Originally Posted by
peterh337
Does the app need a "GPS library"? It should merely need to call the IOS API. But maybe for a bluetooth GPS it can communicate with it directly. The Dual GPS app which shows the satellite constellation is obviously not talking to it via the API because that info is blocked by Apple.
On the plus side, the Dual GPS is doing a good battery life - I am at 15hrs now and it is showing 30% left.
As per my previous post, my understanding is if an app uses the iOS API, it has no way of telling which GPS device, if any, is connected. It also has no way of knowing whether the device has a signal (other than by looking at the horizontal accuracy and time of the most recent "fix"). The API could be reporting a cellular triangulation fix, accurate to maybe a mile, it could be reporting using the internal GPS or it could be reporting using an external GPS. It hides all of this from the developer. Its designed for one off location queries from shopping apps - not navigation.
To get more detailed, and controllable information (such as being able to select a GPS device), a developer has to use code libraries from else where or write the code himself to communicate to the GPS (internal or external) devices.