Plain English Meaning

Learning how your particular GPS unit works -- which buttons to press, how to load a route, and how it behaves -- so you can use it confidently in the air rather than figuring it out on the way.

Full Definition

The process by which a pilot becomes proficient with a specific GPS receiver before using it for navigation in flight, including learning its controls, display pages, data entry methods, flight plan handling, and approach procedures as documented in the manufacturer's operating manual and any aircraft-specific supplement.