Warranty Void

With the new 12.0.013 software version for N95, dated 19th of June 2007, Nokia introduces a feature that will boost the poor performance of N95's GPS receiver. The worst thing of N95 GPS has been the slow initial startup, ie. getting the position fix. This is the most demanding phase of GPS receiver's work. Calculating the initial position out of the signal noise can be quite tricky, especially in poor conditions and with limited computation power.

Here comes Assisted GPS, or AGPS for short, to help. It is not the same as Differential GPS, or DGPS, where the receiver gets additional error correction data from another party to improve position accuracy. Assisted GPS enabled receiver takes a quick snapshot what satellites it can hear, sends it to an assistance server and receives a reply from the server with pre-calculated data. The assistance server is far superior calculating the initial GPS fix from the messed up signals. From this, sometimes more and sometimes less, good startup point the receiver is able to acquire position fix much more quickly.

Instead what some bloggers have speculated, AGPS does not use cellphone network based positioning. Hey, you all link to the Wikipedia article, don't you read it at all? So it is completely network independent, as long as the phone has data connection available somehow, for example via WiFi.

In Nokia N95 this is implemented by sending the snapshot and receiving the reply via packet data or WiFi connection. The assistance server address can be defined in GPS settings, and it is predefined as supl.nokia.com. The whole AGPS feature can be enabled or disabled whichever the user best sees. When AGPS is enabled and user starts application which requires GPS position data, N95 initiates a data connection only for couple of seconds, and then seem to continue acquiring the position fix normally, but achieves it much faster. Even inside and between tall buildings. This feature makes the N95 GPS usable.