Navigation/guidance system for a land-based vehicle
First Claim
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1. A method of navigating a non-airborne vehicle comprising the steps of:
- providing a position change sensor;
sensing the speed of the vehicle using the position change sensor;
providing an angular change sensor;
sensing the heading and attitude of the vehicle using the angular change sensor;
providing an accelerometer;
correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor;
determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
providing a radio navigation system;
storing positions of the vehicle each relative to a given point in time;
determining an external position reference for a given point in time using data from the radio navigation system; and
correcting any error in the determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time.
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Abstract
A navigation/guidance system uses a dead reckoning navigator with periodic GPS fixes to correct the drift of the inertial system. The navigation system primarily uses speed sensed by Doppler radar and attitude and heading sensed by a set of gyros. The navigation system uses various processes to compensate for any sensor errors. The system uses attitude data to compensate for GPS leverarm errors. The system can be used on a land-based vehicle to economically and accurately provide navigation data.
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Citations
51 Claims
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1. A method of navigating a non-airborne vehicle comprising the steps of:
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providing a position change sensor; sensing the speed of the vehicle using the position change sensor; providing an angular change sensor; sensing the heading and attitude of the vehicle using the angular change sensor; providing an accelerometer; correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle; providing a radio navigation system; storing positions of the vehicle each relative to a given point in time; determining an external position reference for a given point in time using data from the radio navigation system; and correcting any error in the determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A navigation system for a non-airborne vehicle comprising:
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a position change sensor for sensing the speed of the vehicle; a set of gyros for sensing the attitude and heading of the vehicle; a set of accelerometers for sensing the forces acting on the vehicle; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said vehicle at a known location relative to the vehicle; and a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of; correcting the sensed attitude of the vehicle using the sensed forces acting on the vehicle; determining the velocity of the vehicle using the sensed speed, heading and attitude of the vehicle, determining a first position of the vehicle by integrating the determined velocity, storing said first position of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the vehicle and the known location of the antenna relative to the vehicle, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored first position of the vehicle for the same point in time. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of navigating a land-based agricultural vehicle through a field comprising the steps of:
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sensing the speed of the vehicle; providing an inertial sensor system; sensing the heading and attitude of the vehicle using the inertial sensor system; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle; storing positions of the vehicle each relative to a given point in time; providing a radio navigation system; determining an external position reference for a given point in time using data from the radio navigation system; producing true position data by correcting any error in the determined position of the vehicle using the external position reference and comparing it to the stored position of the vehicle for the same point in time; and using the true position data to accurately navigate through a field. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method of compensating for a radio navigation system antenna lever arm for a non-airborne vehicle comprising the steps of:
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providing a radio navigation system antenna having a known location relative to a reference point on the vehicle; providing an inertial system for sensing the angular changes of the vehicle; determining the attitude of the vehicle using data from the inertial system; and determining the position of the radio navigation system antenna based on the attitude of the vehicle and the known location of the radio navigation system antenna relative to the reference point.
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42. A navigation system for a tractor comprising:
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a position change sensor for sensing the speed of the tractor; a set of gyros for sensing the attitude and heading of the tractor; a set of angular change sensors for sensing the pitch and roll of the tractor; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said tractor at a known location relative to the tractor; a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of; correcting the sensed attitude of the tractor using the sensed pitch and roll of the tractor; determining the velocity of the tractor using the sensed speed, heading and attitude of the tractor, determining a first position of the tractor by integrating the determined velocity, storing said first positions of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the tractor and the known location of the antenna relative to the tractor, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored position of the vehicle for the same point in time; an output port connected to said processor for providing data to a tractor guidance system. - View Dependent Claims (43, 44, 45, 46, 47, 48)
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49. A method of navigating a moving non-airborne vehicle comprising the steps of:
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(a) sensing the speed of a vehicle; (b) sensing the heading and attitude of the vehicle from a known initialization position using an inertial sensor system having inherent drift that increases over time; (c) estimating in real time the position of the vehicle for discrete points in time based on steps (a) and (b); (d) storing the estimates correlated to the discrete points in time; (e) correcting error between estimated position and actual position by periodically determining actual position correlated to discrete points in time of the vehicle, comparing a stored estimated position with an actual position for the radio navigation system, and adjusting estimated position if the comparison falls outside a predetermined range; thus periodically producing real-time true position data for navigation of the vehicle by correcting for the inherent drift of the inertial sensor system, by periodically, if needed, comparing past estimated and past actual position and adjusting, if, needed, therebetween. - View Dependent Claims (50, 51)
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Specification