What is GPS?

imageGPSThe Global Positioning System, most commonly known simply as GPS, is a network of 24 satellites that continually orbit the earth at an altitude of over 19,000 kilometres. Each satellite travels at approximately 11,000 km/h which allows it to circle the earth every 12 hours. The satellite constantly travels along a very precise path, and if the satellite veers off this path, small rockets guide the satellite back into place.

The way GPS works is that each satellite continually transmits a signal down towards earth. A GPS receiver is able to lock into this signal and then it performs a number of distance calculations and through triangulation a relative ground location can be determined. A minimum of 3 satellites must be able to communicate with the receiver to calculate a precise latitude and longitude location on the earth's surface. The locational accuracy of a position depends on the quality of the GPS receiver used. Survey grade receivers provide sub-centimetre accuracy, mapping grade receivers provide metre accuracy, and recreational grade receivers provide accuracy down to about 10 metres. As with any technology, the accuracy of these receivers is always improving. Lacombe County currently utilizes GPS in its Agriculture, Public Works and Mapping departments.