Simplified Representation of GPS Constellation
The nominal GPS Operational Constellation consists of 24 satellites that orbit the earth in 12
hours. There are often more than 24 operational satellites as new ones are launched to
replace older satellites. The satellite orbits repeat almost the same ground track (as the earth
turns beneath them) once each day.
The orbit altitude is such that the satellites repeat the same track and configuration over any point
approximately each 24 hours (4 minutes earlier each day). There are six orbital planes (with
nominally four SVs in each), equally spaced (60 degrees apart), and inclined at about fifty-five
degrees with respect to the equatorial plane. This constellation provides the user with between
five and eight SVs visible from any point on