1. Medium Earth Orbit (MEO):
* GPS satellites circle the Earth at an altitude of approximately 20,200 kilometers (12,550 miles). This is significantly higher than low Earth orbit (LEO) used by the International Space Station, but lower than geostationary orbit used for communication satellites.
2. Inclination:
* Their orbital planes are inclined at an angle of 55 degrees relative to the Earth's equator. This inclination allows the satellites to cover both the Northern and Southern Hemispheres.
3. Period:
* Each GPS satellite completes one orbit around the Earth in approximately 12 hours. This means they make two full orbits per day.
4. Constellation:
* The GPS constellation consists of 31 operational satellites, with at least 24 constantly in use. These satellites are arranged in six orbital planes, with four satellites in each plane. This arrangement ensures that at least four satellites are visible from any point on Earth at any given time.
5. Precise Timing:
* The satellites use highly accurate atomic clocks to maintain precise time synchronization. This is crucial for calculating the distance between the satellite and the receiver on Earth, which is fundamental to GPS positioning.
Why this specific configuration?
* Global Coverage: The inclined orbits ensure that at least four satellites are visible from anywhere on Earth, providing global coverage for positioning.
* Accurate Positioning: The precise orbital parameters and timing allow for accurate calculations of distance and location.
* Redundancy: The constellation design ensures that the system remains operational even if some satellites experience malfunctions.
In summary, GPS satellites orbit in a carefully planned configuration to provide continuous, global, and highly accurate positioning information.
