Can someone explain how the android GPS Navigation works?
The Galaxy Player 5 specs straight from Samsung indicate that the device has a receiver for standard GPS satellite signals, which is sufficient for navigation.

Cellular triangulation and WiFi location are examples of Assisted GPS or aGPS. As its name implies it is a supplementary system designed to speed up location finding, because  because it can take time to lock onto GPS satellites, and locking onto enough to be reliable is not always possible.