Very likely, the app has some issues.
Battery drain is fast when GPS is always on. However, even for navigation, it should last close to 3 hours. For your case, very likely, the app is trying to track your track. So, the GPS is actually always on. Normally, the GPS will turn off automatically when it is not in use., and therefore, the power consumption by GPS can be very marginal
If you just want to locate your position, you can use many simple location apps.
To save battery on GPS, you may enable Use sensor aiding (settings–location services)