[Galaxy S I9000 Q&A, Help & Troubleshooting] andrewluecke:
Ignore Damian. Listening to his GPS expertise actually makes you dumber, because it's always wrong (he is an anti-scientist). I think he mean "it seems I (Damian) does not understand how GPS works".

Every opinion does matter, but your unwillingness to actually learn about the topic you claim you are an expert on, has finally gotten to me, and I'm reporting you. You are hindering useful conversations, and whilst I accept disrespect can happen occasionally, we don't need jerks who are littering the forum with incorrect information.

Ignore what DamianGTO said. Quicker locking might be perception for starters. Some Car nav apps start polling the GPS as they are booting (and some I've tried take a while to load). It might also be that some car navigation applications have been tweaked to select the optimum minimum accuracy dynamically. This wouldn't be possible in My Tracks, and if it does happen, it might not be in Google Navigation (this is simply speculation though). In an area where there are no other roads for 50m for instance, you only need an accuracy of 50m to place you on the road in an accurate enough place. When you look at the map it will seem mostly accuracy, but the GPS chip itself might be saying you are actually 24m to the side of the road.

No GPS can lock immediately, so something else must be going on. Even SiftStar 3's take 6 seconds or so to lock on hot start. It may also be that Google maps/mytrack are using more location sources, and some are causing issues. Remember, they all use the same API. When I tried Google maps though, I locked immediately too, probably because it was a warm/hot start (and had recently been used). Remember, GPS has 3 locking modes, hot, warm and cold start. More information is available on: http://www.gsmarena.com/glossary.php3?term=gps . All GPS receivers are affected by this, and all programs.

They are possibly using wireless networks/skyhook too as a location provider, whilst others might not (all android apps use the same location api to interact with the hardware actually). Turn it off in GPS settings, and I wouldn't expect this to be a problem.

Google might have reasons for using it if it's available in Google Maps at least. It might also be that some mobiles use mobile networks for tracking better than ours, and do use them in a way that provides much more accurate results. Summary of this though, is turn use wireless networks off!

For starters, SNR of 40 was probably taken in a field with very few trees around, on a good day without moving. But those values are possibly meaningless anyway. Plenty of us know for instance that the accuracy values can be incorrect.

Secondly, My tracks and other raw GPS tools will show the real track your GPS is producing. On sparse roads, clever algorithms can cover for poor GPS. Whilst commercial apps often do better, and Google nav might be a bit quick to put you on a side street, that's an algorithmic problem with the app. On dense roads or roads with forks, the GPS could be better. We also don't really know the refresh rate either, and that can cause issues.

I haven't really seen much proof the cause is because of your theory though. And I kind of wish you'd stop pretending as though all your guesses are fact.

Anyway, in summary, the GPS is ok for navigation, but isn't really fitness grade. Navigation apps allow a huge range of errors, and whilst I agree the offline apps seem to have better, in dense areas, many have encountered serious navigation issues, and at least in my case, it isn't accurate enough for jogging I feel.