Title: How Pilots Use Air Navigation to Fly
Headings: 
How Pilots Use Air Navigation to Fly
Dead Reckoning and Pilotage
Radio Navigation Methods for Aircraft
Automatic Direction Finder and Nondirectional Radio Beacon
VHF Omnidirectional Range (VOR)
Distance Measuring Equipment (DME)
Instrument Landing System (ILS)
GPS Navigation
How Pilots Use NAVAIDS

Content: A single DME station can handle up to 100 aircraft at one time, and they usually co-exist with VOR ground stations. Instrument Landing System (ILS)
An instrument landing system (ILS) is an instrument approach system used to guide aircraft down to the runway from the approach phase of flight. It uses both horizontal and vertical radio signals emitted from a point along the runway. These signals intercept to give the pilot precise location information in the form of a glideslope—a constant-angle, stabilized descent path all the way down to the approach end of the runway. ILS systems are widely in use today as one of the most accurate approach systems available. GPS Navigation
The global positioning system has become the most valuable method of navigation in the modern aviation world. GPS has proven to be tremendously reliable and precise and is probably the most common NAVAID in use today. The global positioning system uses 24 U.S. Department of Defense satellites to provide precise location data, such as aircraft position, track, and speed to pilots. The GPS system uses triangulation to determine the aircraft's exact position over the earth. To be accurate, a GPS system must have the ability to gather data from at least three satellites for 2-D positioning, and four satellites for 3-D positioning.