GPS tracking requires the use of four or more satellites to accurately locate a GPS tracker on the surface of the earth or flying above the surface. While only three satellites would technically be required for accurate tracking, even minor errors in data received when calculated with the speed of light to determine positioning could lead to grossly inaccurate location results. To offset this possibility as much as possible, one or more additional satellites is used to reduce the chance of erroneous data being used to calculate position.