A. System FunctionThe VHF Omni-Direction Range (VOR)/Instrument Landing Ssytem (ILS)/marker system (VOR/ILS/marker system) is a navigation and landing aid. The VOR/ILS/marker system gives data about the position of the aircraft in relation to the ground navigation and landing aids.
B. System ComponentsThere are two VOR/ILS/marker sub-system. The primary components of the No.1 (No.2) VOR/ILS/marker system are the:
- No.1 (No.2) integrated navigation unit (Nav Unit) (Ref. Fig. 1)
- Two VOR/LOC antenna with an antenna coupler (each system uses two antennas amd the coupler) (Ref. Fig. 1)
- Marker beacon antenna with an antenna coupler (each system uses the antenna and the coupler) (Ref. Fig. 2)
- Glideslope antenna (each system uses one antenna). (Ref. Fig. 2)
C. System OperationThe VOR/ILS/marker system receives Radio Frequency (RF) signals from the VOR, the ILS (glideslope and localizer) and the marker ground radio. The VOR/ILS/marker systemgets the data from the RF signals. The data is the:
- VOR angular direction (bearing) from the set ground radio transmitter (ground station)
- Audio identification of the set ground station
- Vertical postion of the aircraft , in relation to the centerline of the runway glideslope beam
- Horizontal position of the aircraft, in relation to the centerline of the runway localizer beam
- Location of the aircraft above the outer, the center (middle) and the inner marker ground radio transmitters (beacons)