Global Navigation System and PNT
What is it? The FAA Global Navigation System is a Positioning, Navigation and Timing service for airplanes equipped to use the satellite service.
The FAA plans to provide PNT services to improve the accuracy, availability and trustworthiness to support all-weather use of GPS as the primary means of navigation for both IFR and VFR flight.
The basic principles of air navigation are identical to general navigation which includes planning, recording and controlling the movement of a craft from one place to another.
For our environment, airspace, successful navigation air navigation involves piloting a plane from place to place without getting lost, breaking laws that apply to aircraft or endangering the safety of those on board or on the ground.
Air navigation differs on several important points from surface navigation.
- Planes travel at relatively high speeds which leaves less time to calculate their position en-route.
- Planes cannot just stop in midair for a few minutes to take the time to recheck their position. Surface vehicles can take the time to recheck carefully.
- Planes have limited fuel and, if they run out of fuel it can be disastrous. Not so with surface vehicles, like cars, where, if they run out of fuel they can just sit by the road for help.
- Pilots must have a constant navigational position that is critical to their safety and those of their passengers.
The techniques used for navigation by pilots depends on whether the the plane is flying under Visual Flight Rules (VFR) or Instrument Flight Rules (IFR).
In IFR rules the the plane navigates using instruments and radio navigations devices like beacons or under the direct supervision of and control by air traffic controllers.
