Hi Greg,
By chance are you using iFly GPS with a Dual or Bad Elf Bluetooth GPS receiver. Also, have you recently updated to iOS 8.3, there is a major Apple OS bug that does not pass location data from the external Bluetooth GPS to the Apps.
If not, your location services probably got turned off during an update. Try touching Settings from your home page, then touch Privacy -> Location Services and then make sure they are "On" and that iFly GPS is set to "Always". This should resolve your issue. Have a great day!