No Assisted GPS
Troubleshooting S60 3rd Edition, S60 5th EditionQ. I'm having problems with the GPS on my Nokia smartphone - sometimes it will lock in a few seconds and other times, usually while driving, it can take tens of minutes. What's wrong? The only oddity is that I don't have a SIM card in it - I have a cheap throw-it-around phone and use the phone as a PDA, Wi-Fi Internet appliance, music player and camera. And sat-nav - when it's working!
A. Your problems are indeed caused by this oddity. All current GPS-toting smartphones have what's called 'Assisted GPS', in which the current positions of the satellites is downloaded, using a 3G or GPRS data session, from an Internet server (only a few kilobytes of data) as a 'crib' to speed up the process of locking on to the GPS satellites. With no data plan, your Nokia can't grab the crib and, as a result, has to work out where the satellites are the hard (and slow) way.
When you haven't moved from your most recent position the lock can still be quite fast, but move a few tens of miles across the Earth's surface or leave it more than a few days since the last GPS session and the satellites' attributes will have changed sufficiently that the 'hunting' process can take a long time. And by asking it to try and find satellites while you yourself are moving at high speed is asking the impossible. If possible, let the phone see the sky while stationary for a while before setting out - you'll see much faster fixes!
(This original text of mine was originally published in Smartphone Essentials magazine and re-purposed here with kind permission)