[kevkrom]

IIRC, in addition to using WiFi for a more accurate fix, the iOS devices use it to generate a preliminary position estimate while it’s waiting for GPS, which can be relatively slow in comparison (up to 15-20 seconds or so).

[Swordmaker]

IIRC, in addition to using WiFi for a more accurate fix, the iOS devices use it to generate a preliminary position estimate while it’s waiting for GPS, which can be relatively slow in comparison (up to 15-20 seconds or so).

That is essentially correct, but the iOS device already has a general idea of where it is from continually getting WIFI data. So the GPS is very fast when it does get the GPSatellite data.