Inertial MEMS test system and method based on PLC

Abstract

The invention belongs to the field of sensor testing, and particularly discloses an inertial MEMS testing system and method based on a PLC, and the system comprises the steps: when an inertial MEMS sensor is located at a plurality of orthogonal positions under the control of a motion control unit to provide angular velocity and / or acceleration excitation, obtaining the output data of a triaxial accelerometer and / or a triaxial gyroscope, respectively fitting and calculating the inter-axis angle deviation of the triaxial accelerometer and / or the triaxial gyroscope, and determining a corresponding error model; when the MEMS sensor is located at a plurality of orthogonal positions under the control of the motion control unit and the magnetic field control unit provides magnetic field excitation with different intensities, obtaining an output signal of a triaxial magnetometer in the MEMS sensor, fitting an inter-axis angle deviation of the triaxial magnetometer, and determining an error model; when the air pressure control unit provides different air pressures, an output signal of a barometer in the MEMS sensor is obtained, and an error model is fitted. According to the invention, the comprehensive test of the inertial MEMS sensor is realized.

Description

Technical Field

[0001] This application belongs to the field of sensor testing, and more specifically, relates to an inertial micro-electro-mechanical systems (MEMS) testing system and method based on a programmable logic controller (PLC). Background Art

[0002] MEMS sensors are a cutting-edge research field of multidisciplinary intersection developed on the basis of microelectronics technology. It involves multiple disciplines and technologies such as electronics, mechanics, materials, physics, chemistry, biology, and medicine, and has broad application prospects. In the field of inertial navigation, MEMS inertial navigation technology based on MEMS inertial sensors is one of the research hotspots and future main development directions in the field of inertial navigation in recent years.

[0003] Inertial sensors are mainly divided into two categories: gyroscopes and accelerometers. Among them, gyroscopes are used to sense angular velocity changes to calculate the direction information of the sensor, and accelerometers are used to sense acceleration changes to obtain the speed and position information of the sensor. The combination of gyroscopes and accelerometers is the current mainstream inertial navigation principle. However, with the development of MEMS technology and the increasing requirements for navigation accuracy, inertial MEMS sensors have gradually developed into ten-axis inertial MEMS sensors integrated with magnetometers and barometers (3-axis accelerometers, 3-axis gyroscopes, 3-axis magnetometers, 1-axis barometer). Currently, there is no corresponding test method for ten-axis inertial MEMS sensors, and the test requirements of ten-axis inertial MEMS sensors cannot be met.

[0004] In the prior art, a turntable is usually used as a test device to test the parameters of accelerometers and gyroscopes, lacking test means for magnetometers and barometers. Moreover, during the sensor calibration process, the installation error of the sensor will cause the actual angle between sensitive axes to deviate from the ideal orthogonal state (i.e., the axis angle deviation), resulting in systematic errors in parameters such as cross-coupling coefficients and sensitivities obtained by calibration. When the actual installation attitude of the sensor changes, the previously calibrated parameters will become invalid due to the uncorrected axis angle deviation, leading to a decrease in the accuracy of navigation data. The existing method does not independently calibrate the axis angle deviation, making it difficult to accurately separate the installation error and the inherent error of the sensor, which limits the high-precision calibration and application of inertial MEMS sensors.

[0005] Therefore, it is necessary to design a new test scheme to accurately calibrate the axis angle deviation of accelerometers, gyroscopes, and magnetometers before calibration, solve the influence of installation error on calibration parameters, and achieve comprehensive high-precision testing of ten-axis inertial MEMS sensors. Summary of the Invention

[0006] In view of the defects of the prior art, the purpose of this application is to provide an inertial MEMS testing system and method based on PLC, aiming to solve the problem that the prior art cannot perform comprehensive and high-precision testing on ten-axis inertial MEMS sensors.

[0007] To achieve the above objectives, in a first aspect, the present application provides an inertial MEMS test system based on PLC, comprising: a data analysis module and a PLC control module; The PLC control module includes: a motion control unit, a magnetic field control unit and an air pressure control unit; The motion control unit is used to carry the inertial MEMS sensor and provide angular velocity and / or acceleration excitation for the inertial MEMS sensor; the MEMS sensor includes: a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer and a barometer; The magnetic field control unit is used to provide magnetic field excitation for the inertial MEMS sensor; The air pressure control unit is used to provide an air pressure environment for the inertial MEMS sensor; The data analysis module is used to obtain the output data of the three-axis accelerometer and / or the three-axis gyroscope in the MEMS sensor when the inertial MEMS sensor is in multiple orthogonal positions to provide angular velocity and / or acceleration excitation under the control of the motion control unit, and respectively fit and calculate the inter-axis angular deviation of the three-axis accelerometer and / or the three-axis gyroscope to determine the corresponding error model; The data analysis module is further used to obtain the output signal of the three-axis magnetometer in the MEMS sensor, fit and calculate the inter-axis angle deviation of the three-axis magnetometer, and determine the corresponding error model when the inertial MEMS sensor is in multiple orthogonal positions under the control of the motion control unit and the magnetic field control unit provides magnetic field excitations of different intensities; The data analysis module is further used to obtain the output signal of the barometer in the MEMS sensor when the air pressure control unit provides different air pressures, and to fit and calculate the error model of the barometer.

[0008] In a possible implementation, the motion control unit includes: a driver and a turntable; The driver is connected to the turntable and is used to drive the turntable to rotate at a preset speed to provide a stable angular velocity excitation for the inertial MEMS sensor, or to control the turntable to rotate to a preset angular position to provide a stable acceleration excitation for the inertial MEMS sensor.

[0009] In a possible implementation, the magnetic field control unit includes: a power supply and a magnetic coil; The power supply is connected to the magnet coil and is used to supply power to the magnet coil so that the magnet coil provides a magnetic field excitation with a preset intensity.

[0010] In a possible implementation, the air pressure control unit includes: an air compressor, a vacuum pump, and an air pressure tank; The air compressor and the vacuum pump are respectively connected to the air pressure tank; The motion control unit is arranged inside the air pressure tank; The air compressor is used to compress the gas inside the air pressure tank; The vacuum pump is used to extract the gas inside the air pressure tank; The air compressor and the vacuum pump are used to adjust the air pressure inside the air pressure tank.

[0011] In a possible implementation, the turntable is at least one of a single-axis turntable, a two-axis turntable, or a three-axis turntable.

[0012] In a possible implementation, the multiple orthogonal positions include: (0°, 0°, 0°), (90°, 0°, 0°), (0°, 90°, 0°), (0°, 0°, 90°), (90°, 90°, 0°), (90°, 0°, 90°). The three angles in each of the above orthogonal positions represent the rotation angles of the inertial MEMS sensor around the X, Y, and Z axes in the turntable coordinate system.

[0013] In a second aspect, the present application provides a method for testing an inertial MEMS based on a PLC. The method is used to test an inertial MEMS sensor, and the MEMS sensor includes: a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer, and a barometer; the method includes: At multiple orthogonal positions, angular velocity and / or acceleration excitation is provided to the inertial MEMS sensor, output data of the three-axis accelerometer and / or the three-axis gyroscope inside the MEMS sensor is acquired, and the angular deviation between axes of the three-axis accelerometer and / or the three-axis gyroscope is respectively calculated by fitting, and an error model including the angular deviation between axes is determined; At multiple orthogonal positions, when different intensities of magnetic field excitation are provided to the inertial MEMS sensor, the output signal of the three-axis magnetometer inside the MEMS sensor is acquired, the angular deviation between axes of the three-axis magnetometer is calculated by fitting, and the corresponding error model is determined; Different air pressures are provided to the inertial MEMS sensor, the output signal of the barometer inside the MEMS sensor is acquired, and the error model of the barometer is calculated by fitting.

[0014] In a possible implementation, the error model including the angular deviation between axes is:

[0015] Among them, C is the inter-axial angle error matrix, θ xy , θ xz , θ yz is the inter-axial angle deviation, b x , b y , b z is the three-axis zero bias, k x , k y , k z is the three-axis sensitivity coefficient, a x , a y , a z is the three-axis output before compensation, , , is the three-axis output after compensation.

[0016] In a possible implementation, the error model of the three-axis magnetometer is obtained by least squares fitting.

[0017] In a possible implementation, the error model of the barometer is obtained by least squares fitting.

[0018] Generally speaking, compared with the prior art by the above technical solutions conceived in this application, the following beneficial effects are obtained: This application provides an inertial MEMS test system and method based on PLC, and proposes to independently calibrate the inter-axial angle deviation of the accelerometer, gyroscope, and magnetometer by the six-position method before calibrating the inertial MEMS sensor, which solves the problem that the cross-coupling coefficient is inaccurate due to installation errors, and makes the calibration parameters closer to the true characteristics of the sensor; a general error model including the inter-axial angle error is established to support high-precision parameter calibration of multiple types of sensors (accelerometer, gyroscope, magnetometer), covering the full-parameter test requirements of the ten-axis inertial MEMS sensor; after the MEMS sensor is installed in the device in this application, only simple self-calibration is required to compensate for the installation error, avoiding the problem of calibration parameter failure caused by attitude change in the traditional method, and improving the long-term stability and reliability of the inertial navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the architecture diagram of the inertial MEMS test system based on PLC control provided by the embodiment of this application; Figure 2It is a flowchart of an inertial MEMS test method based on PLC control provided by an embodiment of the present application. Specific embodiments

[0020] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] The term "and / or" in this article is an associative relationship describing associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " in this article represents an "or" relationship between associated objects. For example, A / B represents A or B.

[0022] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific manner.

[0023] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality" refers to two or more. For example, a plurality of orthogonal positions refers to two or more orthogonal positions, etc.

[0024] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0025] The present application discloses an inertial MEMS test system based on PLC control, including a PLC control module, a motion control unit, a magnetic field control unit, and a pressure control unit. The motion control unit, the magnetic field control unit, and the pressure control unit are respectively connected to the PLC control module. The motion control unit includes a driver and a turntable, and the rotation of the turntable is controlled by the driver, which is used to provide angular velocity and acceleration excitation for the inertial MEMS sensor; the magnetic field control unit includes a power supply module and a coil, and the power supply module supplies power to the coil to generate a magnetic field, which is used to provide a magnetic field environment for the inertial MEMS sensor; the pressure control unit includes an air compressor, a vacuum pump, and a pressure chamber. The air compressor and the vacuum pump work together to adjust the internal pressure of the pressure chamber to provide a pressure environment for the inertial MEMS sensor. The present application also discloses a test method for inertial MEMS, which realizes a comprehensive test of inertial MEMS parameters by controlling each module to generate different excitations through PLC.

[0026] As Figure 1As shown in the figure, the present application provides an inertial MEMS test system based on a PLC, including: a data analysis module and a PLC control module; The PLC control module includes a motion control unit, a magnetic field control unit, and a pneumatic control unit; The motion control unit is connected to the motion control unit and includes a driver and a turntable, and the driver is connected to the turntable; The magnetic field control unit is connected to the magnetic field control unit and includes a power supply module and a coil, and the power supply module supplies power to the coil; The pneumatic control unit is connected to the pneumatic control unit and includes an air compressor, a vacuum pump, and a pneumatic box, and the air compressor and the vacuum pump are respectively connected to the pneumatic box.

[0027] In one embodiment, the PLC control module controls the motion control unit to make the turntable rotate at a certain speed to provide a stable angular velocity excitation for the inertial MEMS, or controls the motion control unit to make the turntable rotate a certain angular position to provide a stable acceleration excitation for the inertial MEMS; the integrated control system controls the magnetic field control unit to make the coil generate a magnetic field of a certain magnitude to provide a stable magnetic field excitation for the inertial MEMS; the integrated control system controls the pneumatic control unit to change the internal air pressure of the pneumatic box to provide a stable pneumatic environment for the inertial MEMS.

[0028] In one embodiment, the data analysis module is used to read the output signal of the inertial MEMS, perform six-position method axis angle calibration, establish an error model including axis angle deviation, and complete the calculation and analysis of the inertial MEMS parameters according to the read data; the data analysis module reads the position and speed information of the turntable in the motion control unit and sends instructions to the PLC control module to adjust the position and speed of the turntable; the data analysis module reads the magnetic field intensity of the coil in the magnetic field control unit and sends instructions to the PLC control module to adjust the magnetic field intensity of the coil.

[0029] In one embodiment, the PLC control module receives the signal from the data analysis module and sends instructions to adjust the outputs of the driver in the motion control unit, the power supply module in the magnetic field control unit, the air compressor and the vacuum pump in the pneumatic control unit, so as to realize the adjustment of the outputs of the turntable, the coil, and the pneumatic box.

[0030] In one embodiment, the motion control unit includes a driver and a turntable. The driver is used to receive the control signal of the PLC control module, adjust the output signal to control the rotation of the turntable, and an inertial MEMS sensor is placed on the turntable, which is used to receive the control signal of the driver to complete the specified action and provide acceleration and angular velocity excitation for the inertial MEMS sensor.

[0031] In one embodiment, the turntable includes, but is not limited to, a single-axis turntable, a dual-axis turntable, and a three-axis turntable.

[0032] In one embodiment, the magnetic field control unit includes a power supply module and a coil. The power supply module is used to receive the control signal of the PLC control module, adjust the output current to change the magnetic field generated by the coil. An inertial MEMS sensor is placed inside the coil, and a magnetic field is generated through the electromagnetic induction effect of the current to provide a magnetic field excitation for the inertial MEMS sensor.

[0033] In one embodiment, the coil includes, but is not limited to, a one-dimensional coil, a two-dimensional coil, and a three-dimensional coil.

[0034] In one embodiment, the air pressure control unit includes an air compressor, a vacuum pump, and an air pressure box. The air compressor is used to receive the control signal of the PLC control module and compress the air inside the air pressure box. The vacuum pump is used to receive the control signal of the PLC control module and extract the air inside the air pressure box. An inertial MEMS sensor is placed inside the air pressure box to provide an air pressure excitation for the inertial MEMS sensor.

[0035] In one embodiment, the PLC control module receives the signal from the data analysis module and sends instructions to adjust the outputs of the driver in the motion control unit, the power supply module in the magnetic field control unit, the air compressor and the vacuum pump in the air pressure control unit, so as to realize the adjustment of the outputs of the turntable, the coil, and the air pressure box.

[0036] More specifically, the data analysis module is further used to perform the six-position method axis angle calibration before the test. The specific steps include: Fix the MEMS accelerometer on the turntable, and rotate the turntable to six preset orthogonal positions (0°, 0°, 0°), (90°, 0°, 0°), (0°, 90°, 0°), (0°, 0°, 90°), (90°, 90°, 0°), (90°, 0°, 90°) in sequence; Collect the output data of the accelerometer at each position, and calculate the axis angle deviation of the three sensitive axes through least squares fitting to obtain accurate axis angle parameters.

[0037] Furthermore, the data analysis module tests the sensitivity, zero bias, and cross-coupling coefficient of the MEMS accelerometer based on the axis angle parameters, specifically including: Establish an accelerometer error model including axis angle deviation:

[0038] where C is the axis angle error matrix, θ xy , θ xz , θyz is the deviation of the shaft angle, b x , b y , b z is the zero bias, k x , k y , k z is the sensitivity coefficient; Optimize the error model parameters by the least squares method to obtain the sensitivity, zero bias, and cross-coupling coefficient after testing.

[0039] In one embodiment, the six-position method shaft angle calibration method is also applicable to MEMS gyroscopes and MEMS magnetometers. Adjust the sensor attitude or magnetic field direction through a turntable or coil, collect multi-position output data, and calculate the installation error angles between sensitive axes to achieve the shaft angle test of the gyroscope and magnetometer.

[0040] As Figure 2 shown, the embodiment of the present application provides an inertial MEMS test method based on PLC control, including the following steps: S1. Shaft angle calibration: Fix the MEMS sensor on a turntable (for accelerometers and gyroscopes) or a coil (for magnetometers). Through the rotation of the turntable (for accelerometers and gyroscopes) or the adjustment of the magnetic field direction (for magnetometers), collect output data at at least six orthogonal positions (such as the positions of (0°, 0°, 0°), (90°, 0°, 0°), (0°, 90°, 0°), (0°, 0°, 90°), (90°, 90°, 0°), (90°, 0°, 90°), etc. corresponding to the turntable for accelerometers, and the corresponding orthogonal positions after adjusting the magnetic field direction of the coil for magnetometers), calculate the deviation between the actual included angle between sensitive axes and the ideal orthogonal state, and obtain the shaft angle error matrix; S2. Parameter test: 1. Angular velocity measurement ability test: Install the inertial MEMS sensor on the turntable. When the turntable is stationary, use the data analysis module to collect the output data of the inertial MEMS sensor for a period of time to obtain its output angular velocity value; then, the PLC control system controls the driver in the motion control unit to send a drive signal to make the turntable rotate at a speed of ω. The data analysis module collects the output angular velocity data of the inertial MEMS sensor at this rotation speed for a period of time and obtains the corresponding output angular velocity value; then, the PLC control system controls the rotation speed of the turntable to become 2ω, 3ω,... in turn until the angular velocity measurement upper limit of the inertial MEMS sensor is reached, and the data analysis module collects the output angular velocity data of the inertial MEMS sensor at each rotation speed; 2. Acceleration measurement ability test: The PLC control system controls the rotation angle of the turntable to be 0°, 30°, 60°... 360° in sequence. At different rotation angles, the data analysis module collects the acceleration data output by the inertial MEMS sensor to obtain the output acceleration values of the inertial MEMS sensor at different positions. 3. Magnetic field intensity measurement ability test: The inertial MEMS sensor is installed inside the coil. The PLC control system controls the power supply module in the magnetic field control unit to supply power to the coil, so that the magnetic field intensity inside the coil is 0, B, 2B,... up to the upper limit of the magnetic field intensity measurement of the inertial MEMS sensor. The data analysis module collects the magnetic field intensity data output by the inertial MEMS sensor at different magnetic field intensities. 4. Air pressure measurement ability test: The inertial MEMS sensor is installed inside the air pressure chamber. The PLC control system first controls the vacuum pump in the air pressure control unit to work, so that the internal pressure of the air pressure chamber is 0, and then controls the vacuum pump to stop working and starts the air compressor, so that the internal pressure of the air pressure chamber is 0, P, 2P,... until the upper limit of the air pressure measurement of the inertial MEMS sensor is reached, and the output air pressure values of the inertial MEMS sensor at different air pressures are obtained. After the above tests, a sensor error model is established based on the inter-axis angle error matrix, combined with multi-position excitation data (acceleration, angular velocity, magnetic field intensity), and the least squares method is used to fit the error model parameters, so as to test the sensitivity, zero bias and cross-coupling coefficient. S3. Installation error compensation: After the sensor is installed on the target device, the installation error angle between the device coordinate system and the sensor coordinate system is obtained through simple self-calibration, and combined with the pre-calibrated inter-axis angle parameters and error model, the measurement data is compensated in real time.

[0041] It can be understood that the various digital numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0042] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An inertial MEMS test system based on PLC, characterized in that, Including: A data analysis module and a PLC control module; The PLC control module includes: a motion control unit, a magnetic field control unit, and a pneumatic control unit; The motion control unit is used to carry an inertial MEMS sensor and provide angular velocity and / or acceleration excitation for the inertial MEMS sensor; the MEMS sensor includes: a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer, and a barometer; The magnetic field control unit is used to provide magnetic field excitation for the inertial MEMS sensor; The pneumatic control unit is used to provide a pneumatic environment for the inertial MEMS sensor; The data analysis module is used to obtain the output data of the three-axis accelerometer and / or the three-axis gyroscope in the MEMS sensor and respectively fit and calculate the inter-axis angle deviation of the three-axis accelerometer and / or the three-axis gyroscope, and determine the corresponding error model when the inertial MEMS sensor provides angular velocity and / or acceleration excitation at multiple orthogonal positions under the control of the motion control unit; The data analysis module is further used to obtain the output signal of the three-axis magnetometer in the MEMS sensor, fit and calculate the inter-axis angle deviation of the three-axis magnetometer, and determine the corresponding error model when the inertial MEMS sensor is at multiple orthogonal positions under the control of the motion control unit and the magnetic field control unit provides magnetic field excitations of different intensities; The data analysis module is further used to obtain the output signal of the barometer in the MEMS sensor, fit and calculate the error model of the barometer when the pneumatic control unit provides different air pressures.

2. The inertial MEMS test system according to claim 1, wherein The motion control unit includes: a driver and a turntable; The driver is connected to the turntable and is used to drive the turntable to rotate at a preset speed to provide stable angular velocity excitation for the inertial MEMS sensor, or control the turntable to rotate to a preset angular position to provide stable acceleration excitation for the inertial MEMS sensor.

3. The inertial MEMS test system according to claim 1, wherein The magnetic field control unit includes: a power supply and a magnet coil; The power supply is connected to the magnet coil and is used to supply power to the magnet coil so that the magnet coil provides a magnetic field excitation of a preset intensity.

4. The inertial MEMS test system according to claim 1, characterized in that The pneumatic control unit includes: an air compressor, a vacuum pump, and a pneumatic box; The air compressor and the vacuum pump are respectively connected to the pneumatic box; The motion control unit is arranged in the pneumatic box; The air compressor is used to compress the gas in the pneumatic box; The vacuum pump is used to extract the gas in the pneumatic box; The air compressor and the vacuum pump are used to adjust the air pressure in the pneumatic box.

5. The inertial MEMS test system according to claim 2, characterized in that, The turntable is at least one of a single-axis turntable, a two-axis turntable, or a three-axis turntable.

6. The inertial MEMS test system according to claim 1, wherein The multiple orthogonal positions include: (0°, 0°, 0°), (90°, 0°, 0°), (0°, 90°, 0°), (0°, 0°, 90°), (90°, 90°, 0°), (90°, 0°, 90°), and the three angles in each of the above orthogonal positions represent the rotation angles of the inertial MEMS sensor around the X, Y, and Z axes in the turntable coordinate system.

7. An inertial MEMS testing method based on PLC, the method being used to test an inertial MEMS sensor, the MEMS sensor comprising: A three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer, and a barometer; characterized in that the method includes: At multiple orthogonal positions, angular velocity and / or acceleration excitation is provided to the inertial MEMS sensor, the output data of the triaxial accelerometer and / or triaxial gyroscope in the MEMS sensor is acquired, and the inter-axis angular deviation of the triaxial accelerometer and / or triaxial gyroscope is respectively calculated by fitting, and an error model including the inter-axis angular deviation is determined; When magnetic field excitations of different intensities are provided to the inertial MEMS sensor at multiple orthogonal positions, the output signals of the triaxial magnetometer in the MEMS sensor are acquired, the inter-axis angular deviation of the triaxial magnetometer is calculated by fitting, and the corresponding error model is determined; Different air pressures are provided to the inertial MEMS sensor, the output signals of the barometer in the MEMS sensor are acquired, and the error model of the barometer is calculated by fitting.

8. The inertial MEMS testing method according to claim 7, wherein The error model including the inter-axis angular deviation is: Among them, C is the inter-axial angle error matrix, θ xy , θ xz , θ yz is the inter-axial angle deviation, b x , b y , b z is the zero bias of the three axes, k x , k y , k z is the sensitivity coefficient of the three axes, a x , a y , a z is the output of the three axes before compensation, , , is the output of the three axes after compensation.

9. The inertial MEMS testing method according to claim 7, wherein The error model of the triaxial magnetometer is obtained by least squares fitting.

10. The inertial MEMS testing method according to claim 7, wherein The error model of the barometer is obtained by least squares fitting.

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