System for determining error in a sensed machine position
First Claim
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1. A system for determining an error in a sensed position of a machine, comprising:
- a position sensing system, including a GPS sensor, mounted on the machine for determining a sensed position of the machine;
a dead reckoning system, including an inertial measurement unit, mounted on the machine for determining a calculated position of the machine; and
a controller configured to;
store an error threshold defining a maximum acceptable distance between the sensed position of the machine and the calculated position of the machine;
execute a first verification cycle configured to;
determine an initialization position based upon the position sensing system;
determine a calculated position based upon the initialization position and the dead reckoning system;
determine a sensed position based upon the position sensing system;
determine a difference between the calculated position and the sensed position;
compare the difference to the error threshold; and
generate an error signal if the difference exceeds the error threshold;
execute a second verification cycle configured to;
determine a second initialization position of the machine based upon the position sensing system, the second initialization position being spaced from the initialization position,determine a second calculated position based upon the second initialization position and the dead reckoning system,determine a second difference between the second calculated position and the sensed position, compare the second difference to the error threshold; and
generate an error signal if the second difference exceeds the error threshold;
wherein the first and second initialization positions are staggered such that the second verification cycle starts before the first verification cycle is completed.
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Abstract
A system for determining an error in a sensed position of a machine includes a position sensing system, a dead reckoning system, and a controller. The controller is configured to determine a difference between a sensed position and a calculated position determined by dead reckoning. The difference is compared to an error threshold defining a maximum acceptable distance between the sensed position of the machine and the calculated position of the machine and an error signal generated if the difference exceeds the error threshold. A pair of offset dead reckoning processes may be used.
38 Citations
15 Claims
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1. A system for determining an error in a sensed position of a machine, comprising:
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a position sensing system, including a GPS sensor, mounted on the machine for determining a sensed position of the machine; a dead reckoning system, including an inertial measurement unit, mounted on the machine for determining a calculated position of the machine; and a controller configured to; store an error threshold defining a maximum acceptable distance between the sensed position of the machine and the calculated position of the machine; execute a first verification cycle configured to; determine an initialization position based upon the position sensing system; determine a calculated position based upon the initialization position and the dead reckoning system; determine a sensed position based upon the position sensing system; determine a difference between the calculated position and the sensed position; compare the difference to the error threshold; and generate an error signal if the difference exceeds the error threshold; execute a second verification cycle configured to; determine a second initialization position of the machine based upon the position sensing system, the second initialization position being spaced from the initialization position, determine a second calculated position based upon the second initialization position and the dead reckoning system, determine a second difference between the second calculated position and the sensed position, compare the second difference to the error threshold; and generate an error signal if the second difference exceeds the error threshold; wherein the first and second initialization positions are staggered such that the second verification cycle starts before the first verification cycle is completed. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A controller-implemented method for determining an error in a sensed position of a machine, comprising:
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storing an error threshold defining a maximum acceptable distance between a sensed position of the machine based upon a position sensing system including a GPS sensor and a calculated position of the machine based upon a dead reckoning system including an inertial measurement unit which further includes a pitch rate sensor and an acceleration sensor; executing a first verification cycle comprising; determining an initialization position based upon the position sensing system; determining a calculated position based upon the initialization position and the dead reckoning system; determining a sensed position based upon the position sensing system; determining a difference between the calculated position and the sensed position; comparing the difference to the error threshold; and generating an error signal if the difference exceeds the error threshold; executing a second verification cycle comprising; determining a second initialization position of the machine based upon the position sensing system, the second initialization position being spaced from the initialization position; determining a second calculated position based upon the second initialization position and the dead reckoning system; determining a second difference between the second calculated position and the sensed position; comparing the second difference to the error threshold; and generating an error signal if the second difference exceeds the error threshold; wherein the first and second initialization positions are staggered such that the second verification cycle starts before the first verification cycle is completed. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An autonomously operated machine comprising:
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a propulsion system; a steering system; a position sensing system including a GPS sensor mounted on the machine for determining a sensed position of the machine; a dead reckoning system including an inertial measurement unit, mounted on the machine for determining a calculated position of the machine; an accuracy verification system for determining an error in the sensed position; and a controller configured to; store an error threshold defining a maximum acceptable distance between the sensed position of the machine and the calculated position of the machine; execute a first verification cycle configured to; determine an initialization position based upon the position sensing system; determine a calculated position based upon the initialization position and the dead reckoning system; determine a sensed position based upon the position sensing system; determine a difference between the calculated position and the sensed position; compare the difference to the error threshold; and generate an error signal if the difference exceeds the error threshold; execute a second verification cycle configured to; determine a second initialization position of the machine based upon the position sensing system, the second initialization position being spaced from the initialization position; determine a second calculated position based upon the second initialization position and the dead reckoning system; determine a second difference between the second calculated position and the sensed position, compare the second difference to the error threshold; and generate an error signal if the second difference exceeds the error threshold; wherein the first and second initialization positions are staggered such that the second verification cycle starts before the first verification cycle is completed.
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Specification