Azimuth measuring device
By combining the first angular velocity sensor and the second angular velocity sensor, the rotation angle of the rotating mechanism is corrected, which solves the problem of inaccurate orientation measurement caused by rotation in the prior art and achieves higher measurement accuracy.
Patent Information
- Application Number
- CN202480050484.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-29
- Filing Date
- 2024-07-03
- Publication Date
- 2026-03-06
AI Technical Summary
When existing orientation measuring devices rotate around a vertical axis, the rotation angle of the detection axis of the angular velocity sensor deviates from the reference value, resulting in inaccurate orientation calculations.
A combination of a first angular velocity sensor and a second angular velocity sensor is used. The first angular velocity sensor detects the angular velocity in the horizontal direction, and the second angular velocity sensor corrects the rotation angle of the first detection axis in the rotating mechanism. The rotation angle error is calculated by integration, and the orientation is calculated by fitting a sine function.
It improves the accuracy of orientation measurement, reduces errors caused by rotation, and ensures the accuracy of orientation measurement.
Smart Images
Figure CN121620680A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a orientation measuring device. Background Technology
[0002] As a azimuth measuring device, there are various known azimuth measuring methods, such as the analog magnetic method using a magnetic needle, the digital magnetic method using a magnetic sensor, the GPS method, and the gyroscope method.
[0003] For example, Non-Patent Document 1 discloses a azimuth measuring device and a azimuth measuring method as follows: The device includes a measuring unit, in which an angular velocity sensor with a detection axis in the horizontal plane rotates around a vertical axis on a rotating mechanism while detecting the angular velocity accompanying the Earth's rotation. The rotation angle of the angular velocity sensor's detection axis is marked on the horizontal axis of a graph, and the measurement result of the angular velocity is marked on the vertical axis. The azimuth is calculated by fitting a sine function to the marked waveform.
[0004] Existing technical documents
[0005] Non-patent literature
[0006] Non-patent literature 1: IPPrikhodko, SAZotov, Alexander A.Trusov and AMShkel, "What is MEMS Gyrocompassing? Comparative Analysis of Maytagging andCarouseling" Journal of Microelectromechanical Systems, Vol.22, No.6, pp.1257-1266, December 2013. Summary of the Invention
[0007] The problem the invention aims to solve
[0008] However, in the orientation measuring device described in Non-Patent Document 1, when the orientation measuring device rotates around the vertical axis during the orientation measurement, the rotation angle of the detection axis of the angular velocity sensor sometimes deviates from the reference value, making it impossible to accurately calculate the orientation.
[0009] The present invention was made in view of the following circumstances, and provides an orientation measuring device that can improve the accuracy of orientation measurement.
[0010] Solution for solving the problem
[0011] One aspect of the present invention relates to a orientation measuring device comprising: a first angular velocity sensor having a first detection axis extending in a horizontal direction for detecting a first angular velocity about the first detection axis as a rotation center; a rotating mechanism having a rotating axis extending in a vertical direction for rotating the first detection axis of the first angular velocity sensor about the rotating axis as a rotation center; and a second angular velocity sensor for correcting the rotation angle of the first detection axis in the rotating mechanism, the second angular velocity sensor having a second detection axis extending in a vertical direction for detecting a second angular velocity about the second detection axis as a rotation center.
[0012] Invention Effects
[0013] According to the present invention, an orientation measuring device is provided that can improve the accuracy of orientation measurement. Attached Figure Description
[0014] Figure 1 This is a schematic diagram showing the structure of the orientation measuring device according to the first embodiment.
[0015] Figure 2 This is a top view showing the measuring unit.
[0016] Figure 3 This is a diagram illustrating an example of the physical structure of the control unit.
[0017] Figure 4 This is a top view showing the measuring unit rotated about a vertical axis.
[0018] Figure 5 It is a graph showing the first angular velocity corresponding to the rotation angle before correction.
[0019] Figure 6 It is a graph showing the first angular velocity corresponding to the corrected rotation angle.
[0020] Figure 7 This is a schematic diagram showing the structure of the orientation measuring device according to the second embodiment. Detailed Implementation
[0021] Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar constituent elements are indicated by the same or similar reference numerals. The drawings are illustrative, and the dimensions and shapes of the parts are schematic and should not be construed as limiting the scope of the invention to these embodiments.
[0022] In the accompanying drawings, to clarify the interrelationships between the drawings and aid in understanding the positional relationships of the components, an orthogonal coordinate system consisting of the X-axis, Y-axis, and Z-axis is sometimes used for convenience. The X-axis, Y-axis, and Z-axis correspond to each other in the accompanying drawings. The direction parallel to the X-axis is designated as the "X-axis direction," the direction parallel to the Y-axis as the "Y-axis direction," and the direction parallel to the Z-axis as the "Z-axis direction." Furthermore, the direction of the arrowheads on the X-axis, Y-axis, and Z-axis is designated as "positive" or "+ (positive)," and the direction opposite to the arrowhead is designated as "negative" or "- (negative)." The plane defined by the X-axis and Y-axis is designated as the "XY plane," and the same applies to the planes defined by the other axes. The Z-axis direction is equivalent to an example of the "vertical direction," and the direction along the XY plane is equivalent to an example of the "horizontal direction."
[0023] <First Implementation Method>
[0024] First, refer to Figure 1 and Figure 2 The structure of the orientation measuring device 1 according to one embodiment of the present invention will be described below. Figure 1 This is a schematic diagram showing the structure of the orientation measuring device according to the first embodiment. Figure 2 This is a top view showing the measuring unit.
[0025] The orientation measuring device 1 measures orientation by measuring the angular velocity of the Earth's rotation. The orientation measuring device 1 is, for example, a north compass for finding true north. The orientation measuring device 1 includes a measuring unit 10 and a control unit 20.
[0026] Measurement unit 10 measures the Earth's rotational angular velocity. For example... Figure 1 As shown, the measuring unit 10 includes a first angular velocity sensor 11, a second angular velocity sensor 12, a rotating mechanism 13, and a sensor housing 19.
[0027] The first angular velocity sensor 11 has a first detection axis 11D extending along the horizontal direction (XY plane) and detects a first angular velocity about the first detection axis 11D as the center of rotation. The first angular velocity sensor 11 is, for example, a MEMS (Micro ElectroMechanical Systems) gyroscope sensor, but is not limited to this as long as it can detect angular velocity. The first angular velocity when the measuring unit 10 is stationary corresponds to the horizontal component of the Earth's rotational angular velocity at the latitude of the measuring location, about the first detection axis 11D as the center of rotation. That is, the magnitude of the first angular velocity varies based on the azimuth angle of the first detection axis 11D. Specifically, when the Earth's rotational angular velocity is set to Ω... EWhen the latitude of the measurement location is set as φ, the angle between the true north direction in the horizontal plane at the measurement location and the Earth's axis is φ. Therefore, the horizontal component of the rotational angular velocity ω with the true north direction in the horizontal plane at the measurement location as the center of rotation is... h Represented as ω h =Ω E ×cosφ. When the angle between the true north direction in the horizontal plane and the first detection axis 11D is defined as the azimuth angle θ of the first detection axis 11D, the first angular velocity ω originating from the rotation around the first detection axis 11D is expressed as ω=ω h ×cosθ=Ω E ×cosφ×cosθ. According to the above formula, Ω E constant (Ω) E =15.041[dph]), therefore, the angular velocity ω is determined based on the latitude φ and the azimuth angle θ of the first detection axis 11D. With clockwise rotation from the first angular velocity sensor 11 when observing the first detection axis 11D as the positive direction of the first angular velocity, and with the azimuth angle θ of the first detection axis 11D constant, the first angular velocity ω is maximum when the measurement position is at the equator (φ=0). The closer to true north or true south, i.e., the larger φ, the smaller the first angular velocity ω. Furthermore, with the latitude φ constant, the first angular velocity ω is maximum when the first detection axis 11D faces true north, i.e., θ=0. The first angular velocity ω is minimum when the first detection axis 11D faces true south, i.e., θ=180. Additionally, the first angular velocity ω is zero when the first detection axis 11D faces true west or true east, i.e., θ=90 or 270. Under the same measurement position, it can be expressed as Ω. E Since ×cosφ=k (a constant), the first angular velocity ω can be expressed as ω=Ω. E ×cosφ×cosθ=k×sin(90-θ). That is, the first angular velocity ω can be represented by a sine function with the azimuth angle θ of the first detection axis 11D as the variable.
[0028] The rotating mechanism 13 has a rotating shaft 13R extending in the vertical direction (Z-axis), causing the first detection shaft 11D of the first angular velocity sensor 11 to rotate about the rotating shaft 13R as the center of rotation. The angle formed by the first detection shaft 11D, which has rotated through the rotating mechanism 13, with the reference direction RD in the XY plane is defined as the rotation angle α of the first detection shaft 11D. For example, the rotating mechanism 13 is a rotary table, on which the first angular velocity sensor 11 is fixed.
[0029] The rotation angle α is measured by the rotary encoder 13A. The rotary encoder 13A is, for example, mounted on the rotary mechanism 13, but may also be mounted outside the rotary mechanism 13.
[0030] The second angular velocity sensor 12 is used to correct the rotation angle α of the first detection shaft 11D in the rotating mechanism 13. When the measuring unit 10 rotates around its vertical axis due to external impacts, the first angular velocity sensor 11D rotates together with the rotating mechanism 13 and the rotary encoder 13A. Therefore, the rotation angle of the first detection shaft 11D deviates from the rotation angle α measured by the rotary encoder 13A. At this time, the second angular velocity sensor 12 is used to correct the rotation angle α, which is the value measured by the rotary encoder 13A, to obtain the true rotation angle.
[0031] The second angular velocity sensor 12 is, for example, a MEMS gyroscope sensor, similar to the first angular velocity sensor 11, but is not limited thereto. The second angular velocity sensor 12 has a second detection axis 12D extending along the vertical direction (Z-axis), and detects a second angular velocity about the second detection axis 12D as the center of rotation. The second angular velocity is the angular velocity of the measuring unit 10 when it rotates about the vertical axis due to an external impact, etc. Based on the rotation angle calculated by integrating the measured value of the second angular velocity measured by the second angular velocity sensor 12, the angular deviation of the orientation of the measuring unit 10 relative to the reference direction RD can be calculated. Therefore, the rotation angle α can be corrected based on the second angular velocity.
[0032] The second angular velocity sensor 12 is disposed separately from the rotating mechanism 13. In this case, the second angular velocity sensor 12 only detects the angular velocity of the measuring unit 10 about the vertical axis. However, the second angular velocity sensor may also be disposed in the rotating mechanism in the same way as the first angular velocity sensor. In this case, the second angular velocity sensor detects the angular velocity obtained by combining the angular velocity of the rotating mechanism and the angular velocity of the measuring unit about the vertical axis. Therefore, the angular velocity of the measuring unit can be calculated, for example, by subtracting the angular velocity detected when the measuring unit is stationary from the detection result of the second angular velocity sensor. Alternatively, the angular velocity of the measuring unit can also be calculated by subtracting the set angular velocity of the rotating mechanism from the detection result of the second angular velocity sensor.
[0033] The sensor housing 19 houses a first angular velocity sensor 11, a second angular velocity sensor 12, and a rotation mechanism 13. Although not shown in the figure, the sensor housing 19 may have a communication module for the first angular velocity sensor 11, the second angular velocity sensor 12, and the rotation mechanism 13 to communicate with the control unit 20.
[0034] The control unit 20 controls the measuring unit 10 to measure the orientation based on the measurement results of the measuring unit 10. For example... Figure 1 As shown, the control unit 20 is connected to the measurement unit 10 in a manner that enables communication. The control unit 20 includes a drive unit 21, an acquisition unit 22, a calculation unit 23, and a calibration unit 24.
[0035] The drive unit 21 drives the rotation mechanism 13. The acquisition unit 22 acquires a first angular velocity from the first angular velocity sensor 11, a second angular velocity from the second angular velocity sensor 12, and a rotation angle α from the rotary encoder 13A. The calculation unit 23 calculates the orientation by marking the first angular velocity and the rotation angle α correspondingly and fitting the markings using a sine function. Since the first angular velocity is maximum when the first detection axis 11D is facing due north, the calculation unit 23 can also calculate due north based on the rotation angle α that maximizes the first angular velocity without performing a sine function fitting.
[0036] The correction unit 24 corrects the rotation angle α of the first detection shaft 11D in the rotating mechanism 13 based on the second angular velocity. For example, the correction unit 24 corrects the rotation angle α after it has been acquired from the rotating mechanism 13 by changing the position of the marker in the calculation unit 23. However, the correction method of the correction unit 24 is not limited to the above; it can also correct the rotation angle α before it has been acquired from the rotating mechanism 13. For example, the correction unit 24 can use the value obtained by subtracting the second angular velocity from the normally set value as the rotation angular velocity of the rotating mechanism 13. Furthermore, the correction unit 24 can drive the rotating mechanism 13 via the drive unit 21, causing the rotating mechanism 13 to rotate in an orientation consistent with the true rotation angle. Additionally, the correction unit 24 can calibrate the rotary encoder 13A so that the value measured by the rotary encoder 13A is the true rotation angle.
[0037] Next, refer to Figure 3 To illustrate the physical structure of the control unit 20. Figure 3 This is a diagram illustrating an example of the physical structure of the control unit.
[0038] The control unit 20 includes a CPU (Central Processing Unit) 95, RAM (Random Access Memory) 96, ROM (Read Only Memory) 97, and a communication module 98. These components are connected to each other via a bus to transmit and receive data. Furthermore, the CPU 95, RAM 96, ROM 97, and communication module 98 are connected to the operation unit 92 and the display unit 94 via a bus to transmit and receive data. The control unit 20 may be, for example, a MCU (Micro Controller Unit), but it can also be a single computer or a combination of multiple distributed computers. The control unit 20, for example, can enable the drive unit 21, acquisition unit 22, calculation unit 23, and correction unit 24 to function by executing a predetermined program stored in RAM 96 or ROM 97 via the CPU 95.
[0039] Next, refer to Figures 4 to 6 To explain the calibration mechanism in more detail. Figure 4 This is a top view showing the measuring unit rotated about a vertical axis. Figure 5 It is a graph showing the first angular velocity corresponding to the rotation angle before correction. Figure 6 This is a graph showing the first angular velocity corresponding to the corrected rotation angle. Figure 5 In the graph shown, the horizontal axis represents the rotation angle of the first detection axis 11D before correction, and the vertical axis represents the first angular velocity. Figure 6 In the chart shown, the horizontal axis is the corrected rotation angle of the first detection axis 11D, and the vertical axis is the first angular velocity.
[0040] First, the rotating mechanism 13 is driven to rotate the first detection axis 11D of the first angular velocity sensor 11 from the reference direction RD. At the same time, the first angular velocity sensor 11 is activated to detect the first angular velocity at predetermined rotation angles α.
[0041] like Figure 4 As shown, suppose that at a certain moment, the Tm measuring unit 10 rotates by an angle β in the same direction as the rotation direction of the rotating mechanism 13. At this time, when the original reference direction before rotation is set as RD0, the reference direction RD of the rotating mechanism 13 rotates relative to the initial reference direction RD0 by an amount corresponding to the angle β. Therefore, the true rotation angle of the first detection axis 11D of the first angular velocity sensor 11 relative to the initial reference direction RD0 is α+β. Thus, when the rotary encoder 13A measures the rotation angle as α, the first angular velocity sensor 11 detects the first angular velocity at the true rotation angle α+β. Therefore, as Figure 5 As shown, during the rotation of the measuring unit 10 at time Tm, the first angular velocity changes discontinuously. When the first angular velocity changes discontinuously like this, errors will occur when fitting the label of the first angular velocity using a sine function.
[0042] Therefore, when the second angular velocity sensor 12 detects the second angular velocity, the angle β is calculated in the correction unit 24 based on the second angular velocity. Figure 6 As shown, the correction unit 24 adds the rotation angle β to the rotation angle α measured by the rotary encoder 13A after time Tm. The marking of the first angular velocity is interrupted at time Tm, but the deviation of the marking relative to the sine function is suppressed. That is, the error generated when fitting using the sine function is suppressed. Therefore, compared with the one based on... Figure 5 Compared to measuring orientation using the chart shown, using a method based on... Figure 6 Using the chart shown to measure direction can improve the accuracy of direction measurement. Figure 6The azimuth angle calculated by fitting the corrected chart shown is assumed to be the azimuth angle of the measuring unit 10 without rotation, i.e., the angle relative to the initial reference direction RD0. Therefore, in order to calculate the azimuth angle in the measuring unit 10 after rotation by angle β, it is necessary to... Figure 6 The azimuth angle calculated by fitting the corrected chart shown is added to the rotation angle β of the measuring unit 10. For example, if the azimuth angle of true north calculated by fitting the corrected chart is α = 30 degrees, and the rotation angle of the measuring unit 10 calculated by integrating the measured value of the second angular velocity is β = 10 degrees, then the azimuth angle of true north in the measuring unit 10 is α + β = 40 degrees.
[0043] As explained above, according to this embodiment, the orientation measuring device 1 includes: a first angular velocity sensor 11 having a first detection axis 11D extending in the horizontal direction; a rotation mechanism 13 that rotates the first detection axis 11D about a rotation axis 13R extending in the vertical direction as a rotation center; and a second angular velocity sensor 12 for correcting the rotation angle α of the first detection axis 11D in the rotation mechanism 13, the second angular velocity sensor 12 having a second detection axis 12D extending in the vertical direction and detecting a second angular velocity about the second detection axis 12D as a rotation center.
[0044] Therefore, even if the measuring unit 10 rotates around the vertical axis during orientation measurement, the error in the rotation angle α caused by the rotation of the measuring unit 10 can be corrected based on the second angular velocity, thereby suppressing the generation of orientation measurement error.
[0045] Other embodiments will now be described. Furthermore, structures identical or similar to those shown in the first embodiment will be labeled with the same or similar reference numerals, and their descriptions will be omitted where appropriate. Additionally, the same effects obtained based on the same structure will not be mentioned repeatedly.
[0046] <Second Implementation Method>
[0047] Reference Figure 7 The structure of the orientation measuring device 2 according to the second embodiment will be explained. Figure 7 This is a schematic diagram showing the structure of the orientation measuring device according to the second embodiment.
[0048] The orientation measuring device 2 also includes a posture control unit 230. Furthermore, the measuring unit 210 of the orientation measuring device 2 also includes a posture measuring mechanism 214. The control unit 220 of the orientation measuring device 2 also includes a posture information acquisition unit 225 and a posture control unit 226.
[0049] The posture control unit 230 corrects the rotation of the measuring unit 210 about a rotation axis extending along the horizontal direction (XY plane) and controls the posture of the first angular velocity sensor 11, the second angular velocity sensor 12, and the rotation mechanism 13. The posture control unit 230 includes a dual-axis universal joint 231 and a servo motor 232 that actuates the dual-axis universal joint 231.
[0050] The attitude measurement mechanism 214 measures the rotation of the measurement unit 210 about a rotation axis extending along the XY plane. That is, the attitude measurement mechanism 214 measures the attitudes of the first angular velocity sensor 11, the second angular velocity sensor 12, and the rotation mechanism 13. The attitude measurement mechanism 214 is, for example, an inertial measurement unit (IMU). The attitude information acquisition unit 225 acquires information related to the attitude of the measurement unit 210 from the attitude measurement mechanism 214. Based on the attitude information related to the measurement unit 210 acquired by the attitude information acquisition unit 225, the attitude control unit 226 performs servo control on the dual-axis universal joint 231 via the servo motor 232.
[0051] According to this embodiment, the orientation measuring device 2 includes an attitude control unit 230, which can suppress the generation of orientation measurement errors caused by the rotation of the measuring unit 210 about a rotation axis extending in the horizontal direction, thereby improving the orientation measurement accuracy.
[0052] In addition, as one embodiment, the posture control unit 230 performs posture control based on the measurement results of the posture measuring mechanism 214, thus enabling it to maintain the horizontal posture of the measuring unit 210 with high precision.
[0053] Furthermore, in this embodiment, the posture control unit 230 controls the posture of the measurement unit 210 via servo control based on the measurement results of the posture measurement mechanism 214, but is not limited to this. The orientation measuring device may also control the posture of the measurement unit by making the biaxial universal joint always operate with a constant output, without performing posture measurement by the posture control unit.
[0054] Furthermore, the posture control mechanism is not limited to a dual-axis universal joint. For example, the posture control mechanism can also be two or more lifting supports connected to the bottom surface of the measuring unit. The posture control mechanism can also be a passive posture control mechanism with air springs, springs, oil dampers, air dampers, and polyurethane rubber, etc.
[0055] The following notes describe some or all of the embodiments of the present invention. Furthermore, the present invention is not limited to the following notes.
[0056] <1>
[0057] A azimuth measuring device, comprising:
[0058] A first angular velocity sensor has a first detection axis extending in a horizontal direction, and detects a first angular velocity about the first detection axis as the center of rotation.
[0059] A rotating mechanism having a rotating shaft extending in a vertical direction, causing a first detection shaft of a first angular velocity sensor to rotate about the rotating shaft as a center of rotation; and
[0060] A second angular velocity sensor is used to correct the rotation angle of the first detection shaft in the rotating mechanism. The second angular velocity sensor has a second detection shaft extending in the vertical direction and detects a second angular velocity with the second detection shaft as the center of rotation.
[0061] <2>
[0062] according to <1> The aforementioned orientation measuring device, wherein,
[0063] It also includes a correction unit that corrects the rotation angle of the first detection shaft in the rotating mechanism based on the second angular velocity.
[0064] <3>
[0065] according to <2> The aforementioned orientation measuring device, wherein,
[0066] It also includes a calculation unit that calculates the orientation by marking the first angular velocity in relation to the rotation angle and fitting the markings with a sine function.
[0067] <4>
[0068] according to <2> or <3> The aforementioned orientation measuring device, wherein,
[0069] The correction unit corrects the rotation angle obtained from the rotating mechanism.
[0070] <5>
[0071] according to <4> The aforementioned orientation measuring device, wherein,
[0072] The calibration unit adds the rotation angle of the first detection axis obtained from the rotation mechanism to the rotation angle calculated based on the second angular velocity measured by the second angular velocity sensor.
[0073] <6>
[0074] according to <2> or <3> The aforementioned orientation measuring device, wherein,
[0075] The calibration unit calibrates the rotation angle obtained from the rotating mechanism.
[0076] <7>
[0077] according to <6> The aforementioned orientation measuring device, wherein,
[0078] The calibration unit will subtract the second angular velocity measured by the second angular velocity sensor from the normal set value and set the value as the rotational angular velocity of the rotating mechanism.
[0079] <8>
[0080] according to <1> to <7> The orientation measuring device according to any one of the following, wherein,
[0081] It also includes a posture control unit, which controls the posture of the first angular velocity sensor, the rotation mechanism, and the second angular velocity sensor.
[0082] <9>
[0083] according to <8> The aforementioned orientation measuring device, wherein,
[0084] The attitude control unit is a dual-axis universal joint.
[0085] <10>
[0086] according to <8> or <9> The aforementioned orientation measuring device, wherein,
[0087] It also includes an attitude measurement mechanism that measures the attitude of the first angular velocity sensor, the rotation mechanism, and the second angular velocity sensor.
[0088] The posture control unit performs posture control based on the measurement results of the posture measuring mechanism.
[0089] As explained above, according to one aspect of the present invention, it is possible to provide an orientation measuring device that can improve the accuracy of orientation measurement.
[0090] Furthermore, the embodiments described above are intended to facilitate understanding of the invention and are not intended to limit the scope of the invention. The invention can be modified / improved without departing from its spirit, and the invention also includes its equivalents. That is, any method obtained by those skilled in the art through appropriate design changes to the embodiments and / or modifications, as long as it possesses the features of the invention, is also included within the scope of the invention. For example, the elements, their configurations, materials, conditions, shapes, dimensions, etc., of the embodiments and / or modifications are not limited to the illustrative content and can be appropriately modified. In addition, the embodiments and modifications are illustrative, and it is self-evident that partial substitutions or combinations of the structures shown in different embodiments and / or modifications can be made; these substitutions or combinations, as long as they contain the features of the invention, are also included within the scope of the invention.
[0091] Explanation of reference numerals in the attached figures
[0092] 1: Orientation measuring device; 10: Measurement unit; 11: First angular velocity sensor; 11D: First detection axis; 12: Second angular velocity sensor; 12D: Second detection axis; 13: Rotation mechanism; 13R: Rotation axis; 13A: Rotary encoder; RD: Reference direction; α: Rotation angle; 20: Control unit; 21: Drive unit; 22: Acquisition unit; 23: Calculation unit; 24: Calibration unit; 214: Posture measuring mechanism; 230: Posture control unit; 231: Dual-axis universal mechanism; 232: Servo motor; 225: Posture information acquisition unit; 226: Posture control unit.
Claims
1. An azimuth measuring device comprising: a first angular velocity sensor having a first detection axis extending in a horizontal direction, which detects a first angular velocity about the first detection axis as a center of rotation; a rotation mechanism having a rotation axis extending in a vertical direction, which rotates the first detection axis of the first angular velocity sensor about the rotation axis as a center of rotation; and a second angular velocity sensor for correcting a rotation angle of the first detection axis in the rotation mechanism, the second angular velocity sensor having a second detection axis extending in the vertical direction, which detects a second angular velocity about the second detection axis as a center of rotation.
2. The azimuth measuring device according to claim 1, wherein the azimuth measuring device further comprises a correction section that corrects the rotation angle of the first detection axis in the rotation mechanism based on the second angular velocity.
3. The azimuth measuring device according to claim 2, wherein the azimuth measuring device further comprises a calculation section that calculates an azimuth by marking the first angular velocity in correspondence with the rotation angle and fitting the marks with a sine function.
4. The azimuth measuring device according to claim 2 or 3, wherein the correction section corrects the rotation angle after the rotation mechanism is acquired.
5. The azimuth measuring device according to claim 4, wherein the correction section adds a rotation angle calculated based on the second angular velocity measured by the second angular velocity sensor to the rotation angle of the first detection axis acquired from the rotation mechanism.
6. The azimuth measuring device according to claim 2 or 3, wherein the correction section corrects the rotation angle before the rotation mechanism is acquired.
7. The azimuth measuring device according to claim 6, wherein the correction section sets a value obtained by subtracting the second angular velocity measured by the second angular velocity sensor from a set value at a normal time as a rotation angular velocity of the rotation mechanism.
8. The azimuth measuring device according to any one of claims 1 to 7, wherein the azimuth measuring device further comprises a posture control unit that controls a posture of the first angular velocity sensor, the rotation mechanism, and the second angular velocity sensor.
9. The azimuth measuring device according to claim 8, wherein the posture control unit is a two-axis gimbal mechanism.
10. The azimuth measuring device according to claim 8 or 9, wherein the azimuth measuring device further comprises a posture measurement mechanism that measures a posture of the first angular velocity sensor, the rotation mechanism, and the second angular velocity sensor, and the posture control unit performs posture control based on a measurement result of the posture measurement mechanism.