The Location Service Extension unfortunately may not work as you intend. Read HOW TO: use LocationService extension with a GoogleSpreadsheet to record real time locations while the app is in the background . It collects data in real time; however it will not report it to your device until the device later awakes when it will provide the data collected while the device is asleep.
Taifun does provide a free example showing how the LSExtension works; however, yes as mentioned, it is a paid extension. You could try it to see if it meets your requirements.
As an alternative to working in the Background, use the LocationSensor in conjunction with a StayAwake routine. How to do that is discussed briefly at the conclusion of the above tutorial. The alternative solution provides constant location information using StayAwake and it does allow constant use of the gps receiver to report data. Until someone provides a way to use the Background extension, you might try that.