PANS-AIM ENR 4.1 "Radio navigation aids — en-route" and AD 2.19/AD 3.18 "Radio navigation and landing aids" conatins require for the AIP data set the following a publication requirement regarding the Navaid Coverage:
Facility coverage shall be indicated in the remarks column.
The diagram below shows the AIXM classes, including the relevant data types and code lists, needed to encode that information.
PANS-AIM only requires the facility coverage to be provided as part of the remark. Hence, it is sufficaiant to provide that information as an NavaidEquipment.annotation.
However, AIXM 5 also provides the possibility to code that information in a more structured form.
The RadioFrequencyArea class is used to code any kind of limitations of a navaid equipments or service frequencies, such as coverage, unusability, etc.
In particular, it may be used to code the coverage of a radio naviagtion or landing aid.
The limitation (coverage) is not related to the Navaid but the NavaidEquipment class, as each navaid equipment a navaid is composed of may have a different limitation.
A navaid equipment may have different types of limitations.
The code list of the RadioFrequencyArea.type attribute provides the following values in order to define the type of the navaid limitation.
| 'COV' | Actual coverage range (flight checked). Equivalent to Operational Service Volume. |
| 'T_COV' | Theoretical coverage range (not flight checked). Equivalent to Standard Service Volume. |
| 'SCL' | Scalloping. |
| 'RHG' | Roughness (signal roughness experienced). |
| 'UNREL' | Unreliability. |
| 'RES' | Restricted (use is restricted to defined sectors). |
| 'UUS' | Un-usability (use is not permitted in the defined sectors). |
| 'OUT' | Out of tolerance. |
| 'ESV' | Extended Service Volume (Coverage) |
| 'OTHER' | Other |
For coding the facility coverage RadioFrequencyArea.type equal-to 'COV' will be used.
Altough PANS-AIM only requires the facility coverage to be coded also other limitations may be provided in the scope of an AIP data set.
Subsequently the CircleSector class is used to code the details of the coverage, i.e. describe a 3D pattern based on start angle, stop angle, inner distance, outer distance and upper/lower altitude.
Coding Rules for Facility Coverage
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