How many satellite are requird for gps at a moment to cover earth?
Answers
4 satellites are needed. It is a tetrahedral constellation using orbits. The orbital period is approx. 27 hours.
Why 4 satellites are needed?
GPS (Global Positioning System) is a system composed of the receivers, the constellation of satellites that forms trajectory around the Earth, and the control centers that monitor the velocity and shape of the satellite orbits. Together the satellites, control centers and receivers make up the three segments on which GPS relies:
• The space segments
• The control segments
• The user segments
The Space segment
The space segment consists of all the satellites in the GPS constellation, which experiences continuous change as new satellites are launched and others are decommissioned on an intermittent basis.
Three satellites are needed by the receivers to determine the position while the fourth enhances the measurement and provides the ability to calculate elevation. Since four satellites must be visible from any point on the planet and the satellite are arranged into six orbital planes, the minimum number of satellites needed to provide full coverage at any location on Earth is 24.
You need the 32 satellites that exist. The GPS works through a network of at least 24 satellites in orbit on planet Earth, at a height of 20 180 km, with synchronized trajectories to cover the entire surface of the Earth.