I have a simple app that should return my current GPS location, code below, essentially based on the tutorial provided by Embarcadero. When executed, the GPS icon of my Samsung does not display and the location returned is generally 100m off true location.
Delphi Xe5 Serial Communication Arduino. MarshallSoft Delphi serial communication component library. Serial comunication arduino simulink Search and. Heimdall One-click Unbrick.
I've experimented with various valued for 'Accuracy' and tried setting 'Accuracy' both before and after setting the object to active - no change in behaviour. Other apps that I've obtained, including 'maps' which comes with the Galaxy, show the GPS icon when in use and return correct positioning. With the GPS icon not display, I'm assuming that the app is not using GPS - how do I instruct it to do so?
When you request a location, you don't have real guarantees that GPS will be used. When not enough satellites are in direct view, your phone will fall back to other methods to return a position. It can use nearby WiFi hotspots to find out where you are, or it can use GSM towers to determine your location, which of course won't be as accurate as GPS. Try to place your phone near to the window, or go outside, and retry. Make sure to have a clear view to the sky, so don't stand under a tree or between high buildings. Also, if you didn't use GPS for a while, it can take up to 15 minutes before your phone has updated information about the position of satellites (it's broadcasted by the satellies, but it's slow). If you have a data connection, your phone can download that information via the internet, which can speed up your cold start, and you'll get a position fix faster.
Thanks for your input Wouter. In this case I've tried using the app outside but I'm absolutely sure it is not trying to access GPS. I have used other apps (both indoors and outside) and when they access GPS the icon on the phone status bar displays - it flashes while it establishes an initial fix. With the Delphi location service it is not trying to access the GPS provider at all - the icon does not appear or flash. I'm sure there must be some setting that specifies to the service to use the GPS provider, just need to find it.
In the help text, it states that if you set Optimise to false, it will not try to use the other location finders. It also states that it can prang out if you try to change Optimise in your programme rather than setting it up as an initial parameter.
And heaps of other stuff which only works in Windows (WHAT GPS in Windows?) and IOS. At the moment I wait until f:= LocationSensor1.Sensor.Latitude * 1.0 stops producing an exception, (it gives you NANs initially), then wait for 20 GPS OnLocationChanged events before accessing any GPS data. Not wonderful, but works not too badly for me.