Navigation system using external monitoring

• US 20060214844A1
• Filed: 02/15/2006
• Published: 09/28/2006
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Fagan, John E., Wen, Hengqing
• Granted Patent: US 7,548,196 B2
• Time in Patent Office: Days
• US Class Current: 342/357.210
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/08 providing integrity information, e.g. health of satellites or quality of ephemeris data

Abstract

A local area augmentation navigation system for determining the authenticity of the GPS signal. The system is provided with at least one reference station at a known location, a master station, a monitoring receiver, and a LAAS receiver. Each reference station receives a GPS signal from a GPS constellation and collects and outputs pseudo-range data from the GPS signal. The master station receives the pseudo-range data from the reference stations. The master station forms a correction message from the pseudo-range data and the known locations of the reference station. The master station broadcasts the correction message. The monitoring receiver receives the GPS signal from the GPS constellation and the correction message to determine the accuracy of at least one of the broadcasted correction message and the GPS signal. The LAAS receiver receives the correction message broadcast by the master station as well as a GPS signal from the GPS constellation and calculates the location of the LAAS receiver with the correction message and the GPS signal.

Claims

1. A local area augmentation navigation system for determining the authenticity of the GPS signal, the system comprising:

at least one reference station at a known location, each reference station receiving a GPS signal from a GPS constellation and collecting and outputting pseudo-range data from the GPS signal;

a master station receiving the pseudo-range data from the at least one reference station, the master station forming a correction message from the pseudo-range data and the known location of the at least one reference station, the master station broadcasting the correction message;

a monitoring receiver receiving the GPS signal from the GPS constellation and the correction message to determine the accuracy of at least one of the broadcasted correction message and the GPS signal, and

a LAAS receiver receiving the correction message broadcast by the master station as well as a GPS signal from the GPS constellation and calculating the location of the LAAS receiver with the correction message and the GPS signal.

2. The local area augmentation navigation system of claim 1, where in the monitoring receiver transmits received signals to an evaluation computer that evaluates signal accuracy.

3. The local area augmentation navigation system of claim 2, where in the evaluation computer issues an alert when an inaccurate signal is detected.

4. The local area augmentation navigation system of claim 2, where in the evaluation computer analyzes the GPS signal received by the monitoring receiver and issues an alert when an ionosphere turmoil is detected.

5. The local area augmentation navigation system of claim 2, where in the evaluation computer issues a correction message to the master station when an error is detected.

6. The local area augmentation navigation system of claim 2, where in the evaluation computer determines the GPS signal to be authentic and allows the continuation of the broadcast of the GPS signal.

7. The local area augmentation navigation system of claim 2, where in the evaluation computer includes at least one redundant backup system.

8. The local area augmentation navigation system of claim 1, where in the monitoring receiver includes at least one antenna that monitors GPS signal broadcasts in the area.

9. The local area augmentation navigation system of claim 1, where in the monitoring receiver includes at least one redundant backup monitoring receiver system.

10. The local area augmentation navigation system of claim 1, where in the master station and the monitoring receiver communicate by at least one of a wireless and a cable connections.

11. The local area augmentation navigation system of claim 1, where in the monitoring receiver is able to detect an unauthentic signal or an ionosphere turmoil.

12. The local area augmentation navigation system of claim 1, where in the monitoring receiver is able to detect an unauthentic signal or an ionosphere turmoil and issue an alert.

13. The local area augmentation navigation system of claim 1, where in the monitoring receiver detects an unauthentic signal and instruct the broadcast of a GPS signal.

14. The local area augmentation navigation system of claim 1, where in the monitoring receiver detects an ionosphere turmoil and instruct the broadcast of a GPS signal.

15. The local area augmentation navigation system of claim 1, where in the monitoring receiver determines the GPS signal to be authentic and allow the continuation of the broadcast of the GPS signal or send a correction message.

16. The local area augmentation navigation system of claim 1, where in the monitoring receiver monitors residual signal power.

17. The local area augmentation navigation system of claim 10, where in the monitoring receiver detects and above threshold increase in residual signal and accordingly issue an alert.

18. The local area augmentation navigation system of claim 1, where in the master station includes at least one antenna that monitors GPS signal broadcasts in the area.

19. A method for enhancing the accuracy of a broadcast between a master station of a local area augmentation system and a LAAS receiver, comprising the step of:

providing a monitoring receiver for installation remotely from the master station of the local area augmentation system to receive a GPS signal and a correction message and to determine the accuracy of at least one of the broadcasted correction message and the GPS signal using a known location of the monitoring receiver.

20. A method for enhancing the accuracy of a broadcast between a master station of a local area augmentation system and a LAAS receiver, comprising the step of:

selling and distributing at least one of a monitoring receiver and an evaluation computer to receive a GPS signal and a correction message and to determine the accuracy of at least one of the correction message and the GPS signal using a known location of the monitoring receiver.

21. A method for enhancing the accuracy of a broadcast between a master station of a local area augmentation system and a LAAS receiver, comprising the step of:

installing a monitoring receiver at a known location remotely from the master station of the local area augmentation system to receive a GPS signal and a correction message and to determine the accuracy of at least one of the broadcasted correction message and the GPS signal using the known location of the monitoring receiver.