Hi, welcome to Android Forums.
There are currently two major satellite systems providing global positioning, GPS has been around a long time and is operated by the US, recently, GLONASS has come on the scene, and is under Russian control.
Your GPS receiver, when switched on, will 'look for' the satellites and will lock on and synchronize to as many as possible. The latest devices are compatible with both systems and my HTC One will pick up satellites from both.
The number of satellites that your device locks to will determine the accuracy of the given location, in good conditions I can lock on to 10 - 12 satellites giving accuracy down to a few metres.
Yes, to make use of your GPS, you need to have one or more apps to display the results, and there are dozens of them available on Google Play Store.
Probably the most popular is Google Maps, although with version 7 that may not be the case!!.
Google maps is free both for mapping and route checking and also for navigation, but the downside is that you need a data connection.
For offline use I have Route66, the app is free to download along with the comprehensive range of maps, and I use it extensively. As with most map apps you can purchase a navigation licence if you so wish.
Because there are so many apps available from basic satellite status display to comprehensive mapping and navigation, I would recommend you join us so you can browse the dedicated threads and read the dozens of contributions about the dozens of apps.
As with so many things, it comes down to personal choice, but the more info you can get, the easier that choice becomes.
Hope this helps
