Vehicle guidance system
First Claim
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1. Apparatus for use in guiding a vehicle on a roadway along an elongated guide member emitting a magnetic field, said apparatus comprising, in combination:
- a first sensor attached to the vehicle for detecting both the magnetic field emitted by the elongated guide member and an ambient magnetic field not emitted by the elongated guide member, said first sensor producing a primary signal representative of the detected magnetic field emitted by the elongated guide member and the ambient magnetic field;
a second sensor attached to the vehicle for detecting the ambient magnetic field but not a substantial portion of the magnetic field emitted by the elongated guide member, said second sensor producing a reference signal representative of the ambient magnetic field; and
a signal processor for processing the primary and reference signals to subtract the reference signal from the primary signal and produce a steering signal for transmission to an automatic steering system on said vehicle.
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Abstract
A system for use in guiding a vehicle on a roadway along an elongated guide member emitting a magnetic field includes an upper sensor and a lower sensor connected to the vehicle. The lower sensor detects a magnetic field emitted by the elongated guide member and an ambient magnetic field. The upper sensor detects only the ambient magnetic field. The signals produced by the detectors are processed to subtract the signal from the upper sensor of that of the lower sensor to produce a steering signal for transmission to an automatic steering system on the vehicle.
23 Citations
18 Claims
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1. Apparatus for use in guiding a vehicle on a roadway along an elongated guide member emitting a magnetic field, said apparatus comprising, in combination:
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a first sensor attached to the vehicle for detecting both the magnetic field emitted by the elongated guide member and an ambient magnetic field not emitted by the elongated guide member, said first sensor producing a primary signal representative of the detected magnetic field emitted by the elongated guide member and the ambient magnetic field;
a second sensor attached to the vehicle for detecting the ambient magnetic field but not a substantial portion of the magnetic field emitted by the elongated guide member, said second sensor producing a reference signal representative of the ambient magnetic field; and
a signal processor for processing the primary and reference signals to subtract the reference signal from the primary signal and produce a steering signal for transmission to an automatic steering system on said vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method employed when guiding a vehicle on a roadway along an elongated guide member emitting a magnetic field, said method comprising the steps of:
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attaching a first sensor to the vehicle;
attaching a second sensor to the vehicle;
maintaining said first sensor and said second sensor spaced from one another;
during movement of said vehicle on the roadway detecting at said first sensor both the magnetic field emitted by the elongated guide member and an ambient magnetic field not emitted by said elongated guide member;
producing at said first sensor a primary signal representative of the detected magnetic field emitted by the elongated guide member and the ambient magnetic field;
during movement of said vehicle on the roadway, detecting at said second sensor the ambient magnetic field but not a substantial portion of the magnetic field emitted by the elongated guide member;
producing at said second sensor a reference signal representative of the ambient magnetic field;
processing the primary and reference signals to subtract the reference signal from the primary signal; and
subsequent to said processing step, producing a steering signal for transmission to an automatic steering system on said vehicle. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification