Not quite. Phones use assisted GPS, which means that they download GPS ephemeris data over the internet instead of getting it from the the satellite signal (bec

Not quite. Phones use assisted GPS, which means that they download GPS ephemeris data over the internet instead of getting it from the the satellite signal (because the satellites transmit data at 50 bps). So the time to first position is faster. Differential GPS, by contrast, transmits the difference between the surveyed location of a base station and the GPS-derived position of the same station. That offset can be used locally to correct other nearby GPS receivers. Phones also use trilateration on the cell tower signals to get an approximate solution before trying to solve 3d+time on the GPS signal.