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Question about GPS functionality on iPhone
- Thread starter tpcollins
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No not required, what you may be getting confused with is that some apps need to download maps to display the GPS data on and this will require a data connection.
Some apps can download and cache maps so once done no data connection is needed, others always do it on the fly.
Some apps can download and cache maps so once done no data connection is needed, others always do it on the fly.
this thread looks answered. but i would like to explain that wifi assists gps.
a full gps lock can take anywhere from 90 seconds to 12 or 20 minutes maximum. wifi like other gps assistive technologies is a cheat , to save you those 24 minutes.
wifi scans the neighborhood of ssid and submits those wifi networks to apple, wigle.net or skyhook wireless. they send back your location and the phone uses that as your location until a full gps lock can be made.
another cheat that apple uses is "frequent locations" , that caused quite a stir in china!
apple uses your iPhone to crowdsource its database of wifi hotspots.
other cheats are
download constellation tables for the next week, so at any given time the gps receiver knows where to look, so it does not have to do a full scan
scan more then one channel at a time. most modern receivers scan 12 to 24 channels at once.
use the cell phone towers
a gps receiver needs 3 or more satellites to get a lock and it scans for those signals. and those satellites only transmit every 30 seconds or so. so gps companies use various cheats to get a faster lock.
if you interested, you can google for the full explanation. this is just something top off my head. i think it would be helpful
a full gps lock can take anywhere from 90 seconds to 12 or 20 minutes maximum. wifi like other gps assistive technologies is a cheat , to save you those 24 minutes.
wifi scans the neighborhood of ssid and submits those wifi networks to apple, wigle.net or skyhook wireless. they send back your location and the phone uses that as your location until a full gps lock can be made.
another cheat that apple uses is "frequent locations" , that caused quite a stir in china!
apple uses your iPhone to crowdsource its database of wifi hotspots.
other cheats are
download constellation tables for the next week, so at any given time the gps receiver knows where to look, so it does not have to do a full scan
scan more then one channel at a time. most modern receivers scan 12 to 24 channels at once.
use the cell phone towers
a gps receiver needs 3 or more satellites to get a lock and it scans for those signals. and those satellites only transmit every 30 seconds or so. so gps companies use various cheats to get a faster lock.
if you interested, you can google for the full explanation. this is just something top off my head. i think it would be helpful
Exactly what he said above.
That's why you see some older stand alone car gps units will take a few minutes or longer to lock in to gps signal and start navigation.
Its satellite triangulation. It needs 3 signals locked to get accurate location information.
With wifi on getting a general idea from local wifi access points and cell tower search it finds and locks in a lot faster.
But to the original question to use your GPS you don't need any data at all. No wifi or carrier data. If you a have gps app for example like navigon or tomtom that download the maps before and have them stored locally on your device then you will not need any data to use and navigate yourself to your destination.
Other gps apps don't store any map info on your device but they use its servers map data as you drive to update and pull more map and location information. With those if you don't have any signal in remote areas you could get stuck driving without really knowing where you are or where you will need to turn. And also can use up much of your data if driving for long periods of time.
That's why you see some older stand alone car gps units will take a few minutes or longer to lock in to gps signal and start navigation.
Its satellite triangulation. It needs 3 signals locked to get accurate location information.
With wifi on getting a general idea from local wifi access points and cell tower search it finds and locks in a lot faster.
But to the original question to use your GPS you don't need any data at all. No wifi or carrier data. If you a have gps app for example like navigon or tomtom that download the maps before and have them stored locally on your device then you will not need any data to use and navigate yourself to your destination.
Other gps apps don't store any map info on your device but they use its servers map data as you drive to update and pull more map and location information. With those if you don't have any signal in remote areas you could get stuck driving without really knowing where you are or where you will need to turn. And also can use up much of your data if driving for long periods of time.