Iphone gps question?

Question

does the little blue ball only show up during driving directions? Or does it show up when it is finding your current location when GPS is in range? Couls someone please explain how this whole gps thing works

Answer 1

The GPS ball shows you where you are at the moment. Saddly, at the moment the iPhone doesn't give voice directions.

The way it works is first it shows a big blue circle of your area. Then within the next few seconds it shrinks in on your exact location and the ball shows up right where you are.

Answer 2

The blue dot shows up when the device is reasonable certain that it has pinpointed your location. This happens more frequently when you are moving at a decent speed because the software has more data to go on (that is, multiple positions over a span of time).

GPS works on the principle of triangulation to determine location so there is some room for error. When you are standing in one spot it can only approximate your position to within a certain degree of accuracy which is why you see the big circle and not a dot (sometimes). As with all GPS devices, the more satellites it can acquire a signal with, the more accurate the location reading.

On top of all this, you might've noticed that even when driving the little dot goes off the road or isn't exactly pinpointing you. This is mainly due to the software component. Dedicated in-car GPS units make certain logical deductions based on a few assumptions in order to increase the perception of pinpoint accuracy. For instance, the program assumes that you are in your car and driving, so unless you are way off the road the little navigation arrow will stay within the lines. The iPhone's navigation logic isn't quite as sophisticated.

Hopefully a third party will be able to release an iPhone app that will provide turn-by-turn navigation. TomTom is rumoured to have a working navigation system working on the iPhone but isn't able to release it in the App Store due to apple's SDK licensing limitations. It is also unclear whether the GPS related hardware in the iPhone is truly up to the task.

Well, that's the skinny on iPhone GPS as far as I know it. Hope that makes sense for you. Cheers.