Several people found that there are some troubles in GPS at their Galaxy S6. Although it just a few people, this problem is quite serious because it could make people confused when their GPS keeps loosing the lock or when their GPS track runs are get lost to somewhere with unclear results.
If this happen to your GPS at Galaxy S6, you can try to change some settings in your phone to make it better.
The simple way to anticipate this kind of problem is to set your GPS in high accuracy. You can set this up by clicking Settings, then choose Location and ensure that it is already turned on then you can set to High Accuracy.
However, this is the setting that naturally set your GPS so that it goes on the right track. If this step is not gives a satisfying result, you can try other options that could be the potential solution as the following explanation.
It is possible that your battery usage could impact GPS that running in your phone. You can check it with looking into Settings, then go to Battery, and choose Power saving mode.
Other option is there some applications in your phone that use GPS and you need to clear the caches of those apps. Please look into Settings, then go to Application Manager, and choose Clear cache.
If these steps are not useful, you can try a factory reset. You can do it after you back up everything in your phone and go to Settings, then go to Back up & Reset, Reset Device and choose Erase Everything.
Because there may be a hardware or software malfunction as the cause of this problem, you can ensure it with installing GPS Test app and see the result. If it not picking up the same satellites as other phone that also uses GPS, it may be a hardware malfunction and you can ask a replacement to Samsung or the retailer.