How Does Satellite Navigation Work?

Satellite Navigation is possible thanks to GPS. GPS is a group of 24 satellites each orbiting the earth at around 11000 miles above the surface. Each Satellite circumnavigates every 12 hours. At all times at least four satellites will be in view at any given point on the globe. GPS has been fully operational since 1990.

As long as a GPS device can see a minimum of 3 satellites then an accurate position of your location can be calculated. This enables hill walkers to see where they are, emergency services to pin point locations and accurate records of gas pipes and underground cable locations to be maintained to within centimetres. Add this to digital mapping and interfaces to read and interpret these maps and you have satellite navigation, or sat nav for short. GPS systems generally check their position every second.