A system-level calibration method for correcting zero bias of an acceleration channel of an inertial measurement device

Abstract

The present application relates to a kind of system level calibration method for correcting the zero offset of acceleration channel of inertial measuring device, belongs to the field of inertial measurement.The zero position error of acceleration channel is compensated, the method does not need to disassemble inertial measuring device, by the vertical direction of three axes of aircraft respectively, the zero position error of acceleration channel of inertial measuring device can be calculated.The present application proposes the system level calibration method for quickly correcting the zero offset of acceleration channel of inertial measuring device, by simple calibration path setting, the zero offset error of acceleration channel can be effectively calculated.When the change of accelerometer itself zero offset error occurs, it is no longer necessary to disassemble inertial measuring device from aircraft and re-performs discrete calibration, and the influence of installation error caused by repeated installation of inertial measuring device is avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inertial measurement, and particularly relates to a system-level calibration method for correcting zero offset of an acceleration channel of an inertial measurement device. BACKGROUND

[0002] The inertial measurement device is a navigation and stable control equipment of an aircraft, and is used to perceive position and attitude information of the aircraft. The angular velocity channel information is measured by an inertial sensitive device fiber-optic gyroscope, and the acceleration channel information is measured by an inertial sensitive device accelerometer.

[0003] The working principle of the currently commonly used acceleration channel of the inertial measurement device is as follows: the quartz accelerometer converts the sensitive acceleration into an analog current, the accelerometer measurement circuit of a measurement circuit board collects the analog current and outputs the analog current to an information processing circuit at a fixed time, and the information processing circuit processes the acceleration channel data and outputs the processed data.

[0004] The main error items of the acceleration channel of the inertial measurement device include zero offset error, scale factor error and installation error. Due to the process of some quartz accelerometers, the zero offset error of the quartz accelerometers will change greatly after being subjected to temperature stress, which leads to that the zero offset of the acceleration channel of the delivered product will change greatly after the temperature test, and the navigation result of the aircraft will be poor. In this case, the inertial measurement device is usually disassembled from the aircraft, and the zero offset error of the acceleration channel is corrected by separate calibration. SUMMARY

[0005] (I) Technical problem to be solved

[0006] The present application aims to provide a system-level calibration method for correcting the zero offset of the acceleration channel of the inertial measurement device, so as to solve the problem that the zero offset of the acceleration channel of the delivered product will change greatly after the temperature test, and the navigation result of the aircraft will be poor.

[0007] (II) Technical scheme

[0008] In order to solve the above technical problem, the present application provides a system-level calibration method for correcting the zero offset of the acceleration channel of the inertial measurement device, which comprises the following steps:

[0009] S1, device arrangement

[0010] The inertial measurement device is fastened on a calibration tool, and the inertial measurement device is connected with an inertial measurement device test system.

[0011] S2, making the X axis of the inertial measurement device vertical upward, and collecting and outputting incremental data

[0012] The rotation position makes the X axis of the inertial measurement device vertical upward, the Y and Z axes horizontal, and ensures that the errors of the Y and Z axes with the horizontal plane are not greater than a first preset angle; incremental data of the three acceleration channels are collected, and 1-second average values of the data are calculated;

[0013] S3, making the Y axis of the inertial measurement device vertical upward, collecting the output incremental data

[0014] The Y axis of the inertial measurement device is made vertical upward, the X and Z axes are horizontal, and it is ensured that the errors of the X and Z axes with the horizontal plane are not greater than a first preset angle; incremental data of the three acceleration channels are collected, and 1-second average values of the data are calculated;

[0015] S4, making the Z axis of the inertial measurement device vertical upward, collecting the output incremental data

[0016] The Z axis of the inertial measurement device is made vertical upward, the X and Y axes are horizontal, and it is ensured that the errors of the X and Y axes with the horizontal plane are not greater than a first preset angle; incremental data of the three acceleration channels are collected, and 1-second average values of the data are calculated;

[0017] S5, calculating the zero offset error of the acceleration X channel

[0018] According to the average values of the acceleration channel output in the X axis upward position obtained in step S2, the zero offset error of the acceleration X channel is calculated;

[0019] S6, calculating the zero offset error of the acceleration Y channel

[0020] According to the average values of the acceleration channel output in the Y axis upward position obtained in step S3, the zero offset error of the acceleration Y channel is calculated;

[0021] S7, calculating the zero offset error of the acceleration Z channel

[0022] According to the average values of the acceleration channel output in the Z axis upward position obtained in step S4, the zero offset error of the acceleration Z channel is calculated;

[0023] S8, compensating the obtained zero offset error and iterating

[0024] The zero offset errors of the three acceleration channels are calculated through steps S5 to S7, the zero offset errors of the three acceleration channels are compensated into the three channel acceleration data that have been collected, and the zero offset error of the three acceleration channels after compensation is calculated; if the synthesized zero offset error is less than 5*10 -5 g, it is considered that the compensation has ended, and the obtained result is the zero offset error to be compensated; if the synthesized zero offset error is greater than 5*10 -5g, then the compensated acceleration channel data is again calculated for three acceleration channel zero offsets according to steps S5 to S7, respectively, and iterated into the acceleration channel data again until the three-axis synthesized acceleration channel zero offset is less than 5*10 -5 g, the resulting result is the zero offset error to be compensated, and the system level calibration ends.

[0025] Further, the first preset angle is 5°.

[0026] Further, in the step S2, the increment data of the three acceleration channels is collected, and the 1-second average value of the data is calculated, which specifically includes: powering the product, preheating for a first preset time, collecting the acceleration channel increment data output by the inertial measurement device using the inertial measurement device test system in the X sky position, the time is a second preset time, saving the collected increment data, and calculating the 1-second average value of the three acceleration channel output data.

[0027] Further, in the step S3, the increment data of the three acceleration channels is collected, and the 1-second average value of the data is calculated, which specifically includes: powering the product, preheating for a first preset time, collecting the acceleration channel increment data output by the inertial measurement device using the inertial measurement device test system in the Y sky position, the time is a second preset time, saving the collected increment data, and calculating the 1-second average value of the three acceleration channel output data.

[0028] Further, in the step S4, the increment data of the three acceleration channels is collected, and the 1-second average value of the data is calculated, which specifically includes: powering the product, preheating for a first preset time, collecting the acceleration channel increment data output by the inertial measurement device using the inertial measurement device test system in the Z sky position, the time is a second preset time, saving the collected increment data, and calculating the 1-second average value of the three acceleration channel output data.

[0029] Further, the first preset time is half an hour.

[0030] Further, the second preset time is 60 seconds.

[0031] Further, the step S5, according to the average value of the acceleration channel output of the X axis in the sky position obtained in step S2, the calculation of the acceleration X channel zero offset error specifically includes: according to the average value of the acceleration channel output of the X axis in the sky position obtained in step S2, first by the output data of Y, Z two acceleration channel calculates the angle between X channel and the sky direction: the output of Y, Z axis is synthesized into horizontal acceleration output, the horizontal acceleration output is calculated by the inverse trigonometric function, and the angle between X channel and the sky direction is obtained, which is denoted as θ; the standard value of the local gravity acceleration is multiplied by the cosine value of the calculated angle θ, and is taken as the standard value of the theoretical output result of the X channel; according to the average value of the acceleration channel output obtained in step S2, the average value of the X channel output is subtracted from the standard value of the theoretical output result of the X channel, and the difference value is the zero offset error of the acceleration X channel.

[0032] Further, the step S6, according to the average value of the acceleration channel output of the Y axis in the sky position obtained in step S3, the calculation of the acceleration Y channel zero offset error specifically includes: according to the average value of the acceleration channel output of the Y axis in the sky position obtained in step S3, first by the output data of X, Z two acceleration channel calculates the angle between Y channel and the sky direction: the output of X, Z axis is synthesized into horizontal acceleration output, the horizontal acceleration output is calculated by the inverse trigonometric function, and the angle between Y channel and the sky direction is obtained, which is denoted as α; the standard value of the local gravity acceleration is multiplied by the cosine value of the calculated angle α, and is taken as the standard value of the theoretical output result of the Y channel; according to the average value of the acceleration channel output obtained in step S3, the average value of the Y channel output is subtracted from the standard value of the theoretical output result of the Y channel, and the difference value is the zero offset error of the acceleration Y channel.

[0033] Further, the step S7, according to the average value of the acceleration channel output of the Z axis in the sky position obtained in step S3, the calculation of the acceleration Z channel zero offset error specifically includes: according to the average value of the acceleration channel output of the Z axis in the sky position obtained in step S3, first by the output data of X, Y two acceleration channel calculates the angle between Z channel and the sky direction: the output of X, Y axis is synthesized into horizontal acceleration output, the horizontal acceleration output is calculated by the inverse trigonometric function, and the angle between Z channel and the sky direction is obtained, which is denoted as β; the standard value of the local gravity acceleration is multiplied by the cosine value of the calculated angle β, and is taken as the standard value of the theoretical output result of the Z channel; according to the average value of the acceleration channel output obtained in step S3, the average value of the Z channel output is subtracted from the standard value of the theoretical output result of the Z channel, and the difference value is the zero offset error of the acceleration Z channel

[0034] (Three) beneficial effects

[0035] The present application provides a system-level calibration method for correcting the zero offset of an acceleration channel of an inertial measurement device, and provides a system-level calibration method for quickly correcting the zero offset of an acceleration channel of an inertial measurement device, which can effectively calculate the zero offset error of the acceleration channel through simple calibration path setting. When the self-zero offset error of the accelerometer changes, the inertial measurement device no longer needs to be disassembled from the aircraft for separate calibration, and the installation error caused by repeated installation of the inertial measurement device is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The system-level calibration device of the present application is connected as shown in the figure.

[0037] Figure 2 The data processing flowchart of the system-level calibration of the present application is shown in the figure. DETAILED DESCRIPTION

[0038] In order to make the purpose, content and advantages of the present application clearer, the specific embodiments of the present application are described in further detail below in combination with the drawings and examples.

[0039] The technical problem to be solved by the present application is to quickly correct the zero offset error of the acceleration channel without disassembling the inertial measurement device from the aircraft. When the self-zero offset error of the accelerometer changes, it can be calibrated through a simple calibration path, thereby improving the reliability of the inertial measurement device.

[0040] In order to solve the above technical problem and ensure that the zero offset error of the acceleration channel of the inertial measurement device meets the use requirements during use, a method for quickly correcting the zero offset of the acceleration channel of the inertial measurement device is designed to compensate for the zero offset error of the acceleration channel. The method does not need to disassemble the inertial measurement device, and the zero offset error of the acceleration channel of the inertial measurement device can be calculated by directing the three axes of the aircraft in the vertical direction.

[0041] The present application provides a system-level calibration method for correcting the zero offset of an acceleration channel of an inertial measurement device, and provides a system-level calibration method for quickly correcting the zero offset of an acceleration channel of an inertial measurement device, which can effectively calculate the zero offset error of the acceleration channel through simple calibration path setting. When the self-zero offset error of the accelerometer changes, the inertial measurement device no longer needs to be disassembled from the aircraft for separate calibration, and the installation error caused by repeated installation of the inertial measurement device is avoided.

[0042] 1. Calibration method:

[0043] S1, device arrangement

[0044] The inertial measurement device is fastened on the calibration tool, and the inertial measurement device is connected with the inertial measurement device test system.

[0045] S2, make the X-axis of the inertial measurement device vertical upward, and collect the output incremental data

[0046] The rotation position makes the X axis of the inertial measurement device vertical upward to the sky, and the Y and Z axes horizontal. At this time, it is ensured that the Y and Z axes are as horizontal as possible, and the error with the horizontal plane is not greater than a first preset angle. The first preset angle is 5°. The product is powered on, and preheated for a first preset time. The first preset time is half an hour. After half an hour, the inertial measurement device test system is used to collect the incremental data of the acceleration channel output of the inertial measurement device at the X upward position, and the time is a second preset time. The second preset time is 60 seconds. The collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

[0047] S3, making the Y axis of the inertial measurement device vertical upward to the sky, collecting the incremental data output

[0048] The Y axis of the inertial measurement device is made vertical upward to the sky, and the X and Z axes are horizontal. It is ensured that the X and Z axes have an error with the horizontal plane not greater than a first preset angle. The first preset angle is 5°. The incremental data of the three acceleration channels is collected by repeating step S2, and the 1-second average value of the data is calculated.

[0049] Specifically, the product is powered on, and preheated for a first preset time. The inertial measurement device test system is used to collect the incremental data of the acceleration channel output of the inertial measurement device at the Y upward position, and the time is a second preset time. The collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

[0050] S4, making the Z axis of the inertial measurement device vertical upward to the sky, collecting the incremental data output

[0051] The Z axis of the inertial measurement device is made vertical upward to the sky, and the X and Y axes are horizontal. It is ensured that the X and Y axes have an error with the horizontal plane not greater than a first preset angle. The first preset angle is 5°. The incremental data of the three acceleration channels is collected by repeating step S2, and the 1-second average value of the data is calculated.

[0052] Specifically, the product is powered on, and preheated for a first preset time. The inertial measurement device test system is used to collect the incremental data of the acceleration channel output of the inertial measurement device at the Z upward position, and the time is a second preset time. The collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

[0053] 2. Data processing method:

[0054] S5, calculating the zero offset error of the acceleration X channel

[0055] According to the average value of the acceleration channel output at the X upward position obtained in step S2 in the calibration method, the angle between the X channel and the sky is first calculated from the output data of the Y and Z acceleration channels: the output of the Y and Z axes is integrated into the horizontal acceleration output, and the inverse trigonometric function calculation of the horizontal acceleration output can obtain the angle between the X channel and the sky, denoted as θ.

[0056] The standard value of the local gravitational acceleration is multiplied by the cosine value of the calculated angle θ, and the result is taken as the standard value of the theoretical output of the X channel. The average value of the acceleration channel output obtained in step S2 is subtracted from the average value of the X channel output, and the difference is the zero offset error of the acceleration X channel.

[0057] S6, Calculate the acceleration Y channel zero offset error

[0058] The average value of the acceleration channel output at the Y-axis pointing sky position obtained in step S3 of the calibration method is used to calculate the acceleration Y channel zero offset error, and the calculation method is the same as step S5 of the data processing.

[0059] The average value of the acceleration channel output at the Y-axis pointing sky position obtained in step S3 of the calibration method is used to calculate the angle between the Y channel and the sky direction: the outputs of the X and Z axes are combined into horizontal acceleration output, and the inverse trigonometric function calculation of the horizontal acceleration output can obtain the angle between the Y channel and the sky direction, denoted as α; The standard value of the local gravitational acceleration is multiplied by the cosine value of the calculated angle α, and the result is taken as the standard value of the theoretical output of the Y channel; The average value of the Y channel output is subtracted from the average value of the acceleration channel output obtained in step S3, and the difference is the zero offset error of the acceleration Y channel.

[0060] S7, Calculate the acceleration Z channel zero offset error

[0061] The average value of the acceleration channel output at the Z-axis pointing sky position obtained in step S4 of the calibration method is used to calculate the acceleration Z channel zero offset error, and the calculation method is the same as step S5 of the data processing.

[0062] The average value of the acceleration channel output at the Z-axis pointing sky position obtained in step S3 of the calibration method is used to calculate the angle between the Z channel and the sky direction: the outputs of the X and Y axes are combined into horizontal acceleration output, and the inverse trigonometric function calculation of the horizontal acceleration output can obtain the angle between the Z channel and the sky direction, denoted as β; The standard value of the local gravitational acceleration is multiplied by the cosine value of the calculated angle β, and the result is taken as the standard value of the theoretical output of the Z channel; The average value of the Z channel output is subtracted from the average value of the acceleration channel output obtained in step S3, and the difference is the zero offset error of the acceleration Z channel.

[0063] S8, After the zero offset error is compensated, iteration is performed

[0064] The zero offset errors of the three acceleration channels are calculated through steps S5 to S7, and the zero offset errors of the three acceleration channels are compensated into the three-channel acceleration data that has been collected, and the zero offset error of the three acceleration channels after compensation is calculated.

[0065] If the synthesized zero offset error is less than 5*10 -5 g, it is considered that the compensation has ended, and the obtained result is the zero offset error to be compensated. If the synthesized zero offset error is greater than 5*10 -5 g, the compensated acceleration channel data is calculated again according to steps S5 to S7, and the zero offset errors of the three acceleration channels are calculated again, and the iteration is performed again into the acceleration channel data until the three-axis synthesized acceleration channel zero offset is less than 5*10 -5 g, and the iteration is terminated, and the obtained result is the zero offset error to be compensated, and the system-level calibration is ended.

[0066] The system-level calibration method for quickly correcting the zero offset of the acceleration channel of the inertial measurement device is provided, and the zero offset error of the acceleration channel can be effectively calculated through a simple calibration path setting. When the self-zero offset error of the accelerometer changes, the inertial measurement device no longer needs to be disassembled from the aircraft for separate calibration, and the installation error caused by repeated installation of the inertial measurement device is also avoided.

[0067] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A system-level calibration method for correcting the zero bias of an acceleration channel of an inertial measurement device, characterized in that, The method comprises the following steps: S1, device arrangement Fasten the inertial measurement device on the calibration tool, and connect the inertial measurement device with the inertial measurement device test system; S2, make the X axis of the inertial measurement device vertical upward, and collect the output incremental data Turn the position to make the X axis of the inertial measurement device vertical upward, and the Y and Z axes horizontal, ensure that the errors of the Y and Z axes with the horizontal plane are not greater than a first preset angle; collect the incremental data of the three acceleration channels, and calculate the 1-second average value of the data; S3, make the Y axis of the inertial measurement device vertical upward, and collect the output incremental data Make the Y axis of the inertial measurement device vertical upward, and the X and Z axes horizontal, ensure that the errors of the X and Z axes with the horizontal plane are not greater than a first preset angle; collect the incremental data of the three acceleration channels, and calculate the 1-second average value of the data; S4, make the Z axis of the inertial measurement device vertical upward, and collect the output incremental data Make the Z axis of the inertial measurement device vertical upward, and the X and Y axes horizontal, ensure that the errors of the X and Y axes with the horizontal plane are not greater than a first preset angle; collect the incremental data of the three acceleration channels, and calculate the 1-second average value of the data; S5, calculate the zero offset error of the acceleration X channel According to the average value of the acceleration channel output at the X axis upward position obtained in step S2, calculate the zero offset error of the acceleration X channel; S6, calculate the zero offset error of the acceleration Y channel According to the average value of the acceleration channel output at the Y axis upward position obtained in step S3, calculate the zero offset error of the acceleration Y channel; S7, calculate the zero offset error of the acceleration Z channel According to the average value of the acceleration channel output at the Z axis upward position obtained in step S4, calculate the zero offset error of the acceleration Z channel; S8, compensate the obtained zero offset error and iterate The zero offset errors of the three acceleration channels are calculated through steps S5 to S7. The zero offset errors of the three acceleration channels are compensated into the three-channel acceleration data that has been collected, and the zero offset error of the three acceleration channels after compensation is calculated. If the synthesized zero offset error is less than 5*10 -5 g, it is considered that the compensation has ended, and the result is the zero offset error to be compensated. If the synthesized zero offset error is greater than 5*10 -5 g, the compensated acceleration channel data is again calculated according to steps S5 to S7 to calculate the zero offset errors of the three acceleration channels, and the acceleration channel data is iterated again until the three-axis synthesized acceleration channel zero offset is less than 5*10 -5 g, and the iteration is terminated. At this time, the result is the zero offset error to be compensated, and the system level calibration is ended. Wherein, In step S5, according to the average value of the acceleration channel output at the X axis upward position obtained in step S2, the calculation of the zero offset error of the acceleration X channel specifically comprises: according to the average value of the acceleration channel output at the X axis upward position obtained in step S2 of the calibration method, first calculate the angle between the X channel and the sky direction from the output data of the Y and Z two acceleration channels: synthesize the output of the Y and Z axes into the horizontal acceleration output, and the horizontal acceleration output is calculated by the inverse trigonometric function to obtain the angle between the X channel and the sky direction, which is denoted as θ; multiply the standard value of the local gravitational acceleration by the cosine value of the calculated angle θ, and take it as the standard value of the theoretical output result of the X channel; according to the average value of the acceleration channel output obtained in step S2, subtract the average value of the X channel output from the standard value of the theoretical output result of the X channel, and the difference obtained is the zero offset error of the acceleration X channel; The step S6, according to the average value of the Y-axis acceleration channel output in the step S3, the calculation of the acceleration Y channel zero offset error specifically includes: according to the average value of the Y-axis acceleration channel output in the step S3 of the calibration method, first, the output data of X, Z two acceleration channels are used to calculate the angle between Y channel and the sky direction: the output of X, Z axis is synthesized into horizontal acceleration output, and the inverse trigonometric function calculation of the horizontal acceleration output can obtain the angle between Y channel and the sky direction, which is denoted as α; the standard value of the local gravity acceleration is multiplied by the cosine value of the calculated angle α, and the standard value is taken as the standard value of the theoretical output result of Y channel; according to the average value of the acceleration channel output obtained in the step S3, the difference between the average value of Y channel output and the standard value of the theoretical output result of Y channel is obtained, which is the zero offset error of the acceleration Y channel; The step S7, according to the average value of the Z-axis acceleration channel output in the step S3, the calculation of the acceleration Z channel zero offset error specifically includes: according to the average value of the Z-axis acceleration channel output in the step S3 of the calibration method, first, the output data of X, Y two acceleration channels are used to calculate the angle between Z channel and the sky direction: the output of X, Y axis is synthesized into horizontal acceleration output, and the inverse trigonometric function calculation of the horizontal acceleration output can obtain the angle between Z channel and the sky direction, which is denoted as β; the standard value of the local gravity acceleration is multiplied by the cosine value of the calculated angle β, and the standard value is taken as the standard value of the theoretical output result of Z channel; according to the average value of the acceleration channel output obtained in the step S3, the difference between the average value of Z channel output and the standard value of the theoretical output result of Z channel is obtained, which is the zero offset error of the acceleration Z channel.

2. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device according to claim 1, wherein, The first preset angle is 5°.

3. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device according to claim 1, wherein, The step S2, the collection of the incremental data of three acceleration channels and the calculation of the 1-second average value of the data specifically includes: the product is powered on, the first preset time is preheated, the incremental data of the acceleration channel output by the inertial measurement device is collected in the X sky position using the inertial measurement device test system, the time is the second preset time, the collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

4. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device according to claim 3, wherein, The step S3, the collection of the incremental data of three acceleration channels and the calculation of the 1-second average value of the data specifically includes: the product is powered on, the first preset time is preheated, the incremental data of the acceleration channel output by the inertial measurement device is collected in the Y sky position using the inertial measurement device test system, the time is the second preset time, the collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

5. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device according to claim 4, wherein, The step S4, the collection of the incremental data of three acceleration channels and the calculation of the 1-second average value of the data specifically includes: the product is powered on, the first preset time is preheated, the incremental data of the acceleration channel output by the inertial measurement device is collected in the Z sky position using the inertial measurement device test system, the time is the second preset time, the collected incremental data is saved, and the 1-second average value of the output data of the three acceleration channels is calculated.

6. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device according to claim 5, wherein, The first preset time is half an hour.

7. The system-level calibration method for correcting the bias of the acceleration channel of an inertial measurement device as claimed in claim 5, wherein, The second preset time is 60 seconds.

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