A simple online calibration method for heading error of strapdown inertial navigation based on one-time forward-backward rotation sequence

Abstract

The application is a simple online calibration method for heading error of strapdown inertial navigation based on one-time forward and reverse sequence. The application relates to the technical field of error calibration and compensation of inertial navigation system. After initial alignment of the strapdown inertial navigation system is completed, new heading angle information is obtained by designing two 360-degree rotations in clockwise and counterclockwise directions, the new heading angle information is compared with the initial alignment heading angle information to construct a scale factor error compensation quantity online, then the scale factor error compensation quantity is stored and real-time compensation is performed on the output of the gyroscope sky direction axis, the required calibration time is short, only one flat surface is needed without auxiliary equipment such as a double-axis turntable, online calibration of the heading error of the strapdown inertial navigation system is realized, and high-precision measurement and output of the heading angle information are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of error calibration and compensation of inertial navigation system, and is a simple online calibration method for heading error of strapdown inertial navigation based on one-time forward and reverse sequence. BACKGROUND

[0002] Inertial navigation is a completely autonomous navigation technology that is not affected by external environment. It uses inertial sensors such as gyroscopes and accelerometers to measure the angular velocity and acceleration of the carrier in the inertial space, and thus calculates the attitude, velocity and position information of the carrier. Inertial navigation technology can continuously provide the carrier with navigation information such as position, velocity, attitude, angular velocity and acceleration. Inertial navigation systems are widely used in military and civilian fields such as aviation, aerospace and navigation.

[0003] Inertial navigation systems are generally divided into platform-type inertial navigation systems and strapdown-type inertial navigation systems. In the platform-type inertial navigation system, the accelerometer is placed on the inertial stabilization platform, and the gyro stabilization platform is used to accurately maintain the angular position of the accelerometer in space, providing a reference for velocity and position calculation. In the strapdown-type inertial navigation system, the inertial measurement device is directly "bound" to the carrier, and the "mathematical platform" is used to replace the "physical platform" by solving the strapdown matrix in real time. The accelerometer measurement data is converted into acceleration in the navigation coordinate system through the "mathematical platform", and then the velocity and position of the carrier are obtained through integral operation. The strapdown inertial navigation system has a simpler structure than the platform inertial navigation system, and thus has been more widely used.

[0004] In high-precision navigation and positioning measurement, in order to obtain high-precision measurement output data, the strapdown inertial navigation system is usually calibrated and compensated accurately before leaving the factory. However, there are still some residual errors, such as residual bias and residual scale factor errors of the gyroscope, especially the residual scale factor errors which are more affected by environmental temperature changes. If not compensated in time, it will have a great impact on the heading measurement output of the strapdown inertial navigation system, making the heading angle measurement output unstable and reducing the precision.

[0005] Previous literature has addressed methods for calibrating and compensating residual scaling factor errors in strapdown inertial navigation systems. For example, patent application number 202010690327.1, entitled "A Self-calibration Method for a Fiber Optic Strapdown Inertial Navigation System," discloses a self-calibration method for errors in a fiber optic strapdown inertial navigation system. By pre-constructing a Kalman filter model and combining it with the system's 180-degree heading angle rotation information, this method achieves self-calibration of gyroscope constant drift and accelerometer constant zero bias, as well as high-precision attitude maintenance. Patent application number 201711143868.7, entitled "A Referenceless System-Level Calibration Method for a Strapdown Inertial Navigation System," discloses a referenceless system-level calibration method for a strapdown inertial navigation system. This method can achieve high-precision calibration of the inertial navigation system under different initial attitudes and rotation sequences without a reference. In published articles, such as the paper "Rapid Online Calibration of Shipborne Strapdown Inertial Navigation Systems During Navigation" by Yuan Peng, Yang Yu, Chen Guang, et al., in Volume 18, Issue 4 of *Navigation and Control*, a method for rapid online calibration of strapdown inertial navigation systems during navigation was proposed. This method establishes a simplified Kalman filter model with 15 error quantities, including gyroscope and accelerometer bias and scale factor error, as state quantities, and velocity and position errors as measurements. Simultaneously, a calibration path that can be implemented by a dual-axis rotation mechanism within the inertial navigation system was designed, achieving rapid self-calibration of the error quantities within 1800 seconds. While the above-mentioned strapdown inertial navigation system calibration methods have achieved beneficial calibration results, they all require the prior construction of an error calibration state model and measurement model based on Kalman filtering. Furthermore, although they do not require reference information, they all require a two-axis rotation mechanism to achieve the different rotation sequences required for online calibration.

[0006] To address the issues of unstable heading scale factor error and large heading measurement output error in high-precision strapdown inertial navigation systems (SINS), this invention proposes a simplified online calibration method for heading error based on a single forward and reverse rotation sequence. After initial alignment of the SINS, this invention acquires new heading angle information through two clockwise and counterclockwise 360-degree rotations. The new heading angle information is compared with the initial alignment heading angle information to construct an online scaling factor error compensation value. This compensation value is then stored and used to compensate the gyroscope's azimuth axis output in real time, achieving online calibration of heading error and high-precision measurement and output of heading angle information for the SINS. Summary of the Invention

[0007] This invention, after the initial alignment of the strapdown inertial navigation system (SINS), acquires new heading angle information through two clockwise and counterclockwise 360-degree rotations. The new heading angle information is compared with the initial alignment heading angle information to construct a scaling factor error compensation online. This compensation is then stored and used to compensate the gyroscope's azimuth axis output in real time, achieving online calibration of the SINS heading error and high-precision measurement and output of heading angle information. Based on this, this invention provides a simplified online calibration method for SINS heading error based on a single forward and reverse rotation sequence.

[0008] This invention provides a simplified online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. The invention provides the following technical solution:

[0009] A simplified online calibration method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence, the method comprising the following steps:

[0010] The method includes the following steps:

[0011] Step 1: Bind the initial position information of the strapdown inertial navigation system to complete the system startup and initialization;

[0012] Step 2: Set the strapdown inertial navigation system to stand still for 60 seconds, collect static data from the inertial measurement unit over a period of time to complete the initial alignment, construct the initial attitude matrix, and obtain the initial heading angle ψ. ori ;

[0013] Step 3: Convert the initial attitude matrix into an initial quaternion and normalize the initial quaternion;

[0014] Step 4: Rotate the strapdown inertial navigation system 360 degrees counterclockwise and update the attitude quaternion in real time;

[0015] Step 5: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after counterclockwise rotation. + :

[0016]

[0017] Step 6: Use the new heading angle ψ obtained after counterclockwise rotation. + The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk + :

[0018]

[0019] Step 7: Rotate the strapdown inertial navigation system 360 degrees clockwise and update the attitude quaternion in real time;

[0020] Step 8: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after clockwise rotation. - :

[0021]

[0022] Step 9: Use the new heading angle ψ obtained after clockwise rotation. - The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk - ;

[0023] Step 10: Compensate the obtained forward and reverse scaling factor error amounts δk + and δk - The sampled gyroscope output data is stored and compensated in real time using the scaling factor error compensation.

[0024] Preferably, step 2 specifically comprises:

[0025] The method for obtaining the initial attitude matrix is ​​as follows:

[0026]

[0027] in, This indicates the output value measured by the triaxial accelerometer of the inertial measurement unit. This represents the output value measured by the three-axis gyroscope of the inertial measurement unit, where L is the local latitude and g is the local gravitational acceleration.

[0028] The method for obtaining the initial heading angle is as follows:

[0029]

[0030] Preferably, step 3 specifically comprises:

[0031] The initial attitude matrix is ​​transformed into the initial quaternion:

[0032]

[0033] Initial quaternion normalization:

[0034]

[0035] Among them, C ij (i = 1, 2, 3; j = 1, 2, 3) represents the attitude matrix. The element in the expression, q0, represents the initial attitude quaternion.

[0036] Preferably, step 4 specifically comprises:

[0037] The quaternion real-time update equation is:

[0038]

[0039] Among them, Ω i (i = 1, 2, 3) represents the antisymmetric matrix formed by the three sampled outputs of the gyroscope, T is the sampling time interval, and Ω i (i = 1, 2, 3) yields the following:

[0040]

[0041]

[0042]

[0043]

[0044] in, This represents the angular rate of rotation of the carrier system relative to the navigation system, obtained from the output of the third-order gyroscope sampling; v E v N These represent the eastward and northward velocities of the strapdown inertial navigation system, respectively. Since only rotational wireless motion occurs during calibration, both eastward and northward velocities are typically set to 0 during normal operation. M R is the radius of curvature of the Earth's meridian. N Let be the radius of curvature of the Earth's east-west surface;

[0045] Updated quaternion normalization:

[0046]

[0047] Preferably, step 7 specifically comprises:

[0048] The strapdown inertial navigation system is rotated 360 degrees clockwise, and its attitude quaternions are updated in real time. The specific method is as follows:

[0049]

[0050] Normalized quaternions after each update:

[0051]

[0052] Preferably, step 9 specifically comprises:

[0053] The new heading angle ψ obtained by clockwise rotation - The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk - for:

[0054]

[0055] Preferably, step 10 specifically includes:

[0056] Determine if the output of the astronomical gyroscope is greater than zero. If it is, then the astronomical gyroscope output compensation is:

[0057]

[0058] If the output of the upward-axis gyroscope is less than zero, then the output compensation of the upward-axis gyroscope is:

[0059]

[0060] in, This is the original measurement output value of the gyroscope's azimuth axis. The gyroscope's azimuth axis measurement output value is used to compensate for scaling factor errors.

[0061] A simplified online calibration system for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence is characterized in that: the system executes a simplified online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence.

[0062] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a simple online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence.

[0063] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement a simple online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence.

[0064] The present invention has the following beneficial effects:

[0065] Compared with the prior art, the present invention:

[0066] After the initial alignment of the strapdown inertial navigation system is completed, this invention acquires new heading angle information by designing two 360-degree clockwise and counterclockwise rotations. The new heading angle information is compared with the initial alignment heading angle information to construct a scaling factor error compensation online. Then, the scaling factor error compensation is stored and output to the gyroscope's azimuth axis in real time for compensation. The required calibration time is short, and only a flat surface is needed without auxiliary equipment such as a dual-axis turntable. This invention realizes online calibration of heading error and high-precision measurement and output of heading angle information for the strapdown inertial navigation system. Attached Figure Description

[0067] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0068] Figure 1 The flowchart shows the online calibration and compensation method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence.

[0069] Figure 2 This is a photo of the test site for the temperature chamber turntable.

[0070] Figure 3 A comparison chart of the online heading calibration measurement output results and the uncalibrated measurement output results at -10℃;

[0071] Figure 4 A comparison chart of the online heading calibration measurement output results and the uncalibrated measurement output results at -20℃;

[0072] Figure 5 This is a comparison chart of the online heading calibration measurement output results at room temperature (20℃) and the uncalibrated measurement output results.

[0073] Figure 6 This is a comparison chart of the online heading calibration measurement output results at a high temperature of 30℃ and the uncalibrated measurement output results. Detailed Implementation

[0074] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0076] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0077] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0078] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1:

[0080] according to Figures 1 to 6 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to a simple online calibration method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence.

[0081] A simplified online calibration method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence, the method comprising the following steps:

[0082] Step 1: Bind the initial position information of the strapdown inertial navigation system to complete the system startup and initialization;

[0083] Step 2: Set the strapdown inertial navigation system to stand still for 60 seconds, collect static data from the inertial measurement unit over a period of time to complete the initial alignment, construct the initial attitude matrix, and obtain the initial heading angle ψ. ori ;

[0084] Step 3: Convert the initial attitude matrix into an initial quaternion and normalize the initial quaternion;

[0085] Step 4: Rotate the strapdown inertial navigation system 360 degrees counterclockwise and update the attitude quaternion in real time;

[0086] Step 5: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after counterclockwise rotation. + :

[0087]

[0088] Step 6: Use the new heading angle ψ obtained after counterclockwise rotation. + The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk + :

[0089]

[0090] Step 7: Rotate the strapdown inertial navigation system 360 degrees clockwise and update the attitude quaternion in real time;

[0091] Step 8: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after clockwise rotation. - :

[0092]

[0093] Step 9: Use the new heading angle ψ obtained after clockwise rotation. - The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk - ;

[0094] Step 10: Compensate the obtained forward and reverse scaling factor error amounts δk + and δk - The sampled gyroscope output data is stored and compensated in real time using the scaling factor error compensation. Specific Implementation Example 2:

[0096] The only difference between Embodiment 2 and Embodiment 1 of this application is that:

[0097] Step 2 specifically involves:

[0098] The method for obtaining the initial attitude matrix is ​​as follows:

[0099]

[0100] in, This indicates the output value measured by the triaxial accelerometer of the inertial measurement unit. This represents the output value measured by the three-axis gyroscope of the inertial measurement unit, where L is the local latitude and g is the local gravitational acceleration.

[0101] The method for obtaining the initial heading angle is as follows:

[0102] Specific Implementation Example 3:

[0104] The only difference between Embodiment 3 and Embodiment 2 of this application is that:

[0105] Step 3 specifically involves:

[0106] The initial attitude matrix is ​​transformed into the initial quaternion:

[0107]

[0108] Initial quaternion normalization:

[0109]

[0110] Among them, C ij (i = 1, 2, 3; j = 1, 2, 3) represents the attitude matrix. The element in the expression, q0, represents the initial attitude quaternion. Specific Implementation Example 4:

[0112] The only difference between Embodiment 4 and Embodiment 3 of this application is that:

[0113] Step 4 specifically involves:

[0114] The quaternion real-time update equation is:

[0115]

[0116] Among them, Ω i (i = 1, 2, 3) represents the antisymmetric matrix formed by the three sampled outputs of the gyroscope, T is the sampling time interval, and Ω i (i = 1, 2, 3) yields the following:

[0117]

[0118]

[0119]

[0120]

[0121] in, This represents the angular rate of rotation of the carrier system relative to the navigation system, obtained from the output of the third-order gyroscope sampling; v E v N These represent the eastward and northward velocities of the strapdown inertial navigation system, respectively. Since only rotational wireless motion occurs during calibration, both eastward and northward velocities are typically set to 0 during normal operation. M R is the radius of curvature of the Earth's meridian. N Let be the radius of curvature of the Earth's east-west surface;

[0122] Updated quaternion normalization:

[0123] Specific Implementation Example 5:

[0125] The only difference between Embodiment 5 and Embodiment 4 of this application is that:

[0126] Step 7 specifically involves:

[0127] The strapdown inertial navigation system is rotated 360 degrees clockwise, and its attitude quaternions are updated in real time. The specific method is as follows:

[0128]

[0129] Normalized quaternions after each update:

[0130] Specific Implementation Example Six:

[0132] The only difference between Embodiment Six and Embodiment Five of this application is that:

[0133] Step 9 specifically involves:

[0134] The new heading angle ψ obtained by clockwise rotation - The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk - for:

[0135] Specific Implementation Example 7:

[0137] The only difference between Embodiment 7 and Embodiment 6 of this application is that:

[0138] Step 10 specifically involves:

[0139] Determine if the output of the astronomical gyroscope is greater than zero. If it is, then the astronomical gyroscope output compensation is:

[0140]

[0141] If the output of the upward-axis gyroscope is less than zero, then the output compensation of the upward-axis gyroscope is:

[0142]

[0143] in, This is the original measurement output value of the gyroscope's azimuth axis. The gyroscope's azimuth axis measurement output value is used to compensate for scaling factor errors. Specific Implementation Example 8:

[0145] The difference between Embodiment 8 and Embodiment 7 of this application lies only in:

[0146] This invention provides a simplified online calibration system for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. The system is characterized by executing a simplified online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. Specific Implementation Example Nine:

[0148] The difference between Embodiment Nine and Embodiment Eight in this application lies only in:

[0149] The present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a simple online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. Specific Implementation Example 10:

[0151] The only difference between Embodiment 10 and Embodiment 9 of this application is that:

[0152] The present invention provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement a simple online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. Specific Implementation Example Eleven:

[0154] To verify the effectiveness of the present invention, the method of the present invention was tested and verified using a fiber optic gyroscope inertial navigation system independently developed in the laboratory.

[0155] First, the local latitude and longitude (L=45.7265, λ=126.6258) are loaded into the program to complete parameter initialization. The inertial navigation system is then kept stationary for 60 seconds to complete initial alignment and obtain the initial attitude matrix. The formula for obtaining the initial matrix is:

[0156]

[0157] in, This indicates the output value measured by the triaxial accelerometer of the inertial measurement unit. This represents the output value measured by the three-axis gyroscope of the inertial measurement unit, where L is the local latitude and g represents the local gravitational acceleration.

[0158] Simultaneously obtain the initial heading angle:

[0159]

[0160] Next, the obtained initial attitude matrix is ​​transformed into a normalized initial attitude quaternion q0, that is:

[0161] The initial attitude matrix is ​​transformed into the initial quaternion:

[0162]

[0163] Initial quaternion normalization:

[0164]

[0165] Among them, C ij(i = 1, 2, 3; j = 1, 2, 3) represents the attitude matrix. The element in the expression, q0, represents the initial attitude quaternion.

[0166] Next, the strapdown inertial navigation system is rotated 360 degrees counterclockwise, and the attitude quaternions are updated in real time:

[0167] The quaternion real-time update equation is:

[0168]

[0169] Among them, Ω i (i = 1, 2, 3) represents the antisymmetric matrix formed by the three sampled outputs of the gyroscope, T is the sampling time interval, and Ω i (i = 1, 2, 3) yields the following:

[0170]

[0171]

[0172]

[0173]

[0174] in, This represents the angular rate of rotation of the carrier system relative to the navigation system, obtained from the output of the third-order gyroscope sampling; v E v N These represent the eastward and northward velocities of the strapdown inertial navigation system, respectively. Since only rotational wireless motion occurs during calibration, both eastward and northward velocities are typically set to 0 during normal operation. M R is the radius of curvature of the Earth's meridian. N Let be the radius of curvature of the Earth's east-west plane.

[0175] Updated quaternion normalization:

[0176]

[0177] Then, keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after counterclockwise rotation. + :

[0178]

[0179] Next, the new heading angle ψ obtained after counterclockwise rotation is used. + The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk + :

[0180]

[0181] Next, the strapdown inertial navigation system is rotated 360 degrees clockwise again, and the attitude quaternion is updated in real time. The specific operation is as follows:

[0182]

[0183] Normalized quaternions after each update:

[0184]

[0185] Next, keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle ψ after clockwise rotation. - The specific method is as follows:

[0186]

[0187] Then, the new heading angle ψ obtained after clockwise rotation is used. - The original heading angle ψ obtained after initial alignment ori Construct the heading scale factor error compensation amount δk - ,Right now:

[0188]

[0189] Finally, the obtained positive and negative scaling factor error compensation amounts δk are... + and δk - The data is stored and the scaling factor error compensation is used to compensate the sampled gyroscope output data in real time, that is:

[0190] First, determine if the output of the top axis gyroscope is greater than zero. If it is, then compensate the output of the top axis gyroscope.

[0191]

[0192] If the output of the astronomical gyroscope is less than zero, then the astronomical gyroscope output compensation is applied.

[0193]

[0194] Then, the updated program is generated by using the compensated astronomical gyroscope output to achieve high-precision heading angle measurement and output.

[0195] To verify the effectiveness of the simplified online calibration method for heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence proposed in this invention, relevant turntable tests were conducted, and the output results after heading scale factor error compensation and the uncompensated output results were compared and analyzed respectively.

[0196] The parameters of the inertial measurement unit (IMU) components in the strapdown inertial navigation system are as follows:

[0197]

[0198] Figure 1 A flowchart of a simplified online calibration method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence is presented. Figure 2 This is a field photo of the test and verification of the strapdown inertial navigation system in a temperature chamber turntable. Figure 3 A comparison chart of the online heading calibration measurement output results and the uncalibrated measurement output results at -10℃; Figure 4 A comparison chart of the online heading calibration measurement output results and the uncalibrated measurement output results at -20℃; Figure 5 This is a comparison chart of the online heading calibration measurement output results at room temperature (20℃) and the uncalibrated measurement output results. Figure 6 This is a comparison chart of the online heading calibration measurement output results at a high temperature of 30℃ and the uncalibrated measurement output results.

[0199] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or N embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified. Any process or method described in the flowcharts or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logical functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain. The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection having one or N wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic device, and portable optical disc read-only memory (CDROM).Furthermore, the computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory. It should be understood that various parts of the invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0200] The above description is merely a preferred embodiment of a simplified online calibration method for strapdown inertial navigation heading error based on a single forward and reverse rotation sequence. The scope of protection for this simplified online calibration method for strapdown inertial navigation heading error is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the scope of protection of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A simplified online calibration method for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence, characterized by: The method includes the following steps: Step 1: Bind the initial position information of the strapdown inertial navigation system to complete the system startup and initialization; Step 2: Set the strapdown inertial navigation system to stand still for 60 seconds, collect static data from the inertial measurement unit over a period of time to complete the initial alignment, construct the initial attitude matrix, and obtain the initial heading angle. ; Step 3: Convert the initial attitude matrix into an initial quaternion and normalize the initial quaternion; Step 4: Rotate the strapdown inertial navigation system 360 degrees counterclockwise and update the attitude quaternion in real time; Step 5: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle after counterclockwise rotation. : ； Step 6: Use the new heading angle obtained after counterclockwise rotation The original heading angle obtained after initial alignment Constructing the heading scale factor error compensation amount : ； Step 7: Rotate the strapdown inertial navigation system 360 degrees clockwise and update the attitude quaternion in real time; Step 8: Keep the strapdown inertial navigation system stationary for 5 seconds and obtain the heading angle after clockwise rotation. : ； Step 9: Use the new heading angle obtained after clockwise rotation. The original heading angle obtained after initial alignment Constructing the heading scale factor error compensation amount ; Step 10: Compensate for the obtained positive and negative scaling factor errors. and The sampled astronomical gyroscope output data is stored and compensated in real time using the scaling factor error compensation amount; Step 10 specifically involves: Determine if the output of the astronomical gyroscope is greater than zero. If it is, then the astronomical gyroscope output compensation is: If the output of the upward-axis gyroscope is less than zero, then the output compensation of the upward-axis gyroscope is: in, This is the original measurement output value of the gyroscope's azimuth axis. The gyroscope's azimuth axis measurement output value is used to compensate for scaling factor errors.

2. The method according to claim 1, characterized in that: Step 2 specifically involves: The method for obtaining the initial attitude matrix is ​​as follows: in, , This indicates the output value measured by the triaxial accelerometer of the inertial measurement unit. , This represents the output value measured by the three-axis gyroscope in the inertial measurement unit. The latitude is the local latitude. Indicates the local gravitational acceleration; The method for obtaining the initial heading angle is as follows: 。 3. The method according to claim 2, characterized in that: Step 3 specifically involves: The initial attitude matrix is ​​transformed into the initial quaternion: Initial quaternion normalization: in, Represents the attitude matrix The elements in , This represents the initial attitude quaternion.

4. The method according to claim 3, characterized in that: Step 4 specifically involves: The quaternion real-time update equation is: in, This represents the antisymmetric matrix formed by the three sampled outputs of the gyroscope. , The sampling time interval, , The following information was obtained: in, This represents the angular rate of rotation of the carrier system relative to the navigation system, obtained from the output of the third gyroscope sampling. , ; , These represent the eastward and northward velocities of the strapdown inertial navigation system, respectively. Since there is only rotational wireless motion during calibration, the eastward and northward velocities are generally set to 0 during normal operation. The radius of curvature of the Earth's meridian. Let be the radius of curvature of the Earth's east-west surface; Updated quaternion normalization: 。 5. The method according to claim 4, characterized in that: Step 7 specifically involves: The strapdown inertial navigation system is rotated 360 degrees clockwise, and its attitude quaternions are updated in real time. The specific method is as follows: Normalized quaternions after each update: 。 6. The method according to claim 5, characterized in that: Step 9 specifically involves: The new heading angle obtained by clockwise rotation The original heading angle obtained after initial alignment Constructing the heading scale factor error compensation amount for: 。 7. A simplified online calibration system for the heading error of strapdown inertial navigation based on a single forward and reverse rotation sequence, characterized in that: The system performs the steps of the method of claim 1.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in any one of claims 1-6.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the method of any one of claims 1-6.

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