Vehicular traveling direction measuring system
First Claim
1. A system for measuring a traveling direction of a vehicle, comprising:
- a geomagnetic sensor, mounted to the vehicle, which produces a first output signal indicative of directional data relating to a geomagnetic field around the vehicle;
a gyro sensor, mounted to the vehicle, which produces a second output signal indicative of angular variation data independently of the geomagnetic field; and
a control circuit operatively connected to said geomagnetic sensor and said gyro sensor for receiving said first and second output signals and modifying said first and second output signals to derive a corrected traveling direction based on said modified output signals, said control circuit including;
first means for deriving a first variation in a traveling direction of the vehicle based on said second output signal from the gyro sensor;
second means for deriving a first vehicle traveling direction based on said first directional variation;
third means for deriving a second vehicle traveling direction based on said first output signal from the geomagnetic sensor;
fourth means for deriving a second variation in said second vehicle traveling direction;
fifth means for deriving a first value indicative of a disturbance of the geomagnetic field on a short interval basis, said first short interval based value being derived by calculating a difference between said first and second directional variations;
sixth means for deriving a second value indicative of a disturbance of the geomagnetic field on a long interval basis said second long interval based value being derived by calculating a difference between said first and second vehicle traveling directions;
seventh means for deriving a first correction value indicative of a drift error causes by said gyro sensor; and
eighth means for deriving a third vehicle traveling direction as said corrected traveling direction based on said first and second derived vehicle traveling directions by changing a rate of dependence upon said first and second vehicle traveling directions depending on said first short interval based value, said second long interval based value and said first correction value.
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Abstract
A system for measuring a traveling direction of a vehicle includes a geomagnetic sensor and a gyro sensor. The system utilizes first and second indicies for deriving the vehicle traveling direction. The first index is indicative of disturbance of a geomagnetic field on a short interval basis, and the second index is indicative of disturbance of the geomagnetic field on a long interval basis. The system further utilizes a correction value indicative of a drift error caused by the gyro sensor for deriving the vehicle traveling direction. The system varies a rate of dependence upon an output of the geomagnetic sensor and an output of the gyro sensor based on the first and second indicies and the correction value when calculating the vehicle traveling direction.
31 Citations
14 Claims
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1. A system for measuring a traveling direction of a vehicle, comprising:
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a geomagnetic sensor, mounted to the vehicle, which produces a first output signal indicative of directional data relating to a geomagnetic field around the vehicle; a gyro sensor, mounted to the vehicle, which produces a second output signal indicative of angular variation data independently of the geomagnetic field; and a control circuit operatively connected to said geomagnetic sensor and said gyro sensor for receiving said first and second output signals and modifying said first and second output signals to derive a corrected traveling direction based on said modified output signals, said control circuit including; first means for deriving a first variation in a traveling direction of the vehicle based on said second output signal from the gyro sensor; second means for deriving a first vehicle traveling direction based on said first directional variation; third means for deriving a second vehicle traveling direction based on said first output signal from the geomagnetic sensor; fourth means for deriving a second variation in said second vehicle traveling direction; fifth means for deriving a first value indicative of a disturbance of the geomagnetic field on a short interval basis, said first short interval based value being derived by calculating a difference between said first and second directional variations; sixth means for deriving a second value indicative of a disturbance of the geomagnetic field on a long interval basis said second long interval based value being derived by calculating a difference between said first and second vehicle traveling directions; seventh means for deriving a first correction value indicative of a drift error causes by said gyro sensor; and eighth means for deriving a third vehicle traveling direction as said corrected traveling direction based on said first and second derived vehicle traveling directions by changing a rate of dependence upon said first and second vehicle traveling directions depending on said first short interval based value, said second long interval based value and said first correction value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification