Civilian applications of GPS – Surveying and Mapping

The surveying and mapping community was one of the first to take advantage of GPS because it dramatically increased productivity and resulted in more accurate and reliable data. Today, GPS is a vital part of surveying and mapping activities around the world.

When used by skilled professionals, GPS provides surveying and mapping data of the highest accuracy. GPS-based data collection is much faster than conventional surveying and mapping techniques, reducing the amount of equipment and labor required. A single surveyor can now accomplish in one day what once took an entire team weeks to do.

GPS supports the accurate mapping and modeling of the physical world -- from mountains and rivers to streets and buildings to utility lines and other resources. Features measured with GPS can be displayed on maps and in geographic information systems (GIS) that store, manipulate, and display geographically referenced data.

Governments, scientific organizations, and commercial operations throughout the world use GPS and GIS technology to facilitate timely decisions and wise use of resources. Any organization or agency that requires accurate location information about its assets can benefit from the efficiency and productivity provided by GPS positioning.

"The most effective way to achieve a robust and globally consistent continental reference system is through the technology of the Global Positioning System," said Claude Boucher, Former Secretary General, International Association of Geodesy. "The explosive growth of GPS applications and the economics of GPS make it the technique of choice for sustainable geodetic operations within Africa."

Unlike conventional techniques, GPS surveying is not bound by constraints such as line-of-sight visibility between survey stations. The stations can be deployed at greater distances from each other and can operate anywhere with a good view of the sky, rather than being confined to remote hilltops as previously required.

GPS is especially useful in surveying coasts and waterways, where there are few land-based reference points. Survey vessels combine GPS positions with sonar depth soundings to make the nautical charts that alert mariners to changing water depths and underwater hazards. Bridge builders and offshore oil rigs also depend on GPS for accurate hydrographic surveys.

Land surveyors and mappers can carry GPS systems in backpacks or mount them on vehicles to allow rapid, accurate data collection. Some of these systems communicate wirelessly with reference receivers to deliver continuous, real-time, centimeter-level accuracy and unprecedented productivity gains. To achieve the highest level of accuracy, most survey-grade receivers use two GPS radio frequencies: L1 and L2. The ongoing GPS modernization program added a dedicated civil signal at L2 that supports high-accuracy positioning. The GPS program also added a third civil signal at the L5 frequency that will enhance performance even further.

 - Significant productivity gains in terms of time, equipment, and labor required
 - Fewer operational limitations compared to conventional techniques.
 - Accurate positioning of physical features that can be used in maps and models.
 - Faster delivery of geographic information needed by decision makers.
 - Centimeter-level surveying results in real-time.

Operated by Air Force Space Command's 50th Space Wing at Schriever Air Force Base, located east of Colorado Springs, Colo., the GPS constellation provides precise positioning, navigation and timing services worldwide as a free service provided by the U.S. Air Force, seven days a week, 24 hours a day. The GPS constellation is healthy, stable and robust with 12 GPS IIRs, seven GPS IIR-Ms, and 12 GPS IIF satellites on orbit providing precise global positioning, navigation, and timing services to users around the globe.

The latest generation of GPS IIF satellites provides improved signals to support both the warfighter and the growing civilian needs of a global economy. Featuring a new third civil signal -- L5 -- that benefits commercial aviation and safety-of-life applications, the GPS IIF series provides improved accuracy through advanced atomic clocks, and a longer design life than previous GPS satellites on orbit.

The Space and Missile Systems Center, located at Los Angeles Air Force Base in El Segundo, Calif., is the Air Force's center of acquisition excellence for acquiring and developing military space systems. Its portfolio includes the Global Positioning System, military satellite communications, defense meteorological satellites, space launch and range systems, satellite control networks, space based infrared systems and space situational awareness capabilities.