Precise position determination using VHF omni-directional radio range signals

• US 8,179,318 B1
• Filed: 09/10/2009
• Issued: 05/15/2012
• Est. Priority Date: 09/28/2005
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Furman, Scott, Opshaug, Guttorm
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Nguyen, Nga X
• Application Number:
  US12/556,714
• Time in Patent Office: 978 Days
• Field of Search: 342404-411
• US Class Current: 342/404
• CPC Class Codes: G01S 1/045 Receivers
• CPC Class Codes: G01S 1/50 wherein the phase angle of the direction-dependent envelope signal is compared with a non-direction-dependent reference signal, e.g. VOR

Abstract

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.

Claims

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.