How does GPS work?
The satellites travel at 7,000 miles/ 11,250 kilometres per hour, which means they circle the earth once every 12 hours.
GPS satellites are powered by solar energy. Smart enough. But smarter still is the fact that if their solar energy supply temporarily fails (e.g. because of an eclipse of the Sun), the satellites have back-up batteries on board to keep them running.
The satellite signals have low power; about 20-50 watts. Compare that with the signals from an FM radio station, which are about 100,000 watts. If you imagine trying to pick up a 20 watt signal from over 12,000 miles/ 19,000 kilometres away, you’ll realise why you need a clear view for a GPS signal…
Like to know more satellite facts?
Altitude: 20,200 kilometers
Weight: 860 kilograms (in orbit)
Size: 5 meters with solar panels extended
Orbital Period: 12 hours
Orbital Plane: 55 degrees to equatorial plane
Planned Lifespan: 7.5 years
Current constellation: 24 satellites