3 ms·

I have similar experience on the iPhone 3GS right after I start some GPS-using application (like TomTom). It is sometimes really terrible in the first 10-15 min

I have similar experience on the iPhone 3GS right after I start some GPS-using application (like TomTom). It is sometimes really terrible in the first 10-15 minutes. Though after that, it becomes quite accurate. Often also earlier. Also it is often better when I start it already when being outside of the car and not when being in the car. I guess that it searches each time for new satellite signals if the last usage of GPS was too long ago.

bigiain 16y ago
That sounds a lot like the time required to acquire the complete almanac from the GPS signals. See the almanac section of: http://en.wikipedia.org/wiki/GPS_signals http://en.wikipedia.org/wiki/GPS_signals If a GPS receiver has no current satellite orbit data, it'll need to listen for 12.5 minutes to determine the current set of satellite orbit information. There's a useful explanation of the various possiblilities of GPS startup (specifically talking about Garmin models and terminology, but more broadly applicable too) here: http://gpsinformation.net/main/warmcold.htm http://gpsinformation.net/main/warmcold.htm