1. General. A datalink is a means of transmitting information from one point to another. When the transmission is accomplished using a wireless means, the datalink may also be referred to as a 'radio link' or 'radio modem'.
1. Air data information is a key issue for use onboard aircraft in order to estimate current altitude and airspeed. Such flight parameters may be measured using a variety of different sensors.
1. The Global Positioning System (GPS) system is designed so that from any point on the surface of the planet at least four satellites of the GPS constellation are always visible.
In the very early stages of aviation, control of an aircraft was based purely on visual feedback and sensorial perception: flying ‘by the seat of the pants’. Such instruments as were available in the cockpit were very basic and limited in their capacity. As aircraft complexity has increased, more information and more complex instruments have become available.
Altimeters are devices designed to calculate the height of an aircraft above the surface directly below it. This height may be Above Ground Level (AGL) or Above Sea Level (ASL).
Different types of altimeter use different technologies to calculate this height, including pressure-density to altitude relationship and the propagation and reflection of electromagnetic waves etc.
Navigation is a process involving three steps:
- Establish the track that needs to be followed (i.e. Flight Plan)
- Establish current position relative to the FP
- Execute all necessary guidance actions to correct any deviation in position
There are different types of navigation system: