5) VOR, positioning & interceptions FIXED ROSE
As per CIRC FCL 19: LONG BRIEFING 3
1. VOR (VHF OMNI RANGE)
2. AVAILABILITY OF VOR STATIONS EN-ROUTE
3. STATION FREQUENCIES AND IDENTIFICATION
4. SIGNAL RECEPTION RANGE
5. EFFECT OF ALTITUDE
6. VOR RADIALS
7. USE OF OMNI BEARING SELECTOR
8. TO/FROM INDICATOR
9. ORIENTATION
10. SELECTING RADIALS
11. INTERCEPTING A PRE-SELECTED RADIAL
12. ASSESSMENT OF DISTANCE TO INTERCEPTION
13. EFFECTS OF WIND
14. MAINTAINING A RADIAL
15. TRACKING TO/FROM A VOR STATION
16. STATION PASSAGE
17. INTERCEPTIONS
18. VOR OPERATIONAL ERRORS
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 1
, 1. VOR (VHF OMNI-DIRECTIONAL RANGE)
D-VOR
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 2
,Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 3
, VORTAC TGO
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 4
, • VOR = primary NAVAID used by civil aviation in Europe.
• VOR ground station = oriented to magnetic north
• Transmits azimuth information to the aircraft,
• Providing 360 courses TO or FROM the VOR station.
• When DME is installed with the VOR, it is referred to as a VOR/DME and provides both
azimuth and distance information.
• When military tactical air navigation (TACAN) equipment is installed with the VOR, it
is known as a VORTAC and provides both azimuth and distance information.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 5
, VOR is a system that gives accurate bearings with reference to ground-based stations using the principle
of Phase Comparison between two waveforms.
Principle of Operation
• VOR stations transmit a carrier wave that is modulated in A9W.
This is to say that the single carrier wave is both frequency and amplitude modulated at the
same time.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 6
, • By frequency modulating the carrier wave with a simple 30 Hz waveform, the reference signal is
achieved. This signal is so named since all airborne receivers at a given range from the station will
receive a reference signal which is at the same phase, regardless of the aircraft bearing from the
station.
• The VOR station transmits in all directions (omni-directionally),
however the signal strength varies depending on the bearing from the station at a given
point in time.
• The polar diagram for VOR transmitter, which is known as a limacon:
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 7
, • The limacon itself is rotated at the rate of 30 revolutions per second and this has the effect of
amplitude modulating the carrier wave arriving at an airborne receiver. The phase of the
amplitude modulated signal will depend upon the bearing of the airborne receiver from the
ground station. The amplitude modulated is therefore known as the variphase signal.
• At (a), the aircraft to the east of the beacon is receiving a signal of minimum strength, since the
shortest radius of the limacon is facing the aircraft.
• At (b), the amplitude of the signal arriving at the aircraft is of mean value, since the limacon has
rotated through 90°.
• At (c), the signal is at maximum amplitude, the limacon having rotated through a further 90°.
• At (d), the signal is back to a mean value,
• At (e), the signal is at minimum strength, since the limacon has now rotated through one
complete revolution.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 8
, • The phase of the amplitude modulated signal will depend upon the bearing of the airborne
receiver from the ground station. The amplitude modulation is therefore known as the variphase
signal.
• Each airborne receiver is now receiving both a reference and a variphase signal and rotation of
limacon is so arranged that the two signals are in phase to any observer on a magnetic bearing of
360° from VOR beacon.
• The phase difference between reference and variphase signals will now relate directly to the
magnetic bearing of the receiver from the beacon.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 9
, AIP GEN 2.2
HX : Pas d’heures
2. AVAILABILITY OF VOR STATIONS précises de
EN-ROUTE
fonctionnement
• See AIP ENR 4 No specific working hours
o E.g.: GOSLY VOR GSY 115,7
H24 = usable all day long
• Else : check NOTAMS
3. STATION FREQUENCIES AND IDENTIFICATION
• From 108.0 to 117.95 MHz
a. 40 channels : 108.0; 108.05; 108.2; 108.25; 108.4; 108.45 and so on up to 111.8 and
111.85 MHz (EVEN ONLY)
b. 120 channels : 112.0; 112.05; 112.1; 112.15; 112.2 and so on at 0.05 MHz (50 KHz)
spacing to 117.9 and finally 117.95 MHz. (EVEN and ODD)
The reason for the gaps (for example 108.1 and 108.15 MHz) between 108 and 112 MHz is
that the 40 frequencies allocated to the ILS Localiser also lie between 108 and 112 MHz.
(ODD ONLY)
• subject to line-of-sight restrictions
b. Most VORs are equipped for voice transmission on VOR frequency.
VORs without voice capability are indicated by the letter “W ” (without voice) included in the class
designator (VORW).
c. The only positive method of identifying a VOR is by its Morse Code identification or by the
recorded automatic voice identification which is always indicated by use of the word “VOR” following
the range’s name. Reliance on determining the identification of an omni-range should never be placed
on listening to voice transmissions by the Flight Service Station (FSS) (or approach control facility)
involved. Many FSSs remotely operate several omni-ranges with different names. In some cases,
none of the VORs have the name of the “parent” FSS.
During periods of maintenance, the facility may radiate a test code
• T (e) S T : – (•) ••• –
• or the code may be removed.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 10
As per CIRC FCL 19: LONG BRIEFING 3
1. VOR (VHF OMNI RANGE)
2. AVAILABILITY OF VOR STATIONS EN-ROUTE
3. STATION FREQUENCIES AND IDENTIFICATION
4. SIGNAL RECEPTION RANGE
5. EFFECT OF ALTITUDE
6. VOR RADIALS
7. USE OF OMNI BEARING SELECTOR
8. TO/FROM INDICATOR
9. ORIENTATION
10. SELECTING RADIALS
11. INTERCEPTING A PRE-SELECTED RADIAL
12. ASSESSMENT OF DISTANCE TO INTERCEPTION
13. EFFECTS OF WIND
14. MAINTAINING A RADIAL
15. TRACKING TO/FROM A VOR STATION
16. STATION PASSAGE
17. INTERCEPTIONS
18. VOR OPERATIONAL ERRORS
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 1
, 1. VOR (VHF OMNI-DIRECTIONAL RANGE)
D-VOR
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 2
,Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 3
, VORTAC TGO
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 4
, • VOR = primary NAVAID used by civil aviation in Europe.
• VOR ground station = oriented to magnetic north
• Transmits azimuth information to the aircraft,
• Providing 360 courses TO or FROM the VOR station.
• When DME is installed with the VOR, it is referred to as a VOR/DME and provides both
azimuth and distance information.
• When military tactical air navigation (TACAN) equipment is installed with the VOR, it
is known as a VORTAC and provides both azimuth and distance information.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 5
, VOR is a system that gives accurate bearings with reference to ground-based stations using the principle
of Phase Comparison between two waveforms.
Principle of Operation
• VOR stations transmit a carrier wave that is modulated in A9W.
This is to say that the single carrier wave is both frequency and amplitude modulated at the
same time.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 6
, • By frequency modulating the carrier wave with a simple 30 Hz waveform, the reference signal is
achieved. This signal is so named since all airborne receivers at a given range from the station will
receive a reference signal which is at the same phase, regardless of the aircraft bearing from the
station.
• The VOR station transmits in all directions (omni-directionally),
however the signal strength varies depending on the bearing from the station at a given
point in time.
• The polar diagram for VOR transmitter, which is known as a limacon:
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 7
, • The limacon itself is rotated at the rate of 30 revolutions per second and this has the effect of
amplitude modulating the carrier wave arriving at an airborne receiver. The phase of the
amplitude modulated signal will depend upon the bearing of the airborne receiver from the
ground station. The amplitude modulated is therefore known as the variphase signal.
• At (a), the aircraft to the east of the beacon is receiving a signal of minimum strength, since the
shortest radius of the limacon is facing the aircraft.
• At (b), the amplitude of the signal arriving at the aircraft is of mean value, since the limacon has
rotated through 90°.
• At (c), the signal is at maximum amplitude, the limacon having rotated through a further 90°.
• At (d), the signal is back to a mean value,
• At (e), the signal is at minimum strength, since the limacon has now rotated through one
complete revolution.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 8
, • The phase of the amplitude modulated signal will depend upon the bearing of the airborne
receiver from the ground station. The amplitude modulation is therefore known as the variphase
signal.
• Each airborne receiver is now receiving both a reference and a variphase signal and rotation of
limacon is so arranged that the two signals are in phase to any observer on a magnetic bearing of
360° from VOR beacon.
• The phase difference between reference and variphase signals will now relate directly to the
magnetic bearing of the receiver from the beacon.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 9
, AIP GEN 2.2
HX : Pas d’heures
2. AVAILABILITY OF VOR STATIONS précises de
EN-ROUTE
fonctionnement
• See AIP ENR 4 No specific working hours
o E.g.: GOSLY VOR GSY 115,7
H24 = usable all day long
• Else : check NOTAMS
3. STATION FREQUENCIES AND IDENTIFICATION
• From 108.0 to 117.95 MHz
a. 40 channels : 108.0; 108.05; 108.2; 108.25; 108.4; 108.45 and so on up to 111.8 and
111.85 MHz (EVEN ONLY)
b. 120 channels : 112.0; 112.05; 112.1; 112.15; 112.2 and so on at 0.05 MHz (50 KHz)
spacing to 117.9 and finally 117.95 MHz. (EVEN and ODD)
The reason for the gaps (for example 108.1 and 108.15 MHz) between 108 and 112 MHz is
that the 40 frequencies allocated to the ILS Localiser also lie between 108 and 112 MHz.
(ODD ONLY)
• subject to line-of-sight restrictions
b. Most VORs are equipped for voice transmission on VOR frequency.
VORs without voice capability are indicated by the letter “W ” (without voice) included in the class
designator (VORW).
c. The only positive method of identifying a VOR is by its Morse Code identification or by the
recorded automatic voice identification which is always indicated by use of the word “VOR” following
the range’s name. Reliance on determining the identification of an omni-range should never be placed
on listening to voice transmissions by the Flight Service Station (FSS) (or approach control facility)
involved. Many FSSs remotely operate several omni-ranges with different names. In some cases,
none of the VORs have the name of the “parent” FSS.
During periods of maintenance, the facility may radiate a test code
• T (e) S T : – (•) ••• –
• or the code may be removed.
Briefings IRI 05 VOR pos’t & interc ROSE FIXE rev 2 :05 2021 Page 10
