Provides significant productivity gains over traditional surveying by eliminating many of its inherent limitations, such as the requirement for a line of sight between surveying points.
  • Provides accurate positioning of natural and artificial features that can be used to create maps and models that are used for a wide range of services such as disaster relief and public safety.
  • Gives decision-makers timely and valuable information for wise use of resources.
  • Yields highly accurate surveying results in real-time at the centimeter - level.
  • Allows surveyors to work uninterrupted in periods of poor weather conditions or reduced sunlight.

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