Inertia combination goniometer and automatic measurement method for earth rotation angular rate error thereof

Abstract

The invention discloses an inertial combination goniometer and an automatic measurement method for earth rotation angular rate errors thereof. The inertial combination goniometer comprises a single-axis high-precision optical gyroscope and an inertial measurement unit, the single-axis high-precision optical gyroscope is installed on a measured carrier to sense the change of the rotation angle of the measured carrier rotating around the Z axis in real time. The inertial measurement unit is installed on a measured carrier to sense the rotation angle changes of the measured carrier rotating around the X axis and the Y axis in real time. The rotation angle sensor is connected with the single-axis high-precision optical gyroscope to obtain rotation angle change data of the measured carrier rotating around the Z axis; and according to the rotation angle change data of the X-axis, the Y-axis and the Z-axis, performing real-time calculation by using a strapdown inertial navigation attitude updating algorithm so as to obtain the earth rotation angle rate error in real time.

Description

Technical Field

[0001] The present invention relates to the field of high-precision angle measurement, and particularly to a high-precision optical inertial combined angle measuring instrument and an automatic measurement method for the earth's rotation angular rate error thereof. Background Art

[0002] A high-precision optical angle measuring instrument is a rotation angle measuring device based on a high-precision optical gyroscope, and the angle measurement accuracy can reach the order of 0.1". A high-precision optical gyroscope (laser gyroscope or fiber optic gyroscope) is an optical gyroscope based on the Sagnac effect. When it is fixedly connected to a measured carrier (turntable or other rotating mechanism) to ensure that the sensitive axis of the optical gyroscope is strictly parallel to the rotation direction of the measured carrier, it can be used to measure the rotation angular rate of the measured carrier relative to the inertial space (the earth). The measured values of this rotation angular rate mainly include: 1. The rotation angular rate of the measured carrier relative to the earth, that is, the target measurement value; 2. The projection component of the rotation angular rate of the earth relative to the inertial space (the earth's rotation angular rate, with a value of 15.041 deg / h) on the sensitive axis of the optical gyroscope, that is, the earth's rotation angular rate error; 3. The angular rate measurement error introduced by the optical gyroscope itself.

[0003] For the application of rotation angle measurement, only the first item is the valid signal, and the second and third items are errors that need to be reduced or eliminated. Among them, the measurement error introduced by the optical gyroscope itself in the third item can be eliminated by using a higher-precision optical gyroscope (for example, an optical gyroscope with a precision of 0.005 deg / h) for measurement or by means of calibration compensation. However, for the second item, the earth's rotation angular rate error, it can only be eliminated by specific measurement and calculation methods.

[0004] In the application of angle measurement with a high-precision optical angle measuring instrument, a single-axis high-precision optical gyroscope with a precision of about 0.005 deg / h is usually selected to measure the earth's rotation angular rate error. Generally, before the measurement is prepared, the angle measuring instrument is installed on the measured carrier, and the angle measuring instrument is kept powered on and in a static state. At this time, the output of the gyroscope is the earth's rotation angular rate error. By collecting the output of the gyroscope for a period of time, the time average value of this error can be calculated. However, the disadvantage of this method is that when the installation state of the angle measuring instrument changes, it is necessary to re-align statically and then collect and measure again, and the measurement error is large. This process is not only cumbersome and inefficient, but also has high requirements for the closed-loop stability characteristics of the measured carrier. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0006] To this end, the present invention proposes an inertial combined angle measuring instrument and an automatic measurement method for the earth rotation error thereof, which omits the static alignment link before the formal angle measurement of the angle measuring instrument, simplifies the angle measurement process, and effectively improves the angle measurement efficiency.

[0007] According to an embodiment of the first aspect of the present application, there is provided an inertial combined angle measuring instrument, characterized by comprising: a single-axis high-precision optical gyroscope and an inertial measurement unit; the single-axis high-precision optical gyroscope is installed on the measured carrier to sensitively sense the change in the rotation angle of the measured carrier rotating around the Z axis in real time; the inertial measurement unit is installed on the measured carrier to sensitively sense the change in the rotation angles of the measured carrier rotating around the X axis and the Y axis respectively; and is connected to the single-axis high-precision optical gyroscope to obtain the rotation angle change data of the measured carrier rotating around the Z axis; and according to the rotation angle change data of the three axes of the X axis, the Y axis and the Z axis, real-time calculation is performed by using the strapdown inertial attitude update algorithm to obtain the earth rotation angular rate error in real time.

[0008] According to some embodiments of the present application, the initial state of the carrier coordinate system XYZ of the measured carrier coincides with the northeast-up direction of the geographic coordinate system; the sensitive axis of the single-axis high-precision optical gyroscope is parallel to the Z axis in the carrier coordinate system of the measured carrier to sensitively sense the change in the rotation angle of the measured carrier rotating around the Z axis; the three orthogonal axes x, y, and z in the sensor coordinate system of the inertial measurement unit are respectively parallel to the orthogonal axes X, Y, and Z in the carrier coordinate system of the measured carrier to sensitively sense the change in the rotation angles of the measured carrier rotating around the X axis and the Y axis.

[0009] According to some embodiments of the present application, the inertial measurement unit adopts a MEMS three-axis sensor, and the MEMS three-axis sensor internally has an x-axis gyroscope, a y-axis gyroscope and a z-axis gyroscope; the single-axis high-precision optical gyroscope replaces the z-axis gyroscope inside the MEMS three-axis sensor; the x-axis gyroscope, the y-axis gyroscope and the single-axis high-precision optical gyroscope output corresponding rotation angle change data, and real-time calculation is performed by using the strapdown inertial attitude update algorithm.

[0010] According to an embodiment of the second aspect of the present application, there is provided an automatic measurement method for the earth rotation angular rate error, which is applied to the inertial combined angle measuring instrument described in the embodiment of the first aspect, and includes the following steps: S1. Calibration of the inertial combined angle measuring instrument, including calibrating the single-axis high-precision optical gyroscope and the x-axis gyroscope and the y-axis gyroscope in the inertial measurement unit; S2. In the angular measurement working state of the inertial combined angle measuring instrument, the strapdown inertial navigation attitude update algorithm is used to calculate the output data of the x-axis gyroscope, y-axis gyroscope and the single-axis high-precision optical gyroscope in the calibrated inertial measurement unit to obtain the earth's angular rotation rate error in real time.

[0011] In the above method, the step S1 includes: calibrating the scale factor matrix in the linear calibration model of the gyroscope; and calibrating the drift based on the calibrated scale factor matrix.

[0012] In the above method, the step of calibrating the scale factor matrix in the linear calibration model of the gyroscope includes: using the rotation of a highly accurate turntable after metrological calibration to provide angular rate excitation, so that the inertial combined angle measuring instrument rotates around three orthogonal axes X, Y, and Z at a given angular rate, and intercepting appropriate-duration gyroscope output pulse sampling data during the period of stable rotation speed. The calibration value of the scale factor matrix is the ratio of the output angle value (i.e., the rotation angle value) of the turntable during the corresponding period to the pulse sampling data output by the gyroscope during the corresponding period.

[0013] In the above method, the step of calibrating the drift based on the calibrated scale factor matrix includes: calibrating the drift by the two-position method, which is expressed by the formula:

[0014] In the formula, represents the drift of the gyroscope; , represent the average values of the pulse sampling data output by the gyroscope at the first position and the second position respectively; represents the calibrated scale factor matrix; represents the value of the earth's angular rotation rate, with a value of 15.041 deg / h; represents the latitude where the measured carrier is located.

[0015] In the above method, the step S2 includes: based on the strapdown inertial navigation attitude update algorithm, calculating in real time the attitude update matrix of the gyroscope in the current state under the carrier coordinate system of the measured carrier, then the earth's angular rotation rate in the carrier coordinate system

[0016] In the formula, represents the attitude update matrix in the current state; represents the earth's angular rotation rate vector; According to the carrier coordinate system The angular velocity of the Earth's rotation in the system to calculate the projection component of the Earth's angular rotation rate on the sensitive axis of the single-axis high-precision optical gyroscope that is, the Earth's angular rotation rate error.

[0017] According to an embodiment of the third aspect of the present application, a terminal is provided, including a memory and a processor. A computer program that can run on the processor is stored on the memory. It is characterized in that when the processor runs the computer program, it executes the automatic measurement method of the Earth's angular rotation rate error described in the embodiment of the second aspect.

[0018] According to an embodiment of the fourth aspect of the present application, a computer-readable storage medium is provided. The computer-readable storage medium includes a stored computer program. Wherein, when the computer program is run by a processor, it controls the terminal where the storage medium is located to execute the automatic measurement method of the Earth's angular rotation rate error described in the embodiment of the second aspect.

[0019] According to the technical solution provided by the present application, it has at least the following beneficial effects: By configuring a small high-precision inertial measurement unit on a single-axis high-precision optical gyroscope, integrating the data output by the single-axis high-precision optical gyroscope and the inertial measurement unit into the inertial measurement unit, and using the strapdown inertial attitude update algorithm in the inertial measurement unit to perform calculations in real time, the projection component (the Earth's angular rotation rate error) of the Earth's angular rotation rate on the sensitive axis of the single-axis high-precision optical gyroscope can be obtained in real time, and then the Earth's angular rotation rate error is eliminated. This method omits the static alignment link before angle measurement, and the obtained Earth's angular rotation rate error is greatly reduced, improving the measurement efficiency while further improving the measurement accuracy. The process is simple, efficient, and has low requirements for the closed-loop stability characteristics of the measured carrier.

[0020] Other features and advantages of the present application will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present application. The purpose and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where: Figure 1 is a schematic installation structure diagram of the optical inertial combined angle measuring instrument provided by the embodiment of the present application; Figure 2 is a functional component block diagram of the optical inertial combined angle measuring instrument provided by the embodiment of the present application; Figure 3The measurement error graph provided by the embodiments of the present application. Detailed implementation manners

[0022] 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.

[0023] It should be noted that although the functional modules are divided in the device schematic diagram and the logical sequence is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order from the module division in the device or the sequence in the flowchart.

[0024] In the description of the present application, the meaning of "a number of" is one or more, the meaning of "a plurality of" is more than two, "greater than", "less than", "exceeding", etc. are understood as not including the present number, "above", "below", "within", etc. are understood as including the present number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0025] To make the objectives, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0026] As Figure 1 shown, it is a schematic structural diagram of an inertial combined angle measuring instrument provided by an embodiment of the first aspect of the present invention. The angle measuring instrument includes a single-axis high-precision optical gyroscope 1 and an inertial measurement unit 2 (MEMS IMU). The single-axis high-precision optical gyroscope 1 is installed on the measured carrier 3 (i.e., in the Z-axis direction of the measured carrier 3) to sensitively sense the change in the rotation angle of the measured carrier 3 around the Z-axis in real time; the inertial measurement unit 2 is installed on the measured carrier 3 to sensitively sense the change in the rotation angle of the measured carrier 3 around the X-axis and the Y-axis respectively in real time; the inertial measurement unit 2 is connected to the single-axis high-precision optical gyroscope 1 to obtain the rotation angle change data of the measured carrier 3 around the Z-axis; by combining the rotation angle change data of the three axes of the X-axis, the Y-axis, and the Z-axis, the strapdown inertial attitude update algorithm is used to perform calculations in real time to obtain the earth's angular velocity error. Using this combined angle measuring instrument solution, the real-time measurement of the earth's angular velocity error can be realized.

[0027] In this application, the initial state of the carrier coordinate system XYZ of the carrier under test 3 coincides with the northeast-up direction of the geographic coordinate system; the sensitive axis of the single-axis high-precision optical gyroscope 1 is parallel to the carrier rotation axis (the Z-axis of the carrier coordinate system) of the carrier under test 3, and is used to sense the change in the rotation angle of the carrier under test 3 around the Z-axis; the three orthogonal axes x, y, and z in the inertial measurement unit 2 are respectively parallel to the three orthogonal axes X, Y, and Z in the carrier coordinate system of the carrier under test 3, so as to sense the change in the rotation angle of the carrier under test 3 around the X-axis and Y-axis.

[0028] In this application, the single-axis high-precision optical gyroscope 1 uses an optical gyroscope with an accuracy of 0.005 deg / h; the inertial measurement unit 2 uses a relatively low-cost MEMS three-axis sensor. Inside the inertial measurement unit 2, there are an x-axis gyroscope, a y-axis gyroscope, and a z-axis gyroscope. The x-axis gyroscope, y-axis gyroscope, and z-axis gyroscope are respectively used to measure the angular rate of rotation of the carrier around the three orthogonal axes (x-axis, y-axis, z-axis) of the sensor. Since the accuracy of the gyroscopes inside the inertial measurement unit 2 is lower than that of the high-precision optical gyroscope and its own noise is relatively large, it is impossible to effectively distinguish the earth's angular rate of rotation signal. Therefore, in this application, as Figure 2 shown, the z-axis gyroscope in the inertial measurement unit 2 is replaced by the single-axis high-precision optical gyroscope 1, and together with the x-axis gyroscope and y-axis gyroscope inside the inertial measurement unit 2, the angular rate of rotation of the three orthogonal axes (x-axis, y-axis, z-axis) of the sensor is measured, which is used for strapdown inertial navigation attitude update solution.

[0029] In this application, since the accuracy of the single-axis high-precision optical gyroscope 1 is relatively high, it can effectively distinguish the earth's angular rate of rotation signal; due to its own large noise, the inertial measurement unit 2 cannot effectively distinguish the earth's angular rate of rotation signal. Therefore, when using the optical-inertial combined angle measuring instrument in this application for optical gyro calibration and attitude update, the influence of the earth's angular rate of rotation on different devices needs to be considered.

[0030] Based on Figure 1 and Figure 2 the angle measuring instrument shown, the second aspect of the embodiments of the present invention provides an automatic measurement method for the earth's angular rate of rotation error, including the following steps: S1: Inertial combined angle measuring instrument calibration, including calibrating the single-axis high-precision optical gyroscope and the x-axis gyroscope and y-axis gyroscope in the inertial measurement unit.

[0031] In the inertial combined angle measuring instrument, the navigation coordinate system is system, the carrier coordinate system of the carrier under test is system, and the inertial coordinate system is system, then the linear calibration model of the gyroscope is as follows: (1.1) Wherein, is the rotational angular velocity value of the gyroscopes in three axial directions relative to the inertial space, ; is the scale factor matrix of the gyroscopes; is the real-time sampled data of the output pulses of the gyroscopes, ; is the drift of the gyroscopes.

[0032] The calibration of the gyroscopes is mainly carried out for the scale factor matrix and the drift . After calibration, the accurate angular velocity components in three axial directions of the measured carrier coordinate system can be obtained respectively.

[0033] (1) The calibration process of the scale factor matrix is as follows: Use a high-precision turntable (the measured carrier 3) that has been calibrated by metrology to provide angular velocity excitation. The turntable rotates around three orthogonal axes X, Y, and Z at a given angular velocity respectively. The inertial combined angle measuring instrument follows the turntable and rotates around three orthogonal axes X, Y, and Z at a given angular velocity respectively. During the period of stable rotation speed, intercept the gyroscope output pulse sampled data with an appropriate time length (usually select the period of rotating a full circle or a multiple of a full circle). The rotational angular velocity values can be 10° / s, 20° / s, 30° / s. Then the calibration value of the scale factor matrix is the ratio of the output angle value (i.e., the rotation angle value) of the turntable during the corresponding period to the pulse sampled data output by the gyroscope during the corresponding period.

[0034] When using the turntable as the angular velocity excitation source for calibrating the single-axis high-precision optical gyroscope 1, the influence of the earth's rotation needs to be considered and compensated or eliminated during data processing or experimental design; while due to the large output noise of the x-axis gyroscope and y-axis gyroscope in the inertial measurement unit 2, the influence of the earth's rotation can be ignored during their calibration to simplify the calculation process. Then the angular velocity of the angle measuring instrument fixedly connected to the turntable surface relative to the inertial space is expressed by the formula: (1.2) Wherein, is the earth's rotation angular velocity vector; is the angular velocity of the angle measuring instrument fixedly connected to the turntable surface relative to the ground, given by the turntable reading; represents the attitude matrix from the system to the system. It can be seen from formula (1.2) that when projecting the earth's rotation angular velocity onto the

[0035] In summary, after temporarily ignoring the influence of gyroscope drift, the linear calibration model formula of the gyroscope is as follows: After ignoring the influence of , the linear calibration model formula of the gyroscope is as follows: (1.3) In the formula: The scale factor matrix contains 9 parameters. By using the angular rate excitation sources in the X, Y, and Z axis directions of the measured carrier for calibration respectively, the can be solved.

[0036] It should be noted that when calibrating the z-axis gyroscope in the inertial measurement unit, the inertial measurement unit is rotated so that the sensitive axis of the z-axis gyroscope is parallel and in the same direction as the carrier rotation axis (the Z axis of the carrier coordinate system) of the measured carrier; when calibrating the x-axis gyroscope in the inertial measurement unit, the inertial measurement unit is rotated so that the sensitive axis of the x-axis gyroscope is parallel and in the same direction as the carrier rotation axis (the Z axis of the carrier coordinate system) of the measured carrier; when calibrating the y-axis gyroscope, the inertial measurement unit is rotated so that the sensitive axis of the y-axis gyroscope is parallel and in the same direction as the carrier rotation axis (the Z axis of the carrier coordinate system) of the measured carrier.

[0037] (2) The calibration process of the drift is as follows: After completing the calibration of the scale factor matrix , the double-position method is used to calibrate the drift . Based on the goniometers shown in Figure 1 and Figure 2 , in the static state, the single-axis high-precision optical gyroscope can measure the component of the earth's angular rotation rate in the system, and the outputs of the x-axis gyroscope and y-axis gyroscope in the inertial measurement unit in the static state can be regarded as the drift of the gyroscope. Therefore, the theoretical angular rate output of the gyroscope (the x-axis gyroscope, y-axis gyroscope and single-axis high-precision optical gyroscope (z-axis) in the inertial measurement unit) at the first position is: (1.4) In the formula, represents the scalar value of the earth's angular rotation rate; represents the latitude where the measured carrier is located.

[0038] Rotate the measured carrier 180° around the carrier rotation axis (Z axis). At this time, the theoretical angular rate output of the gyroscope (x-axis gyroscope, y-axis gyroscope and single-axis high-precision optical gyroscope (z-axis)) at the second position is: (1.5) In the formula, represents the scalar value of the earth's angular rotation rate; represents the latitude where the measured carrier is located.

[0039] In the dual-position case, substitute the theoretical angular rate output and its sampled output into the linear calibration model formula (Formula 1.1) to obtain (1.6) (1.7) where and represent the average values of the output pulse sampled data of the gyroscopes (the x-axis gyroscope, y-axis gyroscope, and single-axis high-precision optical gyroscope in the inertial measurement unit) at the first position and the second position, respectively; represents the calibrated scale factor matrix; Adding Formulas (1.6) and (1.7) gives: (1.8) where represents the calibrated scale factor matrix; and represent the average values of the output pulse sampled data of the gyroscopes (the x-axis gyroscope, y-axis gyroscope, and single-axis high-precision optical gyroscope in the inertial measurement unit) at the first position and the second position, respectively; represents the value of the earth's angular rotation rate, with a value of 15.041 deg / h; represents the latitude where the measured carrier is located.

[0040] After completing the calibration of the gyroscope drift , if it is found that the drift value is too large, the scale factor matrix can be recalibrated. For the calibrated scale factor matrix and the drift , they can be directly used in angle measurement applications.

[0041] S2: In the angle measurement working state of the inertial combined angle measuring instrument, use the strapdown inertial attitude update algorithm to calculate the output data of the x-axis gyroscope, y-axis gyroscope, and single-axis high-precision optical gyroscope in the calibrated inertial measurement unit to obtain the earth's angular rotation rate error in real time.

[0042] In this step, the attitude differential equation with the system as the reference system is: (2.1) where represents the attitude matrix of the system relative to the system; represents the rotation angular rate of the system relative to the system.

[0043] The measured gyro angular rate values of the three orthogonal axes are: (2.2) In the formula, represents the rotation angular rate of the system relative to the inertial system, which can be directly measured by the gyroscope; is the x-axis angular rate measured by the x-axis gyroscope in the inertial measurement unit; is the y-axis angular rate measured by the y-axis gyroscope in the inertial measurement unit; is the z-axis angular rate measured by the single-axis high-precision optical gyroscope.

[0044] There is: (2.3) (2.4) In the formula, represents the rotation angular rate of the system relative to the system; represents the rotation angular rate of the system relative to the system, represents the attitude matrix of the system relative to the system; represents the rotation angular rate of the system relative to the system; is the angular rate vector of the Earth's rotation; represents the rotation angular rate of the system caused by the movement of the carrier on the Earth's surface. And , are the eastward and northward velocities; , are the latitude and altitude of the measured carrier; and are the Earth's meridian radius and prime vertical radius respectively; is the value of the Earth's rotation angular rate.

[0045] Based on the application scenarios of the goniometers shown in Figure 1 and Figure 2 for the The solution is simplified. In this goniometer, since the accuracy of the single-axis high-precision optical gyroscope is 0.005 deg / h, it can effectively measure the angular velocity of the Earth's rotation; while the output noise levels of the x-axis and y-axis gyroscopes carried by the inertial measurement unit itself are much greater than the angular velocity of the Earth's rotation, and it is impossible to effectively distinguish the angular velocity signal of the Earth's rotation. Therefore, the influence of the Earth's angular velocity component on the x-axis and y-axis gyroscopes is not considered, and only the influence of the Earth's angular velocity component on the z-axis, that is, the influence on the single-axis high-precision optical gyroscope, is considered. And when the motion speed of the measured carrier is small (in line with the situation of angle measurement usually under static conditions), or when the speed drift error is too large, the rotation of the system can also be not considered, then Equation (2.3) can be simplified as: (2.7) The attitude update algorithm adopts the matrix chain multiplication rule, and there is (2.8) In the formula, and respectively represent and the attitude matrices at represent the system from time to time rotation change; represent the system from time to time rotation change, which can be determined by the gyro angular velocity; the gyro is sampled twice at equal intervals in the time period , and the angle turned by the gyroscope in the time period from to is divided into and , and the two-sample conical compensation algorithm is adopted to have (2.9) In the formula, represents: ; represents the equivalent rotation vector. Then (2.10) (2.11) In the formula, represents time system relative to system rotation angular velocity.

[0046] Formulas 2.8 to 2.11 are the attitude update algorithm formulas.

[0047] In this step, based on the strapdown inertial attitude update algorithm, the attitude update matrix of the gyroscope in the current state can be calculated in real time Then, in the body coordinate system of the measured vehicle the earth's angular velocity of rotation is expressed by the formula as follows:

[0048] In the formula, represents the attitude update matrix in the current state; represents the earth's angular velocity vector.

[0049] Thus, the projection component of the earth's angular velocity of rotation on the sensitive axis of the single-axis high-precision optical gyroscope can be calculated , that is, the earth's angular velocity error. Thus, this error can be compensated automatically in real time, improving the measurement efficiency of the goniometer. In this application, compensation can be performed by setting compensation parameters in software, and the compensation method is not specifically limited in this application.

[0050] It should be noted that considering that the x-axis gyroscope and y-axis gyroscope in the inertial measurement unit are low-cost devices with relatively low accuracy, there may be a measurement error of up to 1° magnitude during actual measurement. Therefore, the installation error of the sensor can be ignored, that is, it is considered that the z-axis of the inertial measurement unit coincides exactly with the sensitive axis of the single-axis high-precision optical gyroscope. For economic considerations and actual usage scenarios, this algorithm allows a measurement error within 1° for the measurement of the angle between the high-precision optical gyroscope and the earth's axis of rotation. The rotation angle measurement error that may be caused by a 1° angle measurement error can be theoretically expressed as: (2.14) In the formula, represents the earth's angular velocity of rotation, and its value is 15.041 deg / h; represents the angle between the sensitive axis of the single-axis high-precision optical gyroscope and the earth's axis of rotation, and its value range is 0 to 180°.

[0051] The simulation results are as Figure 3 shown. It can be seen from Figure 3 that when there is an error of 1° magnitude in the angle measurement, the maximum possible measurement error of the projection component is about 0.25 deg / h theoretically, that is, based on Figure 1 and Figure 2The error of the earth's angular rotation rate is calculated by the goniometer in and the automatic measurement method of the earth's angular rotation rate error described above. The introduced angular measurement error is about 0.25 deg / h. Compared with the original maximum possible error of 30.082 deg / h (twice the earth's angular rotation rate), an accuracy improvement of two orders of magnitude can be achieved.

[0052] Using the optical inertial combined goniometer and its automatic measurement method of the earth's angular rotation rate error in the above technical solution, by combining a single-axis high-precision optical gyroscope with a low-cost inertial measurement unit and using the strapdown inertial navigation attitude update algorithm, the real-time calculation of the earth's angular rotation rate error is achieved. This solution eliminates the static alignment link before the formal angle measurement of the goniometer, simplifies the angle measurement process, and improves the angle measurement efficiency; and when the installation state of the goniometer changes, there is no need to re-align statically.

[0053] The strapdown inertial navigation attitude update algorithm used in this application can still effectively calculate the attitude matrix under the condition that the measured carrier rotates or shakes, and can realize the calculation of the earth's angular rotation rate error during the angle measurement (the calculation frequency is equal to the update frequency of the attitude matrix), or be used for the angle measurement of carriers with poor closed-loop stability characteristics, greatly expanding the motion state measurement ability of the optical gyro goniometer.

[0054] The above is a specific description of the preferred embodiment of this application, but this application is not limited to the above implementation manner. Those skilled in the art can also make various equivalent deformations or substitutions without violating the spirit of this application, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An inertial combined angle measuring instrument, characterized in that, Comprising: A single-axis high-precision optical gyroscope and an inertial measurement unit; The single-axis high-precision optical gyroscope is mounted on the measured carrier to sensitively detect the change in the rotation angle of the measured carrier rotating around the Z axis in real time; The inertial measurement unit is mounted on the measured carrier to sensitively detect the change in the rotation angle of the measured carrier rotating around the X axis and the Y axis respectively in real time; and is connected to the single-axis high-precision optical gyroscope to obtain the rotation angle change data of the measured carrier rotating around the Z axis; and based on the rotation angle change data of the three axes of the X axis, the Y axis and the Z axis, real-time calculation is performed using the strapdown inertial navigation attitude update algorithm to obtain the earth's angular rotation rate error in real time.

2. The inertial combined angle measuring instrument according to claim 1, wherein The initial state of the carrier coordinate system XYZ of the measured carrier coincides with the northeast celestial direction of the geographical coordinate system; the sensitive axis of the single-axis high-precision optical gyroscope is parallel to the Z axis in the carrier coordinate system of the measured carrier to sensitively detect the change in the rotation angle of the measured carrier rotating around the Z axis; the three orthogonal axes x, y, z in the sensor coordinate system of the inertial measurement unit are respectively parallel to the orthogonal axes X, Y, Z in the carrier coordinate system of the measured carrier to sensitively detect the change in the rotation angle of the measured carrier rotating around the X axis and the Y axis.

3. The inertial combined angle measuring instrument according to claim 1, characterized in that, The inertial measurement unit uses a MEMS three-axis sensor, and the MEMS three-axis sensor internally has an x-axis gyroscope, a y-axis gyroscope and a z-axis gyroscope; the single-axis high-precision optical gyroscope replaces the z-axis gyroscope inside the MEMS three-axis sensor; the x-axis gyroscope, the y-axis gyroscope and the single-axis high-precision optical gyroscope output corresponding rotation angle change data, and real-time calculation is performed using the strapdown inertial navigation attitude update algorithm.

4. An automatic measurement method for the angular rate error of the Earth's rotation, characterized in that, Applied to the inertial combined angle measuring instrument according to any one of claims 1 to 3, comprising the following steps: S1. Calibration of the inertial combined angle measuring instrument, including calibrating the single-axis high-precision optical gyroscope and the x-axis gyroscope and y-axis gyroscope in the inertial measurement unit; S2. In the angle measuring working state of the inertial combined angle measuring instrument, use the strapdown inertial navigation attitude update algorithm to calculate the output data of the x-axis gyroscope, y-axis gyroscope and the single-axis high-precision optical gyroscope after calibration to obtain the earth's angular rotation rate error in real time.

5. The automatic measurement method according to claim 4, wherein The step S1 includes: Calibrating the scale factor matrix in the linear calibration model of the gyroscope; Calibrating the drift based on the calibrated scale factor matrix.

6. The automatic measurement method according to claim 5, wherein The step of calibrating the scale factor matrix in the linear calibration model of the gyroscope includes: Using the rotation of a highly precise turntable calibrated by metrology to provide an angular rate excitation, so that the inertial combined angle measuring instrument rotates around the three orthogonal axes X, Y, Z at a given angular rate respectively, and intercept the gyroscope output pulse sampling data with an appropriate length during the period of stable rotation speed. The calibration value of the scale factor matrix is the ratio of the output angle value of the turntable to the pulse sampling data output by the gyroscope during the corresponding period.

7. The automatic measurement method according to claim 5, characterized in that The step of calibrating the drift based on the calibrated scale factor matrix includes: Calibrating the drift using the two-position method, which is expressed by the formula: In the formula, represents the drift of the gyroscope; , represent the average values of the output pulse sampling data when the gyroscope is at the first position and the second position respectively; represents the calibrated scale factor matrix; represents the value of the earth's angular rotation rate, with a value of 15.041 deg / h; represents the latitude where the measured carrier is located.

8. The automatic measurement method according to claim 4, wherein The step S2 includes: Based on the strapdown inertial navigation attitude update algorithm, the attitude update matrix of the gyroscope in the current state is calculated in real time. Then, the earth's angular rotation rate in the body coordinate system of the measured vehicle is expressed by the formula: ​ In the formula, represents the attitude update matrix in the current state; represents the angular velocity vector of the Earth's rotation; According to the carrier coordinate system of the carrier under test the earth's angular velocity of rotation , calculate the projection component of the earth's angular velocity of rotation on the sensitive axis of the single-axis high-precision optical gyroscope , that is, the earth's angular velocity error.

9. A terminal, comprising a memory and a processor, wherein a computer program capable of running on the processor is stored on the memory, characterized in that, When the processor runs the computer program, it executes the automatic measurement method for the earth's angular rotation rate error according to any one of claims 4 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein when the computer program is run by a processor, it controls the terminal where the storage medium is located to execute the automatic measurement method for the earth's angular rotation rate error according to any one of claims 4 to 8.

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