Definition
The angle, measured in the vertical plane, at which a radio wave or signal reaches a receiving antenna relative to the horizontal. It describes the direction from which an incoming signal arrives at the receiver.
Plain English
The angle above the horizon at which a radio signal hits the antenna that's picking it up.
Context Anchor
Seen in radio navigation, direction-finding, antenna, and signal-tracking discussions.
Derivation
Straightforward: the angle at which a signal arrives. The phrase is descriptive, but the key idea worth holding onto is that it's measured vertically — from the horizontal up to the line the signal is travelling along — not horizontally like a bearing.
Why Pilots Care
Provides the bearing to a radio station or beacon, enabling navigation without visual references.
Intuition Check
Do not read “arrival” here as an aircraft landing or reaching a destination. In this term, it means a radio signal reaching a receiving antenna from a certain direction.
Example Sentence 1
At long range from the ground station, the angle of arrival is shallow because the signal is travelling almost level with the horizon.
Example Sentence 2
Comparing the angle of arrival at two ground stations allows the pilot to determine position by triangulation.