Why Android LocationManager has long delay before location updates start if setting accuracy

Question

If I set any ACCURACY to criteria, it takes long time to LocationManager to start updating location:

Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
provider = locationManager.getBestProvider(criteria, true);
locationManager.requestLocationUpdates(provider, 0, 0, this);

If I remove ACCURACY flag, it starts immediately but sometimes not accurate.

How can I make it start updating immediately and with good accuracy?

Answer 1

Unfortunately, no way.

If you use ACCURACY_FINE, you will use GPS only, but GPS have "cold start" effect. It means that if you device not used GPS long time, it needs a lot of time for connecting with satellites and download almanac and ephemeris. You can't change this behavior.

If you don't use ACCURACY_FINE, you will use both GPS and network (mobile, wi-fi) signals. So you will receive quick first position from network, because they don't have "cold start" effect, but accuracy of this method is low. When your GPS module will ready, you will start receive updates from it too.

Answer 2

If you care only about accuracy and not things like bearing or altitude I suggest switching to the new fused provider in the LocationClient API from Google.

It is very quick to get the first fix, more accurate than network based and doesn't depend on GPS.

It requires a bit more setup then the built-in LocationManager, so you may read this training article: http://developer.android.com/training/location/receive-location-updates.html

Answer 3

I suspect that at least with ACCURACY_FINE, it's waiting to get an initial GPS fix. You may find that if you've already got GPS turned on for another reason (e.g. if you're in the middle of navigation) that it starts reporting immediately.

It can take a while to get a GPS fix - I think it's just a natural part of how GPS works.