Why does GPS work when underground and under big buildings but radio signals, Wi-Fi, and cell phone signals struggle?

Question

Why does GPS work when underground and under big buildings but radio signals, Wi-Fi, and cell phone signals struggle?

In: 4773

Answer 1

Many tunnels in California have Bluetooth beacons at regular intervals, according to Waze at least. This combined with speed information is probably giving you a good estimate of your position during the loss of GPS fix.

GPS bands are
L1 1575.42 MHz
L2 1227.60 MHz

Both of these are much higher than FM radio and struggle to penetrate far through buildings, so they are almost always blocked by concrete, brick and tinted windows.