Carrier track loop for GNSS derived attitude

• US 7,388,539 B2
• Filed: 10/19/2005
• Issued: 06/17/2008
• Est. Priority Date: 10/19/2005
• Status: Active Grant

• Current Assignee: Hemisphere GNSS(USA) Incorporated
• Original Assignee: Hemisphere GNSS(USA) Incorporated
• Inventors: Whitehead, Michael L., Davis, Cary
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/253,871
• Publication Number:
  US 20070085738A1
• Time in Patent Office: 972 Days
• Field of Search: 342/357.04, 342/357.06, 342/357.07, 342/357.11, 342/357.12, 701/213, 701/215
• US Class Current: 342/357.36
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 19/55 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

A method and system for reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities comprising: receiving a plurality of GNSS satellite signals with a first antenna in operable communication with a first tracking device and a second antenna in communication with a second tracking device in at least one GNSS receiver; and sharing of data between the first tracking device and the second tracking device. The sharing is configured to facilitate a commonality in a carrier phase derived in the first and second tracking devices. The sharing also results in a cancellation of the commonality when a difference phase is formed between a carrier phase from the first tracking device and a carrier phase from the second tracking device.

Claims

1. A method of reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities comprising:

receiving a plurality of GNSS satellite signals with a first antenna in operable communication with a first tracking device and a second antenna in communication with a second tracking device in at least one GNSS receiver; and

sharing of data between said first tracking device and said second tracking device, said sharing configured to facilitate a commonality in a carrier phase derived in said first tracking device and said second tracking device;

said sharing resulting in a cancellation in said commonality when a difference phase is formed between a carrier phase from said first tracking device and another carrier phase from said second tracking device.

2. The method of claim 1 wherein said difference phase is single- or double-difference phases corresponding to one or more GNSS satellites for said first tracking device and said second tracking device.

3. The method of claim 2 further including determining at least one of an integer ambiguity value, a position corresponding to said first antenna, or a position corresponding to said second antenna.

4. The method of claim 2 further including determining at least one altitude angle for at least said first antenna and said second antenna.

5. The method of claim 1 wherein said data includes at least one of in-phase data or quadrature-phase data.

6. The method of claim 1 wherein said commonality includes at least one of common mode phase error and common ½

cycle ambiguity for said carder phase derived in each of said first tracking device and said second tracking device.

7. The method of claim 1 wherein at least one of said first tracking device or said second tracking device employs a Costas loop.

8. The method of claim 7 further including ensuring that any cycle slip that arises on a carrier signal tracked from one said first antenna or first tracking device is compensated for the carrier signal tracked for said second antenna or second tracking device.

9. A storage medium encoded with a machine-readable computer program code for reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities, said storage medium including instructions for causing a computing system to implement the method of claim 1.

10. A computer data signal for reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities, the computer data signal comprising code configured to cause a processor to implement the method of claim 1.

11. A system for reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities comprising:

a first antenna in operable communication with a first tracking device configured to receive a plurality of GNSS satellite signals;

a second antenna in communication with a second tracking device configured to receive a plurality of GNSS satellite signals;

said first tracking device and said second tracking device in at least one GNSS receiver; and

wherein said first tracking device and said second tracking device are configured to share data between said first and second tracking devices to facilitate a commonality in a carrier phase derived in said first tracking device and said second tracking device and resulting in a cancellation in said commonality when a difference phase is formed between a carrier phase from said first tracking device and another carrier phase from said second tracking device.

12. The system of claim 11 wherein said difference phase is single- or double-difference phases corresponding to one or more GNSS satellites for said first tracking device and said second tracking device.

13. The system of claim 12 wherein at least one of said first tracking device or said second tracking device is configured to facilitate determining at least one of an integer ambiguity value, a position corresponding to said first antenna, or a position corresponding to said second antenna.

14. The system of claim 12 wherein at least one of said first tracking device or said second tracking device is configured to facilitate determining at least one attitude angle based on known geometry constraints for at least said first antenna and said second antenna.

15. The system of claim 11 wherein said data includes at least one of in-phase data or quadrature-phase data.

16. The system of claim 11 wherein said commonality includes at least one of common mode phase error and common ½

cycle ambiguity for said carrier phase derived in each of said first tracking device and said second tracking device.

17. The system of claim 11 wherein said first tracking device and said second tracking device are established as a master tracking device and slave tracking device respectively in that said slave tracking device receives said data from said master tracking device.

18. The system of claim 11 wherein at least one of said first tracking device or said second tracking device employs a Costas loop.

19. A system for reducing Global Navigation Satellite System (GNSS) carrier tracking loop ambiguities comprising:

means for receiving a plurality of GNSS satellite signals with a first antenna in operable communication with a first tracking device and a second antenna in communication with a second tracking device in at least one GNSS receiver; and

means for sharing of data between, said first tracking device and said second tracking device, said sharing configured to facilitate a commonality in a carrier phase derived in said first tracking device and said second tracking device;

said sharing resulting in a cancellation in said commonality when a difference phase is formed between a carrier phase from said first tracking device and another carrier phase from said second tracking device.

20. A method of reducing half cycle ambiguities or cycle slips in GNSS differential carrier phase determinations comprising:

designating a first tracking device as a master tracking device;

designating a second tracking device as a slave tracking device;

sharing information between Costas tracking loops of said master tracking device and said slave tracking device;

said slave tracking device driven by a carrier discriminator employing in-phase data from said master tracking device in place of internally generated in-phase data.