⏱️Signalseach satellite broadcasts the exact time

💡Speed of light300,000 km/s

📏Distancetime delay × speed of light

⚠️Precisiona 1-microsecond error = 300 m off!

⚛️Atomic clocksaccurate to billionths of a second

🌌Einsteinrelativity makes satellite clocks run ~38 µs/day fast; GPS corrects for it