Method for combined use of local positioning system and a global positioning system

• US 20050264444A1
• Filed: 07/13/2005
• Published: 12/01/2005
• Est. Priority Date: 01/13/2004
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Frederick W. Nelson, Richard T. Sharpe, Ronald R. Hatch, Terence D. Pickett, Yang Yunchun
• Inventors: Yunchun, Yang, Hatch, Ronald R., Sharpe, Richard T., Pickett, Terence D., Nelson, Frederick W.
• Granted Patent: US 7,071,870 B2
• Time in Patent Office: Days
• US Class Current: 342/357.310
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

The present invention includes a method for a combined use of a local RTK system and a regional, wide-area, or global differential carrier-phase positioning system (WADGPS) in which disadvantages associated with the RTK and the WADGPS navigation techniques when used separately are avoided. The method includes using a known position of a user receiver that has been stationary or using an RTK system to initialize the floating ambiguity values in the WADGPS system when the user receiver is moving. Thereafter, the refraction-corrected carrier-phase measurements obtained at the user GPS receiver are adjusted by including the corresponding initial floating ambiguity values and the floating ambiguity values are treated as well known (small variance) in subsequent processes to position the user receiver in the WADGPS system.

Claims

1. A method for positioning or navigating an object associated with both a local reference receiver and a wide-area differential satellite positioning system, comprising:

determining a floating ambiguity value and a first position of the object in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

determining a first position of the local reference receiver in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

determining a position offset of the local reference receiver in accordance with the first position of the local reference receiver and a second position of the local reference receiver, wherein the second position of the local reference receiver is pre-determined; and

determining a second position of the object in accordance with the first position of the object and the position offset.

2. The method of claim 1, further comprising initializing the floating ambiguity value in accordance with the position offset of the local reference receiver.

3. The method of claim 1, wherein a known position of the object input by a user is used to initialize the floating ambiguity value.

4. A method for positioning or navigating an object associated with both a local reference receiver and a wide-area differential satellite positioning system, comprising:

determining a floating ambiguity value and a first position of the object in accordance with carrier-phase measurements using the wide-area differential satellite positioning system in a first mode of operation; and

determining a second position of the object in accordance with information received from the local reference receiver using real-time kinematic positioning in a second mode of operation.

5. The method of claim 4, wherein a known position of the object is used to initialize the floating ambiguity value.

6. The method of claim 5, wherein the known position of the object is the second position.

7. The method of claim 5, wherein the known position of the object is input by a user.

8. The method of claim 4, wherein the second mode of operation is used if communication with the local reference receiver is available.

9. The method of claim 4, wherein the first mode of operation is used when communication with the local reference receiver is lost and the second mode of operation is used when the communication with the local reference receiver is available again, and wherein the first position and an offset between the first position and the second position are used to initialize the second position when switching from the first mode of operation to the second mode of operation.

10. The method of claim 4, wherein the second mode of operation is used if a distance from the local reference receiver to the object is less than a pre-determined value.

11. The method of claim 4, wherein the first mode of operation is used if communication with the local reference receiver is lost.

12. The method of claim 4, wherein the first and second modes of operation are used substantially simultaneously, and a difference between the second position and the first position is used to initialize the floating ambiguity value.

13. A computer readable medium storing therein computer readable program instructions that, when executed by a processor, cause the processor to perform a method for positioning or navigating an object associated with both a local reference receiver and a wide-area differential satellite positioning system, the program instructions comprising:

instructions for determining a floating ambiguity value and a first position of the object in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

instructions for determining a first position of the local reference receiver in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

instructions for determining a position offset of the local reference receiver in accordance with the first position of the local reference receiver and a second position of the local reference receiver, wherein the second position of the local reference receiver is pre-determined; and

instructions for determining a second position of the object in accordance with the first position of the object and the position offset.

14. A computer readable medium storing therein computer readable program instructions that, when executed by a processor, cause the processor to perform a method for positioning or navigating an object associated with both a local reference receiver and a wide-area differential satellite positioning system, the program instructions comprising:

instructions for determining a floating ambiguity value and a first position of the object in accordance with carrier-phase measurements using the wide-area differential satellite positioning system in a first mode of operation; and

instructions for determining a second position of the object in accordance with information received from the local reference receiver using real-time kinematic positioning in a second mode of operation.

15. A satellite navigation receiver configured to operate in a first mode and a second mode of operation, wherein in the first mode of operation a floating ambiguity value and a first position of an object are determined in accordance with carrier-phase measurements using a wide-area differential satellite positioning system, and wherein in the second mode of operation a second position of the object is determined in accordance with information received from a local reference receiver using real-time kinematic positioning.

16. A satellite navigation receiver, comprising:

a memory;

a processor; and

a program, stored in the memory and executed by the processor, the program including;

instructions for determining a floating ambiguity value and a first position of an object in accordance with carrier-phase measurements using a wide-area differential satellite positioning system;

instructions for determining a first position of a local reference receiver in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

instructions for determining a position offset of the local reference receiver in accordance with the first position of the local reference receiver and a second position of the local reference receiver, wherein the second position of the local reference receiver is pre-determined; and

instructions for determining a second position of the object in accordance with the first position of the object and the position offset.

17. A satellite navigation receiver, comprising an integrated circuit configured to perform:

operations for determining a floating ambiguity value and a first position of an object in accordance with carrier-phase measurements using a wide-area differential satellite positioning system;

operations for determining a first position of a local reference receiver in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

operations for determining a position offset of the local reference receiver in accordance with the first position of the local reference receiver and a second position of the local reference receiver, wherein the second position of the local reference receiver is pre-determined; and

operations for determining a second position of the object in accordance with the first position of the object and the position offset.

18. A satellite navigation receiver, comprising:

a memory means;

a processor means; and

a program means, stored in the memory means and executed by the processor means, for positioning or navigating an object, the program means including;

instructions for determining a floating ambiguity value and a first position of an object in accordance with carrier-phase measurements using a wide-area differential satellite positioning system;

instructions for determining a first position of a local reference receiver in accordance with carrier-phase measurements using the wide-area differential satellite positioning system;

instructions for determining a position offset of the local reference receiver in accordance with the first position of the local reference receiver and a second position of the local reference receiver, wherein the second position of the local reference receiver is pre-determined; and

instructions for determining a second position of the object in accordance with the first position of the object and the position offset.