Method for correcting scale coefficient of gyroscope, integrated navigation system and medium

Abstract

The invention discloses a method for correcting a scale coefficient of a gyroscope, an integrated navigation system and a medium, and relates to the technical field of navigation positioning, the method is applied to an inertial navigation unit arranged in a movable carrier, and the method comprises the following steps: acquiring original measurement data of the gyroscope in a plurality of time periods and course angle variation of the carrier in each time period, the original measurement data comprises sampling data acquired by the gyroscope in a time period, and the sampling data comprises a three-axis measurement value acquired by the gyroscope; determining a projection component accumulated value of the original measurement data on a sky axis of the carrier coordinate system; based on the course angle variable quantity, the projection component accumulated value and the number of the sampling periods corresponding to each time period, determining a scale coefficient correction value and zero offset of the gyroscope; and correcting the original measurement data based on the scale coefficient correction value and the zero offset to obtain the angular velocity of the carrier. The adverse effect of the scale coefficient error of the gyroscope on the inertial measurement precision can be reduced, and the inertial navigation precision during continuous turning of the carrier is improved.

Description

Technical Field

[0001] The present invention relates to the field of navigation and positioning technology, and in particular to a method for correcting a gyroscope scale coefficient, a combined navigation system and a medium. Background Art

[0002] The measurement error of the Inertial Measurement Unit (IMU) is one of the key factors that restrict the accuracy of inertial navigation. An IMU usually includes a gyroscope and an accelerometer. In the absence of absolute position and velocity constraints, it is impossible to effectively estimate the heading error caused by the gyroscope's zero bias and scale coefficient errors, which in turn causes the heading error to become one of the main sources of error in inertial navigation. For example, for a gyroscope, its scale coefficient error will cause the heading to diverge rapidly when the carrier is maneuvering, making it difficult to meet the requirements for inertial navigation accuracy in continuous turning scenarios.

[0003] In the related art, the impact of the gyroscope's scale coefficient error on navigation accuracy is reduced mainly through the following two methods: the first method is device calibration, that is, the actual rotation angular velocity and sensor output value of the gyroscope are recorded through turntable tests, and the relevant algorithm is used to estimate the zero bias and scale coefficient error curve of the gyroscope at different temperatures. The second method is online estimation, which generally uses Kalman filtering to estimate the above error terms in the integrated navigation stage.

[0004] Although the first method can obtain the zero bias and scale factor of the gyroscope more accurately, the calibration cost is high and requires a precision turntable to collect and calculate a large amount of data at different temperatures. In addition, devices in the same batch are also inconsistent, so individual devices need to be calibrated. This results in the calibration cost accounting for a large proportion of the device cost, and the cost is high. The second method has very strict requirements on the conditions for estimating the heading error. It is restricted by the principle of low maneuverability of the carrier and low objective heading measurement. In addition, due to the low observability of the zero bias and scale factor errors of the gyroscope, this method has a poor effect on estimating the scale factor error of the gyroscope. Summary of the invention

[0005] Embodiments of the present application provide a method for correcting a gyroscope scale coefficient, a combined navigation system, and a medium.

[0006] In a first aspect, an embodiment of the present application provides a method for correcting a gyroscope scale coefficient, which is applied to an inertial navigation unit provided in a movable carrier, the inertial navigation unit including a gyroscope, the method including: obtaining raw measurement data of the gyroscope in multiple time periods and a heading angle change of the carrier in each time period, wherein the raw measurement data of each time period includes sampling data collected by the gyroscope in the time period, and the sampling data includes three-axis measurement values ​​collected by the gyroscope in the sampling period; determining an accumulated value of a projection component of the raw measurement data of each time period on a celestial axis of a carrier coordinate system; determining a scale coefficient correction value and a zero bias of the gyroscope based on the heading angle change, the accumulated value of the projection component and the number of sampling periods corresponding to each time period; and correcting the raw measurement data based on the scale coefficient correction value and the zero bias to obtain an angular velocity of the carrier.

[0007] In a second aspect, an embodiment of the present application provides a combined navigation system, which is applied to a movable carrier. The combined navigation system includes an inertial navigation unit and other navigation units. The inertial navigation unit includes a gyroscope and a scale coefficient correction module. The scale coefficient correction module is configured to correct the scale coefficient of the gyroscope by the method of correcting the gyroscope scale coefficient in the above embodiment to determine the angular velocity of the carrier.

[0008] In a third aspect, an embodiment of the present application provides a non-transitory computer storage medium, which stores a computer program. When the computer program is executed by a processor, the method for correcting the gyroscope scale coefficient in the above embodiment is implemented.

[0009] The method for correcting the gyroscope scale coefficient in the embodiment of the present application determines the accumulated value of the projection component of the original measurement data on the celestial axis of the northeast celestial coordinate system according to the original measurement data of the gyroscope in each time period, separates the observable multiplicative error component of the gyroscope, and smoothes the influence of random noise. Combined with the heading angle change of the carrier and the number of sampling cycles, the scale coefficient correction value and zero bias of the gyroscope can be determined more accurately, and the original measurement data of the gyroscope can be corrected in this way, which can reduce the adverse effect of the scale coefficient error of the gyroscope on the inertial measurement accuracy and greatly improve the inertial navigation accuracy when the carrier makes continuous turns.

[0010] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0012] Figure 1 A schematic diagram of a flow chart of an embodiment of a method for correcting a gyroscope scale coefficient of the present application;

[0013] Figure 2 A schematic diagram of a flow chart of determining a scale coefficient correction value in one embodiment of a method for correcting a gyroscope scale coefficient of the present application;

[0014] Figure 3 A schematic diagram of a flow chart of using a recursive least square method to determine correction of a scale coefficient in an embodiment of a method for correcting a gyroscope scale coefficient of the present application;

[0015] Figure 4 A schematic diagram of a process for obtaining raw measurement data in one embodiment of a method for correcting a gyroscope scale coefficient of the present application;

[0016] Figure 5 It is a schematic diagram of the architecture of an embodiment of the combined navigation system of the present application. DETAILED DESCRIPTION

[0017] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0018] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0019] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0020] Figure 1 The flowchart of an embodiment of the method for correcting the gyroscope scale factor of the present application is shown, and the method is applicable to an inertial navigation unit arranged in a movable carrier, and the inertial navigation unit includes a gyroscope. Figure 1 As shown, the process may include the following steps.

[0021] Step 110: Acquire the original measurement data of the gyroscope in multiple time periods and the heading angle change of the carrier in each time period.

[0022] The original measurement data of each time period includes sampling data collected by the gyroscope in the time period, and the sampling data includes three-axis measurement values ​​collected by the gyroscope in the sampling period.

[0023] In this embodiment, the movable carrier can be a car, a wheeled robot or other movable ground carrier equipped with an inertial navigation unit. The measuring unit in the inertial navigation unit can generally include a gyroscope and an accelerometer, wherein the gyroscope is used to collect the angular velocity of the carrier, and the three-axis measurement value represents the components of the angular velocity in the three coordinate axes in the inertial coordinate system. The scale factor of the gyroscope represents the ratio of the output of the gyroscope to the input angular velocity, which is used to describe the sensitivity and response characteristics of the gyroscope, where the output can represent the angular velocity of the carrier, and the input angular velocity can represent the true angular velocity of the carrier.

[0024] The zero bias of a gyroscope refers to the non-zero angular velocity output by the gyroscope when there is no angular velocity input. It is the static error of the gyroscope and is usually affected by factors such as temperature and usage time. The gyroscope can collect data once in each sampling cycle within a time period, so that the original measurement data can include multiple sampling data.

[0025] The heading angle change of the carrier within the time period is used to represent the change in the heading of the carrier at the end of the time period relative to the heading at the beginning of the time period (or the angular change in the carrier's traveling direction).

[0026] In an optional example, the heading angle change can be calculated by an inertial navigation unit based on the sampled data of a gyroscope and an accelerometer. For example, the first speed of the carrier at the start time of the time period and the second speed at the end time can be obtained by solving the calculation respectively; then, based on the first speed and the second speed, the heading angle change can be determined. Here, the vector angle between the first speed and the second speed can be used as the heading angle change.

[0027] In another optional example, the heading angle change can also be determined by a device or navigation unit other than an inertial navigation unit, for example, the heading change of the carrier at the beginning and end of the time period can be determined by using a global satellite navigation positioning system (GNSS) using RTK (Real-Time Kinematic) or PPP-RTK (Precise Point Positioning) high-precision satellite positioning technology. In this way, the gyroscope measurement error can be shielded, which helps to improve the accuracy of the heading angle change.

[0028] In some optional implementations of this embodiment, a certain moment before the carrier turns can be determined as the starting moment of the time period, and a certain moment after the turn is completed can be determined as the ending moment of the time period. In this way, the original measurement data within the time period can represent the data collected by the gyroscope during the carrier's turning process, and the heading angle change is large, which helps to reduce the impact of random noise on accuracy.

[0029] Step 120: Determine the cumulative value of the projection component of the original measurement data of each time period on the celestial axis of the northeast celestial coordinate system.

[0030] Generally, the Northeastern Heaven coordinate system (also called the ENU coordinate system) is widely used in navigation, remote sensing, geographic information systems and other fields, which can accurately describe the target position and motion status, where E represents the east axis, N represents the north axis, and U represents the celestial axis.

[0031] In this embodiment, the cumulative value of the projection component is the projection component of each sampled data of the original measurement data on the celestial axis after being accumulated, which can represent the heading angle change estimated according to the original measurement data of the gyroscope. The value after the accumulation of each sampled data can be converted into the value of the northeast celestial coordinate system through the projection matrix of the carrier coordinate system relative to the northeast celestial coordinate system, and then the component of the value on the celestial axis can be determined to obtain the cumulative value of the projection component of the original measurement data.

[0032] In an optional example, when the carrier is a ground car, the pitch and roll attitudes of the carrier coordinate system can be ignored. At this time, the z-axis of the carrier coordinate system coincides with the celestial axis of the northeast celestial coordinate system. The various sampling data of the original measurement data can be directly accumulated and converted to the carrier coordinate system, and the projection of the converted data on the z-axis is used as the accumulated value of the projection component of the original measurement data on the celestial axis.

[0033] Step 130: Determine the scale coefficient correction value and zero bias of the gyroscope based on the heading angle change amount corresponding to each time period, the projection component accumulated value and the number of sampling cycles.

[0034] In this embodiment, the number of sampling cycles can represent the length of a time period. According to the heading angle change, the projection component accumulation value and the number of sampling cycles corresponding to the multiple time periods, the scale coefficient correction value and the zero bias of the gyroscope can be estimated.

[0035] As an example, the ratio of the heading angle change after removing random noise and zero bias error terms to the two types of projection values ​​can be used as the calibration coefficient correction value of the gyroscope.

[0036] Step 140: Based on the scale factor correction value and the zero bias, correct the original measurement data to obtain the angular velocity of the carrier.

[0037] In some optional implementations of this embodiment, the original measurement data may be corrected according to the following formula (1) to obtain the angular velocity of the carrier.

[0038]

[0039] Where:

[0040]

[0041] represents the angular velocity of the carrier, represents the gyroscope correction matrix in the IMU (Inertial Measurement Unit) coordinate system; k g represents the scale factor correction value; Represents the projection matrix from the inertial coordinate system to the carrier coordinate system; represents the three-axis measurement value collected by the gyroscope; b g represents the zero bias of the gyroscope.

[0042] The method for correcting the gyroscope scale coefficient in the present embodiment determines the accumulated value of the projection component of the original measurement data on the celestial axis of the northeast celestial coordinate system based on the original measurement data of the gyroscope in multiple time periods, separates the observable multiplicative error component of the gyroscope, and smoothes the influence of random noise. Combined with the heading angle change of the carrier and the number of sampling cycles, the scale coefficient correction value and zero bias of the gyroscope can be determined more accurately, and the original measurement data of the gyroscope can be corrected in this way, which can reduce the adverse effect of the gyroscope scale coefficient error on the inertial measurement accuracy and greatly improve the inertial navigation accuracy when the carrier makes continuous turns.

[0043] In some embodiments, the above step 130 can determine the scale factor correction value of the gyroscope by: taking the heading angle change as the observed value, taking the projection component accumulation value and the number of sampling cycles as the system state, constructing an observation equation; and determining the scale factor correction value based on the observation equation. The observation equation is shown in formula (2):

[0044] Δψ=θk g +Nb+v(2)

[0045] Where:

[0046]

[0047] Δψ represents the change in heading angle, θ represents the accumulated value of the projection component, b represents the zero bias of the gyroscope, v represents the noise term, and k g represents the scale factor correction value, Δt represents the sampling period of the gyroscope, N represents the number of sampling periods, Indicates the original measurement data at the tth n The projection component of the three-axis measurement values ​​collected in the sampling period on the celestial axis, Indicates that the gyroscope is n The projection component of the observation noise in the sampling period on the celestial axis is, Represents the projection of the gyroscope's zero bias on the celestial axis.

[0048] In this embodiment, an observation equation is constructed based on the heading angle change, the accumulated value of the projection component and the number of sampling cycles to characterize and determine the mathematical relationship between the three. The gyroscope's scale coefficient correction value can be estimated by solving the observation equation, so that the gyroscope's scale coefficient can be corrected more accurately and efficiently.

[0049] In some embodiments, Figure 2 The process shown in the figure determines the scale factor correction value and zero bias of the gyroscope, such as Figure 2 As shown, the process may include the following steps.

[0050] Step 210: Acquire the original measurement data and heading angle changes of multiple time periods, and determine the cumulative value of the projection component of the original measurement data of each time period on the celestial axis and the number of sampling periods.

[0051] Step 220: The heading angle change, the projection component accumulation value and the number of sampling cycles corresponding to each time period are taken as a node data, and the scale coefficient correction value and the zero bias are determined by recursive least square method.

[0052] Recursive least squares (RLS) is an adaptive filtering algorithm that updates the filter coefficients at each time step to improve the estimation of model parameters using newly observed node data so that the sum of squares of the prediction error is minimized.

[0053] As an example, two node data can be selected from multiple node data for initialization to obtain the initial scale coefficient correction value (i.e., the initial parameters of the filter), and then the prediction error is calculated recursively using other node data and the parameters of the current filter, and the scale coefficient correction value is updated based on the calculated error.

[0054] In this embodiment, the accumulated values ​​of the projection components of multiple time periods, the number of sampling cycles and the heading angle change are used as node data, and the scale coefficient correction value is used as the parameter of the filter. The recursive least squares method is used to gradually update the scale coefficient correction value and zero bias, which can improve the accuracy of the scale coefficient of the corrected gyroscope.

[0055] In some embodiments, the above step 220 may include Figure 3 The process shown is as follows Figure 3 As shown, the process includes the following steps.

[0056] Step 310: Estimate the initial value of the scale factor correction value and the initial value of the zero bias based on the first two node data obtained.

[0057] Step 320: When new node data is obtained, the scale factor correction value and the zero bias are updated based on the new node data, the initial value of the scale factor correction value and the initial value of the zero bias.

[0058] In this embodiment, after the gyroscope completes data collection for two time periods, the accumulated values ​​of the projection components, the number of sampling cycles, and the heading angle change corresponding to the two time periods can be used as initial node data, and the initial values ​​of the scale coefficient correction value and the zero bias can be estimated according to the observation equation to implement the model initialization of the recursive least squares method. Afterwards, the initial values ​​of the scale coefficient correction value can be used as parameters of the model. When the gyroscope collects new node data, the initial values ​​of the scale coefficient correction value and the zero bias can be updated using the new node data, and the scale coefficient of the gyroscope can be corrected online, which not only helps to improve the accuracy of the correction, but also does not need to save the calculated node data, and can reduce the usage of storage resources.

[0059] In some optional implementations of this embodiment, the above step 310 can estimate the initial value of the scale factor correction value according to the following formula (3).

[0060]

[0061] Where:

[0062]

[0063] k is the scale factor correction value g The initial value and zero bias b g The vector composed of the initial values ​​of represents the initial value of the system state; Δψ represents the change in heading angle; θ represents the accumulated value of the projection component; N represents the number of sampling cycles; A 0 With y 0 Indicates the first two node data sets obtained.

[0064] In this embodiment, the observation equation can be rewritten from formula (2) to formula (3). When the gyroscope collects two node data, the initial value of the scale coefficient correction value and the initial value of the zero bias can be estimated according to formula (3), thereby realizing the initialization of the recursive least squares method.

[0065] In some optional implementations of this embodiment, the above step 320 can update the scale factor correction value according to the following formula (4).

[0066]

[0067] In the formula,

[0068]

[0069] k is an integer not less than 1, indicating the number of updates; is a vector composed of the scale coefficient correction value and the zero bias, which represents the system state; y represents the change in heading angle; K represents the model gain matrix; P represents the covariance matrix, α represents the forgetting factor; I represents the two-dimensional unit matrix;.

[0070] In this embodiment, when new node data is collected, the gain matrix K and covariance matrix P of the recursive least squares model are updated according to the new node data, and then the scale coefficient correction value and zero bias calculated by the previous node data are updated according to formula (4) to obtain the updated scale coefficient correction value. When new node data is collected again in the future, the above process is repeated to achieve the re-update of the scale coefficient correction value and zero bias, thereby achieving the online correction of the scale coefficient and zero bias of the gyroscope, which helps to improve the real-time performance of the scale coefficient correction of the gyroscope, thereby improving the navigation accuracy.

[0071] In some embodiments, the carrier is provided with an integrated navigation system, the integrated navigation system includes an inertial navigation unit and other navigation units; and the heading angle change amount is determined by the other navigation units.

[0072] As an example, the other navigation unit may be a global satellite navigation positioning system. By determining the heading angle change of the carrier within a time period by other navigation units independent of the inertial navigation unit, the introduction of measurement errors of the inertial navigation unit can be avoided, thereby improving the accuracy of the heading angle change.

[0073] In some optional implementations of this embodiment, other navigation systems can determine the heading angle change in the following manner: obtain the first horizontal speed v of the carrier at the start time of the time period 1 The second horizontal velocity v at the end time 2 ; The heading angle change corresponding to this time period is determined by the following formula (5).

[0074] Δψ=actan2(‖v 1 ×v 2 ‖ 2 ,v 1 ·v 2 ) (5)

[0075] Where actan2(·) is the four-quadrant inverse tangent function, ‖v 1 ×v 2 ‖ 2 is the modulus of the cross product vector of the first horizontal velocity and the second horizontal velocity, v 1 ·v 2 is the dot product of the first horizontal velocity and the second horizontal velocity.

[0076] In this embodiment, the heading angle change is determined by the speed at the start time and the end time, which can reduce the adverse effects of random errors on the accuracy of the heading angle change. This is particularly suitable for scenarios where the carrier heading changes greatly (such as turning), and can significantly improve the calculation accuracy of the heading angle change.

[0077] In practice, the error in the gyroscope's scale factor is small, on the order of about 10 -3 , and the original measurement data is directly related to the correction accuracy of the gyroscope's scale coefficient. In order to more accurately correct the gyroscope's scale coefficient, Figure 4 The process shown in the figure obtains the original measurement data to improve the quality of the original measurement data. Figure 4 As shown, the process may include the following steps.

[0078] Step 410: After the inertial navigation unit is aligned, the gyroscope is turned on to collect data.

[0079] In this embodiment, after the inertial navigation unit completes the alignment, the attitude of the carrier can be estimated more accurately, thereby ensuring the accuracy of the projection of the original observation quantity on the celestial axis, thereby improving the correction accuracy of the gyroscope's scale coefficient.

[0080] Step 420: After the other navigation units generate observation values, use the other navigation units to determine the speed of the carrier.

[0081] The integrated navigation system usually settles at a fixed frequency, and the inertial navigation unit usually settles at a higher frequency than other navigation units (such as the global satellite navigation positioning system). When other navigation units generate observations, the other navigation units can be used to accurately calculate the speed of the vehicle.

[0082] Step 430: For any moment, if the speed of the carrier is not less than the preset speed threshold, the moment is determined as the starting moment of the time period, the first horizontal speed of the carrier at the starting moment is determined, and the data collected by the gyroscope is accumulated from the starting moment.

[0083] Taking the global satellite navigation positioning system as an example, the greater the speed of the carrier, the higher the accuracy of the positioning solution.

[0084] In this embodiment, the speed of the carrier can be used as a start condition for collecting raw measurement data. Other navigation units can calculate the speed of the carrier at a fixed frequency, and compare the calculated speed with a preset speed threshold to determine whether the start condition for collecting raw measurement data is met, and determine whether other navigation systems can more accurately calculate the change in the heading angle of the carrier within the time period. When it is determined that the instantaneous speed at a certain moment is greater than the speed threshold, the component of the instantaneous speed in the horizontal plane can be used as the first horizontal speed.

[0085] In some optional implementations of this embodiment, the conditions for starting to collect raw measurement data may also include the signal quality of other navigation systems. Taking the global satellite navigation and positioning system as an example, its solution accuracy is affected by the satellite visibility conditions. Here, the signal quality can be characterized by the number of visible satellites, and then the number threshold is pre-set according to the performance of the receiver and the positioning algorithm. When the number of visible satellites of the global navigation system reaches the number threshold and the speed of the carrier is not less than the speed threshold, this moment can be determined as the starting moment of the time period, that is, the collection of raw measurement data is started.

[0086] Step 430: For any moment after the start moment of the time period, if the heading angle change determined by other navigation units based on the second horizontal velocity and the first horizontal velocity of the carrier at that moment is not less than a preset change threshold, this moment is determined as the end moment of the time period, and the accumulation of data collected by the gyroscope is stopped to obtain the original measurement data within the time period.

[0087] Generally, the larger the heading change, the better the shielding effect of random errors, and accordingly, the higher the observability of the scale coefficient error.

[0088] In this embodiment, the heading angle change determined by other navigation units can be used as a judgment condition for terminating data collection. Other navigation units can determine the heading angle change of the carrier at any time relative to the starting time based on the second horizontal speed and the first horizontal speed calculated in real time, and compare the heading angle change with the change threshold to determine whether the condition for terminating data collection is met.

[0089] As an example, the change threshold can be 60 degrees. When the heading angle change calculated by other navigation units at a certain moment is greater than or equal to 60 degrees, this moment can be determined as the end moment of the time period, and the accumulation of data collected by the gyroscope can be stopped. Then the data accumulated by the gyroscope from the starting moment to the end moment is the original measurement data of the time period.

[0090] In this embodiment, by limiting the judgment conditions of the start and end times of the time period, it helps to improve the quality of the original measurement data and the accuracy of the heading angle change, thereby improving the observability of the gyroscope's scale coefficient error, thereby improving the correction accuracy of the gyroscope's scale coefficient.

[0091] In some optional implementations of the present embodiment, the cumulative value of the projection component of the original measurement data on the celestial axis can be determined in the following manner: starting from the start time of the time period, the data collected by the gyroscope is converted to the carrier coordinate system to obtain the converted data; the value of the converted data on the z-axis of the carrier coordinate system is determined and accumulated until the end time of the time period to obtain the accumulated data as the cumulative value of the projection component.

[0092] In this embodiment, when the carrier moves on the ground, it can have a pitch and roll attitude in the carrier coordinate system. At this time, the z-axis of the carrier coordinate system coincides with the celestial axis of the northeast celestial coordinate system. After the data collected by the gyroscope (i.e., the three-axis measurement value) is converted to the carrier coordinate system, the value of the z-axis is taken, which is the projection of the original measurement data on the celestial axis. The value is accumulated point by point until the end of the time period, and the accumulated value of the projection component of the original measurement data of the time period on the celestial axis can be obtained.

[0093] As an example, the data collected by the gyroscope can be converted to the carrier coordinate system by the following formula (6):

[0094]

[0095] In the formula, The data collected by the gyroscope is It is the transformation matrix from the IMU coordinate system to the carrier coordinate system.

[0096] After that, the converted data is plotted on the z-axis. By accumulating point by point, the accumulated value θ of the projection component of the original measurement data on the celestial axis can be obtained, as shown in formula (7):

[0097]

[0098] In this embodiment, by utilizing the principle that the z-axis of the carrier coordinate system of the ground carrier coincides with the celestial axis of the northeast celestial coordinate system, the data collected by the gyroscope can be processed in real time to obtain the projection component of the collected data on the celestial axis, and then the accumulated value of the projection component of the original measurement data of the time period on the celestial axis is obtained by adding them up point by point, which can simplify the calculation process and improve efficiency.

[0099] Figure 5 A schematic diagram of the architecture of an embodiment of a combined navigation system of the present application is shown, wherein the combined navigation system is applied to a movable carrier, and the combined navigation system includes an inertial navigation unit 510 and other navigation units 520, wherein the inertial navigation unit 510 includes a gyroscope 511 and a scale coefficient correction module 512; the scale coefficient correction module 512 is configured to correct the scale coefficient of the gyroscope 511 by the method for correcting the gyroscope scale coefficient in the above-mentioned embodiment, so as to determine the angular velocity of the carrier.

[0100] In this embodiment, the inertial navigation unit 510 may also include an accelerometer, and the other navigation unit may be a global satellite navigation positioning system.

[0101] The scale coefficient correction module 512 can obtain the original measurement data within a certain time period from the gyroscope 510, and obtain the heading angle change of the carrier within the time period from other navigation units 520, and then determine the accumulated value of the projection component of the original measurement data on the celestial axis, and then determine the scale coefficient correction value of the gyroscope, and after correcting the original measurement data, output the angular velocity of the carrier.

[0102] In some optional implementations of this embodiment, the scale coefficient correction module 512 may further include a recursive submodule configured to perform online correction on the scale coefficient of the gyroscope by using a recursive least squares method.

[0103] An embodiment of the present application further provides a non-transitory computer storage medium storing a computer program. In some embodiments, when the computer program is executed by a processor, the method for correcting the gyroscope scale coefficient in any of the above embodiments is implemented.

[0104] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term "computer storage medium" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for correcting a gyroscope scale factor, applied to an inertial navigation unit provided in a movable carrier, the inertial navigation unit comprising a gyroscope, characterized in that: The method comprises: Acquire raw measurement data of the gyroscope in multiple time periods and a change in the heading angle of the carrier in each time period, wherein the raw measurement data of each time period includes sampled data collected by the gyroscope in the time period, and the sampled data includes three-axis measurement values ​​collected by the gyroscope in a sampling period; Determine the cumulative value of the projection component of the original measurement data of each time period on the celestial axis of the northeast celestial coordinate system; Determine a scale coefficient correction value and a zero bias of the gyroscope based on the heading angle change amount corresponding to each of the time periods, the projection component accumulated value and the number of sampling cycles; Based on the scale factor correction value and the zero bias, the original measurement data is corrected to obtain the angular velocity of the carrier.

2. The method according to claim 1, characterized in that Determining the scale coefficient correction value of the gyroscope based on the heading angle change amount corresponding to each time period, the projection component accumulated value and the number of sampling cycles includes: The heading angle change amount, the projection component accumulated value and the number of sampling cycles corresponding to each time period are taken as a node data, and the scale coefficient correction value and the zero bias are determined by recursive least square method.

3. The method according to claim 2, characterized in that The heading angle change amount, the projection component accumulated value and the number of sampling cycles corresponding to each time period are taken as a node data, and the scale coefficient correction value and the zero bias are determined by recursive least square method, including: Based on the first two node data obtained, an initial value of the scale factor correction value and an initial value of the zero bias are estimated; When new node data is acquired, the scale factor correction value and the zero bias are updated based on the new node data, the initial value of the scale factor correction value and the initial value of the zero bias.

4. The method according to claim 3, characterized in that Based on the first two node data obtained, estimating the initial value of the scale factor correction value and the initial value of the zero bias includes: Estimate the initial value of the scale factor correction value according to the following formula: In the formula, is the scale factor correction value k g The initial value and the zero bias b g A vector composed of the initial values ​​of represents the initial value of the system state; Δψ represents the change in the heading angle; θ represents the accumulated value of the projection component; N represents the number of sampling cycles in the time period; A0 and y0 represent the two node data sets obtained first.

5. The method according to claim 4, characterized in that Based on the new node data, the initial value of the scale factor correction value and the initial value of the zero bias, updating the scale factor correction value and the zero bias comprises: Update the scale factor correction value according to the following formula: In the formula, is a vector composed of the scale coefficient correction value and the zero bias, indicating the system state; k is an integer not less than 1, indicating the number of updates; I represents a two-dimensional unit matrix; y represents the heading angle change; K represents a gain matrix; P represents a covariance matrix, and α represents a forgetting factor.

6. The method according to claim 1, characterized in that Based on the scale factor correction value and the zero bias, the original measurement data is corrected to obtain the angular velocity of the carrier, including: The original measurement data is corrected according to the following formula: In the formula, represents the angular velocity of the carrier, represents the gyroscope correction matrix in the IMU coordinate system; k g represents the scale factor correction value; Represents the projection matrix from the inertial coordinate system to the carrier coordinate system; represents the three-axis measurement value collected by the gyroscope; b g represents the zero bias.

7. The method according to any one of claims 1 to 6, characterized in that: The carrier is provided with an integrated navigation system, which includes the inertial navigation unit and other navigation units; and the heading angle change amount is determined by the other navigation units.

8. The method according to claim 7, characterized in that The original measurement data in each time period is obtained in the following way: After the inertial navigation unit is aligned, turning on the gyroscope to collect data; After the other navigation unit generates the observation value, using the other navigation unit to determine the speed of the carrier; At any time, if the speed of the carrier is not less than a preset speed threshold, determine the time as the starting time of the time period, determine the first horizontal speed of the carrier at the starting time, and accumulate the data collected by the gyroscope from the starting time; For any moment after the starting moment of the time period, if the heading angle change determined by the other navigation units based on the second horizontal velocity of the carrier at that moment and the first velocity is not less than a preset change threshold, the moment is determined as the end moment of the time period, and the accumulation of data collected by the gyroscope is stopped to obtain the original measurement data within the time period.

9. The method according to claim 8, characterized in that Determining the cumulative value of the projection component of the original measurement data on the celestial axis of the northeast celestial coordinate system includes: Starting from the start time of the time period, the data collected by the gyroscope is converted into a carrier coordinate system to obtain converted data; The values ​​of the converted data on the z-axis of the carrier coordinate system are determined and accumulated until the accumulated data are obtained at the end of the time period as the projection component accumulated value.

10. The method according to claim 8, characterized in that The heading angle change is determined by: Obtaining a first horizontal speed v1 of the carrier at the start time and a second horizontal speed v2 at the end time of the time period; Determine the heading angle change based on the following formula; Δψ=actan2(‖v1×v2‖2,v1·v2) In the formula, actan2(·) is the four-quadrant inverse tangent function, ‖v1×v2‖2 is the modulus of the cross product vector of the first horizontal velocity and the second horizontal velocity, and v1·v2 is the dot product of the first horizontal velocity and the second horizontal velocity.

11. A combined navigation system, applied to a movable carrier, characterized in that: The integrated navigation system comprises an inertial navigation unit and other navigation units, wherein the inertial navigation unit comprises a gyroscope and a scale factor correction module; The scale factor correction module is configured to correct the scale factor of the gyroscope by the method for correcting the scale factor of a gyroscope according to any one of claims 1 to 10, so as to determine the angular velocity of the carrier.

12. A non-transitory computer storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for correcting the gyroscope scale coefficient according to any one of claims 1 to 10 is implemented.

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