Open a map indoors, underground, or in a canyon of skyscrapers, and the dot still appears, often within seconds. Pure satellite physics cannot explain that speed or that stubbornness. The secret is that your phone is not using one system; it is quietly blending four.
The first ingredient is GNSS, the satellite layer, great outdoors and useless in a basement. The second is wifi positioning: your phone notices the names of nearby wireless networks and checks them against a vast crowd-sourced map of where those networks have been seen before. That is how it can place you inside a shopping centre where no satellite reaches.
The third is cell-tower location, a coarse fallback covered in our GPS versus GSM explainer. The fourth is the set of tiny motion sensors, accelerometer, gyroscope, and compass, that let the phone dead-reckon your steps when everything else drops out, keeping the dot moving through a tunnel. A piece of software called a sensor-fusion filter melts all of this into one confident-looking point.
Confident-looking is the phrase to sit with. The dot projects certainty it does not always have, which is comforting when you are navigating and worth remembering when you are worrying. The phone knowing where it is does not mean anyone else does. That information stays local unless an app you installed and permitted decides to send it onward, which is the real story of location privacy.
Understanding this makes you calmer and harder to fool. It also demystifies the prank: Live Sat Tracker shows a confident dot too, except ours is pure fiction attached to nothing, computed from no signals, saving no data. If you want to reduce how much your genuine location gets shared, our guide on protecting your location privacy is the useful sequel to this cheerful one.