[XPERIA X1 Q&A, Help & Troubleshooting] JKingDev:
The X1 has been marketed and advertised as having aGPS but thus far it seems no one can get it working. It seems SE no longer maintains a working SUPL aGPS server. The server found in the settings is in the 10.1.x.x IP range which is NOT a real server. It is a private IP (look up network address translation on wikipedia to see what that means). I am tired of 5-10 minute locks sometimes and terrible performance in a city with tall buildings. I am getting ready to visit NYC and this will probably render my GPS useless. When I visited Georgetown which isnt even as dense, the GPS went nuts. Do you think we can do something about this? Does anyone know any public SUPL aGPS servers? Also can someone with a completely stock X1 ROM post the contents of the following reg key:

[HKEY_LOCAL_MACHINE\Software\HTC\SUPL AGPS]

Please post your ROM version if you do. Thanks!

*edit. Please read!*

Ok, let me throw in a little explanation to aid this conversation. A stand alone GPS works by listening to satellite signals and calculating your distance from each satellite it hears. In order for this to work the gps reciever needs to know where in the sky the satellites are. The satellites broadcast what is called ephemeris data that contains this info. This is why your initial lock can take quite some time. If you start listening in the middle of the broadcast you must wait for it to start again. If you loose signal during the broadcast you need to wait for it to start over. Once you have the ephemeris data you can begin working on a fix.

QuickGPS is NOT aGPS. What QuickGPS does is download the ephemeris data from the internet so that you dont need to download it from the satellites. This can speed up your initial lock.

aGPS is another thing entirely. It is not a carrier service. All you need for aGPS is a GPS reciever and an internet connection of ANY kind and an aGPS server to connect to. You could use wifi. Since you have a phone though and you are moving it makes sense to use a cellular connection. In this case your carrier can only charge you for data transfer. Lastly, your carrier may maintain their own aGPS server. aGPS has several functions. First it detects the cell sites you are connected to to get a rought idea of where you are (like google's mylocation feature). Now that you know where you are you know which satellites to look for (since aGPS also does have ephemeris data). Once you start recieving GPS signals, rather than calcutaing a fix yourself you can send the info about the signals to the server which has a much more powerful CPU. It will calculate a fix for you and send you your position.

Another thing. GPS software does not need to be in any way aware of aGPS or QuickGPS. These are both utilities used directly by the GPS reciever itself to help get a fix. GPS programs use a standard API to get position information from the GPS reciever. How the underlying reciever goes about getting that information is of no importance to the GPS program. Wouldnt it kind of suck if every GPS software had to have its own algorithm for calculating a GPS fix from satellite location data? These are not simple calculations (one of the reasons it is nice to have a server doing the calcs for you). This is why there is an API for this.

Hope this clears up misconception and leads to a more informed discussion of the issue. Posted from my X1 with Opera Mobile 9.7 on my way to NY with CorePlayer playing the music and iGo8 navigating running in the background. I love this phone.