Apparatus and method for detecting azimuth and inclination angel, program for detecting the same, and portable terminal device for detecting the same
First Claim
1. An apparatus for detecting azimuth and inclination angle of a device, the apparatus having an azimuth sensor for detecting geomagnetism components in a coordinate system fixed to the device and an acceleration sensor for detecting gravitational force components in the coordinate system fixed to the device and adapted to generate final detection values of the azimuth and the inclination angle of the device in a terrestrial coordinate system by use of the geomagnetism components and the gravitational force components, the apparatus further comprising:
- first computation means for performing coordinate conversion of the geomagnetism components by use of the gravitational force components to thereby obtain the azimuth and the inclination angle to be used as reference data;
geomagnetism-depression-angle obtaining means for obtaining a geomagnetism depression angle, which is an angle formed between a horizontal plane and a direction of geomagnetism;
second computation means for solving simultaneous equations of the azimuth and the inclination angle, the simultaneous equations being obtained on the basis of the relation between the geomagnetism components in the coordinate system fixed to the device and the geomagnetism components in the terrestrial coordinate system and being specified by the geomagnetism depression angle, to thereby obtain at least one set of computed values of the azimuth and the inclination angle to be used as candidates of the azimuth and the inclination angle; and
selection means, operable when a plurality of sets of computed values are obtained, for selecting one set of the computed values among the candidates by referring to the reference data, the selected one set of computed values being used as the final detection values of the azimuth and the inclination angle.
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Abstract
In an azimuth/inclination-angle detection apparatus, a measurement data obtaining unit obtains first and second measurement data sets g and h from acceleration and magnetic sensors, respectively. A first computation unit calculates an azimuth α0, an elevation angle β0, and a geomagnetism depression angle θ0 from the measurement data sets g and h. An averaging unit accumulates and averages the geomagnetism depression angle θ0 so as to obtain a value to be used as a geomagnetism depression angle θ. A second computation unit calculates an azimuth α and an elevation angle β from the second measurement data set h and the geomagnetism depression angle θ. When a plurality of solutions exist, they are stored as candidates (α1, β1) and (α2, β2). A selection unit selects a detection value (α, β) from the candidates (α1, β1) and (α2, β2) with reference to the above-described values α0 and β0 serving as reference values.
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Citations
10 Claims
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1. An apparatus for detecting azimuth and inclination angle of a device, the apparatus having an azimuth sensor for detecting geomagnetism components in a coordinate system fixed to the device and an acceleration sensor for detecting gravitational force components in the coordinate system fixed to the device and adapted to generate final detection values of the azimuth and the inclination angle of the device in a terrestrial coordinate system by use of the geomagnetism components and the gravitational force components, the apparatus further comprising:
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first computation means for performing coordinate conversion of the geomagnetism components by use of the gravitational force components to thereby obtain the azimuth and the inclination angle to be used as reference data;
geomagnetism-depression-angle obtaining means for obtaining a geomagnetism depression angle, which is an angle formed between a horizontal plane and a direction of geomagnetism;
second computation means for solving simultaneous equations of the azimuth and the inclination angle, the simultaneous equations being obtained on the basis of the relation between the geomagnetism components in the coordinate system fixed to the device and the geomagnetism components in the terrestrial coordinate system and being specified by the geomagnetism depression angle, to thereby obtain at least one set of computed values of the azimuth and the inclination angle to be used as candidates of the azimuth and the inclination angle; and
selection means, operable when a plurality of sets of computed values are obtained, for selecting one set of the computed values among the candidates by referring to the reference data, the selected one set of computed values being used as the final detection values of the azimuth and the inclination angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of detecting azimuth and inclination angle of a device in which geomagnetism components in a coordinate system fixed to the device and gravitational force components in the coordinate system fixed to the device are detected and final detection values of the azimuth and the inclination angle of the device in a terrestrial coordinate system are generated by use of the geomagnetism components and the gravitational force components, the method comprising steps of:
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performing coordinate conversion of the geomagnetism components by use of the gravitational force components to thereby compute the azimuth and the inclination angle, and storing the computed azimuth and inclination angle as reference data;
obtaining a geomagnetism depression angle, which is an angle formed between a horizontal plane and a direction of geomagnetism;
solving simultaneous equations of the azimuth and the inclination angle, the simultaneous equations being obtained on the basis of the relation between the geomagnetism components in the coordinate system fixed to the device and the geomagnetism components in the terrestrial coordinate system and being specified by the geomagnetism depression angle, to thereby obtain at least one set of computed values of the azimuth and the inclination angle to be used as candidates of the azimuth and the inclination angle; and
selecting, when a plurality of sets of computed values are obtained, one set of computed values among the candidates by referring to the reference data, the selected one set of computed values being used as the final detection values of the azimuth and the inclination angle.
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10. A program for causing a computer to perform the steps of:
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detecting geomagnetism components in a coordinate system fixed to a device;
detecting gravitational force components in the coordinate system fixed to the device;
performing coordinate conversion of the geomagnetism components by use of the gravitational force components to thereby compute the azimuth and the inclination angle, and storing the computed azimuth and inclination angle as reference data;
obtaining a geomagnetism depression angle, which is an angle formed between a horizontal plane and a direction of geomagnetism;
solving simultaneous equations of the azimuth and the inclination angle, the simultaneous equations being obtained on the basis of the relation between the geomagnetism components in the coordinate system fixed to the device and the geomagnetism components in the terrestrial coordinate system and being specified by the geomagnetism depression angle, to thereby obtain at least one set of computed values of the azimuth and the inclination angle to be used as candidates of the azimuth and the inclination angle; and
selecting, when a plurality of sets of computed values are obtained, one set of computed values among the candidates by referring to the reference data, the selected one set of computed values being used as final detection values of the azimuth and the inclination angle.
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Specification