Sensor module, electronic apparatus, mobile body positioning device, and mobile body

Abstract

To provide an inertia measurement device capable of suppressing influence due to combination of different kinds of inertia sensor elements.SOLUTION: An inertia measurement device 100 includes: a Z-axis angular speed sensor element Gz1 for detecting an angular speed around a Z-axis; and a Z-axis angular speed sensor element Gz2 for detecting the angular speed around the Z-axis, whose type is different from that of the Z-axis angular speed sensor element Gz1. Each one of the elements includes: a plurality of inertia sensor elements for detecting the angular speed around the Z-axis; and an arithmetic circuit 30 for weighted-averaging angular speed ωz1, ωz2 of the inertia sensor elements with the use of a plurality of weighting coefficients A1, A2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor module, an electronic device, a mobile object positioning device, and a mobile object. [Background technology]

[0002] Patent document 1 describes that the accuracy of Z-axis angular velocity data can be improved by providing multiple angular velocity sensor devices and having a microcontroller calculate the average value of Z-axis angular velocity data from these multiple angular velocity sensor devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-163955 Summary of the Invention [Problem to be solved by the invention]

[0004] As a method for using multiple angular velocity sensor devices to improve accuracy, combining different types of sensor devices is being considered. In this case, the impact of combining different types of sensor devices must be taken into consideration. [Means for solving the problem]

[0005] A sensor module according to one aspect of the present application includes a first inertial sensor element that detects a first physical quantity, a second inertial sensor element that detects the first physical quantity and is of a different type from the first inertial sensor element, and is equipped with a plurality of inertial sensor elements each detecting the first physical quantity, and a calculation unit that calculates a weighted average of the detection signals of the plurality of inertial sensor elements using a plurality of weighting coefficients.

[0006] An electronic device according to one aspect of the present application includes the sensor module described above.

[0007] A mobile body positioning device according to one embodiment of the present application includes a first inertial sensor element that detects a first physical quantity, and a second inertial sensor element that detects the first physical quantity and is of a different type from the first inertial sensor element, and is equipped with a plurality of inertial sensor elements each detecting the first physical quantity, a calculation unit that uses a plurality of weighting coefficients to weight-average the detection signals of the plurality of inertial sensor elements, a receiving unit that receives satellite signals from a positioning satellite on which position information is superimposed, an acquisition unit that acquires the position information based on the satellite signals, and a calculation unit that calculates the position of the mobile body based on the position information and the weighted-averaged detection signals from the calculation unit.

[0008] A mobile object according to one aspect of the present application includes the mobile object positioning device described above. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of a sensor module according to a first embodiment. [Figure 2] 1 is an explanatory diagram of a sensor coordinate system. [Figure 3] FIG. 2 is a perspective view showing the appearance of the sensor module. [Figure 4] FIG. 1 is a block diagram of a correction circuit. [Figure 5] FIG. 10 is a block diagram of a sensor module according to a second embodiment. [Figure 6] FIG. 11 is a perspective view showing an example of an electronic device according to a third embodiment. [Figure 7] FIG. 11 is a perspective view showing another example of the electronic device according to the third embodiment. [Figure 8] FIG. 10 is a block diagram of a mobile object positioning device according to a fourth embodiment. [Figure 9] FIG. 2 is a diagram showing the operation of the mobile object positioning device. DETAILED DESCRIPTION OF THE INVENTION

[0010] In each drawing, the dimensions of some components may be drawn to different scales to make the components easier to see.

[0011] 1. Embodiment 1 1.1.Inertial Measurement Unit 1 to 4 show an inertial measurement unit (IMU) 100 as a sensor module. Fig. 1 is a block diagram showing the configuration of an inertial measurement unit 100. Fig. 2 is an explanatory diagram of a sensor coordinate system. Fig. 3 is a perspective view showing the appearance of the inertial measurement unit 100. Fig. 4 is a block diagram showing the configuration of a correction circuit 40 of the inertial measurement unit 100.

[0012] In this embodiment, the inertial measurement unit 100 measures angular velocity and / or acceleration in the sensor coordinate system of the inertial measurement unit 100 . The inertial measurement unit 100 is mounted on electronic devices such as mobile devices such as smartphones (described later) and mobile objects such as automobiles, and is used to detect the attitude and behavior of the electronic devices. The inertial measurement unit 100 is also used in mobile object positioning devices (described later). The mobile object positioning devices are mounted on mobile objects such as automobiles and are used to calculate the attitude, position, etc. of the mobile object.

[0013] 1.2.Sensor Coordinate System The sensor coordinate system of the inertial measurement unit 100 is a three-dimensional Cartesian coordinate system consisting of three coordinate axes: X-axis, Y-axis, and Z-axis. 2 is a diagram illustrating the relationship between the sensor coordinate system of the inertial measurement unit 100 and the direction of movement of an automobile 130 equipped with the inertial measurement unit 100. The inertial measurement unit 100 is mounted on the automobile 130 so that the sensor coordinate system satisfies the following predetermined relationship with respect to the automobile 130:

[0014] In this embodiment, the X-axis of the sensor coordinate system of the inertial measurement unit 100 is set to the front-to-rear direction of the automobile 130. The positive X-axis direction of the sensor coordinate system is the front direction (forward direction) of the automobile 130. The Y axis of the sensor coordinate system of the inertial measurement unit 100 is set to the left-right direction of the automobile 130. The positive Y axis direction of the sensor coordinate system is the right direction of the automobile 130. The Z axis of the sensor coordinate system of the inertial measurement unit 100 is a direction perpendicular to the X axis and Y axis, and is considered to be the up-down direction of the automobile 130. The positive Z axis direction of the sensor coordinate system is the downward direction of the automobile 130. Because the automobile 130 moves on a substantially horizontal plane, the XY plane is the plane of movement of the moving body, and the positive Z axis direction can be considered to coincide with the direction of gravity.

[0015] The attitude of the automobile 130 is expressed by the roll angle around the X axis, the pitch angle around the Y axis, and the yaw angle around the Z axis. The roll angle corresponds to the left-right tilt of the automobile 130, the pitch angle corresponds to the front-rear tilt of the automobile 130, and the yaw angle corresponds to the change in the direction of movement or orientation of the automobile 130.

[0016] According to experiments and studies by the inventors, when the inertial measurement unit 100 is used in a mobile positioning system, it has been found that in order to efficiently improve the positioning accuracy, it is most preferable to make the accuracy of the yaw angle measurement value of the inertial measurement unit 100 higher than the accuracy of the roll angle and pitch angle measurement values.

[0017] In the inertial measurement unit 100 of this embodiment, the accuracy of the angular velocity around the Z axis, which is the yaw angle, is higher than the accuracy of the angular velocity around the X axis and the Y axis. To achieve this, the inertial measurement unit 100 is equipped with multiple different types of Z-axis angular velocity sensor elements and is designed to obtain a more accurate angular velocity around the Z axis than if these multiple different types of Z-axis angular velocity sensor elements were used individually. This will be explained in more detail in Section 1.4 below.

[0018] 1.3.Appearance FIG. 3 is a perspective view showing the appearance of the inertial measurement unit 100. As shown in FIG. 3, the inertial measurement unit 100 has a housing 1. The housing 1 has a rectangular parallelepiped shape, and is sized such that the length of one side of a square is, for example, about 24 mm, and the thickness is about 10 mm.

[0019] The housing 1 is a case for housing a plurality of inertial sensors, which will be described later. The housing 1 is composed of a box 2 and a lid 3. Box 2 houses a number of inertial sensors, which will be described later. The housing 1 has screw holes 4. By passing screws 7 through these two screw holes 4, the inertial measurement unit 100 is fixed to a mounting surface 8 of a mounted device such as an automobile 130 and used.

[0020] 1.4.Function Block Configuration FIG. 1 is a block diagram showing the functional block configuration of an inertial measurement unit 100. As shown in FIG. As shown in FIG. 1, the inertial measurement unit 100 includes a first sensor 10, a second sensor 20, a data processing circuit 50, and an I / F circuit 60.

[0021] Inertial Sensors The inertial measurement unit 100 includes a first sensor 10 and a second sensor 20 as inertial sensors that detect angular velocity and / or acceleration as physical quantities.

[0022] The first sensor 10 and the second sensor 20 are different types of inertial sensors. In other words, the first sensor 10 and the second sensor 20 are inertial sensors with different performance and / or characteristics. The inertial measurement unit 100 is designed to perform highly accurate detection using these different types of first sensor 10 and second sensor 20.

[0023] In this embodiment, the first sensor 10 is a Si-MEMS (Micro Electro Mechanical Systems) sensor that uses silicon (Si) as its material. In this embodiment, the second sensor 20 is a quartz gyro sensor made of quartz (SiO2).

[0024] The first sensor 10 and the second sensor 20 are not limited to Si-MEMS sensors and quartz gyro sensors. For example, the first sensor 10 and the second sensor 20 can be MEMS sensors using LiNbO3 (lithium niobate), fiber-optic gyroscopes (FOGs), ring laser gyroscopes (RLGs), gas rate gyro sensors, or rotary gyro sensors. In other words, the inertial measurement unit 100 of this embodiment employs different types of inertial sensors for the first sensor 10 and the second sensor 20 from among these inertial sensors.

[0025] The first sensor 10 and the second sensor 20 are inertial sensors that detect the same physical quantity. The inertial measurement unit 100 is provided with redundancy by including multiple inertial sensors that detect the same physical quantity.

[0026] In this embodiment, the first sensor 10 and the second sensor 20 detect the angular velocity around the Z axis as the same physical quantity. In this embodiment, the angular velocity around the Z axis is an example of the first physical quantity. The first physical quantity is not limited to the angular velocity around the Z axis. The first physical quantity may be the angular velocity around the X axis, the angular velocity around the Y axis, the acceleration in the X axis direction, the acceleration in the Y axis direction, or the acceleration in the Z axis direction, and is appropriately selected depending on the purpose and application.

[0027] 1.4.1.1. First Sensor The first sensor 10 is a multi-axis inertial sensor that detects three-dimensional inertial motion. Specifically, the first sensor 10 is a six-axis inertial sensor that detects translational motion and rotational motion in three orthogonal directions of a sensor coordinate system. In other words, the first sensor 10 is a six-degrees-of-freedom (Dof) sensor.

[0028] The first sensor 10 includes an X-axis acceleration sensor element Ax, a Y-axis acceleration sensor element Ay, a Z-axis acceleration sensor element Az, an X-axis angular velocity sensor element Gx, a Y-axis angular velocity sensor element Gy, and a Z-axis angular velocity sensor element Gz1.

[0029] The X-axis acceleration sensor element Ax detects acceleration in the X-axis direction and outputs the acceleration α x Output. The Y-axis acceleration sensor element Ay detects the acceleration in the Y-axis direction and outputs the acceleration α y Output. The Z-axis acceleration sensor element Az detects acceleration in the Z-axis direction and outputs the acceleration α z Output. The X-axis angular velocity sensor element Gx detects the angular velocity around the X-axis and outputs the angular velocity ω x Output. The Y-axis angular velocity sensor element Gy detects the angular velocity around the Y-axis and outputs the angular velocity ω y Output. The Z-axis angular velocity sensor element Gz1 detects the angular velocity around the Z-axis and outputs the angular velocity ω z1 In this embodiment, the Z-axis angular velocity sensor element Gz1 is an example of a first inertial sensor element among the multiple inertial sensor elements.

[0030] In this embodiment, the first sensor 10 is a capacitance change type Si-MEMS sensor. The X-axis acceleration sensor element Ax, the Y-axis acceleration sensor element Ay, the Z-axis acceleration sensor element Az, the X-axis angular velocity sensor element Gx, the Y-axis angular velocity sensor element Gy, and the Z-axis angular velocity sensor element Gz1 are preferably formed on a single silicon chip, but may also be formed separately on multiple silicon chips and packaged in a single package.

[0031] 1.4.1.2. Secondary Sensor The second sensor 20 is a quartz gyro sensor. The second sensor 20 detects the angular velocity around the Z axis from the Coriolis force acting on the quartz oscillator, and outputs the angular velocity ω z2 In this embodiment, the Z-axis angular velocity sensor element Gz2 is an example of a second inertial sensor element among the plurality of inertial sensor elements.

[0032] Angular velocity ω of Z-axis angular velocity sensor element Gz2 z2 is the angular velocity ω of the first sensor 10 z1 In other words, the Z-axis angular velocity sensor element Gz2 is a sensor element with higher accuracy than the Z-axis angular velocity sensor element Gz1.

[0033] 1.4.2. Data Processing Circuit The data processing circuit 50 includes an arithmetic circuit 30 and a correction circuit 40. The data processing circuit 50 is configured with a processor such as an MPU (Micro Processing Unit), DSP (Digital Signal Processor), or ASIC (Application Specific Integrated Circuit). The data processing circuit 50 causes the arithmetic circuit 30 and the correction circuit 40 to execute various processes based on a program stored in a storage unit (not shown). The arithmetic circuit 30 and the correction circuit 40 may be programs that cause the processor to execute an arithmetic function and a correction function. The data processing circuit 50 is preferably a one-chip processor, but may be configured with multiple chips.

[0034] 1.4.2.1. Arithmetic circuit The calculation circuit 30 calculates the angular velocity ω of the Z-axis angular velocity sensor element Gz1. z1 and the angular velocity ω of the Z-axis angular velocity sensor element Gz2 z2 and are weighted averaged to obtain the resultant angular velocity ω z Output.

[0035] Resultant angular velocity ω z is the angular velocity ω of the Z-axis angular velocity sensor element Gz1 z1and the angular velocity ω of the Z-axis angular velocity sensor element Gz2 z2 In other words, the calculation circuit 30 uses a plurality of different types of Z-axis angular velocity sensor elements Gz1 and Gz2 to calculate the angular velocities ω z1 ,ω z2 than the more accurate resultant angular velocity ω z Output.

[0036] The arithmetic circuit 30 includes multiplication units 31 and 32 and an addition unit 33 . The multiplication unit 31 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz1 of the first sensor 10 by z1 is multiplied by a weighting coefficient A1. In this embodiment, the weighting coefficient A1 is an example of a first weighting coefficient. The multiplication unit 32 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz2 of the second sensor 20 by z2 is multiplied by a weighting coefficient A2. In this embodiment, the weighting coefficient A2 is an example of a second weighting coefficient. The adder 33 adds the output of the multiplier 31 and the output of the multiplier 32 to obtain a resultant angular velocity ω z Output.

[0037] Resultant angular velocity ω z is calculated by the following formula 1.

number

[0038] In this embodiment, the weighting coefficients A1 and A2 are calculated based on the root mean square (RMS) error of the Z-axis angular velocity sensor element Gz1 of the first sensor 10 and the RMS error of the Z-axis angular velocity sensor element Gz2 of the second sensor 20.

[0039] The error RMS of the Z-axis angular velocity sensor element Gz1 of the first sensor 10 is σ 1、When the error RMS of the Z-axis angular velocity sensor element Gz2 of the second sensor 20 is σ2, the weighting coefficient A1 is calculated by the following formula 2, and the weighting coefficient A2 is calculated by the following formula 3. The calculated weighting coefficients A1 and A2 are stored in a storage unit or the like (not shown) and used for calculation by the calculation circuit 30.

number

number

[0040] Resultant angular velocity ω z Error RMS σ z is calculated by Equation 4.

number

[0041] Angular velocity ω of Z-axis angular velocity sensor element Gz1 z1 and the angular velocity ω of the Z-axis angular velocity sensor element Gz2 z2 The error (error variance σ 2 ) is determined by the width of the bandwidth B, which is the angular velocity noise density N0 or the angular random walk R ω Therefore, the angular velocity ω of the Z-axis angular velocity sensor element Gz1 is z1 and the angular velocity ω of the Z-axis angular velocity sensor element Gz2 z2 The error variance σ contained in 2 can be approximately estimated by Equation 5. In other words, the weighting coefficients may be calculated based on the angular velocity noise density N0 or the angular random walk Rω.

number

[0042] For example, the angular velocity noise density N of the Z-axis angular velocity sensor element Gz1 0,z1 and the angular velocity noise density N of the Z-axis angular velocity sensor element Gz2 0,z2 In the following cases, if the bandwidth B is the same, the weighting coefficient A1, the weighting coefficient A2, and the combined noise density N 0,z is calculated by the following Equations 6, 7, and 8.

number

number

number

[0043] In this embodiment, the arithmetic circuit 30 is an example of a calculation unit. The sensor module 100a indicated by the dashed line includes a Z-axis angular velocity sensor element Gz1, a Z-axis angular velocity sensor element Gz2, and the arithmetic circuit 30, and shows a minimum configuration as an example of a sensor module.

[0044] 1.4.2.2. Compensation Circuit FIG. 4 is a block diagram of the correction circuit 40. As shown in FIG. 4, the correction circuit 40 includes single-axis correction units 41, 42, 43, 44, 45, and 46, and an inter-axis correction unit 47.

[0045] The single-axis correction unit 41 calculates the acceleration α of the X-axis acceleration sensor element Ax. x The desired correction processing is performed on the signal. The desired correction processing includes temperature correction, zero point correction, sensitivity adjustment, filter processing, etc. The single-axis correction unit 42 corrects the acceleration α of the Y-axis acceleration sensor element Ay.y The desired correction process is performed on the The single-axis correction unit 43 corrects the acceleration α of the Z-axis acceleration sensor element Az. z The desired correction process is performed on the

[0046] The single-axis correction unit 44 corrects the angular velocity ω of the X-axis angular velocity sensor element Gx. x The desired correction process is performed on the The single-axis correction unit 45 corrects the angular velocity ω of the Y-axis angular velocity sensor element Gy. y The desired correction process is performed on the The single-axis correction unit 46 calculates a resultant angular velocity ω of the Z-axis angular velocity sensor element Gz1 and the Z-axis angular velocity sensor element Gz2. z In this embodiment, the single-axis correction unit 46 is disposed after the arithmetic circuit 30, but the single-axis correction unit 46 may be disposed between the Z-axis angular velocity sensor element Gz1 and the arithmetic circuit 30, and between the Z-axis angular velocity sensor element Gz2 and the arithmetic circuit 30. In this case, the arithmetic circuit 30 calculates the angular velocity ω after the correction process. z1 ,ω z2 Based on this, the resultant angular velocity ω z The following is calculated and processed.

[0047] The inter-axis correction unit 47 performs alignment correction. The alignment correction is called installation error correction, and corrects the acceleration α x ,α y ,α z , angular velocity ω x ,ω y , and the resultant angular velocity ω z Correct the following.

[0048] 1.4.3.I / F circuit The I / F circuit 60 communicates the detected resultant angular velocity ω with the host 200 based on a communication standard such as SPI (Serial Peripheral Interface) or I2C (Inter Integrated Circuit). zIt performs interface processing for sending and receiving data including inertial data such as the above.

[0049] The host 200 is a device that is electrically connected to the inertial measurement unit 100 and acquires the inertial data output from the inertial measurement unit 100 . The host 200 includes a processing unit (not shown), which can be realized by a processor or the like, similar to the data processing circuit 50 described above.

[0050] For example, the host 200 may be an electronic device, which will be described later. The electronic device may be a moving object such as an automobile 130, an airplane, or a ship, or a portable device such as a smartphone, a personal computer, a tablet terminal, or a watch. The electronic device, such as a smartphone, calculates the attitude of the electronic device based on the inertial data output from the inertial measurement unit 100.

[0051] For example, host 200 may be part of a mobile positioning device, which will be described later. The mobile positioning device includes inertial measurement unit 100, a GPS receiver, a receiving antenna for GPS reception, etc., and is mounted on a mobile object such as automobile 130, and calculates the attitude and position of the mobile object based on data from inertial measurement unit 100 and the GPS receiver.

[0052] As described above, the inertial measurement unit 100 serving as a sensor module of this embodiment has the following advantages. The inertial measurement device 100 of this embodiment includes a Z-axis angular velocity sensor element Gz1 as a first inertial sensor element that detects an angular velocity around the Z-axis as a first physical quantity, and a Z-axis angular velocity sensor element Gz2 as a second inertial sensor element that detects an angular velocity around the Z-axis and is of a different type from the Z-axis angular velocity sensor element Gz1. The inertial measurement device 100 calculates an angular velocity ω z1 ,ω z2 and a calculation circuit 30 as a calculation unit that performs weighted averaging of the above.

[0053] As described above, the inertial measurement unit 100 of this embodiment includes a plurality of different types of inertial sensor elements, and calculates a weighted average of the detection signals of the plurality of inertial sensor elements using weighting coefficients. Therefore, the inertial measurement unit 100 of this embodiment can suppress the influence of combining multiple different types of inertial sensor elements, thereby improving the accuracy of the inertial measurement unit 100. Specifically, the inertial measurement unit 100 can obtain detection results with higher accuracy than when multiple different types of inertial sensor elements are used individually.

[0054] In the inertial measurement device 100 of this embodiment, the multiple weighting coefficients include a weighting coefficient A1 as a first weighting coefficient used for the Z-axis angular velocity sensor element Gz1 and a weighting coefficient A2 as a second weighting coefficient used for the Z-axis angular velocity sensor element Gz2, and the weighting coefficient A1 and the weighting coefficient A2 are different from each other.

[0055] As described above, the inertial measurement unit 100 of this embodiment includes a plurality of different types of inertial sensor elements, and performs weighted averaging of the detection signals of the plurality of inertial sensor elements using different weighting coefficients. Therefore, the inertial measurement unit 100 of this embodiment can improve the effectiveness of accuracy improvement in a configuration including different types of inertial sensor elements.

[0056] In the inertial measurement device 100 of this embodiment, the multiple weighting coefficients include a weighting coefficient A1 as a first weighting coefficient based on error information of the Z-axis angular velocity sensor element Gz1, and a weighting coefficient A2 as a second weighting coefficient based on error information of the Z-axis angular velocity sensor element Gz2.

[0057] As described above, the inertial measurement unit 100 of this embodiment includes different types of inertial sensor elements, and calculates a weighted average of the detection signals of the multiple inertial sensor elements using weighting coefficients based on the error information of each inertial sensor element. Therefore, in the inertial measurement unit 100 of this embodiment, in a configuration including different types of inertial sensor elements, the inertial sensor elements can be used according to their performance, thereby making it possible to improve the effectiveness of accuracy improvement.

[0058] 2. Embodiment 2 FIG. 5 is a block diagram showing the functional block configuration of an inertial measurement unit 100 as a sensor module according to the second embodiment.

[0059] The second embodiment differs from the first embodiment in that it includes a failure detection circuit 61 and excludes the detection signal of a failed inertial sensor. Note that the same or similar components as those in the first embodiment are denoted by the same reference numerals and descriptions thereof will be omitted.

[0060] Inertial Sensors The inertial measurement unit 100 of the second embodiment includes a third sensor 23 and a fourth sensor 24 in addition to the first sensor 10 and the second sensor 20 of the first embodiment described above.

[0061] The first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 are all different types of inertial sensors. In other words, the first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 are all inertial sensors with different performance and / or characteristics. The inertial measurement unit 100 of the second embodiment is designed to perform highly accurate detection using these different types of first sensor 10, second sensor 20, third sensor 23, and fourth sensor 24.

[0062] In the second embodiment, the third sensor 23 is, for example, a MEMS sensor using LiNbO3 as a material. The third sensor 23 outputs an angular velocity ω z3 It is equipped with a Z-axis angular velocity sensor element Gz3 that outputs

[0063] In the second embodiment, the fourth sensor 24 is, for example, an optical fiber gyroscope. The fourth sensor 24 outputs an angular velocity ω z4It is equipped with a Z-axis angular velocity sensor element Gz4 that outputs

[0064] The first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 are not limited to Si-MEMS sensors, quartz gyro sensors, MEMS sensors using LiNbO3, and fiber optic gyroscopes. Any two of the first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 may be different types of inertial sensors from the inertial sensors described above. The first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 may be different types of inertial sensors from the different types of inertial sensors described above, or any two of the first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 may be the same type of inertial sensor from the inertial sensors described above.

[0065] The first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24 are inertial sensors that detect the same physical quantity. The inertial measurement unit 100 has redundancy by including multiple inertial sensors that detect the same physical quantity.

[0066] 2.2.Data Processing Circuit The data processing circuit 50 includes an arithmetic circuit 300, a correction circuit 40, a failure detection circuit 61, and a weighting coefficient storage circuit 62.

[0067] The failure detection circuit 61 monitors the first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24, and when a failure is detected, outputs information about the failed inertial sensor to the arithmetic circuit 300.

[0068] The weighting coefficient storage circuit 62 outputs weighting coefficients A1, A2, A3, and A4 corresponding to the first sensor 10, the second sensor 20, the third sensor 23, and the fourth sensor 24, respectively, and a weighting coefficient of zero corresponding to the faulty inertial sensor. The weighting coefficient of zero is a weighting coefficient for reducing the detection signal of the faulty inertial sensor to zero. In other words, the weighting coefficient of zero is a weighting coefficient for excluding the detection signal of the faulty inertial sensor.

[0069] The weighting coefficients A1, A2, A3, and A4 are values ​​based on the performance of the Z-axis angular velocity sensor element Gz1 of the first sensor 10, the performance of the Z-axis angular velocity sensor element Gz2 of the second sensor 20, the performance of the Z-axis angular velocity sensor element Gz3 of the third sensor 23, and the performance of the Z-axis angular velocity sensor element Gz4 of the fourth sensor 24, respectively.

[0070] The calculation circuit 300 calculates the angular velocity ω of the Z-axis angular velocity sensor element Gz1. z1 , the angular velocity ω of the Z-axis angular velocity sensor element Gz2 z2 , the angular velocity ω of the Z-axis angular velocity sensor element Gz3 z3 , and the angular velocity ω of the Z-axis angular velocity sensor element Gz4 z4 The weighted average is calculated to obtain the resultant angular velocity ω as the detection signal after the weighted average. z Output.

[0071] The arithmetic circuit 300 includes changeover switches 311, 312, 313, and 314, multiplication units 321, 322, 323, and 324, addition units 331, 332, and 333, addition units 341, 342, and 343, and a division unit 351.

[0072] The changeover switch 311 switches the path of the weighting coefficient to either the weighting coefficient A1 side or the weighting coefficient zero side output from the weighting coefficient storage circuit 62 based on the output from the failure detection circuit 61. When the failure detection circuit 61 detects a failure of the first sensor 10, the changeover switch 311 switches the path of the weighting coefficient from the weighting coefficient A1 side to the weighting coefficient zero side.

[0073] Based on the output from the failure detection circuit 61, the changeover switch 312 switches the path of the weighting coefficient to either the weighting coefficient A2 side output from the weighting coefficient storage circuit 62 or the weighting coefficient zero side. Based on the output from the failure detection circuit 61, the changeover switch 313 switches the path of the weighting coefficient to either the weighting coefficient A3 side output from the weighting coefficient storage circuit 62 or the weighting coefficient zero side. Based on the output from the failure detection circuit 61, the changeover switch 314 switches the path of the weighting coefficient to either the weighting coefficient A4 side output from the weighting coefficient storage circuit 62 or the weighting coefficient zero side.

[0074] The multiplication unit 321 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz1 of the first sensor 10 by z1 is multiplied by a weighting coefficient A1 or zero supplied via a changeover switch 311. The multiplication unit 322 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz2 of the second sensor 20 by z2 is multiplied by a weighting coefficient A2 or zero supplied via a changeover switch 312. The multiplication unit 323 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz3 of the third sensor 23 by z3 is multiplied by a weighting coefficient A3 or zero supplied via a changeover switch 313. The multiplication unit 324 multiplies the angular velocity ω of the Z-axis angular velocity sensor element Gz4 of the fourth sensor 24 by z4 is multiplied by a weighting coefficient A4 or a weighting coefficient of zero supplied via a changeover switch 314.

[0075] The outputs of the multiplication units 321 , 322 , 323 , and 324 are summed by addition units 331 , 332 , and 333 and supplied to a division unit 351 . The outputs of the changeover switches 311 , 312 , 313 , and 314 are added together by adding sections 341 , 342 , and 343 , and the sum is supplied to a dividing section 351 .

[0076] The division unit 351 calculates the resultant angular velocity ω by dividing the sum of the values ​​obtained by multiplying the detection signals of the Z-axis angular velocity sensor elements Gz1, Gz2, Gz3, and Gz4 by their respective weighting coefficients, by the sum of the weighting coefficients used in the multiplication. z and outputs it to the correction circuit 40.

[0077] As described above, the inertial measurement unit 100 serving as the sensor module of the second embodiment can provide the following advantages in addition to the advantages of the first embodiment. The inertial measurement device 100 of embodiment 2 further includes a failure detection circuit 61 as a detection unit that detects a failed inertial sensor element among the multiple inertial sensor elements, and the calculation circuit 300 as a calculation unit sets the weighting coefficient used for the inertial sensor element detected as failed by the failure detection circuit 61 to zero.

[0078] In this way, the inertial measurement unit 100 of the second embodiment sets the weighting coefficient used for the inertial sensor element detected as faulty to zero. Therefore, in a configuration including different types of inertial sensor elements, the inertial measurement unit 100 of the second embodiment can eliminate the influence of a faulty inertial sensor, thereby improving the effectiveness of accuracy improvement.

[0079] 3. Embodiment 3 In the third embodiment, an electronic device including an inertial measurement unit 100 will be described. In the following, examples of a portable device such as a smartphone and examples of a mobile object such as an automobile 130 will be described as examples of electronic devices.

[0080] 3.1. Mobile Device Overview FIG. 6 is a perspective view of a mobile device as an electronic device according to the third embodiment, showing the configuration of a smartphone 110 as an example of the mobile device.

[0081] The smartphone 110 is equipped with an inertial measurement unit 100 . The inertial data of the inertial measurement unit 100 is received by the control unit 111. The control unit 111 recognizes the attitude and behavior of the smartphone 110 from the received inertial data, and can change the image displayed on the screen, sound an alarm or sound effect, or drive a vibration motor to vibrate the main body.

[0082] Inertial measurement unit 100 may be mounted on a mobile device other than smartphone 110. For example, inertial measurement unit 100 may be mounted on a mobile device such as a smartwatch, a portable activity tracker, a head mounted display (HMD), a mobile personal computer (PC), a tablet PC, a camera, or a personal digital assistant (PDA). This enables the mobile device to recognize its own attitude and behavior using inertial data from inertial measurement unit 100, and to change the displayed image, sound an alarm or sound effect, or drive a vibration motor to vibrate the main body.

[0083] In this manner, in the third embodiment, the inertial measurement unit 100 is mounted on a mobile device such as a smartphone 110 as an electronic device. Therefore, according to the third embodiment, the performance of a portable device equipped with the inertial measurement unit 100 can be improved.

[0084] 3.2. Overview of Mobile Objects FIG. 7 is a perspective view of a moving body as an electronic device according to the third embodiment, showing the configuration of an automobile 130 as an example of the moving body.

[0085] The vehicle 130 carries the inertial measurement unit 100 . The inertial measurement unit 100 detects the attitude of the vehicle body 131 and transmits inertial data to the vehicle body attitude control device 132. The inertial data includes angular velocity and acceleration. When the vehicle body attitude control device 132, which controls the attitude of the vehicle body 131, receives inertial data from the inertial measurement unit 100, it detects the attitude of the vehicle body 131 based on the signal, and controls the hardness of the suspension or the brakes on each wheel 133 according to the detection results.

[0086] The inertial data from the inertial measurement unit 100 may also be used in ECUs (Electronic Control Units) such as keyless entry, immobilizers, car navigation systems, car air conditioners, antilock braking systems (ABS), airbags, TPMS (Tire Pressure Monitoring Systems), engine controls, inertial navigation control equipment for autonomous driving, and battery monitors for hybrid and electric vehicles.

[0087] The inertial measurement unit 100 may be mounted on a moving body other than the automobile 130. Examples of other moving bodies include a bipedal robot, a train, an airplane, a ship, a radio-controlled airplane, a radio-controlled helicopter, a drone, agricultural machinery such as a tractor, and construction machinery. A moving body equipped with the inertial measurement unit 100 can utilize the inertial data of the inertial measurement unit for attitude control and position measurement of the moving body.

[0088] In this manner, in this embodiment, the inertial measurement unit 100 is mounted on a moving body such as an automobile 130 as an electronic device. Therefore, according to the third embodiment, the performance of a moving body equipped with the inertial measurement unit 100 can be improved.

[0089] 4. Embodiment 4 4.1. Mobile Positioning Device 8 is a block diagram showing the overall system of the mobile object positioning device 1000 according to the fourth embodiment. FIG.

[0090] As shown in FIG. 9, the mobile object positioning device 1000 is a device that is attached to, for example, a tractor 140 as a mobile object, and measures the position of the tractor 140.

[0091] The mobile positioning device 1000 has an inertial measurement unit 100, an arithmetic processing unit 150, a receiving antenna 410, a GPS receiving unit 420, a position information acquisition unit 430, a position synthesis unit 500, a processing unit 610, a communication unit 620, and a display unit 630.

[0092] The calculation processing unit 150 receives inertial data including three-axis acceleration and three-axis angular velocity from the inertial measurement unit 100, performs inertial navigation calculation processing based on this inertial data, and outputs inertial navigation positioning data. The inertial navigation positioning data indicates the acceleration and attitude of the tractor 140.

[0093] The GPS receiver 420 receives satellite signals from GPS satellites via the receiving antenna 410. The GPS satellites transmit GPS carrier waves onto which position information is superimposed as satellite signals. The position information acquisition unit 430 outputs GPS positioning data indicating the position, speed, and direction of the mobile positioning device 1000 based on the satellite signals received by the GPS receiving unit 420. The position in the GPS positioning data includes latitude, longitude, and altitude. The GPS positioning data also includes status data indicating the reception state, reception time, etc.

[0094] The position synthesis unit 500 calculates the position of the mobile positioning device 1000, specifically, the position on the ground where the tractor 140 is traveling, based on the inertial navigation positioning data output from the calculation processing unit 150 and the GPS positioning data output from the position information acquisition unit 430.

[0095] For example, even if the position of the tractor 140 included in the GPS positioning data is the same, if the posture of the tractor 140 is different due to the influence of the slope of the ground or the like, as shown by the solid and dashed lines in Fig. 9, the tractor 140 will be traveling at a different position on the ground. Therefore, the mobile positioning device 1000 cannot calculate the accurate position of the tractor 140 using only the GPS positioning data.

[0096] Therefore, the position synthesis unit 500 calculates the position on the ground where the tractor 140 is traveling by using the inertial navigation positioning data of the calculation processing unit 150, in particular, data related to the attitude of the tractor 140. This calculation can be performed relatively easily by a calculation using a trigonometric function, that is, the inclination θ with respect to the vertical direction.

[0097] The position data output from the position synthesis unit 500 is subjected to predetermined processing by the processing unit 610 and is displayed as visible information on the display unit 630. The position data may also be transmitted to an external device by the communication unit 620.

[0098] Although the mobile positioning device 1000 of the fourth embodiment has been described using GPS as the satellite positioning system, other global navigation satellite systems (GNSS: Global Navigation Satellite Systems) may also be used. For example, one or more of satellite positioning systems such as EGNOS (European Geostationary-Satellite Navigation Overlay Service), QZSS (Quasi Zenith Satellite System), GLONASS (Global Navigation Satellite System), GALILEO, and BeiDou (BeiDou Navigation Satellite System) may also be used. Furthermore, at least one of the satellite positioning systems may be a satellite-based augmentation system (SBAS: Satellite-based Augmentation System) such as WAAS (Wide Area Augmentation System).

[0099] As described above, according to the mobile object positioning device 1000 of the fourth embodiment, in addition to the effects of the first, second and third embodiments, the following effects can be obtained. The mobile object positioning device 1000 according to the fourth embodiment includes a Z-axis angular velocity sensor element Gz1 as a first inertial sensor element that detects an angular velocity around the Z-axis, and a Z-axis angular velocity sensor element Gz2 as a second inertial sensor element that detects an angular velocity around the Z-axis and is of a different type from the Z-axis angular velocity sensor element Gz1, and calculates an angular velocity ω as a detection signal of the plurality of inertial sensor elements using a plurality of inertial sensor elements that each detects an angular velocity around the Z-axis and weighting coefficients A1 and A2 as a plurality of weighting coefficients. z1 ,ω z2 a GPS receiving unit 420 as a receiving unit that receives satellite signals from positioning satellites on which position information is superimposed; a position information acquiring unit 430 as an acquiring unit that acquires position information of the GPS receiving unit 420 based on the satellite signals; and a position synthesis unit 500 as a calculating unit that calculates the position of an automobile 130 or a tractor 140 as a moving body based on the position information and the detection signal from the arithmetic circuit 30 after weighted averaging.

[0100] In this way, the mobile body positioning device 1000 of embodiment 4 performs a weighted average of the detection signals of multiple inertial sensor elements using a weighting coefficient, obtains position information based on satellite signals on which position information is superimposed, and calculates the position of the mobile body based on the position information and the detection signals after weighted averaging. Therefore, the mobile positioning device 1000 of the fourth embodiment can suppress the influence of combining different types of inertial sensor elements, thereby improving the accuracy of the mobile positioning device 1000. Specifically, the inertial measurement unit 100 can obtain detection results with higher accuracy than when multiple different types of inertial sensor elements are used individually, thereby improving the accuracy of the mobile positioning device 1000 equipped with the inertial measurement unit 100.

[0101] Furthermore, as described above, inertial measurement units 100 of embodiments 1 and 2, the accuracy of the angular velocity around the Z axis, which is the yaw angle, is higher than the accuracy of the angular velocity around the X axis and the accuracy of the angular velocity around the Y axis. Therefore, mobile positioning device 1000 equipped with inertial measurement unit 100 can provide a mobile positioning device with high industrial utility.

[0102] In the fourth embodiment, a mobile object such as an automobile 130 or a tractor 140 is equipped with a mobile object positioning device 1000 . Therefore, according to this embodiment, the performance of a mobile object equipped with the mobile object positioning device 1000 can be improved.

[0103] Although the preferred embodiment has been described above, the present invention is not limited to the above embodiment. The configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above embodiment, and any configuration can be added. [Explanation of symbols]

[0104] 1...housing, 2...box, 3...lid, 4...screw hole, 7...screw, 8...mounting surface, 10...first sensor, 20...second sensor, 23...third sensor, 24...fourth sensor, 30...arithmetic circuit, 31...multiplication unit, 32...multiplication unit, 33...addition unit, 40...correction circuit, 41, 42, 43, 44, 45, 46...single axis correction unit, 47...axis-to-axis correction unit, 50...data processing circuit, 60...I / F circuit, 61...fault detection circuit, 62...weighting coefficient memory circuit, 100...inertial measurement unit, 100a...sensor module, 110...smartphone, 111...control unit, 130...automobile, 131...vehicle body, 132...vehicle body attitude control device, 133...wheel, 140...tractor, 150...arithmetic processing unit, 200...host 300...arithmetic circuit, 311, 312, 313, 314...changeover switches, 321, 322, 323, 324...multiplication units, 331, 332, 333...addition units, 341, 342, 343...addition units, 351...division unit, 410...receiving antenna, 420...GPS receiving unit, 430...position information acquisition unit, 500...position synthesis unit, 610...processing unit, 620...communication unit, 630...display unit, 1000...mobile positioning device, Ax...X-axis acceleration sensor element, Ay...Y-axis acceleration sensor element, Az...Z-axis acceleration sensor element, Gx...X-axis angular velocity sensor element, Gy...Y-axis angular velocity sensor element, Gz1, Gz2, Gz3, Gz4...Z-axis angular velocity sensor element, A1, A2, A3, A4...weighting coefficients.

Claims

1. a plurality of inertial sensor elements each detecting the first physical quantity, the plurality of inertial sensor elements including a first inertial sensor element that detects a first physical quantity and a second inertial sensor element that detects the first physical quantity and is of a different type from the first inertial sensor element; a calculation unit that calculates a weighted average of the detection signals of the plurality of inertial sensor elements using a plurality of weighting coefficients; Sensor module.

2. the plurality of weighting coefficients include a first weighting coefficient used for the first inertial sensor element and a second weighting coefficient used for the second inertial sensor element; the first weighting factor and the second weighting factor are different; The sensor module according to claim 1 .

3. the plurality of weighting coefficients include a first weighting coefficient based on error information of the first inertial sensor element and a second weighting coefficient based on error information of the second inertial sensor element; The sensor module according to claim 1 .

4. a detection unit that detects a failed inertial sensor element among the plurality of inertial sensor elements; the calculation unit sets a weighting coefficient used for the inertial sensor element detected as faulty by the detection unit to zero. The sensor module according to claim 1 .

5. An electronic device comprising the sensor module according to any one of claims 1 to 4.

6. a plurality of inertial sensor elements each detecting the first physical quantity, the plurality of inertial sensor elements including a first inertial sensor element that detects a first physical quantity and a second inertial sensor element that detects the first physical quantity and is of a different type from the first inertial sensor element; a calculation unit that calculates a weighted average of the detection signals of the plurality of inertial sensor elements using a plurality of weighting coefficients; a receiving unit that receives satellite signals having superimposed thereon location information from positioning satellites; an acquisition unit that acquires the location information based on the satellite signal; a calculation unit that calculates a position of the moving object based on the position information and the weighted average detection signal from the calculation unit, Mobile positioning device.

7. A mobile body comprising the mobile body positioning device according to claim 6.

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