Originally Posted by
njkayaker
This is wrong.
Smartphones have GPS receivers and work fine without any access to cell towers.
GPS is a bit slow to get an accurate initial fix. The triangulation helps with that.
Smartphones can also use wifi to assist in getting a fix (there are databases of wifi networks associated with location).
Once an accurate fix is obtained, GPS on smartphones is fast and very accurate (equivalent to a handheld dedicated GPS).
GPS has known limitations in canyons (natural or urban) and heavy tree cover.
True and I stand corrected in that smart phones have a GPS chip in them. They do in fact work even if the phone is in Airplane mode. But the issue is that you still need cell service for most apps to work reliably. And that is the point I was making with the location jumping around on the map. If you ever look at something like google maps on your phone while standing still and see your location move around a bit, thats the cell towers. Turn off cell service and it stops moving. Your phone will use both GPS and cell tower to help locate you faster.
Sorry if I misspoke before. But you are correct.