views:

342

answers:

3

Why is the precision of my location in Mapkit not as good as in the maps app? The accuracy is set to best. If i'm trying to get my location in maps.app i have an acc of 50m in my app i habe 500m. What am i doing wron :)? Any tipps to get a better result?

Thanks for your help :)

A: 

The only thing I can think of, under the assumption that you have looked through all references, is that you test them under different conditions. GPS is very sensitive to obstructions above you, and might even be disturbed by wires etc that are connected (possibly).

Jonatan Hedborg
i've sitting at my desk, starting my app -> accuracy of 500m.Then starting maps.app -> accuracy of 50m.If i use the CLLocationManager the method "didUptateLocation...."is only called twice. I don't really get what wrong here.
rdesign
A: 

Are you testing this outdoors or indoors? The GPS signals are very low power, and the IPhone antenna, being built into the phone, is not optimal.

Also, are you waiting long enough for the GPS to sync up with all the satellites in view. GPS requires time to acquire each of the satellites, and gets more and more accurate as it locks onto more satellites.

Also, if you are simultaneously trying to use a wireless or Bluetooth link while receiving GPS, you could be stepping on the GPS receivers.

Good luck

John R Doner
+1  A: 

For what it's worth, you often have to wait several seconds to get the more accurate fix. A fix with an accuracy of about 500m often comes immediately, based on cell towers or wi-fi. Fixes more accurate than about 100m require GPS, which takes longer to get. So often you will see "didUpdateLocation" happen immediately with a ~500m fix, and then several seconds later with a 50m fix.

If you go back to your app after you get the 50m fix in Maps, what happens? Do you then get a 50m fix? If not, and you've asked for the best accuracy, then I really don't know what's going on.

Incidentally, how do you know that Maps is getting a 50m fix? Just by looking at the map and gauging it by eye?

jasoncrawford