Purpose and Scope

These pages contain the AIXM coding guidelines for the minimum and conditional data items of the AIP data set for the Radio navigation aid subject as defined in PANS-AIM.

AIP context

In an AIP, corresponding Radio navigation aid information may be published in the following sections:

GEN 2.5 List of radio navigation aids
ENR 4.1 Radio navigation aids — en-route
AD 2.19/AD 3.18 Radio navigation and landing aids

AIXM Model Overview

The figure below shows the main AIXM 5 classes used for the navaid concept.

In AIXM 5, a Navaid is composed of one or more NavaidEquipment.

To describe a physical navaid equipment in AIXM 5, the NavaidEquipment class is used. This class is specialised into: Azimuth, DME, DirectionFinder, Elevation, Glidepath, Localizer, MarkerBeacon, NDB, SDF, TACAN, VOR.

Some examples:

A Navaid may be a NDB which will be composed of just one NavaidEquipment, viz. a NDB.

A Navaid may be a VOR/DME which will be composed of two NavaidEquipment, viz. a VOR and a DME.

A Navaid may be an ILS which will be composed of several NavaidEquipment, e.g. a Localizer, a Glidepath and one or more MarkerBeacon or a DME.

The relationship between the NavaidEquipment may be further described by using the NavaidComponent class.

The Navaid class carries the attributes that are common for the composition of the whole navaid. These are some basic data such as the type of the navaid, its designator and name.

In addition, also related to Navaid class are the servedAirport if any, and the availability of the Navaid defined by one or more Timesheet (see Common coding patterns for details).

A Navaid may be used a SignificantPoint, e.g. for the start or end point of a route or terminal procedure or the centre point of a TAA/MSA, etc.

Each NavaidEquipment will have a location defined by the Point class. For certain NavaidEquipment an elevation has to be defined. In this case, the ElevatedPoint class has to be used (e.g. for DME).

This location of each of the NavaidEquipment of a Navaid may be the same (e.g. for a VOR/DME or a NDB collocated with a DME), or different (e.g. for a VOR/DME or the components of an ILS).

Also, the Navaid class itself may have a location. This is the location used when the navaid acts as a significant point (see also SignificantPoint (Overview)). This location is usually the location of one of the navaid equipments (e.g. in case of a VOR/DME it will be in general the location of the VOR).

The NavaidEquipment may also have a designator and a name, which in general will be the same as the one of the Navaid.

In addition, each NavaidEquipment may have a magneticVariation defined. Only VOR and TACAN have also a declination, i.e. the angular difference between True North and the station declination (Magnetic North - as indicated by the station).

Some NavaidEquipment have a frequency (e.g. VOR or NDB), whereas others have a channel defined (e.g. TACAN or DME).

Some NavaidEquipment have a defined magneticBearing and/or trueBearing (e.g. the measured angle between the localizer beam and Magnetic/True North at the localizer antenna).

Only the VOR has also a zeroBearingDirection, a code indicating the direction of the 'zero bearing' provided by the station. For example: magnetic north, true north.

The Navaid class is also used to code landing systems (e.g. ILS, Localizer only, MLS). It will be comopsed of the corresponding instances of NavaidEquipment, e.g. Localizer, Glidepath, MarkerBeacon, DME, etc.). Finally, the Navaid and not its individual components isInstalledAt a RunwayDirection.

A NavaidEquipment isUnderResponsibilityOf an OrganisationAuthority.

AIXM 5.2 Improvements

A change proposal (AIXM-402) for the next AIXM 5.2 version has been approved by the AIXM Change Control Board, which allows the addition of ICAO country code as an attribute.

The coding guidelines provided here are aligned with forward/backward conversion rules contained in the AIXM-402 Change Proposal.

AIXM 5.2 Improvements

A change proposal (AIXM-467) for the next AIXM 5.2 version has been approved by the AIXM Change Control Board, in which additional classes, associations and data types are added in the model representing elements of the GNSS.

The coding guidelines provided here are aligned with forward/backward conversion rules contained in the AIXM-467 Change Proposal.

Coding Example

The figure below shows a simple example of a collocated "VOR/DME" with the designator "BOZ" and the name "BERG-OP-ZEE".

It consists of two navaid equipments, a VOR and a DME. Both have the designator "BOZ".

Both have the same defined magnetic variation and are operational H24.

The VOR and the DME are located at the same position. Only the DME has a defined elevation of "30 meters".

Also, the Navaid has a location which, as there is no dislocation, is the same as the one for the navaid equipments.

The VOR does have a frequency, whereas for the DME a corresponding channel is defined.

The VOR in addition has a defined declination.

Also, the Coverage of the VOR and/or DME may be provided (note that this information is not required for the minimum/conditional AIP data set).

The figures below show the AIXM 5.1 encoding of some of the data described above.

The figure below shows the encoding of one of the referenced navaidEquipment of the figure above, viz. the VOR "DON"

The location is the same as for the Navaid.

Coding examples can also be found in the AIP Data Set - Specimen (DONLON):

No.

Description

XPath Expression

NAV-EX-01

VOR-EX-01

DME-EX-01

VOR/DME (incl. served aerodrome)

//aixm:NavaidTimeSlice [@gml:id ='NAV_BOR'] |

//aixm:VORTimeSlice [@gml:id ='VOR_BOR'] |

//aixm:DMETimeSlice [@gml:id ='DME_BOR']

NAV-EX-02

VOR-EX-02

VOR

//aixm:NavaidTimeSlice [@gml:id ='NAV_EKO'] |

//aixm:VORTimeSlice [@gml:id ='NAV_EKO']

NAV-EX-03

NDB-EX-01

NDB (enroute)

//aixm:NavaidTimeSlice [@gml:id ='NAV_NDB_DON'] |

//aixm:NDBTimeSlice [@gml:id ='NDB_DON']

NAV-EX-04

NDB-EX-02

NDB (Locator)

//aixm:NavaidTimeSlice [@gml:id ='NAV_KL'] |

//aixm:NDBTimeSlice [@gml:id ='NDB_KL']

NAV-EX-05

NDB-EX-03

MKR-EX-01

NDB collocated with Marker Beacon

//aixm:NavaidTimeSlice [@gml:id ='NAV_SCN'] |

//aixm:NDBTimeSlice [@gml:id ='NDB_SCN'] |

//aixm:MarkerBeaconTimeSlice [@gml:id ='MKR_SCN']

NAV-EX-06

LLZ-EX-01

GPT-EX-01

NDB-EX-02

MKR-EX-02

MKR-EX-03

ILS with MM and LOM

//aixm:NavaidTimeSlice [@gml:id ='NAV_OXS'] |

//aixm:LocalizerTimeSlice [@gml:id ='LLZ_OXS'] |

//aixm:GlidepathTimeSlice [@gml:id ='GPT_OXS'] |

//aixm:NDBTimeSlice [@gml:id ='NDB_KL'] |

//aixm:MarkerBeaconTimeSlice [@gml:id ='MKR_OM27R'] |

//aixm:MarkerBeaconTimeSlice [@gml:id ='MKR_MM27R']

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