Precise position determination using VHF omni-directional radio range signals
View Patent ↗Apparatus having corresponding methods and computer programs comprise a wireless receiver to receive a Very High Frequency (VHF) Omni-directional Radio Range (VOR) signal comprising a frequency-modulated (FM) component; an analog-to-digital converter to generate a digital signal based on the VOR signal, the digital signal comprising data representing the FM component; and a FM phase circuit comprising a correlator to generate a correlation peak based on the data representing the FM component and an ideal representation of the FM component, and a peak detector to determine a phase of the FM component based on the correlation peak.
1. A method comprising:
receiving, at a first station, a Very High Frequency (VHF) Omni-directional Radio Range (VOR) signal comprising an amplitude-modulated (AM) component;
generating a digital signal based on the VOR signal, the digital signal comprising data representing the AM component; and
determining a phase of the AM component of the VOR signal as received at a second station based on the data representing the AM component, wherein the second station is remote from the first station.
2. The method of claim 1 :
wherein an azimuth of the second station with respect to a transmitter of the VOR signal is determined based on the phase of the AM component.
3. The method of claim 2 , further comprising:
determining the azimuth of the second station.
4. The method of claim 3 , further comprising:
correcting the azimuth of the second station based on at least one correction signal, wherein each correction signal represents a difference between a first azimuth determined by a respective remote station based on the VOR signal and a second azimuth determined by the respective remote station based on one or more other signals.
5. The method of claim 2 , wherein the VOR signal further comprises a frequency-modulated (FM) component, the method further comprising:
receiving a signal representing a phase of the FM component of the VOR signal as received at the second station; and
determining the azimuth of the second station based on the phase of the AM component and the phase of the FM component.
6. The method of claim 5 :
wherein a position of the second station is determined based on the azimuth of the second station.
7. The method of claim 5 , further comprising:
determining the position of the second station based on the azimuth of the second station.
8. Computer-readable media embodying instructions executable by a computer to perform a method comprising:
generating a digital signal based on a Very High Frequency (VHF) Omni-directional Radio Range (VOR) signal received by a first station, the VOR signal comprising an amplitude-modulated (AM) component, the digital signal comprising data representing the AM component; and
determining a phase of the AM component of the VOR signal as received at a second station based on the data representing the AM component, wherein the second station is remote from the first station.
9. The computer-readable media of claim 8 :
wherein an azimuth of the second station with respect to a transmitter of the VOR signal is determined based on the phase of the AM component.
10. The computer-readable media of claim 9 , wherein the method further comprises:
determining the azimuth of the second station.
11. The computer-readable media of claim 10 , wherein the method further comprises:
correcting the azimuth of the second station based on at least one correction signal, wherein each correction signal represents a difference between a first azimuth determined by a respective further second station based on the VOR signal and a second azimuth determined by the respective further second station based on one or more other signals.
12. The computer-readable media of claim 9 , wherein the VOR signal further comprises a frequency-modulated (FM) component, the method further comprising:
determining a phase of the FM component of the VOR signal as received at the second station based on a signal received by the first station from the second station; and
determining the azimuth of the second station based on the phase of the AM component and the phase of the FM component.
13. The computer-readable media of claim 12 :
wherein a position of the second station is determined based on the azimuth of the second station.
14. The computer-readable media of claim 12 , wherein the method further comprises:
determining the position of the second station based on the azimuth of the second station.