JP2006113031A - Azimuthal angle measurement method and azimuthal angle measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an azimuthal angle measurement method and an azimuthal angle measurement device for obtaining initial azimuth, when a traveling direction azimuth display of a portable terminal having an electronic compass fixed in a car is performed. <P>SOLUTION: At the beginning, an offset value of a terrestrial magnetism is previously calculated (S51), from the terrestrial magnetism measurement data obtained by the portable terminal at the outside of the car. Then, a magnetic intensity of each axis of X, Y, Z is measured outside of the car, by orientating the portable terminal to the car direction (S52). Then, the magnetic intensity of each axis of X, Y, Z is measured (S53), fixing the portable terminal inside of the car. A difference between the magnetic intensity measured at S52 and the magnetic intensity measured at S53 is calculated. Then, addition and subtraction are performed (S54) from the terrestrial magnetism offset value obtained at S51. Accordingly, a precise azimuthal angle measurement can be made. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an azimuth angle measuring method and an azimuth angle measuring device, and more specifically, azimuth angle measurement for obtaining an initial azimuth when a mobile terminal equipped with an electronic compass is fixed to a vehicle and the direction of travel is displayed. The present invention relates to a method and an azimuth measuring device.

  There are cases where a portable device such as a mobile phone equipped with an electronic compass is fixed to a vehicle to obtain azimuth information in the front direction and the direction of the vehicle and used in an application. However, because the car body and internal parts are made of iron and magnetized, the magnetic field inside the car contains an offset component (geomagnetic offset), and the geomagnetic direction indicated by the electronic compass remains unchanged. It contains a lot of errors.

  The geomagnetic offset also differs depending on where in the car the portable device is fixed. Therefore, the electronic compass does not indicate the correct orientation simply by bringing the mobile device into the vehicle and fixing it. In addition, performing a calibration operation such as making a round trip of a portable device in a vehicle does not calibrate the magnetization of the vehicle body, and is meaningless.

  As Patent Document 1 that discloses the prior art of the present invention, there is an “initial orientation setting method for an orientation detection device”. This patent document 1 calculates a direction using a gyro and a geomagnetic sensor. The initial direction immediately after the vehicle is turned on is a backup direction storing the direction indicated by the gyro during the previous driving, and the current geomagnetic sensor. Compared with the geomagnetic direction shown in Fig. 1, the direction information with higher reliability is adopted, and the reliability is checked by looking at the elapsed time since magnetization, the completion status of magnetization correction at the previous power-off, etc. In this case, the initial direction is determined without using the geomagnetic direction when the deterioration of the direction accuracy is expected.

  Patent Document 2 relates to a “moving direction detection method”, which is provided with an angular velocity sensor and a geomagnetic sensor, and for the initial azimuth immediately after the vehicle is turned on, only the signal from the geomagnetic sensor is used to determine the azimuth. Display of the moving direction of the moving object by combining each sensor output with an appropriate ratio according to the situation, such as increasing the contribution of information such as angular velocity sensors over time. It is designed to be highly accurate with continuity.

JP-A-6-3148 JP 59-218913 A

  However, it can be said that both of the above-mentioned Patent Documents 1 and 2 disclose means for solving the same problem for the purpose of knowing the heading direction of the vehicle immediately after the power is turned on, but both are fixed on the vehicle. It relates to a magnetic azimuth sensor, and the technical content is to use a gyro sensor and a magnetic azimuth sensor together to contribute to the mutual contribution to the azimuth output. However, there is still a problem with the method for correctly obtaining the initial orientation when the orientation of the traveling direction is displayed in a fixed state.

  FIG. 1 and FIG. 2 are diagrams for explaining problems of a conventional azimuth measuring method, and FIG. 1 is an explanation of an azimuth indicated by an electronic compass when a pedestrian is holding a portable terminal outside the vehicle. FIG. 2 and FIG. 2 are diagrams showing a case where the portable terminal with an electronic compass is brought into the vehicle and fixed.

  In the figure, reference numeral 1 is a coordinate point of geomagnetic measurement data (x in the figure), 2 is a coordinate point of geomagnetic measurement data acquired outside the vehicle so that the mobile terminal is aligned with the front direction of the vehicle (in the figure) 3) Geomagnetic offset value calculated from geomagnetic measurement data obtained by the electronic compass on the mobile terminal outside the vehicle (coordinate points; ◇ in the figure), 4 indicates the mobile terminal in front of the vehicle The coordinate points (● in the figure) of the geomagnetic measurement data acquired with the direction fixed are shown. In addition, the solid line arc in a figure has shown the geomagnetic data distribution circle calculated from the magnetic field data which the azimuth measuring device (electronic compass) in a portable apparatus detected outside the vehicle.

  As can be seen from FIG. 1 and FIG. 2, the coordinate point (circle mark in the figure) 2 of the geomagnetic measurement data in which the portable terminal is stored outside the vehicle according to the vehicle direction in FIG. 1 is indicated by a solid arrow in FIG. As shown, the mobile terminal is shifted to the coordinate point (● in the figure) 4 of the geomagnetic measurement data acquired by fixing the mobile terminal so as to coincide with the front direction of the vehicle, and the true direction (broken arrow) Therefore, there is a problem that the mobile terminal is shifted to the wrong direction (thick arrow) displayed after being fixed in the vehicle.

  The present invention has been made in view of such a problem, and an object of the present invention is to obtain an initial direction when a mobile terminal equipped with an electronic compass is fixed to a vehicle and the direction of travel is displayed. An object is to provide an azimuth measuring method and an azimuth measuring device.

  The present invention has been made to achieve such an object, and the invention according to claim 1 is directed to a case where a portable terminal equipped with an electronic compass is fixed to a vehicle and the direction of travel is displayed. In the azimuth angle measuring method for obtaining an initial azimuth, a first step of calculating a geomagnetic offset value in advance from geomagnetic measurement data acquired by a portable terminal outside the vehicle, and a first step of aligning the portable terminal with the direction of the vehicle body outside the vehicle. A second step of measuring magnetic strength data; a third step of measuring second magnetic strength data while fixing the portable terminal in the vehicle; and a first magnetic strength measured in the second step. The difference between the data and the second magnetic intensity data measured in the third step is calculated, and the difference is added to or subtracted from the geomagnetic offset value obtained in the first step. Characterized by a fourth step.

  According to a second aspect of the present invention, there is provided an azimuth measuring method for obtaining an initial azimuth when a mobile terminal equipped with an electronic compass is fixed to a vehicle and displaying an azimuth in a traveling direction. A first step of calculating a geomagnetic offset value and a magnitude of a geomagnetic vector in advance from the acquired geomagnetic measurement data; and measuring the first magnetic intensity data by aligning the mobile terminal with the direction of the vehicle body outside the vehicle, and said geomagnetic offset A second step of correcting the value to calculate the azimuth angle, a third step of measuring the second magnetic intensity data while fixing the portable terminal in the vehicle, and the third step measured in the third step A fourth step that assumes a spherical surface separated from the magnetic intensity data of 2 by the magnitude of the geomagnetic vector determined in the first step; and Origin, such as to match the azimuth obtained by the second step, and having a fifth step of finding on the sphere.

  The invention described in claim 3 is characterized in that, in the invention described in claim 2, there is a step of measuring an inclination angle in the second step and the third step.

  According to a fourth aspect of the invention, in the invention of the second or third aspect, in the fifth step, a step of correcting a difference in inclination angle between the second step and the third step. It is characterized by having.

  According to a fifth aspect of the present invention, in the invention of the second, third, or fourth aspect, the tilt information of the mobile terminal is acquired using a uniaxial, biaxial, or triaxial tilt sensor. Features.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein geomagnetic measurement data sensed by the electronic compass is acquired and stored for each of two or three axes. And

  The invention according to claim 7 acquires geomagnetic measurement data in an azimuth measuring device that obtains an initial azimuth when a portable terminal equipped with an electronic compass is fixed to a vehicle and the direction of travel is displayed. Geomagnetic information acquisition means, storage means for storing the first geomagnetic measurement data and second geomagnetism measurement data acquired by the geomagnetic information acquisition means, and a portable terminal from the geomagnetism measurement data acquired by the geomagnetic information acquisition means A first geomagnetic offset calculating means for calculating an internal geomagnetic offset value; and values of the first geomagnetic measurement data and the second geomagnetic measurement data stored in the storage means; The second geomagnetic offset value is calculated by subtracting the difference between the value and the second geomagnetic data value from the first geomagnetic offset value. An off-vehicle state determining means, determining whether the portable terminal is inside or outside the vehicle and instructing the second geomagnetic offset calculating means to calculate a geomagnetic offset value in the vehicle; Azimuth angle calculating means for calculating the azimuth angle from the latest geomagnetic measurement data stored in the storage means and the first geomagnetic offset value or the second geomagnetic offset value passed from the in-vehicle state determination means. It is characterized by.

  The invention according to claim 8 is the invention according to claim 7, further comprising an inclination angle information acquisition unit and an inclination angle correction unit, wherein the inclination angle information of the mobile terminal acquired by the inclination angle information acquisition unit is The tilt angle correction means performs tilt angle correction on the azimuth angle calculated by the azimuth angle calculation means based on the stored tilt angle information.

  The invention according to claim 9 is the invention according to claim 7 or 8, further comprising a geomagnetism size calculating means, wherein the second geomagnetic offset calculating means is the first geomagnetic measurement data at the time of acquisition. 1 tilt angle information, the second tilt angle information at the time of obtaining the second geomagnetic measurement data, the second geomagnetic data, the first geomagnetic data, and the first geomagnetic offset. The second geomagnetic offset value is calculated from the azimuth angle and the geomagnetic size calculated by the geomagnetic size calculating means.

  The invention according to claim 10 acquires geomagnetic measurement data in an azimuth measuring device that obtains an initial azimuth when a portable terminal equipped with an electronic compass is fixed to a vehicle and the direction of travel is displayed. Geomagnetic information acquisition means, storage means for storing the first geomagnetic measurement data and second geomagnetism measurement data acquired by the geomagnetic information acquisition means, and a portable terminal from the geomagnetism measurement data acquired by the geomagnetic information acquisition means A first geomagnetic offset calculating means for calculating an internal geomagnetic offset value; a geomagnetic size calculating means for calculating a geomagnetism size from the geomagnetic measurement data acquired by the geomagnetic information acquiring means and the first geomagnetic offset value; First geomagnetic vector information is calculated from the first geomagnetic measurement data and the first geomagnetic offset value. From the magnetic vector calculation means, the second geomagnetism measurement data stored in the storage means, and the geomagnetism size information calculated by the geomagnetism size calculation means, the first geomagnetism measurement data is stored. A point indicating the same geomagnetic vector as the geomagnetic vector information is calculated, the second geomagnetic offset calculation means for calculating this point as a second geomagnetic offset value, and the geomagnetism measurement data acquired by the geomagnetic information acquisition means Inclination angle acquisition means for acquiring inclination information of the portable terminal and whether the portable terminal is inside or outside the vehicle, and instructing the second geomagnetic offset calculation means to calculate a geomagnetic offset value in the vehicle Vehicle state determination means, the latest geomagnetic measurement data stored in the storage means, and the vehicle state determination means Wherein a first of the geomagnetism offset value or the second geomagnetic offset value, characterized in that a azimuth calculating means for calculating an azimuth angle from the calculated inclination information by the inclination angle obtaining unit.

  The invention according to claim 11 is the invention according to claim 10, further comprising inclination angle acquisition means for acquiring inclination information of the mobile terminal, wherein the geomagnetic vector calculation means also uses the inclination information. It is characterized by calculating a geomagnetic vector.

  The invention according to claim 12 is the invention according to claim 7, wherein the inclination information is an inclination angle acquired outside the vehicle and an inclination angle acquired inside the vehicle.

  According to the present invention, the first step of calculating the geomagnetic offset value in advance from the geomagnetic measurement data acquired by the portable terminal outside the vehicle, and the first magnetic intensity data by aligning the portable terminal with the direction of the vehicle body outside the vehicle. A second step of measuring, a third step of measuring the second magnetic intensity data while fixing the portable terminal in the vehicle, the first magnetic intensity data measured in the second step, and the first And a fourth step of calculating a difference between the second magnetic intensity data measured in the step 3 and adding / subtracting the difference from the geomagnetic offset value obtained in the first step. It is possible to realize an azimuth measuring method in which the portable terminal is fixed to the vehicle and the initial azimuth when displaying the azimuth in the traveling direction is obtained. Similarly, an azimuth measuring device can also be realized.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 3 is a diagram for explaining Example 1 of the azimuth measuring method of the present invention, and is a diagram for explaining a correction method of the azimuth measuring device when the portable terminal is fixed in the vehicle.

  In the figure, reference numeral 11 is a coordinate point of the geomagnetic measurement data stored outside the vehicle in accordance with the vehicle direction (marked with a circle in the figure), and 12 is a geomagnetic offset value (coordinate point; figure obtained from the geomagnetic measurement data). ◇), 13 is a geomagnetic offset value (coordinate point; Δ in the figure) in the in-vehicle environment derived by the present invention, and 14 is in the car so that the mobile terminal coincides with the front direction of the vehicle. The coordinate points (● in the figure) of the geomagnetic measurement data acquired in a fixed manner are shown. In addition, the solid line arc in a figure shows the distribution circle | round | yen of the geomagnetic measurement data calculated from the magnetic field data which the azimuth measuring device (electronic compass) in a portable device detected outside the vehicle as shown in FIG. The arc indicates a distribution circle of the geomagnetic measurement data calculated from the magnetic field data detected by the azimuth measuring device (electronic compass) in the portable device in the vehicle.

  As shown in FIG. 1, in a place where the magnetic field is normal outside the vehicle, the direction of the automobile on board is aligned with the direction of the mobile terminal, and a predetermined button provided on the mobile terminal is pressed. Is used as a trigger, and magnetic data sensed by the electronic compass is acquired and stored for each of two or three axes. At this time, it is assumed that the offset component of the portable terminal and the geomagnetic sensor has been measured or calibrated in advance.

  Next, as shown in FIG. 3, the portable terminal is moved into the vehicle and fixed. At this time, the mobile terminal needs to be fixed in alignment with the front direction of the car so as to match the orientation of the terminal when the azimuth is stored outside the vehicle.

  When the mobile terminal is fixed, magnetic data sensed by the electronic compass is acquired for each of the two axes or three axes. The difference between the coordinate point 11 of the geomagnetic measurement data obtained outside the vehicle and the coordinate point 14 of the geomagnetic measurement data obtained inside the vehicle is the difference between the geomagnetic offset values outside the vehicle and inside the vehicle (marked with ◇ in the figure and in the figure). The difference between the geomagnetic measurement data is subtracted from the offset value obtained in advance outside the vehicle. At this time, the inclination angle of the portable terminal is made substantially the same when measuring the geomagnetic measurement data outside the vehicle and when measuring the geomagnetic measurement data outside the vehicle.

FIG. 5 is a flowchart for explaining the first embodiment of the azimuth measuring method of the present invention.
First, a geomagnetic offset value is calculated in advance from geomagnetic measurement data acquired by a portable terminal outside the vehicle (S51). Next, the magnetic strength of each of the X, Y, and Z axes is measured outside the vehicle by aligning the mobile terminal with the direction of the vehicle body (S52). Next, the portable terminal is fixed in the vehicle, and the magnetic strength of each of the X, Y, and Z axes is measured (S53).

  Table 1 shows the measured values of the magnetic strength of the triaxial geomagnetic sensor inside and outside the automobile. Table 1 shows the geomagnetic measurement data acquired with the mobile terminal facing the front direction of the vehicle outside the vehicle, and the geomagnetic measurement acquired by fixing the mobile terminal inside the vehicle to match the front direction of the vehicle. An example of data is shown.

  Next, the difference between the magnetic intensity measured in S52 described above and the magnetic intensity measured in S53 is calculated, and addition / subtraction is performed from the geomagnetic offset value obtained in S51 described above (S54). In this way, accurate azimuth measurement is possible.

(Unit is optional)
FIG. 7 is a block diagram for explaining the embodiment 1 of the azimuth angle measuring apparatus of the present invention, in which reference numeral 31 is a geomagnetic information acquisition unit, 32 is a storage unit, 33 is a first geomagnetic offset calculation unit, 34. Is a second geomagnetic offset calculation unit, 35 is an in-vehicle state determination unit, 36 is an azimuth angle calculation unit, 37 is a display unit, 38 is an inclination angle information acquisition unit, 39 is an inclination angle correction calculation unit, and 40 is a geomagnetic size calculation unit. , 41 indicate geomagnetic vector calculation units.

  First, when using a portable device outside the vehicle, biaxial or triaxial geomagnetic measurement data is acquired from the geomagnetic information acquisition unit 31 and stored in the storage unit 32. The first geomagnetic offset calculation unit 33 calculates and estimates a geomagnetic offset component inside the portable device from the acquired geomagnetic measurement data, and stores it in the storage unit.

  Since the vehicle is out of the vehicle, the in-vehicle state determination unit 35 determines that the vehicle is not in the on-vehicle state (outside the vehicle), and passes the first geomagnetic offset value calculated by the first geomagnetic offset calculation unit 33 to the azimuth angle calculation unit 36. The azimuth calculation unit 36 calculates the azimuth based on the latest geomagnetic measurement data stored in the storage unit 32 and the first geomagnetic offset value passed from the vehicle-mounted state determination unit 35, and the calculation result is displayed on the display unit. 37.

  Before bringing the mobile device into the vehicle, the user obtains geomagnetic data (first geomagnetic measurement data) by combining the front direction of the vehicle and the front direction of the mobile device outside the vehicle, and stores the first geomagnetism stored. Based on the offset value, the azimuth is calculated and stored. The inclination angle of the portable device when acquiring this data needs to coincide with the inclination angle when the portable device is fixed in the vehicle.

  Next, the portable device is brought into the vehicle, and the portable device is fixed in the vehicle with the same inclination angle as when the geomagnetic measurement data was acquired outside the vehicle with the front direction of the vehicle facing. At this time, the geomagnetism measurement data (second geomagnetism measurement data) acquired by the geomagnetism information acquisition unit 31 and stored in the storage unit 32 has the same orientation as the first geomagnetism measurement data acquired outside the vehicle. The difference between the first geomagnetic measurement data and the second geomagnetic measurement data can be determined as the geomagnetic offset value added in the vehicle.

  When the in-vehicle state determination unit 35 determines that the portable device is fixed inside the vehicle, the in-vehicle state determination unit 35 instructs the second geomagnetic offset calculation unit 34 to calculate the geomagnetic offset value inside the vehicle. . In response to this, the second geomagnetic offset calculation unit 34 acquires the first geomagnetic offset value, the first geomagnetic measurement data, and the second geomagnetic measurement data value from the storage unit 32, and The difference between the first geomagnetic offset value and the second geomagnetic offset value is subtracted from the first geomagnetic offset value, stored in the storage unit 32 as a new second geomagnetic offset value, and passed to the in-vehicle state determination unit 35. .

  The in-vehicle state determination unit 35 sends the second geomagnetic offset value to the azimuth angle calculation unit 36, and the azimuth angle calculation unit 36 receives the second geomagnetic measurement data value and the second geomagnetic offset value acquired from the storage unit 32. The azimuth angle is calculated from the above and output to the display unit 37. Since the magnitude and dip angle of the geomagnetism do not change greatly inside and outside the vehicle, the correct geomagnetic offset value can be obtained when the portable device is brought into the vehicle and fixed by such an azimuth measuring method.

  Thereafter, until the in-vehicle state determination unit 35 detects that the in-vehicle state is lost, the geomagnetism measurement data acquired by the geomagnetic information acquisition unit 31 is obtained by the azimuth calculation unit 36 using the second geomagnetic offset value. Azimuth calculation is performed.

  FIG. 4 is a diagram for explaining Example 2 of the azimuth measuring method of the present invention, and is a diagram for explaining a correction method of the azimuth measuring device when the portable terminal is fixed in the vehicle.

  In the figure, reference numeral 21 is a coordinate point (○ mark in the figure) of the geomagnetic measurement data in which the portable terminal is stored outside the vehicle in accordance with the vehicle direction, and 22 is a geomagnetic offset value (coordinate point; figure shown in FIG. ◇ in the figure), 23 is the geomagnetic offset value (coordinate point; △ mark in the figure) in the in-car environment derived by the present invention, and 24 is in the car so that the mobile terminal matches the front direction of the vehicle. The coordinate points (● in the figure) of the geomagnetic measurement data acquired in a fixed manner are shown. In addition, the broken line arc in a figure has shown the circle | round | yen (it is assumed that there exists a magnetic offset on this circumference) centering on the geomagnetic measurement data measured in the car and having a radius equivalent to geomagnetic intensity.

  As shown in FIG. 1, in a place where the magnetic field is normal outside the vehicle, the direction of the automobile on board is aligned with the direction of the mobile terminal, and a predetermined button provided on the mobile terminal is pressed. Is used as a trigger, and the geomagnetic measurement data sensed by the electronic compass is acquired and stored for each of two or three axes. In addition, the tilt information of the mobile terminal is acquired using a one-axis, two-axis, or three-axis tilt angle sensor. Next, the geomagnetic direction outside the vehicle is calculated and stored from the geomagnetic measurement data acquired outside the vehicle and the tilt angle information. At this time, it is assumed that the offset component of the portable terminal and the geomagnetic sensor has been measured or calibrated in advance.

  Next, as shown in FIG. 4, the portable terminal is moved and fixed in the vehicle. At this time, when the portable terminal is fixed, geomagnetic measurement data sensed by the electronic compass is acquired for each of the two axes or three axes, and the tilt information of the portable terminal is tilted by one, two, or three axes. Acquire using a sensor.

  A circumference or a spherical surface having a radius corresponding to a geomagnetic intensity outside the vehicle is assumed from the coordinate point 21 of the geomagnetic measurement data acquired inside the vehicle. In addition, the geomagnetic direction measured and stored outside the vehicle is corrected based on the tilt angle information acquired inside the vehicle, and a point indicating the corrected direction is indicated by the geomagnetic measurement data acquired inside the vehicle. Or it selects on a spherical surface and makes this a new geomagnetic offset value. In other words, it is a distance equivalent to the geomagnetic intensity inside the car from the coordinate point of the geomagnetism measurement data (indicated by ◇ in the figure), and only the direction (solid arrow) opposite to the value corrected by the tilt angle of the bearing stored outside the car (broken arrow) A remote coordinate point (Δ mark in the figure) is set as a new geomagnetic offset value.

  At this time, it is assumed that the geomagnetic vector size is the same outside the vehicle and inside the vehicle. That is, it is assumed that the circumference or spherical radius drawn by the output of the biaxial or triaxial azimuth sensor does not change outside the vehicle as compared to that obtained outside the vehicle.

FIG. 6 is a flowchart for explaining the embodiment 2 of the azimuth measuring method of the present invention.
First, the geomagnetic offset value and the magnitude of the geomagnetic vector are calculated in advance from geomagnetic measurement data acquired by the mobile terminal outside the vehicle (S61). Next, the magnetic strength of each of the X, Y, and Z axes is measured outside the vehicle by aligning the mobile terminal with the direction of the vehicle body, and the azimuth angle is calculated by correcting the geomagnetic offset value (S62). Next, the portable terminal is fixed in the vehicle, the magnetic strength of each of the X, Y, and Z axes is measured, and the tilt angle is measured as necessary (S63). Table 1 shows the measured values of magnetic strength with a triaxial geomagnetic sensor inside and outside the automobile. Next, a spherical surface that is separated by the magnitude of the geomagnetic vector obtained in S61 described above from the geomagnetic measurement data in S63 described above is assumed (S64). Next, a starting point on the spherical surface is obtained such that the geomagnetic measurement data matches the azimuth angle obtained in S62 described above. Further, the inclination angle is corrected as necessary (S65). In this way, accurate azimuth measurement is possible.

  The configuration diagram of the azimuth measuring apparatus of the present invention in the second embodiment is the same as the configuration diagram in the first embodiment shown in FIG. 7, but the operation is different. In the second embodiment, a description will be given of an embodiment that can be used when the geomagnetic data is acquired outside the vehicle and when the inclination angle is different between when the portable device is fixed inside the vehicle.

  First, when using a portable device outside the vehicle, 2-axis or 3-axis geomagnetism measurement data is acquired from the geomagnetic information acquisition unit 31, and the tilt angle information acquisition unit 38 acquires 1 axis, 2 axes of the mobile device. Or, the three-axis tilt angle information is acquired and stored in the storage unit 32. The first geomagnetic offset calculator 33 calculates and estimates a geomagnetic offset component inside the portable device from the acquired geomagnetic measurement data, and stores it in the storage unit 32. The tilt angle correction calculation unit 39 uses the acquired tilt angle information to perform tilt angle correction calculation with respect to the azimuth angle of the mobile device when the azimuth angle calculation unit 36 calculates the azimuth angle.

  Since the vehicle is outside the vehicle, the vehicle-mounted state determination unit 35 determines that the vehicle is not in a vehicle-mounted state (outside the vehicle), and the first geomagnetic offset value and inclination angle correction calculation unit 39 calculated by the first geomagnetic offset calculation unit 33 calculates. The tilt angle is passed to the azimuth angle calculator 36.

  The azimuth angle calculation unit 36 generates the geomagnetic vector information (first geomagnetic vector) based on the latest geomagnetism measurement data stored in the storage unit 32 and the first geomagnetic offset value and tilt angle passed from the vehicle-mounted state determination unit 35. Information) and azimuth angle, and the calculation result is displayed on the display unit 37, and the geomagnetic size calculation unit 40 calculates the geomagnetic size from the first geomagnetic offset value and the geomagnetic measurement data stored in the storage unit 32. And it memorize | stores in the memory | storage part 32 with 1st azimuth angle information.

  The geomagnetic vector calculation unit 41 calculates first geomagnetic vector information from the first geomagnetic measurement data and the first geomagnetic offset value.

  Before bringing the mobile device into the vehicle, the user aligns the front direction of the vehicle with the front direction of the mobile device outside the vehicle, and the geomagnetic measurement data (first geomagnetic measurement data), and the tilt angle information of the mobile device at that time (First tilt angle information) is acquired, and the azimuth angle is calculated and stored based on the stored first geomagnetic offset value.

  Next, the portable device is brought into the vehicle, the portable device is fixed in the vehicle with the front direction of the vehicle facing, and geomagnetic information (second geomagnetic measurement data) is obtained from the geomagnetic information acquisition unit 31 and the inclination angle information acquisition unit 38. ), Inclination angle information (second inclination angle information) is acquired.

  At this time, the geomagnetic measurement data (second geomagnetic measurement data) acquired by the geomagnetic information acquisition unit 31 and stored in the storage unit 32 has the same orientation as the first geomagnetic measurement data acquired outside the vehicle. If the mobile device tilt angle when the azimuth is measured outside the vehicle and the mobile device tilt angle when the mobile device is fixed inside the vehicle are not the same, the difference between the first geomagnetic measurement data and the second geomagnetic measurement data is However, it is not necessarily the geomagnetic offset value added in the vehicle, and a tilt angle correction calculation is required.

  When the in-vehicle state determination unit 35 determines that the portable device is fixed inside the vehicle, the in-vehicle state determination unit 35 instructs the second geomagnetic offset calculation unit 34 to calculate the geomagnetic offset value inside the vehicle. .

  The second geomagnetic offset calculation unit 34 estimates a circle or a sphere that may have a geomagnetic offset value from the second geomagnetic measurement data and the geomagnetic size information stored in the storage unit 32, Alternatively, in a spherical shape, a point indicating the same geomagnetic vector as the first geomagnetic vector information in which the second geomagnetic measurement data is stored is calculated, and this point is calculated as the second geomagnetic offset value and stored in the storage unit 32. At the same time, it is sent to the in-vehicle state determination unit 35. At this time, if the mobile device tilt angle when the azimuth is measured outside the vehicle and the mobile device tilt angle when the mobile device is fixed inside the vehicle are not the same, the first geomagnetic vector information is represented by the first tilt angle. Information and the second tilt angle information are corrected, converted into geomagnetic vector information (second geomagnetic vector information) at the tilt angle when fixed in the vehicle, and replaced with the first geomagnetic vector information. A geomagnetic offset value of 2 is calculated.

  The in-vehicle state determination unit 35 sends the second geomagnetic offset value to the azimuth angle calculation unit 36, and the azimuth angle calculation unit 36 receives the second geomagnetic measurement data value and the second geomagnetic offset value acquired from the storage unit 32. The azimuth angle is calculated from the data and output to the display unit 37.

  Since the magnitude and dip angle of the geomagnetism do not change greatly inside and outside the vehicle, the correct geomagnetic offset value can be obtained when the portable device is brought into the vehicle and fixed by such an azimuth measuring method.

  Thereafter, until the in-vehicle state determination unit 35 detects that the in-vehicle state is lost, the geomagnetism measurement data acquired by the geomagnetic information acquisition unit 31 is obtained by the azimuth calculation unit 36 using the second geomagnetic offset value. Azimuth calculation is done.

  As described above, the first embodiment and the second embodiment of the present invention have been described. However, the tilt angle information of the mobile terminal is acquired by using the tilt angle sensor inside the mobile terminal, and the handheld posture outside the vehicle or the fixed posture inside the vehicle. There is a method of calculating that each inclination is fixed. In the latter case, the setting of the inclination angle outside the vehicle or inside the vehicle may be different.

  There is also a method of using an inclination angle sensor only on either the outside or the inside of the vehicle. Although the portable terminal is not provided with an inclination angle sensor, a cradle for fixing the portable terminal when mounted on a vehicle has an inclination angle sensor.

  Furthermore, the geomagnetic vector size is not the same inside the vehicle and outside the vehicle, and a coefficient calculated based on geomagnetic measurement data obtained in advance during measurement or operation may be used. Generally, in a vehicle, the geomagnetic size tends to decrease due to the influence of surrounding iron materials.

It is a figure for demonstrating the problem of the conventional azimuth angle measuring method, and is explanatory drawing of the azimuth | direction which an electronic compass shows when the pedestrian is holding the portable terminal outside a vehicle. It is a figure for demonstrating the problem of the conventional azimuth measuring method, and is a figure which shows when a portable terminal with an electronic compass is brought into the vehicle and fixed. It is a figure for demonstrating Example 1 of the azimuth angle measuring method of this invention, and is a figure for demonstrating the correction method of the azimuth angle measuring apparatus when the portable terminal is being fixed in the vehicle. It is a figure for demonstrating Example 2 of the azimuth angle measuring method of this invention, and is a figure for demonstrating the correction method of the azimuth angle measuring apparatus when the portable terminal is being fixed in the vehicle. It is a figure which shows the flowchart for demonstrating Example 1 of the azimuth measuring method of this invention. It is a figure which shows the flowchart for demonstrating Example 2 of the azimuth measuring method of this invention. It is a block diagram for demonstrating Example 1 and 2 of the azimuth measuring apparatus which concerns on this invention.

Explanation of symbols

1 Geomagnetic measurement data coordinate points (x in the figure)
2 Coordinate points of geomagnetic data acquired outside the vehicle with the mobile terminal aligned with the front direction of the vehicle (marked with a circle in the figure)
3 Geomagnetic offset value calculated from the geomagnetic data obtained by the electronic compass on the mobile terminal outside the vehicle (coordinate points; ◇ in the figure)
4 Geomagnetic data coordinate points obtained by fixing the mobile terminal in the car to match the front direction of the vehicle (● in the figure)
11, 21 Coordinate points of geomagnetism measurement data stored outside the vehicle according to the direction of the vehicle (○ mark in the figure)
12, 22 Offset value obtained from geomagnetic measurement data (coordinate points; ◇ in the figure)
13, 23 Magnetic offset value in the in-vehicle environment derived by the present invention (coordinate points; Δ mark in the figure)
14,24 Coordinate points of the geomagnetic measurement data obtained by fixing the mobile terminal in the car to match the front direction of the vehicle (● in the figure)
Reference Signs List 31 Geomagnetic information acquisition unit 32 Storage unit 33 First geomagnetic offset calculation unit 34 Second geomagnetic offset calculation unit 35 In-vehicle state determination unit 36 Azimuth angle calculation unit 37 Display unit 38 Inclination angle information acquisition unit 39 Inclination angle correction calculation unit 40 Geomagnetic size calculator 41 Geomagnetic vector calculator

Claims (12)

In an azimuth measuring method for obtaining an initial azimuth when a mobile terminal equipped with an electronic compass is fixed to a vehicle and displaying the azimuth in the traveling direction,
A first step of calculating a geomagnetic offset value in advance from geomagnetic measurement data acquired by a mobile terminal outside the vehicle;
A second step of measuring the first magnetic strength data by aligning the portable terminal with the direction of the vehicle body outside the vehicle;
A third step of measuring the second magnetic intensity data while fixing the portable terminal in the vehicle;
A difference between the first magnetic intensity data measured in the second step and the second magnetic intensity data measured in the third step is calculated, and from the geomagnetic offset value obtained in the first step And a fourth step of adding / subtracting the difference. In an azimuth measuring method for obtaining an initial azimuth when a mobile terminal equipped with an electronic compass is fixed to a vehicle and displaying the azimuth in the traveling direction,
A first step of calculating a geomagnetic offset value and a magnitude of a geomagnetic vector in advance from geomagnetic measurement data acquired by a mobile terminal outside the vehicle;
A second step of measuring the first magnetic intensity data by aligning the mobile terminal with the direction of the vehicle body outside the vehicle, correcting the geomagnetic offset value, and calculating the azimuth angle;
A third step of measuring the second magnetic intensity data while fixing the portable terminal in the vehicle;
A fourth step assuming a spherical surface that is separated from the second magnetic intensity data measured in the third step by the magnitude of the geomagnetic vector determined in the first step;
An azimuth measuring method comprising: a fifth step of obtaining a starting point on a spherical surface such that the magnetic intensity data coincides with the azimuth obtained in the second step.   The azimuth measuring method according to claim 2, further comprising a step of measuring an inclination angle in the second step and the third step.   The azimuth angle measuring method according to claim 2 or 3, wherein the fifth step includes a step of correcting a difference in tilt angle between the second step and the third step.   5. The azimuth measuring method according to claim 2, 3 or 4, wherein the tilt information of the portable terminal is acquired using a uniaxial, biaxial or triaxial tilt sensor.   6. The azimuth measuring method according to claim 1, wherein geomagnetic measurement data sensed by the electronic compass is acquired and stored for each of two or three axes. In an azimuth measuring device for obtaining an initial azimuth when displaying a azimuth in a traveling direction by fixing a mobile terminal equipped with an electronic compass to a vehicle,
Geomagnetic information acquisition means for acquiring geomagnetic measurement data;
Storage means for storing the first geomagnetic measurement data and the second geomagnetic measurement data acquired by the geomagnetic information acquisition means;
First geomagnetic offset calculation means for calculating a geomagnetic offset value inside the portable terminal from the geomagnetism measurement data acquired by the geomagnetic information acquisition means;
The values of the first geomagnetic measurement data and the second geomagnetic measurement data stored in the storage means are acquired, and the difference between the first geomagnetic data value and the second geomagnetic data value is determined as the first geomagnetic data value. A second geomagnetic offset calculating means for calculating a new second geomagnetic offset value by subtracting from the offset value;
Vehicle state determination means for determining whether the portable terminal is inside or outside the vehicle and instructing the second geomagnetic offset calculation means to calculate a geomagnetic offset value in the vehicle;
Azimuth angle calculating means for calculating an azimuth angle from the latest geomagnetic measurement data stored in the storage means and the first geomagnetic offset value or the second geomagnetic offset value passed from the in-vehicle state determining means. An azimuth measuring device characterized by the above.   An inclination angle information acquisition unit and an inclination angle correction unit are provided, the inclination angle information of the mobile terminal acquired by the inclination angle information acquisition unit is stored in the storage unit, and the inclination angle correction unit stores the stored inclination angle information. The azimuth angle measuring apparatus according to claim 7, wherein tilt angle correction is performed on the azimuth angle calculated by the azimuth angle calculating means.   The second geomagnetic offset calculating means includes first inclination angle information at the time of obtaining the first geomagnetic measurement data and a second inclination angle at the time of obtaining the second geomagnetic measurement data. The second geomagnetic offset from the information, the second geomagnetic data, the azimuth calculated from the first geomagnetic data and the first geomagnetic offset, and the geomagnetic size calculated by the geomagnetic size calculating means The azimuth measuring apparatus according to claim 7 or 8, wherein a value is calculated. In an azimuth measuring device for obtaining an initial azimuth when displaying a azimuth in a traveling direction by fixing a mobile terminal equipped with an electronic compass to a vehicle,
Geomagnetic information acquisition means for acquiring geomagnetic measurement data;
Storage means for storing the first geomagnetic measurement data and the second geomagnetic measurement data acquired by the geomagnetic information acquisition means;
First geomagnetic offset calculation means for calculating a geomagnetic offset value inside the portable terminal from the geomagnetism measurement data acquired by the geomagnetic information acquisition means;
A geomagnetism size calculating means for calculating a geomagnetism size from the geomagnetism measurement data acquired by the geomagnetism information acquiring means and the first geomagnetic offset value;
A geomagnetic vector computing means for computing first geomagnetic vector information from the first geomagnetic measurement data and the first geomagnetic offset value;
The same geomagnetism as the first geomagnetic vector information in which the second geomagnetism measurement data is stored from the second geomagnetism measurement data stored in the storage means and the geomagnetism size information calculated by the geomagnetism size calculation means. A second geomagnetic offset calculating means for calculating a point indicating a vector and calculating this point as a second geomagnetic offset value;
An inclination angle acquisition means for acquiring inclination information of the mobile terminal from the geomagnetism measurement data acquired by the geomagnetism information acquisition means;
Vehicle state determination means for determining whether the portable terminal is inside or outside the vehicle and instructing the second geomagnetic offset calculation means to calculate a geomagnetic offset value in the vehicle;
The latest geomagnetic measurement data stored in the storage means, the first geomagnetic offset value or the second geomagnetic offset value passed from the in-vehicle state determination means, and the inclination information calculated by the inclination angle acquisition means And an azimuth angle calculating means for calculating an azimuth angle from the azimuth angle measuring device.   The azimuth angle measuring apparatus according to claim 10, further comprising an inclination angle acquisition unit that acquires inclination information of the mobile terminal, wherein the geomagnetic vector calculation unit calculates a geomagnetic vector also using the inclination information. .   The azimuth angle measuring apparatus according to claim 11, wherein the inclination information includes an inclination angle acquired outside the vehicle and an inclination angle acquired inside the vehicle.

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