Description

The most important concept in aeronautical frequency management is the “designated operational coverage”, abbreviated as DOC. The DOC of a frequency assignment is the volume of airspace where the use of that frequency is protected from interference from other frequency assignments.

DOCs are expressed as a circle or a polygon with a maximum and a minimum flight level, therefore their geometrical forms are cylinders or prisms.

The frequency planning rules, used to plan new frequency assignments, prescribe the minimum distance between the DOCs of two frequency assignments using the same frequency. This distance is required to ensure protection from interferences.