Why Your GPS Dies in Tunnels 🚇 (It's Just Too Faint)

: Your blue dot freezes in a tunnel for a simple reason: GPS signals are whisper-faint radio waves that have travelled 20,200 km from space. By the time they reach you, they are incredibly weak, and they need a clear view of the sky. Concrete, rock, and metal roofs block them completely — a tunnel acts like a cage for radio waves. Inside, your phone loses the four satellites it needs, so it guesses instead, using nearby Wi-Fi networks and cell towers. That is why indoor locations are rough and your dot jumps around. The moment you see open sky again, the satellites lock back on. #Science #GPS #HowItWorks #KLYPS #ScienceShorts