Data processing: measuring – calibrating – or testing – Calibration or correction system – Direction
Reexamination Certificate
2001-04-18
2004-07-27
Barlow, John (Department: 2857)
Data processing: measuring, calibrating, or testing
Calibration or correction system
Direction
C073S001760, C033S356000
Reexamination Certificate
active
06768957
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic azimuth meter and, more particularly, to the correction or calibration of the electronic azimuth meter and to an electronic timepiece having the electronic azimuth meter.
2. Description of the Prior Art
There is known an electronic azimuth meter having X-direction and Y-direction magnetic sensors comprising MR (magnetoresistive effect) elements for detecting intensity of a magnetic field with regard to respectives of two directions X and Y orthogonal to each other and calculating azimuth from the X-direction and Y-direction magnetic fields detected by the magnetic sensors. Further, it is also known that according to the electronic azimuth member, since a magnetic field by the geomagnetism is inherently small, when a portion of material constituting the azimuth meter is magnetized, a magnetic field produced by the magnetization is superposed on the magnetic field produced by the geomagnetism, a magnetic field sensed or detected by the magnetic sensors is deviated from the magnetic field produced by the geomagnetism and as a result, the azimuth is difficult to measure accurately.
Further, it is also known that in order to correct influence of remnant magnetization of a material of a constituent member of such an electronic azimuth meter, there are measured maximum values and minimum values of magnetic field detecting values by respectives of X-direction and Y-direction magnetic sensors when azimuth of the electronic azimuth meter is variously changed and the magnetic field detecting values are corrected based on the maximum values and the minimum values (for example, Japanese Patent Publication No. 30364/1987).
However, as described above, since the magnetic field produced by the geomagnetic on the earth (surface thereof) is inherently small (at a vicinity of Tokyo, the horizontal magnetic horizontal force is about 30 &mgr;T (strictly speaking, magnetic flux density), further, the dip is about 50 degree, the declination is about 6 degree to the west), detected output of the magnetic field is also small, there is a concern that a variation caused by noise is difficult to avoid and accordingly, accurate determination of the maximum values and the minimum values simply and in a short period of time, is not necessarily facilitated actually.
Further, since the magnetic sensors of the electronic azimuth meter detect magnitudes of components in predetermined directions of the magnetic field (magnetostatic field) or the magnetic flux density in the air, there is no actual benefit in discriminating between the magnetic field and the magnetic density in the air and, therefore, in the specification, the technical term of the magnetic field is used.
SUMMARY OF THE INVENTION
The present invention has been carried out in view of the above-described problem and it is an object thereof to provide a correcting mechanism of an electronic azimuth member facilitating to determine the maximum values and the minimum values, an electronic azimuth meter having the correcting mechanism and an electronic time piece having the electronic azimuth meter.
In order to achieve the above-described object, according to the invention, there is provided a correcting mechanism of an electronic azimuth meter having an X-direction magnetic sensor and a Y-direction magnetic sensor for detecting intensities of a magnetic field in two orthogonal directions X and Y and constituted to calculate an azimuth from magnetic field detecting values of the X- and the Y-direction magnetic sensors, comprising storing means for storing respectives of a maximum value and a minimum value with regard to the magnetic field detecting value by each of the X-direction and the Y-direction magnetic sensors, updating means for updating the maximum value or the minimum value to a newly detected magnetic field detecting value when the magnetic field value which is newly detected by each of the X-direction and the Y-direction magnetic sensors is larger than the maximum value stored in the storing means or smaller than the minimum value stored therein, azimuth change inducing means for providing a display of inducing a continuous change of the azimuth of an electronic azimuth meter main body over a range larger than 360 degree, predicting means for predicting that the maximum value or the minimum value in the X- or Y-direction is a true value when each of the maximum values and the minimum values of the magnetic field detecting values in the X-direction and the Y-direction is not updated during a predetermined time period in accordance with rotation of the electronic azimuth meter main body in accordance with an induction display of the azimuth change inducing means and canceling a prediction indicating the true value when the maximum value or the minimum value predicted to be the true value is updated by the updating means, and stop control means for stopping an updating processing by the updating means when all of the maximum values and the minimum values in the X-direction and the Y-direction are predicted to be the true values and induction by induction display of the azimuth change inducing means reaches 360 degree or more.
In the correcting mechanism of an electronic azimuth meter according to the invention, there are provided “the updating means for updating the maximum value or the minimum value to the newly detected magnetic field detecting value when the magnetic field detecting value which is newly detected by each of the X-direction and the Y-direction magnetic sensors is larger than the maximum value stored in the storing means or smaller than the minimum value stored therein, and predicting means for predicting that the maximum value or the minimum value in the X- or the Y-direction is the true value when updating is not carried out during a predetermined time period in accordance with rotation of the electronic azimuth meter main body in accordance with the induction display of the azimuth change inducing means with regard to respectives of the maximum values and the minimum values of the magnetic field detecting values in the X-direction and the Y-direction”, and accordingly, with regard to respectives of the X-direction and the Y-direction, (except that an initial detecting value is adopted as the maximum value or the minimum value) so far as the magnetic field detecting values are provided in the forms of a maximum and a minimum, the magnetic field detecting values are adopted as the maximum value and the minimum value.
Further, according to the correcting mechanism of the invention, “the azimuth change inducing means is constituted to provide the display of inducing the continuous change of the azimuth of the electronic azimuth meter main body over the range of at least 360 degree”, further, “the stop control means is constituted to stop the updating processing by the updating means when all of the maximum values and the minimum values in the X-direction and the Y-direction are predicted to be the true values and the induction by the induction display of the azimuth change inducing means reaches 360 degree or more” and accordingly, with regard to respectives of the X-direction and the Y-direction, the magnetic field detecting values provided as the maximum value and the minimum value are selected from detected values with regard to the azimuth of 360 degree, that is, all of the azimuth and therefore, the magnetic field detecting values can be the maximum value and the minimum value in two directions in principle.
Further, according to the correcting mechanism of the invention, “the continuous azimuth change induction display by the azimuth change inducing means is constituted to be able to carry out over a range larger than 360 degree” and “the update stop processing by the stop control means is constituted to carry out so far as all of the maximum values and the minimum values in the X-direction and the Y-direction are predicted to be the true values and the induction display by the azimuth change inducting means reaches 360 d
Adams & Wilks
Barlow John
Cherry Stephen J.
Seiko Instruments Inc.
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