GPS Accuracy issues / Limitations

There will be uch more technical references available, but from https://www.aclu.org/report/aclu-white-paper-limits-location-tracking-epidemic

(ACLU whitepaper on the limits of location tracking).

”GPS.When mobile phones have satellite sensing turned on, they can identify their own location with a best-casetheoreticalaccuracy of 1 meter, but more typically 5 to 20 metersunder an open sky. GPS radio signals are relatively weak; the technology does not work indoors and works poorly near large buildings, in large cities, and during thunderstorms, snowstorms,and other bad weather. It can also take a GPS receiver up to several minutesto perceive its location when first turned on or brought outdoors. In addition, phones receivetransmissions from GPS satellites, but theydo not automatically calculate, save, or broadcast GPS location information. That only happens when a user installs an app on their phone that is designed to do that. Those apps may send that data to dozens of different companiesor to none at all; there is not a single repository.”