EASA ATPL062 radio-navigation foundations key terms

A direction extending from a VOR station in its declared reference system, distinguished from the aircraft’s heading or a selected inbound course.

A direction measured relative to the aircraft’s nose on the specified instrument, requiring the heading reference for conversion to an absolute bearing.

A magnetic bearing to a station in the relevant radiotelephony/navigation context, distinguished from the reciprocal bearing from that station.

The direct spatial distance between aircraft and facility, including vertical separation rather than only horizontal distance across the ground.

The lateral-guidance component of an ILS, whose displayed deviation and published use must be distinguished from the separate glide-path signal.

Vertical approach guidance from the specified system, distinguished from a universal permission to descend whenever any similar indication appears.

Rapid fluctuation of a received bearing indication associated with reflected-signal effects, requiring distinction from an actual commanded turn or steadily changing track.

An apparent satellite range measurement containing clock-related and other error components, not yet the final corrected geometric aircraft-to-satellite distance.

A measure of how satellite geometry affects position-solution sensitivity, rather than a guarantee that every signal error is absent.

Receiver Autonomous Integrity Monitoring, whose available function depends on measurements, geometry, algorithm and applicable aiding rather than merely displaying coordinates.

The capability to identify and remove an unacceptable input while maintaining the required solution, distinguished from detecting a fault alone.

A satellite-based augmentation system providing its defined corrections and integrity information, distinguished from a conventional ground localizer or an aircraft-only algorithm.

A ground-based augmentation system using local reference information and the defined broadcast service, distinguished from a worldwide satellite-constellation name.

Required Navigation Performance in the PBN framework, including onboard performance monitoring and alerting requirements in addition to the specified navigation performance.

The spatial length of one cycle of a wave, calculated from propagation speed divided by frequency in the stated physical model.

A surveillance method using reflected transmitted energy to detect targets, distinguished from requiring each aircraft to send a transponder reply.

A surveillance method involving airborne transponder replies to interrogations, with information depending on the actual mode and installation.

A selective-addressing transponder capability with defined data functions, whose name alone does not establish every position-source or altitude-resolution property.

Reduction in signal strength through the propagation path, which can hide targets behind heavy precipitation rather than establish clear air.

The range over which a simple pulse-timing system can associate an echo with its transmitting pulse under the stated repetition model.