What is a VOR? | Functioning of a VOR | Cockpit Indications | Uses of VOR | Aircraft Navigation |

Summary

This video explains the VOR (VHF Omnidirectional Range), a key navigational aid in aviation. It covers how VOR operates, including its 360 radials, and the phase differences between the reference and directional signals. The video also describes how VOR information is presented in the cockpit, using a Course Deviation Indicator, and how pilots determine whether they're flying towards or away from a VOR. Factors affecting VOR transmission, the concept of the cone of ambiguity, and how to identify VORs are also discussed. Although GPS is more commonly used today, VOR remains a vital backup for navigation and certain air traffic control procedures.

Takeaways

• 😀 VOR stands for VHF Omnidirectional Range, a short-range navigational aid used since 1960.
• 😀 VOR can be used both during the day and at night, and may be paired with DME for additional range and bearing information.
• 😀 VOR produces 360 radials, each with 1-degree spacing, aligned with magnetic north at the VOR location.
• 😀 The VOR transmits two signals: a reference signal (frequency modulated) and a directional signal (amplitude modulated).
• 😀 The phase difference between the reference signal and the directional signal determines the aircraft's position relative to the VOR.
• 😀 The phase difference of the signals corresponds to the radial the aircraft is on (e.g., 0° for north, 90° for east, etc.).
• 😀 The aircraft can determine if it's flying towards or away from the VOR using a 'to' or 'from' flag on the cockpit indicator.
• 😀 The omni bearing selector (OBS) knob on the cockpit instrument allows the pilot to select a bearing and adjust flight direction accordingly.
• 😀 VOR signal transmission range is affected by transmitter power and terrain around the VOR location.
• 😀 The 'cone of ambiguity' can cause rapid oscillation on the course deviation indicator, making the reading inaccurate temporarily.
• 😀 VOR stations can be identified by a three-letter code transmitted along with the reference signal, monitored by a system at the VOR location.
• 😀 While GPS is the primary navigational aid in modern aircraft, VOR still serves as a backup and is used for marking airways, approach procedures, and holding points.

Q & A

What is a VOR?

VOR stands for VHF Omnidirectional Range, which is a short-range navigational aid used in aviation since 1960.

How does a VOR function?

A VOR produces 360 radials at one-degree spacing, which are aligned to magnetic north. It transmits two signals: a reference signal (frequency modulated) and a directional signal (amplitude modulated), which help determine an aircraft's bearing.

What is the role of the phase difference between the reference and directional signals?

The phase difference between the reference signal and the directional signal indicates the aircraft's radial position relative to the VOR. For example, if the aircraft is north of the VOR, the phase difference will be 0 degrees, and if it is east, the phase difference will be 90 degrees.

How are VOR radials spaced?

VOR radials are spaced at one-degree intervals, covering a full 360 degrees around the VOR transmitter.

What is the purpose of the 'TO' or 'FROM' flag on the cockpit instrument?

The 'TO' or 'FROM' flag on the cockpit instrument indicates whether the aircraft is flying towards ('TO') or away from ('FROM') the VOR.

What is the function of the Omni Bearing Selector (OBS) knob?

The Omni Bearing Selector (OBS) knob is used to select a specific bearing or radial from the VOR frequency tuned in the navigation radio. The selected bearing is shown on the cockpit instrument.

What factors can affect VOR signal transmission?

VOR signal transmission can be affected by the transmitter power, the terrain around the VOR, and the line of sight range due to VHF frequency limitations.

What is the 'Cone of Ambiguity' in VOR navigation?

The 'Cone of Ambiguity' occurs when the aircraft flies towards the VOR, causing the radials to converge. This results in the course deviation indicator becoming inaccurate, with rapid oscillations of the needle and possible appearance of the 'OFF' flag.

How can a VOR be identified?

A VOR can be identified by a three-letter code transmitted along with the reference signal. A monitoring system at the VOR site ensures that the identifier signal, navigation signals, and system status are continuously checked.

What role does GPS play in modern aviation compared to VOR?

While GPS has become the primary navigational aid in most modern aircraft, VOR still serves as a backup and is used for marking certain airways, approach procedures, and holding points.