System for determining error in a sensed machine position

A controller-implemented method for determining an error in a sensed position of a machine, comprising:

• 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.

An autonomously operated machine comprising:

• 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.