But, just because they are turned on doesn't mean it always accessing something.
Only items with a gray or purple arrow have been accessed recently or within the last 24 hours.
Settings> privacy> location services> system services
Look at the ones with the grey arrow next to them. These are what drain your battery be it the cloud based traffic mapping to the location based iAds. These do not show the GPS icon unless you tell them to so you never realise there firing up the GPS chip.