Global Positioning System (GPS) technology is a space-based radio-navigation system that provides users worldwide with valuable information including three-dimensional position, navigation, velocity and time data. It comprises of 24 satellites, which are in orbit some 12,000 miles above the earth’s surface. GPS operates on the principle of triangulation. The satellites broadcast their position on a continuous basis, and by combining the measurements from different satellites.
Another user-friendly aspect of GPS is the fact that it is not affected by weather conditions. This technology is easily integrated with geographic information systems and is, therefore, very useful for engineering and surveying applications. GPS technology provides highly accurate information, including digital maps of land and infrastructure, such as highways.
How GPS Can Assist in Surveying
Conventional surveying can be extremely costly and time-consuming. Surveyors often need to make multiple visits to the same site in order to gather data and ensure that it is accurate. They must also be trained in the operation of complex technical equipment. Weather conditions such as snow, rain and extreme temperatures can also delay the collection and checking of data. The surveying industry is increasingly coming to recognize the need to reduce labor costs, while increasing the accuracy of surveys. An effective way of doing this is to use GPS technology.
There is a current GPS surveying project at the Utah Department of Transportation in the United States, which found that one surveyor operating GPS surveying equipment is twice as fast as a conventional surveying crew, and a GPS system with two units has the potential to be four times faster than crews using conventional technologies to complete surveys. Another advantage of the GPS surveying technology is the fact that it can be used over long distances with far fewer setups. It can be setup and surveys can be performed over a distance of six miles from the base unit, whereas with conventional equipment the base unit would have to be moved every 600 feet. In one surveying project GPS surveying equipment recorded more than 5,500 topographical points in 30 man-hours, whereas conventional equipment could record only 1,500 topographical points in 120 man-hours.
– GPS surveying can save significantly on labor costs
– GPS surveying is highly accurate
– GPS is time saving for civil engineers
For more information, check out the Federal Highway Administration’s Resource Center: www.fhwa.dot.gov
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