POSITIONING SYSTEM AND METHOD FOR DETERMINING LOCATION OF MACHINE

• US 20170010363A1
• Filed: 07/09/2015
• Published: 01/12/2017
• Est. Priority Date: 07/09/2015
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Friend, Paul R.
• Granted Patent: US 9,945,100 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: E02F 9/205 Remotely operated machines, e.g. unmanned vehicles E02F3/8866 takes precedence
• CPC Class Codes: E02F 9/2054 Fleet management
• CPC Class Codes: E02F 9/268 with failure correction follow-up actions
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 19/426 by combining or switching between position solutions or signals derived from different modes of operation in a single system
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

A positioning system for a machine is disclosed. The positioning system includes a satellite positioning unit to generate signals indicative of a location of the machine in a worksite and an inertial measurement unit (IMU) to generate signals indicative of a position of the machine. A controller is communicated with the satellite positioning unit and the IMU. The controller determines a first error value associated with a location of the machine based on signals received from the satellite positioning unit. The controller further determines a second error value associated with a location and a position of the machine based on signals received from the satellite positioning unit and signals received from the IMU, respectively. Further, a location of the machine is determined based on signals received from the satellite positioning unit and the IMU if the first error value is less than the second error value.

Claims

1. A positioning system for a machine comprising:

a satellite positioning unit disposed on the machine, the satellite positioning unit configured to generate signals indicative of a location of the machine in a worksite;

an inertial measurement unit (IMU) disposed in the machine, the IMU configured to generate signals indicative of a position of the machine; and

a controller in communication with the satellite positioning unit and the IMU, the controller configured to;

determine a first error value associated with a location of the machine based on the signals received from the satellite positioning unit;

determine a second error value associated with a location and a position of the machine based on the signals received from the satellite positioning unit and the signals received from the IMU, respectively;

compare the first error value with the second error value; and

determine a location of the machine based on the signals received from the satellite positioning unit and the IMU, if the first error value is less than the second error value.

2. The positioning system of claim 1, wherein the controller is further configured to determine the location of the machine based on the signals received from the IMU if the first error value is greater than the second error value.

3. The positioning system of claim 1, wherein the controller is further configured to determine a mode at which the satellite positioning unit receives signals from satellites.

4. The positioning system of claim 3, wherein the controller is further configured to determine the first error value based on the determined mode.

5. The positioning system of claim 4, wherein the controller is further configured to:

select a threshold error value based on the determined mode; and

determine the first error value as being equal to the selected threshold error value.

6. The positioning system of claim 3, wherein the mode comprises one of RTK fixed mode, RTK float mode, differential mode and autonomous mode.

7. The positioning system of claim 1 further comprising a sensing unit disposed in communication with the controller, the sensing unit configured to generate signals indicative of an operating parameter of the machine.

8. The positioning system of claim 7, wherein the controller is configured to determine the location of the machine further based on the signals received from the sensing unit.

9. A method of determining a location of a machine, the method comprising:

determining a first error value associated with a location of the machine based on signals received from a satellite positioning unit;

determining a second error value associated with a location and a position of the machine based on signals received from the satellite positioning unit and signals received from an inertial measurement unit (IMU), respectively;

comparing the first error value with the second error value; and

determining a location of the machine based on the signals received from the satellite positioning unit and the IMU, if the first error value is less than the second error value.

10. The method of claim 9 further comprising determining a location of the machine based on the signals received from the IMU if the first error value is greater than the second error value.

11. The method of claim 9 further comprising determining a mode at which the satellite positioning unit receives signals from satellites.

12. The method of claim 11 further comprising determining the first error value based on the determined mode.

13. The method of claim 9 further comprising determining the location of the machine further based on signals received from a sensing unit disposed in communication with a controller, the sensing unit configured to generate signals indicative of an operating parameter of the machine.

14. A machine comprising:

a frame;

a satellite positioning unit disposed on the frame of the machine, the satellite positioning unit configured to generate signals indicative of a location of the machine in a worksite;

an inertial measurement unit (IMU) disposed in the machine, the IMU configured to generate signals indicative of a position of the machine; and

a controller in communication with the satellite positioning unit and the IMU, the controller configured to;

determine a first error value associated with the location of the machine based on the signals received from the satellite positioning unit;

determine a second error value associated with the location and the position of the machine based on the signals received from the satellite positioning unit and the signals received from the IMU, respectively;

compare the first error value with the second error value; and

determine the location of the machine based on the signals received from the satellite positioning unit and the IMU, if the first error value is less than the second error value.

15. The machine of claim 14, wherein the controller is configured to determine the location of the machine based on the signals received from the IMU if the first error value is greater than the second error value.

16. The machine of claim 14, wherein the controller is further configured to determine a mode at which the satellite positioning unit receives signals from satellites, wherein the mode comprises one of RTK fixed mode, RTK float mode, differential mode and autonomous mode.

17. The machine of claim 16, wherein the controller is further configured to determine the first error value based on the determined mode.

18. The machine of claim 17, wherein the controller is further configured to:

select a threshold error value based on the determined mode; and

determine the first error value as being equal to the selected threshold error value.

19. The machine of claim 14 further comprising a sensing unit disposed in communication with the controller, the sensing unit configured to generate signals indicative of an operating parameter of the machine.

20. The machine of claim 19, wherein the controller is configured to determine the location of the machine further based on the signals received from the sensing unit.