What is the inclination of the GPS satellite orbital planes?

• A. 60 degrees
• B. 55 degrees
• C. 90 degrees
• D. 30 degrees

Answer: (B)

Inclination is the tilt of the orbital plane relative to the Earth's equator. For GPS, the satellites are placed in orbits inclined about 55 degrees to the equator. This angle lets the constellation provide reliable visibility across a wide range of latitudes, including high-latitude regions, while keeping the constellation geometry manageable. It balances how often satellites pass over different parts of the globe and how well their signals geometry supports accurate positioning. A higher inclination like 60 degrees would still cover polar areas but isn’t as optimal for the overall geometry; a polar orbit (90 degrees) would change the ground-track pattern and isn’t used for GPS needs, and a shallow 30-degree inclination would leave high-latitude users with poorer coverage. Hence, 55 degrees is chosen for global, consistent coverage.