GPS orbit type?

• A. LEO
• B. GEO
• C. MEO
• D. HEO

Answer: (C)

Global navigation systems like GPS need a balance: enough satellites in the sky at once, reasonable signal travel time, and a stable geometry for accurate fixes. That balance is achieved in Medium Earth Orbit. GPS satellites sit about 20,200 kilometers above Earth, completing a roughly 12-hour orbit. This altitude lets the constellation be spread across several orbital planes so receivers anywhere on the globe can see multiple satellites simultaneously, providing good geometry for a precise position and time solution without the long delays you’d see from much higher orbits.

LEO would require many more satellites because objects move quickly across the sky, making tracking and geometry harder for continuous global coverage. GEO would place satellites so they appear stationary relative to a single point on the equator, which gives excellent coverage only near the equator and poor geometry at higher latitudes, plus the long distance reduces signal strength and timing precision. HEO involves highly elliptical paths with changing distance and visibility, which would disrupt consistent, reliable global positioning.

So, Medium Earth Orbit is the effective choice for GPS, delivering reliable global coverage with manageable signal characteristics and stable geometry.