>> What's the impact on the battery when doing frequent GPS resolutions?
The answer is battery life varies dependent on phone...
On an iPhone you have to really mess about to improve battery life -
the only way of doing it on older phones is to start playing out audio
(e.g. a playlist) - then you can turn the screen off but still keep
your app alive and capturing GPS.
On my WM6.5 Omnia II, it's easy to keep the app/GPS alive but to save
some power. If I do that and still monitor the GPS, then up to 6 hours
battery life is OK - so pretty good.
On a Bada Wave, there's a SYSTEM_SERVICE level call to make so that
the app can carries on even when the screen is off - locked I can
manage 3-4 hours easy - not tried any longer yet - but suspect 6 is
about the current limit.
On my Nokia 5800, it seems that the Nokia ST app managed 2-3 hours OK
- not tried it any longer.
On Android, it's too early for me to say - but I know that the Google
MyTracks app can manage long sessions - 6 hours+ - although they do
have some sample-rate dropping code to do that - basically it depends
what your activity is:
- if you're walking, then you can probably get away with sampling only
every few minutes
- but if you ever want to do turn-by-turn directions in a car, then
you'll need to up the sampling rate to something much more frequent.