I don't think you need to pay anything to the network provider for the A-GPS capability as it uses Satellite directly. Unless one day Garmin decided to charge us for that.
Anyway, I am using Nokia 5800XM and this problem doesn't arise.
Just use Assisted GPS should be OK.
how does nokia AGPS work? basically, the moment u switch on your AGPS enabled phone's GPS, your phone will collect your current cellular broadcasting station's unique ID, and send it to Nokia's server (you can see it defined on your 5800xm menu->settings->Phone->Application Sett.->Positioning->Positioning Server, it is defined as supl.nokia.com. However, if your Access Point is not defined, OR you did not set the GPRS/3G/EDGE/3.5G settings properly, then AGPS jst simply dont function and normal GPS will take effect.)
The server then checks with its database, on the strongest satelites covering your cell broadcast tower, and sends it to your phone.
Your phone's GPS will then attempt to connect to those satelites. Result: GPS lock in less than 3 secs, and data charges of 7kb each time you use your AGPS.
to comfirm if there is any data transfered, reset your data usage counter, then start up your garmin.. after you get a lock, exit the program and check the counter. you will see 3kb out going and 4kb incoming data transfer..
Copy and paste from Nokia Website: http://europe.nokia.com/A4480068
What is A-GPS?
Assisted GPS (A-GPS) is an enhanced version of GPS. A-GPS retrieves assistance data over a data connection (like GPRS or 3G)
, which helps your device calculate the coordinates of your current location when receiving signals from satellites.
What are the benefits of A-GPS?
A-GPS is designed to get a fix on satellites faster and more reliably, meaning you get a smoother GPS experience. It reduces the time a GPS enabled device requires to find its current position, known as Time To First Fix (TTFF), for most geographical locations worldwide.
A-GPS is most useful in urban areas, where you could be navigating through "urban canyons", or in a moving car.
A-GPS improves user experience for all applications on your device which use integrated GPS.
Are there any extra costs for using A-GPS?You pay your service provider for data transferred over the cellular network.
Please keep in mind that the charges might be higher while roaming.
How do I activate A-GPS?
The first time you use an application that involves GPS (and A-GPS) service, the device will automatically ask for the access point with the question: "Access point is required for secure positioning. Define now?" If you want to enable A-GPS usage, answer "Yes".
If you select "No", you can define the access point later: select Menu > Tools > Settings > General > Positioning > Positioning Methods > Assisted GPS.
Now you only need to define the correct access point. Select your service provider's access point for accessing the internet.
If you want to change the A-GPS access point, go to the main menu > Tools > Settings > General > Positioning
* > Positioning methods - enable/disable positioning methods. If you do not want to use A-GPS (e.g. while roaming) you can disable it from here.
* > Positioning server - change the access point and the positioning server address used for A-GPS (and network based positioning when available).
How do I know if I have A-GPS activated on my device?
Please check following settings from your Nokia device:
Main menu > Tools > Settings > General > Positioning
* > Positioning methods - select assisted GPS.
* > Positioning server > Access point - Select your service provider's access point.
* > Positioning server > Server address - the positioning server address used for A-GPS (default supl.nokia.com)
To confirm that A-GPS is working, open an application that shows the Satellite status such as Nokia Maps: (Menu > Maps > Options > Maps options > Satellite info).
When A-GPS info is received successfully, there should be a list of satellites with very short strength bars visible soon after the Nokia Maps application is opened.