What is the VOR (VHF Omnidirectional Range) reference signal? I have to calculate the spectrum of this signal.
VOR Ground Station is aligned with magnetic North. It emits two signals:
- a 360° sweeping variable signal
- an omni-directional reference signal
When an aircraft receives those signals, its receiver compares those and a measures the phase difference. This gives a precise radial position of the aircraft which is displayed on its Omni-Bearing Indicator (OBI), Horizontal Situation Indicator (HSI) or a Radio Magnetic Indicator (RMI), or a combination of two different kinds.
This picture shows the two signals:
- Blue is 360° sweeping signal
- Green is omni-directional reference signal