Aeronautica

Glossary

Above ground level (AGL).

Distance of the aircraft above the ground Synonyms: radar altitude;

Above sea level (ASL).

Distance of the aircraft above mean sea level

Absolute.

A standard, fixed reference, as opposed to moving reference; Compare: relative;

Acceleration.

Rate of change of velocity, either scalar or vector, often with subscripts such as ENU or XYZ to denote the coordinate frame; time derivative of velocity; time integral of jerk; Symbols: a, A; Typical Units: ft/s-squared, g; Dimensions: Length / Time-squared;

Acceleration east.

Aircraft acceleration in true east direction; Symbols: A sub E; Typical Units: ft/s-squared; Dimensions: Length / Time-squared;

Acceleration north.

Aircraft acceleration in true north direction; Symbols: A sub N; Typical Units: ft/s-squared; Dimensions: Length / Time-squared;

Accelerometer.

An inertial device for measuring acceleration, usually in three orthogonal axes (lateral X, longitudinal Y, and vertical Z); accelerometers usually consist of a mass, spring, and damper; accelerometers are usually included in inertial sensors, such as AHRS and INS;

Accept.

To allow to proceed, for example with a position update, usually by an operator; Compare: reject

Accuracy.

Measure of exactness, possibly expressed in percent; Compare: precision

Acquire.

To begin reception of useful data

Activate.

To begin performing a mission objective, such as flying along a radial of a radio station; usually refers to a mode of radio navigation, such flying along that radial after capturing that radial; See Also: capture criterion; Compare: arm, capture;

ADC.

Air data computer

ADDR.

Air data dead reckoning

ADF.

Automatic Direction Finding

Advisory.

A signal to indicate safe or normal configuration, condition of performance, operation of essential equipment, or to attract attention and impart information for routine action purposes (from MIL-STD-1472D); an