This topic contains only those PANS-AIM requirements relevant for a DME. For general PANS-AIM requirements valid for all kind of Radio navigation aids see topic Navaid [NAV] and subordinated pages.
A DME (Distance Measuring Equipment) is Ultra High Frequency (UHF) ground equipment that is used in conjunction with airborne equipment to determine distance between the airborne and ground equipment.
For a DME, PANS-AIM requires some specific properties as part of the minimum AIP data set. These are
...channel, ...elevation,...
Also PANS-AIM ENR 4.1 states as requirement
elevation of the transmitting antenna of DME to the nearest 30 m (100 ft);
PANS-AIM issue
In PANS-AIM Appendix 1 the accurcy depend on the type of DME, for DME/P it is 3 meters.
The diagram below shows the AIXM classes, including the relevant data types, needed to encode that information The main class is the DME which is a specialisation of the NavaidEquipment.
DME Channel
The channel of the DME is coded using the DME.channel attribute.
In case a DME is collocated with a VOR, certain requirements have to be takein into account regarding the frequency pairing. The DME operating channel shall be paired with the VHF channel and/or MLS angle frequency as given in ICAO Annex 10, chapter 3, Table A.
DME type
PANS-AIM does not require the type of the DME to be provided. However, PANS-AIM requires different accuracy values for the elevation of a DME depending on its type. As elevation for the DME i spart of the minimum AIP data set the type has to be known. In AIXM the tye is coded using the DME.type attribute. The typr defines the particular spectrum characteristics or accuracy of the DME. The list of values for the CodeDMEType class contains:
| Value | Description |
|---|---|
| 'NARROW' | DME/N, narrow spectrum characteristics. |
| 'PRECISION' | DME/P, improved accuracy compared to DME/N |
| 'WIDE' | DME/W, wide spectrum characteristics. |
| 'OTHER' | Other. |
Elevation
PANS-AIM requires for the DME an elevation to be coded. The DME.location will be coded with the ElevatedPoint.elevation attribute used.
Note
Depending on the type of DME different accuracy is required. In AIXM the ElevatedPoint.verticalAccuracy attribute is provided for that purpose. (According PANS-AIM Appendix 1, Table A1-5, for DME.type equal-to 'PRECISION' 3m accuracy is required for all other types it is 30m (100ft)).
Navaid Component
VOR/DME
A DME may be co-located with VOR. Such a VOR/DME will be coded as a Navaid with two correspondning NavaidEquipment instances, a VOR and a DME.
For both NavaidEquipment the NavaidComponent.collocationGroup will be equal-to '1'.
If the VOR is the navigable location of the navaid when the navaid is used as significant point:
the NavaidComponent.providesNavigableLocation for the VOR will be equal-to 'YES' and the NavaidComponent.providesNavigableLocation for the DME will be equal-to 'NO'.
The VOR provides the bearing information, whereas the DME is used for the distance information.
Coding Rules
TBD
Coding Examples
See topic Navaid [NAV].