Does the phone need to be connected to the internet all the time, so that the network provider can determine a location?
When I test my app on my phone, and in Settings->Location only Use wireless network is checked, and I am not connected to the internet via Wi-Fi, I can not get a location fix.
I know there was something that the network provider uses availability of cell tower, but I don’t know how that works exactly and should I have full internet access.
Please someone make this clear for me.
Yes, you need to be connected to the Internet in order to get correct network location fixes. At least most of the time.
The phone collects the following data (it does not need a connection to the Internet to do this):
The phone then sends this data to a server. The server uses this data to look in its database to determine the phone’s most likely position. The server sends the location information back to the phone. This is all done using data connection via Internet (either mobile Internet or wifi).
Some implementations additionally download a small amount of the server’s database to the phone (describing a small area around the phone’s current position) so that the phone doesn’t have to query the Internet all the time. However, once the phone has moved outside of this small area it will need to access the Internet to get correct locations again.
So, basically, without Internet connectivity you can’t (reliably) use network location.