Give this app a try, it contains lots of useful comments and console log messages. However, use Cordova 0.3.10 version of the geo plugin instead of the XDK geo plugin. The XDK buttons on the sample app will not work in a built app because the XDK geo plugin is not included. However, they will partially work in the Emulator and Debug. Test it on a real device, without the XDK geo plugin selected, and you should be able to see what is working and what is not on your devices. There is a problem with the XDK geo plugin. It cannot be used in the same build with the Cordova geo plugin. Do not use the XDK geo plugin, it will be discontinued.
Geo fine might not work because it is possible that your device does not have a GPS chip or it is taking a long time to get a GPS lock (if you are indoors) or the GPS on your device has been disabled in the settings.
Geo coarse is the safest bet to get an initial reading, quickly; it will get a reading based on a variety of inputs, but is usually not as accurate as geo fine but generally more than accurate enough to know what town you are located in and your approximate location in that town. Geo coarse will also prime the geo cache so there is something to read when you try to get a geo fine reading. Prep your code to handle situation where you might not be getting any geo data as there is no guarantee you'll be able to get a geo fine reading at all or in a reasonable period of time. Success with geo fine is highly dependent on a lot of parameters that are typically outside of your control.
