Method and system for detecting measurement precision of inertial measurement assembly

Abstract

The invention discloses a method and a system for detecting the measurement precision of inertial measurement components. The method comprises the following steps: respectively mounting the two inertial measurement components on two swinging platforms which are leveled and north-guided; compensating the installation error of the coordinate system and then accessing the same external timing system signal source; different swing centers are set for the two swing platforms through the upper computer, so that a fixed relative attitude angle deviation exists between the two swing platforms, and the fixed relative attitude angle deviation is defined as a deformation angle true value; the upper computer controls the two swing platforms to synchronously execute the same dynamic motion trail, and synchronously obtains reference attitude data output by the two swing platforms, measurement attitude data output by the two inertial measurement assemblies and real-time deformation angle data; and comparing the real-time deformation angle data with the deformation angle true value, and evaluating the dynamic deformation measurement precision of the inertial measurement assembly according to the difference value. According to the invention, the measurement precision of the inertial product can be efficiently, comprehensively and reliably inspected before the inertial product leaves the factory, so that the inspection efficiency can be effectively improved, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of inertial measurement technology, specifically relating to a method and system for detecting the measurement accuracy of an inertial measurement unit. Background Technology

[0002] Inertial measurement units (IMUs) and inertial navigation systems (INS) based on them provide indispensable motion attitude and trajectory information for navigation, guidance, stabilization, and control by measuring the angular velocity and linear acceleration of a carrier in space. They serve as the perception center of high-end equipment. Their performance and accuracy directly determine the intelligence level and mission execution capability of the entire system, and they are widely used in aircraft attitude references, ship stabilization and aiming, autonomous flight of unmanned aerial vehicles, and advanced driver assistance systems (ADAS).

[0003] As application scenarios continue to deepen, the functions of inertial products are becoming increasingly complex. Among them, dynamic deformation measurement has become an important high-end derivative function, which can calculate the relative deformation angle of a structure in real time due to load, vibration, long-term stress release, sunlight exposure on ship decks, and ocean waves. This function is of vital importance for realizing structural health monitoring, high-precision measurement of local attitude changes, improving control quality, and ensuring operational safety.

[0004] However, currently, inertial products used in this technology are mostly verified for performance and accuracy through computer simulation or by professional measurement and testing institutions using measuring equipment after physical installation. Computer simulation verification relies on an idealized environment without a hardware platform, and the simulation results differ from the product's actual performance in harsh real-world environments, making it unsuitable as a basis for determining the product's final accuracy. Physical installation verification involves installing the inertial product on the final carrier (such as an aircraft or ship), collecting data during field tests, and conducting post-event evaluations. This process is lengthy, and if the inertial product's accuracy fails to meet standards, it will result in substantial rework costs and impact project progress.

[0005] Therefore, efficiently, comprehensively, and reliably inspecting the measurement accuracy of inertial products before they leave the factory is a technical problem that those skilled in the art hope to solve. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide a method and system for testing the measurement accuracy of inertial measurement components. This invention can efficiently, comprehensively and reliably inspect the measurement accuracy of inertial products before they leave the factory, thereby effectively improving inspection efficiency and reducing costs.

[0007] The technical solution of this invention is implemented as follows: A method for detecting the measurement accuracy of an inertial measurement unit (IMU) specifically includes the following steps: Step S1: Place the first and second swaying platforms on their bases and level the two swaying platforms. At the same time, align the two swaying platforms to the north. Step S2: Install the first inertial measurement unit and the second inertial measurement unit on the first rocking platform and the second rocking platform respectively; measure and compensate for the coordinate system installation error between each inertial measurement unit and the corresponding rocking platform; Step S3: Connect the clock synchronization interfaces of the two swing platforms and the two inertial measurement units to the same external time synchronization signal source; Step S4: Set different swing centers for the two swing platforms through the host computer, so that there is a fixed relative attitude angle deviation between them, and define the fixed relative attitude angle deviation as the true value of the deformation angle. Step S5: The host computer controls the two swing platforms to perform the same dynamic motion trajectory around their respective swing centers under the synchronization of an external time signal source; Step S6: Under the synchronization of the external time synchronization signal, synchronously acquire the reference attitude data output by the two swing platforms, the measurement attitude data output by the two inertial measurement units, and the real-time deformation angle data obtained from the measurement attitude data of the two inertial measurement units. Step S7: Compare the real-time deformation angle data with the true value of the deformation angle, and evaluate the dynamic deformation measurement accuracy of the inertial measurement unit based on the difference.

[0008] Further, in step S2, the method for compensating for coordinate system installation error is as follows: obtain the installation error angle between the inertial measurement unit and the corresponding swing table; and preset the installation error angle into the host computer for real-time correction of the measurement attitude data.

[0009] Furthermore, in step S5, the dynamic motion trajectory is sinusoidal motion, frequency sweeping motion, or simulated motion generated based on the actual environment.

[0010] Furthermore, step S7 also includes comparing the measured attitude data of the inertial measurement unit with the reference attitude data of the corresponding swing platform, and evaluating the absolute attitude measurement accuracy of the inertial measurement unit based on the difference.

[0011] Further, in step S7, the specific steps for evaluating the deformation measurement accuracy of the inertial measurement unit are as follows: calculate the error sequence of real-time deformation angle data and relative attitude deviation; calculate the index of the error sequence, wherein the index is one or more of the maximum value, mean, standard deviation and root mean square error; and finally compare the index with a preset accuracy threshold to determine whether the performance of the inertial measurement unit is qualified.

[0012] A system for detecting the measurement accuracy of an inertial measurement unit (IMU) for implementing the aforementioned method of detecting the measurement accuracy of an IMU includes: The first and second swing platforms, both three-axis swing platforms, are used to provide dynamic angular references.

[0013] The first inertial measurement unit and the second inertial measurement unit are placed on the first and second swing platforms respectively, and are used to measure attitude data.

[0014] An external time synchronization signal source is connected to the clock synchronization interface of the two swing platforms and the two inertial measurement units.

[0015] The host computer is used to send motion control commands to the two swing platforms and set the swing center of the two swing platforms to define a fixed true value of the deformation angle; and synchronously acquire the attitude data and deformation angle data of the two swing platforms and the two inertial measurement units under the synchronization of external timing signals; at the same time, it performs installation error compensation for each inertial measurement unit and the corresponding swing platform, and calculates the error between the measurement data and the true value of the deformation angle to complete the accuracy assessment.

[0016] Furthermore, the host computer includes: The control unit is used to send motion control commands to the two rocking platforms and set the rocking center of the two rocking platforms to define a fixed true value of the deformation angle.

[0017] The data acquisition unit is used to synchronously acquire attitude data and deformation angle data of two swing platforms and two inertial measurement units under the synchronization of external time signals.

[0018] The data processing and verification unit is used to perform installation error compensation for each inertial measurement unit and the corresponding swing platform, and to calculate the error between the measurement data and the true value of the deformation angle in order to complete the accuracy assessment.

[0019] Furthermore, the external time source is a GPS clock, a Beidou clock, an IRIG-B code time synchronization device, or a temperature-controlled crystal oscillator time synchronization device.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention can efficiently, comprehensively and reliably inspect the measurement accuracy of inertial products before they leave the factory. This not only shortens the product verification cycle and reduces costs, but also identifies performance risks before delivery, thereby avoiding huge losses due to substandard product performance in the final application, and thus providing a proactive guarantee for product quality.

[0021] 2. This invention provides a precise and traceable deformation measurement benchmark by manually setting a fixed relative attitude angle between two swing platforms. Simultaneously, an external time synchronization signal source ensures the synchronization of all dynamic movements and data acquisition, eliminating errors caused by time asynchrony. Then, by calculating statistical indicators (such as standard deviation and maximum value) of the difference between the measured value and the true value, the measurement accuracy of the inertial measurement unit can be objectively quantified, providing a reliable scientific basis for performance verification.

[0022] 3. This invention can simultaneously detect deformation measurement accuracy and absolute attitude measurement accuracy. Through a host computer, it can simulate various complex and realistic dynamic environments, providing an efficient, reliable, and economical standardized testing method for the research, development, production, and acceptance of high-performance inertial products, which has profound significance for promoting technological progress in the industry. Attached Figure Description

[0023] Figure 1 - A flowchart of the detection method described in this invention.

[0024] Figure 2 - A schematic diagram of the detection system described in this invention.

[0025] Wherein: 1-First swing platform; 2-Second swing platform; 3-First inertial measurement unit; 4-Second inertial measurement unit; 5-Host computer. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Currently, inertial products used in dynamic deformation measurement technology are primarily verified for performance and accuracy through computer simulation or physical installation. However, computer simulation relies on an idealized environment, and the simulation results differ from the product's actual performance in harsh real-world environments, making it unsuitable as a basis for determining the product's final accuracy. Physical installation verification, which involves installing the inertial product on a final carrier (such as an aircraft or ship), collecting data during field testing, and conducting post-event evaluation, is time-consuming. Furthermore, if the inertial product's accuracy fails to meet standards, it will result in substantial rework costs and impact project schedules.

[0028] Based on this, the present invention provides a method for detecting the measurement accuracy of an inertial measurement unit, see [link to relevant documentation]. Figure 1 and Figure 2 Specifically, it includes the following steps: Step S1: Install the first swing platform 1 and the second swing platform 2 on the vibration isolation base, and level the two swing platforms to ensure the horizontal reference of the two swing platforms. At the same time, align the two swing platforms to the north, that is, make the outer frame axis of the two swing platforms coincide with true north.

[0029] Here, precise leveling eliminates the interference of gravitational acceleration on attitude calculation, ensuring the accuracy of the initial attitude angle reference; establishing a unified true north reference through azimuth north eliminates systematic deviations in heading angles. This provides a precise and consistent spatiotemporal reference framework for all subsequent attitude and deformation angle measurements, thereby ensuring the accuracy of the measurement reference from the outset.

[0030] The purpose of leveling and northward adjustment is to establish a unified coordinate system, aligning the coordinate system of the swaying platform with the geographic coordinate system, with the geographic coordinate system serving as the reference coordinate system for measurement.

[0031] Step S2: Install the first inertial measurement unit 3 and the second inertial measurement unit 4 on the first rocking platform 1 and the second rocking platform 2 respectively; measure and compensate for the coordinate system installation error between each inertial measurement unit and the corresponding rocking platform; wherein, the method for compensating for the coordinate system installation error is to obtain the installation error angle between the inertial measurement unit and the corresponding rocking platform; and preset the installation error angle into the host computer 5 for real-time correction of the measured attitude data.

[0032] Here, because mechanical installation makes it difficult to ensure that the coordinate system of the inertial measurement unit (IMU) is completely aligned with the coordinate system of the corresponding swing table, the installation error angle will directly affect the measurement results. By pre-calibrating and compensating with software, the measured values ​​of the IMU are unified to the reference coordinate system of the swing table, effectively isolating the influence of the product's own performance and the installation process. This ensures that subsequent comparisons are based on the actual measurement performance of the IMU, rather than installation errors. For details on installation error compensation, please refer to patent CN112129322.

[0033] Step S3: Connect the clock synchronization interfaces of the first swing platform 1, the second swing platform 2, the first inertial measurement component 3, and the second inertial measurement component 4 to the same external time synchronization signal source.

[0034] Here, by introducing an external time synchronization operator (such as a GPS clock, BeiDou clock, IRIG-B code time synchronization device, or a temperature-controlled crystal oscillator time synchronization device), the problem of asynchronous clock drift between the two swing platforms can be overcome, ensuring that the motion execution and data sampling times of the two swing platforms are strictly aligned. This eliminates the phase difference and comparison error caused by time asynchrony, which is crucial for capturing dynamic processes and performing real-time data comparison, and is the foundation for achieving high-precision dynamic measurement and comparison.

[0035] Step S4: Set different swing centers for the first swing platform 1 and the second swing platform 2 through the host computer, so that there is a fixed relative attitude angle deviation between the two, and define the fixed relative attitude angle deviation as the true value of the deformation angle.

[0036] Here, by artificially setting a fixed relative attitude angle, a static "structural deformation" can be accurately simulated. This serves as a "benchmark" or "true value" for verifying the accuracy of deformation measurement, solving the previous problem of not being able to obtain high-precision deformation true values ​​in real environments. It elevates the verification of deformation measurement from a qualitative and indirect judgment to a quantitative and direct comparison level.

[0037] Here, let the center of the first swing platform be (ψ). a θ a φ a The swing center of the second swing platform is (ψ). b θ b φ b Then the fixed relative attitude angle deviation is: (Δψ, Δθ, Δφ) = (ψ b θ b φ b )-(ψ a θ a φ a In practical applications, the swing center of the first swing platform can be set to (0°, 0°, 0°), and the swing center of the second swing platform can be set to (0.5°, 0.3°, 0.6°). Then, (Δψ, Δθ, Δφ) = (0.5°, 0.3°, 0.6°) is the true value of the deformation angle. Of course, in practical applications, the swing centers of the two swing platforms can be set to other different values.

[0038] Step S5: The host computer controls the two swing platforms to perform the same dynamic motion trajectory around their respective swing centers under the synchronization of an external timing signal source. The dynamic motion trajectory is sinusoidal motion, frequency sweep motion, or simulated motion (random wave) generated based on the actual environment.

[0039] Here, by superimposing various dynamic motions while maintaining a fixed deformation angle, the deformation measurement capabilities of inertial measurement units under various operating conditions, including static, periodic, and highly dynamic conditions, can be comprehensively tested. This greatly expands the test coverage, more realistically reflects the performance of products in actual applications, and achieves a true simulation of complex external environments in a laboratory setting.

[0040] Step S6: Under the synchronization of the external time synchronization signal, synchronously acquire the reference attitude data output by the two swing platforms, the measurement attitude data output by the two inertial measurement units, and the real-time deformation angle data obtained from the measurement attitude data of the two inertial measurement units.

[0041] Here, all data are collected synchronously under a unified time synchronization signal, ensuring that each set of data used for comparison (reference value, measured value, calculated deformation value) strictly corresponds to the same moment, so that the subsequent data difference calculation has physical meaning, avoids additional errors introduced by data asynchrony, and thus makes the accuracy assessment results true and reliable.

[0042] The real-time attitude angle (reference attitude data) output by the first swing platform that can be obtained in this step is (ψ) -a θ -a φ -a The real-time attitude angles (measured attitude data) output by the first inertial measurement unit are (ψ1, θ1, φ1), and the real-time attitude angles (reference attitude data) output by the second swing platform are (ψ1, θ1, φ1). -b θ -b φ -b The real-time attitude angles (measured attitude data) output by the second inertial measurement unit are (ψ2, θ2, φ2). Simultaneously, the real-time deformation angle data (Δψ) is calculated using an internal algorithm. _m , Δθ _m , Δφ _m ).

[0043] Step S7: Compare the real-time deformation angle data with the true deformation angle value, and evaluate the dynamic deformation measurement accuracy of the inertial measurement unit based on the difference. Compare the measured attitude data of the inertial measurement unit with the reference attitude data of the corresponding swing platform, and evaluate the absolute attitude measurement accuracy of the inertial measurement unit based on the difference.

[0044] The specific steps for evaluating the deformation measurement accuracy of an inertial measurement unit (IMU) are as follows: Calculate the error sequence between real-time deformation angle data and relative attitude deviation; calculate the index of the error sequence, which is one or more of the following: maximum value, mean, standard deviation, and root mean square error; finally, compare the index with a preset accuracy threshold to determine whether the IMU performance is qualified. If the index is within the preset accuracy threshold, the IMU performance is qualified; otherwise, it is unqualified.

[0045] Here, by directly subtracting the measured value from the known true value, a clear error sequence can be obtained. By analyzing the statistical characteristics of this error (such as mean, standard deviation, and maximum value), precise, data-driven conclusions can be given regarding the dynamic deformation measurement accuracy (including accuracy, stability, and consistency) of the inertial measurement unit. This provides a scientific and reliable basis for product acceptance testing, completely changing the passive situation of relying on post-event field verification.

[0046] Here, dynamic deformation measurement error = (Δψ) _m , Δθ _m , Δφ _m)-(Δψ, Δθ, Δφ), analyze the statistical characteristics of deformation measurement error. If all indicators are within the product's preset accuracy threshold, the dynamic deformation measurement function of the inertial measurement component is deemed qualified.

[0047] Error of the first inertial measurement unit = (ψ1, θ1, φ1) - (ψ -a θ -a φ -a The error of the second inertial measurement unit = (ψ2, θ2, φ2) - (ψ) -b θ -b φ -b The dynamic deformation measurement error is analyzed, and the statistical characteristics of the errors of the two inertial measurement units are analyzed. If the indicators are all within the product's preset accuracy threshold, the absolute attitude measurement function of the inertial measurement unit is deemed qualified.

[0048] This invention also provides a system for detecting the measurement accuracy of an inertial measurement unit (IMU) in accordance with the above-described method for detecting the measurement accuracy of an IMU, see [link to relevant documentation]. Figure 2 ,include: The first swing platform 1 and the second swing platform 2 are both three-axis swing platforms used to provide dynamic angle references.

[0049] The first inertial measurement unit 3 and the second inertial measurement unit 4 are placed on the first rocking platform 1 and the second rocking platform 2, respectively, for measuring attitude data.

[0050] An external time synchronization signal source is connected to the clock synchronization interface of two swing platforms (first swing platform 1 and second swing platform 2) and two inertial measurement units (first inertial measurement unit 3 and second inertial measurement unit 4).

[0051] The host computer 5 is used to send motion control commands to the two swing platforms and set the swing center of the two swing platforms to define a fixed true value of the deformation angle; and synchronously acquire the attitude data and deformation angle data of the two swing platforms and the two inertial measurement units under the synchronization of the external time signal; at the same time, it performs installation error compensation between each inertial measurement unit and the corresponding swing platform, and calculates the error between the measurement data and the true value of the deformation angle to complete the accuracy assessment.

[0052] In specific implementation, the host computer 5 includes: The control unit is used to send motion control commands to the two rocking platforms and set the rocking center of the two rocking platforms to define a fixed true value of the deformation angle.

[0053] The data acquisition unit is used to synchronously acquire attitude data and deformation angle data of two swing platforms and two inertial measurement units under the synchronization of external time signals.

[0054] The data processing and verification unit is used to perform installation error compensation for each inertial measurement unit and the corresponding swing platform, and to calculate the error between the measurement data and the true value of the deformation angle in order to complete the accuracy assessment.

[0055] In specific implementation, the external time source is a GPS clock, a Beidou clock, an IRIG-B code time synchronization device, or a temperature-controlled crystal oscillator time synchronization device.

[0056] Finally, it should be noted that the above embodiments of the present invention are merely illustrative examples and not intended to limit the implementation of the invention. Those skilled in the art can make other variations and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this invention are still within the scope of protection of this invention.

Claims

1. A method for detecting the measurement accuracy of an inertial measurement unit, characterized in that, Specifically, the following steps are included: Step S1: Place the first and second swaying platforms on their bases and level the two swaying platforms. At the same time, align the two swaying platforms to the north. Step S2: Install the first inertial measurement unit and the second inertial measurement unit on the first rocking platform and the second rocking platform respectively; measure and compensate for the coordinate system installation error between each inertial measurement unit and the corresponding rocking platform; Step S3: Connect the clock synchronization interfaces of the two swing platforms and the two inertial measurement units to the same external time synchronization signal source; Step S4: Set different swing centers for the two swing platforms through the host computer, so that there is a fixed relative attitude angle deviation between them, and define the fixed relative attitude angle deviation as the true value of the deformation angle. Step S5: The host computer controls the two swing platforms to perform the same dynamic motion trajectory around their respective swing centers under the synchronization of an external time signal source; Step S6: Under the synchronization of the external time synchronization signal, synchronously acquire the reference attitude data output by the two swing platforms, the measurement attitude data output by the two inertial measurement units, and the real-time deformation angle data obtained from the measurement attitude data of the two inertial measurement units. Step S7: Compare the real-time deformation angle data with the true value of the deformation angle, and evaluate the dynamic deformation measurement accuracy of the inertial measurement unit based on the difference.

2. The method for detecting the measurement accuracy of an inertial measurement unit according to claim 1, characterized in that, In step S2, the method for compensating for coordinate system installation error is as follows: obtain the installation error angle between the inertial measurement unit and the corresponding swing table; and preset the installation error angle into the host computer for real-time correction of the measurement attitude data.

3. The method for detecting the measurement accuracy of an inertial measurement unit according to claim 1, characterized in that, In step S5, the dynamic motion trajectory is sinusoidal motion, frequency sweeping motion, or simulated motion generated based on the actual environment.

4. The method for detecting the measurement accuracy of an inertial measurement unit according to claim 1, characterized in that, Step S7 also includes comparing the measured attitude data of the inertial measurement unit with the reference attitude data of the corresponding swing platform, and evaluating the absolute attitude measurement accuracy of the inertial measurement unit based on the difference.

5. The method for detecting the measurement accuracy of an inertial measurement unit according to claim 1, characterized in that, In step S7, the specific steps for evaluating the deformation measurement accuracy of the inertial measurement unit are as follows: calculate the error sequence of real-time deformation angle data and relative attitude deviation; calculate the index of the error sequence, wherein the index is one or more of the maximum value, mean value, standard deviation and root mean square error; and finally compare the index with the preset accuracy threshold to determine whether the performance of the inertial measurement unit is qualified.

6. A system for detecting the measurement accuracy of an inertial measurement unit (IMU) for implementing the method for detecting the measurement accuracy of an IMU according to any one of claims 1-5, characterized in that, include: The first and second swing platforms, both of which are three-axis swing platforms, are used to provide dynamic angle references; The first inertial measurement unit and the second inertial measurement unit are respectively placed on the first swing platform and the second swing platform for measuring attitude data; An external time synchronization signal source is connected to the clock synchronization interface of two swing platforms and two inertial measurement units; The host computer is used to send motion control commands to the two swing platforms and set the swing center of the two swing platforms to define a fixed true value of the deformation angle; and synchronously acquire the attitude data and deformation angle data of the two swing platforms and the two inertial measurement units under the synchronization of external timing signals; at the same time, it performs installation error compensation for each inertial measurement unit and the corresponding swing platform, and calculates the error between the measurement data and the true value of the deformation angle to complete the accuracy assessment.

7. The system for detecting the measurement accuracy of an inertial measurement unit according to claim 6, characterized in that, The host computer includes: The control unit is used to send motion control commands to the two rocking platforms and set the rocking center of the two rocking platforms to define a fixed true value of the deformation angle. The data acquisition unit is used to synchronously acquire the attitude data and deformation angle data of the two swing platforms and the two inertial measurement units under the synchronization of external time signals. The data processing and verification unit is used to perform installation error compensation for each inertial measurement unit and the corresponding swing platform, and to calculate the error between the measurement data and the true value of the deformation angle in order to complete the accuracy assessment.

8. The system for detecting the measurement accuracy of an inertial measurement unit according to claim 1, characterized in that, The external time source is a GPS clock, a Beidou clock, an IRIG-B code timekeeping device, or a temperature-controlled crystal oscillator timekeeping device.

Images