Vehicular traveling direction measuring system with automatic center coordinate position correction
First Claim
1. A system for measuring a traveling direction of a vehicle comprising:
- a geomagnetic sensor, mounted to the vehicle, which is operable to sequentially derive a set of data relating to the geomagnetism around the vehicle, said data having components in two directions which are orthogonal to each other on a horizontal plane to define a first coordinate position by each set of said two directional component data,a control circuit operatively connected to said geomagnetic sensor, said control circuitincluding;
first means for sequentially deriving a second center coordinate position of a corresponding output circle based on said first coordinate position;
second means for storing a first group of said second center coordinate position data;
third means for storing a second group of said second center coordinate position data;
fourth means for deriving a third center coordinate position based on said first group of the second center coordinate position data;
fifth means for deriving a first value indicative of reliability of said third center coordinate position based on said first group of the second center coordinate position data and said third center coordinate position;
sixth means for deriving a fourth center coordinate position based on said second group of the second center coordinate position data;
seventh means for deriving a second value indicative of reliability of said fourth center coordinate position based on said second group of the second center coordinate position data and said fourth center coordinate position;
eighth means for deciding which of said third and fourth center coordinate positions is to be selected for deriving a traveling direction of the vehicle;
ninth means, in response to said eighth means selecting said third center coordinate position, for setting said third center coordinate position to be a first finally corrected center coordinate position;
tenth means, in response to said eighth means selecting said fourth center coordinate position, for setting said fourth center coordinate position to be a second finally corrected center coordinate position;
said eighth means selecting said third or fourth center coordinate position based on said first reliability indicative values derived in current and prior executions of said fifth means, respectively, when said first finally corrected center coordinate position being set in the prior execution of said ninth means, and based on said first and second reliability indicative values derived in the current and prior executions of said fifth and seventh means, respectively, when said second finally corrected center coordinate position being set in the prior execution of said tenth means;
whereby said control circuit derives the traveling direction of the vehicle based on a direction from said first or second finally corrected center coordinate position toward said first coordinate position defined by said two directional component data.
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Accused Products
Abstract
A system measures a traveling direction of a vehicle based on a direction toward a coordinate position defined by output data from a geomagnetic direction sensor from a first center coordinate position of a corresponding output circle. The system derives a second center coordinate position based on the output data from the geomagnetic direction sensor. The system utilizes a first group of the second center coordinate positions and a second group of the second center coordinate positions. When it is decided that the first center coordinate position is shifted, then a new or corrected center coordinate position is derived based on the first group of the second center coordinate positions, on the other hand, when it is decided that no shift of the first center coordinate position is generated, then the corrected center coordinate positiion is derived based on the second group of the second center coordinate positions.
29 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 is operable to sequentially derive a set of data relating to the geomagnetism around the vehicle, said data having components in two directions which are orthogonal to each other on a horizontal plane to define a first coordinate position by each set of said two directional component data, a control circuit operatively connected to said geomagnetic sensor, said control circuit including; first means for sequentially deriving a second center coordinate position of a corresponding output circle based on said first coordinate position; second means for storing a first group of said second center coordinate position data; third means for storing a second group of said second center coordinate position data; fourth means for deriving a third center coordinate position based on said first group of the second center coordinate position data; fifth means for deriving a first value indicative of reliability of said third center coordinate position based on said first group of the second center coordinate position data and said third center coordinate position; sixth means for deriving a fourth center coordinate position based on said second group of the second center coordinate position data; seventh means for deriving a second value indicative of reliability of said fourth center coordinate position based on said second group of the second center coordinate position data and said fourth center coordinate position; eighth means for deciding which of said third and fourth center coordinate positions is to be selected for deriving a traveling direction of the vehicle; ninth means, in response to said eighth means selecting said third center coordinate position, for setting said third center coordinate position to be a first finally corrected center coordinate position; tenth means, in response to said eighth means selecting said fourth center coordinate position, for setting said fourth center coordinate position to be a second finally corrected center coordinate position; said eighth means selecting said third or fourth center coordinate position based on said first reliability indicative values derived in current and prior executions of said fifth means, respectively, when said first finally corrected center coordinate position being set in the prior execution of said ninth means, and based on said first and second reliability indicative values derived in the current and prior executions of said fifth and seventh means, respectively, when said second finally corrected center coordinate position being set in the prior execution of said tenth means; whereby said control circuit derives the traveling direction of the vehicle based on a direction from said first or second finally corrected center coordinate position toward said first coordinate position defined by said two directional component data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification