Process for correcting angle errors in an electronic compass in vehicles
First Claim
1. A process for correcting an angle error of a driving direction of a vehicle equipped with an electric compass, the vehicle driving on an incline, the process comprising the steps of:
- detecting electrical signals emitted from a magnetometer of the electronic compass, the magnetometer being stationarily mounted on the vehicle, the electric signals being responsive to a magnetic field measured by the magnetometer as sensed through at most two horizontally disposed probes, the probes being disposed perpendicular to each other;
feeding and storing a first signal indicative of the inclination angle (α
) of earth'"'"'s magnetic field vector (He) into an evaluation circuit of the electronic compass, the first signal thereby representing a stored calibration value (E);
establishing a second signal in the evaluation circuit that is indicative of an inclination angle (ψ
) in a longitudinal drive direction axis (x) of the vehicle;
establishing a third signal in the evaluation circuit that is indicative of an uncorrected direction angle (θ
'"'"') of the vehicle, the uncorrected direction angle (θ
'"'"') of the vehicle being dependent on the said detected electrical signals;
establishing a fourth signal in the evaluation circuit that is indicative of a corrected direction angle (θ
) of the vehicle, the corrected direction angle (θ
) of the vehicle being dependent upon the said established uncorrected direction angle (θ
'"'"'), the said stored calibration value (E), and the said established inclination angle (ψ
) in the longitudinal drive direction axis (x) of the vehicle; and
compensating for angle error (Δ
θ
) of the driving direction of the vehicle based on the said established fourth signal indicative of a corrected direction angle (θ
), the angle error (Δ
θ
) being dependent on said inclination angle (ψ
) of the vehicle.
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Accused Products
Abstract
A process for correcting inclination dependent angle errors when establishing the driving direction of vehicles with an electronic compass for navigation is suggested. The compass comprises a magnetometer (10) with an evaluation circuit (11) for computing the driving direction. For compensating inclination dependent angle errors on the indicator of the drive direction the inclination angle of the earth field is fed into the evaluation circuit (11) as a calibration dimension (E), subsequently the inclination angle (ψ) of the vehicle is established cyclically by means of an inclination measuring device (12) and then the corrected driving direction (θ) is established from the computed driving direction (θ'"'"') as well as from the calibration dimension (E) and the angle of inclination (ψ) in accordance with the equation θ=f (θ'"'"',ψ,E). This corrected driving direction can then be further processed or issued to an indicator (13) (FIG. 1).
41 Citations
6 Claims
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1. A process for correcting an angle error of a driving direction of a vehicle equipped with an electric compass, the vehicle driving on an incline, the process comprising the steps of:
-
detecting electrical signals emitted from a magnetometer of the electronic compass, the magnetometer being stationarily mounted on the vehicle, the electric signals being responsive to a magnetic field measured by the magnetometer as sensed through at most two horizontally disposed probes, the probes being disposed perpendicular to each other; feeding and storing a first signal indicative of the inclination angle (α
) of earth'"'"'s magnetic field vector (He) into an evaluation circuit of the electronic compass, the first signal thereby representing a stored calibration value (E);establishing a second signal in the evaluation circuit that is indicative of an inclination angle (ψ
) in a longitudinal drive direction axis (x) of the vehicle;establishing a third signal in the evaluation circuit that is indicative of an uncorrected direction angle (θ
'"'"') of the vehicle, the uncorrected direction angle (θ
'"'"') of the vehicle being dependent on the said detected electrical signals;establishing a fourth signal in the evaluation circuit that is indicative of a corrected direction angle (θ
) of the vehicle, the corrected direction angle (θ
) of the vehicle being dependent upon the said established uncorrected direction angle (θ
'"'"'), the said stored calibration value (E), and the said established inclination angle (ψ
) in the longitudinal drive direction axis (x) of the vehicle; andcompensating for angle error (Δ
θ
) of the driving direction of the vehicle based on the said established fourth signal indicative of a corrected direction angle (θ
), the angle error (Δ
θ
) being dependent on said inclination angle (ψ
) of the vehicle. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification
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- Resources
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Current AssigneeRobert Bosch GmbH
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Original AssigneeRobert Bosch GmbH
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InventorsHettich, Gerhard, Bauer, Harald, Alberter, Gunther
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Primary Examiner(s)Chin, Gary
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Application NumberUS06/787,796Time in Patent Office853 DaysField of Search364/449, 364/571, 364/424, 364/457, 33/355 R, 33/356, 33/357US Class Current701/224CPC Class CodesG01C 17/38 Testing, calibrating, or co...
