JP2009276307A - Magnetic measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic measurement device that allows a magnetic sensor in a reference attitude to be installed without requiring unnecessary labor and spending much time, performs terrestrial magnetism compensation by a three-axis magnetic sensor in an optional attitude, and accurately measures magnetism without requiring unnecessary labor. <P>SOLUTION: The magnetic measurement device includes: a reference attitude uniaxial magnetic sensor 1-1 having a detection axis in the vertical direction by a gimbal mechanism; a plurality of three-axis magnetic sensors 1-2 and 1-3 installed in optional attitudes; and a signal processing apparatus 2. The signal processing apparatus 2 converts respective output data of the three-axis magnetic sensors 1-2 and 1-3 of the optional attitudes into magnetic data equivalent to data obtained in the case where the sensors are installed in the magnetically east-west direction, magnetically south-north direction and vertical direction by referring to the output data of the reference attitude uniaxial magnetic sensor 1-1, uses the data after conversion as magnetic data for terrestrial magnetism compensation and magnetic data to be compensated, and subtracts the magnetic data to be compensated to perform terrestrial magnetism compensation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

 The present invention relates to a magnetic measuring device that measures minute magnetism in geomagnetism.

  Generally, when measuring magnetism smaller than the fluctuation of geomagnetism, the magnetic sensor output for geomagnetism compensation is subtracted from the output of the compensated magnetic sensor, and the geomagnetic compensation is performed. When the magnetic sensor for compensation is installed, the geomagnetism is used for the east, west, north, and south, and the level is used for the vertical direction to adjust the orientation of the magnetic sensor for compensation and the magnetic sensor for compensation. The directions are matched.

Further, in a place where it is difficult to adjust the attitude of the magnetic sensor, the deviation of the geomagnetic three components measured by the magnetic sensor of an arbitrary attitude from the three geomagnetic components measured by the magnetic sensor of the arbitrary attitude with respect to the sensitivity axis. A magnetic measuring device that calculates an angle, performs a rotation calculation around the axis based on the deviation angle, converts a measured magnetic field value so as to have a desired relationship with the sensitivity axis, and matches the directions of the three axes. The geomagnetic compensation magnetic sensor and the compensated magnetic sensor installed in an arbitrary posture are converted into a reference posture, and 3 of the geomagnetic compensation magnetic sensor and the compensated magnetic sensor are disclosed. The axis directions are matched.
JP-A-7-198809

  When matching the three axial directions of the magnetic sensor for geomagnetism compensation and the magnetic sensor for compensation by the conventional general method described above, the method of matching using the geomagnetism and the level takes time and effort. In addition, in the method described in Patent Document 1, when viewed from a magnetic sensor in an arbitrary posture, there is a posture in which the output of the three geomagnetism axes is the same even if the posture is different from the reference posture magnetic sensor. It is difficult to make the postures of the geomagnetic compensation magnetic sensor and the compensated magnetic sensor coincide with the reference posture. In addition, since a magnetic sensor with a reference posture is required, it is necessary to match the posture of the magnetic sensor with the reference posture using the geomagnetism and the level as in the conventional general method, which takes time and effort.

  The present invention has been made in view of the above-described circumstances. The magnetic sensor of the reference posture is installed without taking time and effort, and the magnetic sensor output of the reference posture is used to install 3 in an arbitrary posture. An object of the present invention is to provide a magnetic measuring device capable of performing geomagnetic compensation by converting the output of each axis magnetic sensor so that the output of each axis is equivalent to the case of being installed in the magnetic east-west, magnetic north-south, and vertical directions. .

 A magnetic measuring device according to claim 1 of the present application includes a plurality of triaxial magnetic sensors operated in geomagnetism and a signal processor for receiving, storing, and processing signals from the uniaxial magnetic sensors. In the measuring apparatus, the output signal of each axis of the three-axis magnetic sensor installed in an arbitrary posture is used for the signal processor by using the output data of the one-axis magnetic sensor oriented in at least one vertical direction. Rotation around each axis of the 3-axis magnetic sensor installed in an arbitrary posture to convert the magnetic sensor axes to data equivalent to magnetic east-west, magnetic north-south, and vertical orientation Calculate the rotation angle at which the output of the 1-axis magnetic sensor and the output of the 3-axis magnetic sensor after the rotation calculation are arbitrarily matched, and the output match between the arbitrary 1-axis of the 3-axis magnetic sensor and the 1-axis magnetic sensor. The two axes obtained from the other two axes output Means for obtaining the rotation angle coefficient of the rotation angle rotating magnetically north-south and magnetic north-south as a reference attitude conversion coefficient, and each axis output of the three-axis magnetic sensor installed in an arbitrary attitude, using the reference attitude conversion coefficient, A means for converting the output of each axis of a 3-axis magnetic sensor installed in an arbitrary posture into data equivalent to the case where it is installed in the magnetic east-west, magnetic north-south, and vertical directions by performing rotation calculation around the axis. It is provided with.

  The magnetic measurement device according to claim 2 classifies the three-axis magnetic sensor after the reference attitude conversion into a magnetic sensor for geomagnetic compensation and a magnetic sensor for compensation, and the signal of the magnetic measurement device according to claim 1 The processor includes means for performing geomagnetic compensation by subtracting the output data of each axis of the compensated magnetic sensor after conversion from the output data of each axis of the compensated magnetic sensor after conversion.

  According to a third aspect of the present invention, there is provided a magnetic measurement apparatus that uses the signal processor of the magnetic measurement apparatus according to the second aspect to multiply the output data of the converted geomagnetic compensation magnetic sensor by a coefficient, Means is provided for subtracting from the output data of the compensating magnetic sensor and performing geomagnetic compensation of the output data of each axis of the compensated magnetic sensor and the output data of the total magnetic force after the conversion.

  According to the present invention, the reference magnetic sensor is a uniaxial magnetic sensor oriented in the vertical direction. For example, since it can be easily realized by a uniaxial sensor having a gimbal mechanism, it can be easily installed without taking time and effort. The three-axis magnetic sensor can be installed without worrying about the posture, that is, without specifying the direction. It is possible to perform magnetic measurement equivalent to the case where it is installed in the north-south and vertical directions and with geomagnetic compensation.

Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a schematic configuration diagram showing a system configuration of a magnetic measuring apparatus according to an embodiment of the present invention.
In this embodiment of the magnetic measuring device, a uniaxial magnetic sensor (one in this example, but may be plural) 1-1 and a plurality of solid three-axis magnetic sensors (two in this example, but three). (1 or 2) 1-2 and 1-3 are arranged. Here, the uniaxial sensor 1-1 is directed in the vertical direction by a gimbal mechanism or the like, and is referred to as a reference posture sensor. The other three-axis magnetic sensors 1-2 and 1-3 are installed in arbitrary postures, and are called arbitrary posture sensors. The uniaxial magnetic data detected by the uniaxial magnetic sensor 1-1 and the triaxial magnetic data detected by the triaxial magnetic sensors 1-2 to 1-3 are captured and stored in the signal processor 2. Data processing.

  The signal processor 2 has a function of executing each signal processing of the flowchart shown in FIG. As a first process, in step S1, conversion coefficients for converting each axis of the three-axis magnetic sensor into data equivalent to the case where each axis is installed in the magnetic east-west, magnetic north-south, and vertical directions (reference posture conversion). Calculation of (reference posture conversion coefficient) is performed for each triaxial magnetic sensor. Next, the process proceeds to step S2.

  In step S2, reference posture conversion is performed as a second process. Here, the reference orientation conversion coefficient for each magnetic sensor obtained in the first process is applied to the output of each sensor of the three-axis magnetic sensors 1-2 and 1-3 having an arbitrary orientation, and converted to the reference orientation output. . Next, the process proceeds to step S3.

  In step S3, geomagnetic compensation coefficient calculation is performed as a third process. Here, in order to perform geomagnetic compensation, the outputs of the three-axis magnetic sensors 1-2 and 1-3 converted to the reference posture are classified into geomagnetic compensation outputs and compensated outputs, and geomagnetic compensation is performed from the compensated magnetic data. The amplitude of the geomagnetic compensation magnetic data and the offset geomagnetic compensation coefficient when the magnetic data is drawn are obtained. Next, the process proceeds to step S4.

  In step S4, geomagnetic compensation is performed as a fourth process. Here, geomagnetic compensation is performed using the geomagnetic compensation coefficient obtained in the third process.

  Details of the first process to the fourth process will be described below.

  First, the first process, the reference attitude conversion coefficient calculation, will be described. Details of the processing will be described with reference to the flowchart shown in FIG. As shown in FIG. 3, the angle between the Z axis of the arbitrary attitude magnetic sensor and the geomagnetism H is θn, the angle between the X axis of the arbitrary attitude magnetic sensor and the XY plane component of the geomagnetism H is φn, and the Z axis of the arbitrary attitude magnetic sensor The rotation angle around is ψn. As for the posture conversion, a general expression relating to rotation around each axis shown in Expression (1) is used. The rotation direction of Formula (1) is shown in FIG. 4, (a) shows rotation around the X axis, (b) shows rotation around the Y axis, and (c) shows rotation around the Z axis.

First, in the process start step ST11, the three-axis magnetic data ^Hx, any ^attitude, Hy,, ^Hz, reads, using Equation (2), .theta.n at time t, determining the .phi.n. The angles θn and φn are one of the reference posture conversion coefficients.

Incidentally, .theta.n, as shown in equation ^{(3), Hx,,} Hy,, ^Hz, the Hx that φn rotated about the Z axis ^_phi,, Hy ^_phi,, Hz ^_phi, determined using. The rotation around the Z axis is performed in the direction of the arrow shown in FIG.

Next, the process proceeds to step ST12.
In step ST12, .phi.n obtained in step ST11, the formula using .theta.n (3), the equation (4), any attitude is inputted in time series 3-axis magnetic data ^Hx,, Hy,, ^Hz, the Z-axis φn around, rotate in the order of θn about the Y-axis (referred to as conversion ^{_{1), Hx θ,, Hy}} θ,, Hz θ, determined using. The rotation around the Y-axis here is performed in the direction of the arrow shown in FIG.

  Next, the process proceeds to step ST13.

In step ST13, Hx ^_theta, obtained in step _{^{ST12, Hy θ,, Hz θ}} , was ψn rotated around the Z axis using the equation (5) (referred to as a conversion ^{_{2), Hx ψ,, Hy}} ψ, obtain Hz ^_[psi, a. The rotation around the Z-axis here is performed in the manner shown in FIG. That is, the rotation angle ψn at this time is changed from 0 ° to 359.9 °, for example, in 0.1 ° steps in the loop processing from step ST13 to step ST16. Specifically, ψn is 0.0 in the first loop processing, and ψn is 0.1 in the second loop processing.

  Next, the process proceeds to step ST14.

In step ST14, obtained in advance dip .theta.f, Hx _[psi calculated in step ^{_{ST13,, Hy ψ,, Hz}} ψ, is rotated (90-.theta.f) around the Y axis by using the equation (6) (conversion 3 and referred ^{_{to), Hx (90-θf)}} ,, Hy (90-θf),, Hz (90-θf), Request. Here, as shown in FIG. 12, the depression angle θf is an angle formed by the geomagnetism H from the horizontal plane to the vertical axis at the measurement point.

  Next, the process proceeds to step ST15.

In step ST15, _Hz calculated in step _{ST14 ^(90-θf),} and using a uniaxial magnetic data Hz. Obtaining Hz and _{Hz ^{(90-.theta.f),}} an error of using Equation (7). In this step, when the error obtained by changing ψn by 0.1 ° is compared with the minimum amount until then, when this time is the minimum, the angle ψn is changed to the angle ψn at which the error is minimized. Output as.

  Next, the process proceeds to step ST16.

  In step ST16, it is checked whether or not ψn has been counted up to 359.9. If not counted, the processing returns to step ST13 and ψn is counted up by 0.1 °. When ψn is counted up to 359.9, the reference posture conversion coefficient calculation calculation is terminated. The angle ψn that minimizes the error obtained at this time is also the reference posture conversion coefficient.

  Next, the process proceeds to step ST17.

In step ST17, from the Hx _{(90−θf) ′,} Hy ₍₉₀₋ θf _{) ′} of the three-axis magnetic data after the conversion 3 obtained in step ST14, the magnetic direction θdir relative to the north is expressed by equation (8). Find using. θdir is also a reference posture conversion coefficient.

 Next, the reference posture conversion process in the second process will be described with reference to the flowchart shown in FIG.

First, in step ST21 at the start of the process, the arbitrary attitude three-axis magnetic sensor data and the reference attitude conversion coefficients θn and φn obtained in the first process are read, and using the expressions (3) and (4), the arbitrary attitude 3-axis magnetic sensor data ^Hx,, Hy,, ^Hz, to φn about the Z axis, is rotated in the order of θn around the Y axis, three-axis magnetic sensor data Hx _theta converted ^1,, Hy ^_theta,, Hz ^_theta, Ask for.

  Next, the process proceeds to step ST22.

In step ST22, it reads the reference attitude transform coefficients Pusaienu obtained in the first process, Hx obtained in step _{^{ST21 θ,, Hy θ,,}} ψn Hz θ, the around the Z axis using the equation (5) rotate, 3-axis magnetic sensor data Hx ^_[psi, the converted _{^{2, Hy ψ,, Hz ψ}} , obtained.

  Next, the process proceeds to step ST23.

In step ST23, Hx _[psi obtained in step ^{_{ST22,, Hy ψ,, Hz}} ψ, the formula (90-.theta.f) around the Y-axis with (6) 3-axis magnetic sensor data Hx converted 3 is rotated ^{_{(90-θf),, Hy}} (90-θf),, Hz (90-θf), Request.

 Next, the process proceeds to step ST24.

In step ST24, reads the reference attitude transform coefficients θdir obtained in the first process, _Hx obtained in step ^{_{ST23 (90-θf),,}} Hy (90-θf),, Hz (90-θf), the formula (9) is θdir rotated about the Z axis is used to obtain each axis magnetic east and west of the 3-axis magnetic sensor, Hx ^Bu toward magnetic north and south and the vertical ku direction, Hy ^Bu, the Hz ^Bu.

  Next, the geomagnetic compensation process in the third process will be described with reference to the flowchart shown in FIG.

  First, in step ST31 of the process start, the magnetic data for geomagnetic compensation after the reference attitude conversion is read.

  Next, the process proceeds to step ST32.

  In step ST32, the compensated magnetic data after the reference attitude conversion is read.

  Next, the process proceeds to step ST33.

  In step ST33, geomagnetic compensation coefficients for three axes are obtained from the data read in step ST31 and step ST32 using the least square method. The geomagnetic compensation coefficients α and β are obtained by executing the equation (10).

N represents the number of data, Hx ₀ ′ represents compensated magnetic data, and Hx ₁ ^′ represents geomagnetic compensation magnetic data. Also, the Y and Z axes are obtained in the same manner as in equation (8).

 Finally, the process of the geomagnetic compensation calculation in the fourth process will be described with reference to the flowchart shown in FIG.

  First, in step ST41, a geomagnetic compensation coefficient is read.

  Next, the process proceeds to step ST42.

  In step ST42, the magnetic data for geomagnetic compensation after the reference attitude conversion is taken.

  Next, the process proceeds to step ST43.

  In step ST43, the compensated magnetic data after the reference attitude conversion is taken.

  Next, the process proceeds to step ST44.

  In step ST44, a result obtained by applying a geomagnetic compensation coefficient to the magnetic data for reference geomagnetic compensation after reference attitude conversion is subtracted from the compensated magnetic data after reference attitude conversion. The geomagnetic compensation data is obtained by calculating and executing the following equation (11).

Here, Hx ₀ ^′ represents compensated magnetic data, Hx ₁ ^′ represents geomagnetic compensation magnetic data, and Hx ₂ ^′ represents geomagnetic compensation results. The same applies to the Y axis and Z axis.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the signal processor 2 in the present invention is configured to be capable of executing only the first process and the second process, and is configured to be capable of executing all of the first to fourth processes. Any of them may be used. However, if the signal processing device 2 configured so as to be able to execute all of the first to fourth processes is employed, it is possible to perform geomagnetic compensation, and thus it is possible to perform micromagnetic measurement. In the above embodiment, the output data of the geomagnetic compensation magnetic sensor after the reference attitude conversion is subtracted by applying the geomagnetic compensation coefficients α, β, etc., but the subtraction may be performed without applying the coefficients. However, it is possible to improve the accuracy of the geomagnetic compensation by multiplying and subtracting the obtained geomagnetic compensation coefficient as in the above embodiment.

It is the schematic which shows the system configuration | structure of the magnetic measuring device of one Embodiment of this invention. It is a figure explaining the process outline | summary of the magnetic measuring apparatus of the embodiment. It is a figure explaining the positional relationship of geomagnetism and a triaxial sensitivity axis. It is a figure explaining the rotational movement of 3 axis | shafts. It is a flowchart explaining the process of the reference | standard attitude | position change coefficient calculation in the magnetic measurement apparatus of the upper embodiment. It is a flowchart explaining process-process conversion of the reference | standard attitude | position conversion in the magnetic measuring device of the embodiment. It is a flowchart explaining the process of the geomagnetic compensation coefficient calculation in the magnetic measuring device of the embodiment. It is a flowchart explaining the process of the geomagnetic compensation in the magnetic measuring device of the embodiment. It is a figure explaining rotation of (phi) n around the Z-axis in the magnetic measuring device of the embodiment. It is a figure explaining the rotation of (theta) n around the Y-axis in the magnetic measuring device of the embodiment. It is a figure explaining the rotation of the small angle ψn around the Z axis in the magnetic measuring apparatus of the same embodiment. It is a figure explaining the depression angle (theta) f in the magnetic measuring device of the embodiment.

Explanation of symbols

1-1 Reference attitude sensor 1-2, 1-3 Arbitrary attitude sensor 2 Signal processor

Claims (3)

In a magnetic measuring device comprising a plurality of three-axis magnetic sensors operated in geomagnetism and a signal processor for receiving, storing and processing signals from the single-axis magnetic sensors,
Using the output data of each axis of the three-axis magnetic sensor installed in an arbitrary posture in the signal processor, the output data of the one-axis magnetic sensor directed to at least one vertical direction, In order to convert the axis into data equivalent to the case of magnetic east-west, magnetic north-south, and vertical installation, rotation calculation is performed around each axis of the 3-axis magnetic sensor installed in an arbitrary posture. The rotation angle at which the output of the one-axis magnetic sensor and the output of any one axis of the three-axis magnetic sensor after rotation calculation coincide, and the three axes after any one axis of the three-axis magnetic sensor matches the output of the one-axis magnetic sensor Means for obtaining the rotation angle coefficient (reference attitude conversion coefficient) of the rotation angle obtained by using the other two axes of the magnetic sensor and rotating to the north, east, west, and north and south, and each axis of the three-axis magnetic sensor installed in an arbitrary attitude Using the reference orientation conversion coefficient for output, each axis is By means of the rotation calculation as described above, there is provided means for converting the output of each axis of the 3-axis magnetic sensor installed in an arbitrary posture into data equivalent to the case where it is installed in the magnetic east-west, magnetic north-south and vertical directions. Magnetic measuring device characterized by that.   The three-axis magnetic sensor after the reference attitude conversion is classified into a magnetic sensor for geomagnetic compensation and a magnetic sensor for compensation, and the signal processor performs post-conversion from the output data of each axis of the compensated magnetic sensor after conversion. 2. The magnetic measuring apparatus according to claim 1, further comprising means for performing geomagnetic compensation by subtracting output data of each axis of the magnetic sensor for magnetic field compensation. The signal processor multiplies the output data of the converted geomagnetic compensation magnetic sensor by a coefficient, subtracts the output data of the compensated magnetic sensor after conversion, and the converted compensated magnetic sensor. 3. A magnetic measuring apparatus according to claim 2, further comprising means for performing geomagnetic compensation of the output data of each axis and the output data of the total magnetic force.