1. Navaids and Points

2. NavaidEquipment
NavaidEquipment has operational hours indicated by the the top relationship “workingBy”. The bottom relationship “unmonitoredBy” gives the hours the equipment is not monitored.

3. Navaid System/Service
This diagram shows the separation between the physical equipment and the Navigational System/Service. For example, an ILS is an Instrument Landing System composed of several pieces of equipment that together provides a vertical and lateral guidance service. The ILS can consist of a localizer, a glideslope antenna, distance measuring equipment and markers.
NavaidComposition provides the use of the navaid equipment within the navaid system/service. collocatedGroup indicates Set of navaid equipment that are collocated. All Navaid equipment that has the same value for this property are collocated together. For example an ILS might have a Glidepath with collocation Group number = 1 and collocated DME and localizer sharing collocationGroup number = 2. markerPostion indicates the position of the markers situated on the centerline of a runway. For example: outer, middle, etc.. The last element indicates the navaid equipment used to specify the navigable location of the Navaid when the navaid is used as significant point.

4. NavaidLimitations
The usage limitations associated with the frequency of a navaid are modeled using sectors of circle. The same concept may apply for the Frequency class, which is associated with a service, and which is shown here for completeness.
Radio Frequency Limitation feature is used to model all usages; service limitations as well as standard service coverage and extended coverage.

5. Significant Points
A "significant point" is a choice between a navaid and a designated point. A DesignatedPoint is a named geographical location not marked by the site of a radio navigation aid, used in defining an ATS route, the flight path of an aircraft or for other navigation or ATS purposes.

6. Point Reference
Defines the location of a point using a combination of angles and distances from a significant point (navaid or from another designated point).

7. Segment Point
Significant Points used for the definition of a route segment or terminal procedure are first modeled as "SegmentPoints". This enables the association with an optional PointLocation and the specification of attributes that are common to both en-route points and terminal points.

8. Segment Points 2. References 3. SegmentPoint Significant Point
(Designated Point)
Name = WABAK
Type = ICAO
3. SegmentPoint
Fly over
Not a WayPoint
No Radar available
A significant point is defined by ICAO as "a specified geographical location used to define an ATS route, the flight path of an aircraft or for other navigation/ATS purposes".
A point on a procedure can be a named point such as a navaid or fix or it can be described by one or more distance(s) and/or radial(s) from a ground point.
An example of a Waypoint (a point used during satellite navigation guided by lat/long) is Funny WP or WACKO WP. This point is not described any further. A couple of examples of points that are named but reference ground objects are TULLU / 5.6 DME from ABC Vortac or SMITH INT
2. References
Uses ODK VORTAC
Angle Indication 010
Distance Indication 10

9. Questions?