System and method for moving-base RTK measurements

• US 8,983,685 B2
• Filed: 05/25/2011
• Issued: 03/17/2015
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Dai, Liwen L., Shao, Yunfeng
• Primary Examiner(s): Olszewski, John R
• Assistant Examiner(s): CASS, JEAN PAUL
• Application Number:
  US13/115,851
• Publication Number:
  US 20120029810A1
• Time in Patent Office: 1,392 Days
• Field of Search: 701/13, 701/25, 701/476, 701/484, 701/492, 701/534, 701/213, 701/468
• US Class Current: 701/13
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems

Abstract

In a system and method for navigating a moving object according to signals from satellite, a moving object receives satellite navigation signals from a number of satellites. The moving object also receives moving base data from a moving base. The received moving base data includes satellite measurement data of the moving base. At the moving object a relative position vector of the moving object relative to the moving base is determined, based on the received moving base data and the received satellite navigation signals. The moving object sends a signal reporting information corresponding to the relative position vector.

Claims

1. A method for navigating a moving object according to signals from satellites, the method comprising:

in a moving object,

receiving satellite navigation signals from a plurality of satellites;

generating satellite navigation data for the moving object from the received satellite navigation signals for a first specific time prior to a current time, wherein the moving object comprises a first system that includes a first receiver and a first transmitter;

receiving moving base data from a moving base that is moving and separated from the moving object, wherein the moving base comprises a second system that includes a second receiver and is configured to receive the satellite navigation signals and to transmit the moving base data, the received moving base data including satellite measurement data of the moving base for the first specific time;

determining a relative position vector of the moving object relative to the moving base for the first specific time, and between the moving object and the moving base, based at least in part on a real-time-kinematic (RTK) value for the relative position vector at the first specific time generated based on the received moving base data for the first specific time and the satellite navigation data for the moving object for the first specific time;

determining a current relative position vector for the current time at least in part by combining the RTK value for the relative position vector at the first specific time and a propagated relative position vector, the propagated relative position vector comprising a position-propagation calculated value for the current relative position vector; and

sending, via the first transmitter of the moving object, a signal reporting information corresponding to the current relative position vector.

2. The method of claim 1, wherein the moving base data comprises satellite measurement data generated at the moving base from satellite navigation signals for a plurality of satellites;

the method further comprising determining, in the moving object, a position of the moving base at the first specific time based on the moving base data.

3. The method of claim 2, further comprising determining a position of the moving object at the first specific time, based on the position of the moving base at the first specific time and the relative position vector.

4. The method of claim 2, further comprising determining a position of the moving object at the current time, based on the position of the moving base at the first specific time, the relative position vector at the first specific time, and a change in position of the moving object between the first specific time and the current time.

5. The method of claim 1, further comprising calculating the position-propagation calculated value based on a change in position of the moving object from the first specific time to the current time, a change in position of the moving base between the first specific time and a second specific time, and a projected change in position of the moving base between the second specific time and the current time, wherein the projected change in position of the moving base is based on a determined velocity of the moving base.

6. The method of claim 1, wherein the current relative position vector is based on attributes of a variance-covariance matrices for both the RTK value and the propagated relative position vector.

7. The method of claim 1, further comprising receiving from the moving base a plurality of successive position-change updates of the moving base for a corresponding plurality of update times after the first specific time.

8. The method of claim 7, further comprising determining a position change of the moving object, and determining an updated relative position vector for a second specific time after the first specific time based on a position change of the moving object between the first specific time and the second specific time and at least one additional position-change update of the plurality of received position-change updates of the moving base.

9. The method of claim 7, further comprising determining a smoothed velocity of the moving base based on two or more of the received position-change updates of the moving base.

10. The method of claim 7, further comprising determining a velocity of the moving base based on one or more of the received position-change updates of the moving base.

11. The method of claim 10, further comprising determining a position of the moving base at the current time, based on a position of the moving base at the first specific time and the determined velocity of the moving base.

12. The method of claim 1, wherein receiving the moving base data comprises receiving the moving base data via a radio communication.

13. A system for navigating a moving object according to signals from satellites, the system comprising:

one or more processors;

a satellite receiver to receive satellite navigation signals from a plurality of satellites;

a receiver to receive moving base data from a moving base that is moving and separated from a moving object, the received moving base data including satellite measurement data of the moving base for a first specific time prior to a current time;

memory storing a determining module to be executed by the one or more processors, the determining module to;

generate satellite navigation data for the moving object from the received satellite navigation signals for the first specific time, wherein the moving object comprises a first system that includes a first receiver and a first transmitter, and the moving base comprises a second system that includes a second receiver and is configured to receive the satellite navigation signals and to transmit the moving base data;

determine a relative position vector of the moving object relative to the moving base for the first specific time, and between the moving object and the moving base, based at least in part on a real-time-kinematic (RTK) value for the relative position vector at the first specific time generated based on the received moving base data for the first specific time and the satellite navigation data for the moving object for the first specific time;

determine a current relative position vector at least in part by combining the RTK value for the relative position vector at the first specific time and a propagated relative position vector, the propagated relative position vector comprising a position-propagation calculated value for the current relative position vector; and

the first transmitter to send a signal reporting information corresponding to the current relative position vector.

14. The system of claim 13, wherein the determining module further includes instructions to determine, in the moving object, a position of the moving base at the first specific time based on the moving base data.

15. The system of claim 14, wherein the determining module further includes instructions to determine a position of the moving object at the first specific time, based on the position of the moving base at the first specific time and the relative position vector.

16. The system of claim 14, wherein the determining module further includes instructions to determine a position of the moving object at the current time, based on the position of the moving base at the first specific time, the relative position vector at the first specific time, at a change in position of the moving object between the first specific time and the current time.

18. The system of claim 13, wherein the current relative position vector is based on attributes of a variance-covariance matrices for both the RTK value and the propagated relative position vector.

19. The system of claim 13, wherein the receiver receives from the moving base a plurality of successive position-change updates of the moving base for a corresponding plurality of update times after the first specific time.

20. The system of claim 19, wherein the determining module further includes instructions to determine a position change of the moving object, and to determine an updated relative position vector for a second specific time after the first specific time based on a position change of the moving object between the first specific time and the second specific time and at least one additional position-change update of the plurality of received position-change updates of the moving base.

21. The system of claim 19, wherein the determining module further includes instructions to determine a smoothed velocity of the moving base based on two or more of the received position-change updates of the moving base.

22. The system of claim 21 wherein the determining module further includes instructions to determine a position of the moving base at the current time, based on a position of the moving base at the first specific time and the determined velocity of the moving base.

17. The system of 13, wherein the determining module further includes instructions to calculate the position-propagation calculated value based on a change in position of the moving object from the first specific time to the current time, a change in position of the moving base between the first specific time and a second specific time, and a projected change in position of the moving base between the second specific time and the current time, wherein the projected change in position of the moving base is based on a determined velocity of the moving base.

23. A non-transitory computer readable storage medium storing including instructions that, when executed by one or more processors of a system for navigating a moving object according to signals from satellites, perform a method comprising:

receiving satellite navigation signals from a plurality of satellites;

generating satellite navigation data for the moving object from the received satellite navigation signals for a first specific time prior to a current time, wherein the moving object comprises a first system that includes a first receiver and a first transmitter;

receiving moving base data from a moving base that is moving and separated from the moving object, wherein the moving base comprises a second system that includes a second receiver and is configured to receive the satellite navigation signals and to transmit the moving base data, the received moving base data including satellite measurement data of the moving base for the first specific time;

determining a relative position vector of the moving object relative to the moving base for the first specific time, and between the moving object and the moving base, based at least in part on a real-time-kinematic (RTK) value for the relative position vector at the first specific time generated based on the received moving base data for the first specific time and the satellite navigation data for the moving object for the first specific time;

determining a current relative position vector for the current time at least in part by combining the RTK value for the relative position vector at the first specific time and a propagated relative position vector, the propagated relative position vector comprising a position-propagation calculated value for the current relative position vector; and

sending, via the first transmitter of the moving object, a signal reporting information corresponding to the current relative position vector.

24. A method for navigating a moving object according to signals from satellites, the method comprising:

in a moving object,

receiving satellite navigation signals from a plurality of satellites;

generating satellite navigation data for the moving object for a first specific time prior to a current time from the received satellite navigation signals, wherein the moving object comprises a first system that includes a first receiver and a first transmitter;

receiving, for the first specific time, moving base data from a moving base that is moving and separated from the moving object, wherein the moving base comprises a second system that includes a second receiver and is configured to receive the satellite navigation signals and to transmit the moving base data, the received moving base data including satellite measurement data of the moving base for the first specific time;

determining a relative position vector of the moving object relative to the moving base for the first specific time, and between the moving object and the moving base, wherein determining the relative position vector comprises generating a real-time-kinematic (RTK) value for the relative position vector at the first specific time, based on the received moving base data and the satellite navigation data for the moving object;

receiving from the moving base position update data representing a change in position of the moving base between the first specific time and a second specific time;

determining a current relative position vector for the current time, based on the relative position vector for the first specific time, a change in position of the moving object from the first specific time to the current time, the change in position of the moving base between the first specific time and the second specific time, and a projected change in position of the moving base between the second specific time and the current time, wherein the projected change in position of the moving base is based on a determined velocity of the moving base; and

sending, via the first transmitter of the moving object, a signal reporting information corresponding to the current relative position vector.