Non-singular linear transfer alignment method and system based on relative attitude matrix

Abstract

The invention discloses a nonsingular linear transfer alignment method and system based on a relative attitude matrix, belongs to the technical field of inertial navigation systems, and particularly relates to a transfer alignment technology. In order to solve the problems that model singularity and alignment precision reduction are easy to occur when the conventional transfer alignment method faces a relatively large installation error angle or a complex dynamic environment, the invention provides the following steps: acquiring a carrier coordinate system of a strapdown inertial navigation system, and determining a main inertial navigation attitude matrix; establishing a transfer alignment error model by adopting the relative attitude matrix based on the main inertial navigation attitude matrix; state information of the flexible lever arm is obtained, and the transfer alignment error model is optimized; and realizing transfer alignment of the strapdown inertial navigation system based on the optimized transfer alignment error model. According to the method, the transfer alignment error model is optimized, so that the alignment precision is remarkably improved, a stable and reliable alignment result can still be kept under a relatively large installation error angle or a complex dynamic environment, and the robustness and the accuracy of the transfer alignment model are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of transfer alignment of inertial navigation systems, and particularly relates to a non-singular linear transfer alignment method and system based on a relative attitude matrix, which is applicable to high-precision transfer alignment between a master inertial navigation unit and a slave inertial navigation unit in a strapdown inertial navigation system. Background Art

[0002] In a strapdown inertial navigation system (DINS), precise synchronization between a high-precision master inertial navigation unit MINS and multiple low-precision slave inertial navigation units SINS is crucial for ensuring the overall performance of the system. Among them, MINS provides accurate attitude, velocity, and position information; SINS are distributed at different positions of the carrier and need to correct their measurement errors through transfer alignment. The carrier coordinate system i is used to describe the state of the carrier's motion. The earth coordinate system e is used to define the navigation velocity.

[0003] Currently, the main challenges faced in the transfer alignment process include: Large angular installation error: When traditional transfer alignment methods deal with relatively large installation error angles (e.g., exceeding 10 degrees), model singularity problems are likely to occur, leading to a significant decline in alignment accuracy (e.g., an error increase of 20%-30%). This singularity problem is mainly manifested as an irreversible matrix or an unsolvable equation in the calculation process of the mathematical model, which makes the alignment process unable to converge or converge to the wrong result. Large angular errors are usually caused by mechanical deviations during installation or mechanical structure deformation due to long-term use. To address this issue, modern alignment methods usually adopt non-linear filtering algorithms (such as extended Kalman filtering or unscented Kalman filtering) to handle large angular errors, thereby improving the robustness and accuracy of alignment. Flexible lever arm effect: The relative displacement change between the master inertial navigation system and the slave inertial navigation system will introduce additional acceleration errors, which are called flexible lever arm effects. When there is elastic deformation in the connection structure between the master and slave inertial navigation systems, the slave inertial navigation system will sense additional accelerations caused by the bending or vibration of the lever arm. These accelerations are not generated by the motion of the carrier itself, but by the elastic deformation of the lever arm. This effect is particularly significant in high-dynamic environments (such as high-speed flight or severe maneuvers), and may lead to an increase in alignment error by 10%-15%. To reduce the influence of the flexible lever arm effect, it is usually necessary to introduce a lever arm compensation algorithm into the model, or to monitor and correct the lever arm deformation in real time through a high-precision inertial measurement unit (IMU). Time-varying factors: Environmental factors such as temperature changes and material aging will cause slight deformations of the mechanical structure, thereby increasing the difficulty of alignment. For example, temperature changes may cause the expansion or contraction of the inertial navigation installation base, and then change the relative position and attitude between the master and slave inertial navigation systems. Material aging may reduce the stiffness of the connection structure, further exacerbating the flexible lever arm effect. These time-varying factors will gradually accumulate during long-term operation, resulting in a gradual decline in alignment accuracy. To address this issue, the system usually needs to introduce a temperature compensation mechanism and a regular calibration procedure to ensure high alignment accuracy under different environmental conditions. In addition, the use of high-stability materials and structural designs can also effectively reduce the influence of time-varying factors on alignment accuracy.

[0004] Therefore, how to solve the problems caused by installation errors, flexible lever arm effects, and time-varying factors, so as to improve the alignment accuracy and the robustness of the system, is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a non-singular linear transfer alignment method and system based on a relative attitude matrix, which solves the problems caused by installation errors, additional acceleration sensitivity caused by flexible lever arms, and time-varying factors, thereby improving the alignment accuracy and the robustness of the system.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A non-singular linear transfer alignment method based on a relative attitude matrix, comprising the following steps:

[0008] Obtain the carrier coordinate system of the strapdown inertial navigation system and determine the master inertial navigation attitude matrix; based on the master inertial navigation attitude matrix, establish a transfer alignment error model using the relative attitude matrix; obtain the flexible rod arm state information and optimize the transfer alignment error model; realize the transfer alignment of the strapdown inertial navigation system based on the optimized transfer alignment error model.

[0009] Further, the obtaining of the carrier coordinate system of the strapdown inertial navigation system and determining the master inertial navigation attitude matrix includes:

[0010] When the carrier of the strapdown inertial navigation system is in a stationary state, use gravity and the geomagnetic field as references to calculate the initial attitude matrix;

[0011] When the carrier of the strapdown inertial navigation system is in a moving state, obtain the angular velocity data and update the attitude matrix based on the angular velocity data using a differential equation, thereby determining the master inertial navigation attitude matrix.

[0012] Further, when the carrier of the strapdown inertial navigation system is in a moving state, obtain the angular velocity data and update the attitude matrix through a differential equation to update the attitude matrix, where is the angular velocity vector transformed into the navigation coordinate system, (·×) represents the rotation operation, is the master inertial navigation attitude matrix, is the updated master inertial navigation attitude matrix.

[0013] Further, based on the master inertial navigation attitude matrix, establishing a transfer alignment error model using the relative attitude matrix includes:

[0014]

[0015] In the formula, is the updated master inertial navigation attitude matrix, is the slave inertial navigation attitude matrix, is the relative attitude matrix;

[0016] Perform a chain decomposition on the relative attitude matrix When considering the time-varying deformation angle, the relative attitude matrix is a time-varying matrix, and the chain decomposition gives:

[0017]

[0018] In the formula, m 0 and s 0respectively represent the inertial coordinate systems obtained by solidifying the master and slave inertial conductor coordinate systems at the initial moment;

[0019] Among them, the time-varying attitude matrix and are obtained by integrating the angular velocities output by the master and slave inertial navigation gyroscopes using the attitude matrix differential equation:

[0020]

[0021] In the formula, is the angular velocity of the master inertial navigation, is the angular velocity of the slave inertial navigation;

[0022] Taking the attitude matrix and the error angle as state variables, a non-singular linear transfer alignment error model under arbitrary installation error angles is established:

[0023]

[0024] In the formula, is the error of the time-varying attitude matrix , is the error angle.

[0025] Furthermore, obtaining the flexible lever arm state information and optimizing the transfer alignment error model includes:

[0026] Establishing the vector representation form from the inertial coordinate system i to the slave inertial navigation coordinate system s;

[0027] Establishing the vector representation form from the navigation coordinate system e to the slave inertial navigation coordinate system s;

[0028] While considering the time-variability of the flexible lever arm, differentiating the vector representation form;

[0029] Defining the velocities in each coordinate system and establishing the velocity and vector relationship;

[0030] The velocity and vector relationship establish the velocity error model;

[0031] Based on the velocity error model, the velocity linear differential equation in the final navigation coordinate system is obtained, that is, the optimized transfer alignment error model.

[0032] Furthermore, the vector representation form established from the inertial coordinate system i to the slave inertial navigation coordinate system s is:

[0033]

[0034] In the formula, represents the vector from the inertial coordinate system i to the master inertial navigation coordinate system m; represents the vector from the master inertial navigation coordinate system m to the slave inertial navigation coordinate system s; Represents the rotation matrix from the main inertial navigation coordinate system m to the inertial coordinate system i; Represents the vector from the inertial coordinate system i to the sub-inertial navigation coordinate system s.

[0035] Furthermore, a vector representation form from the navigation coordinate system e to the sub-inertial navigation coordinate system s is established as:

[0036]

[0037] In the formula, Represents the vector from the navigation coordinate system e to the main inertial navigation coordinate system m, Represents the rotation matrix from the main inertial navigation coordinate system m to the navigation coordinate system e; Represents the vector from the main inertial navigation coordinate system m to the sub-inertial navigation coordinate system s; The vector from the navigation coordinate system e to the sub-inertial navigation coordinate system s.

[0038] Furthermore, based on the velocity error model, the velocity linear differential equation in the final navigation coordinate system is expressed as:

[0039]

[0040] In the formula, Represents the change rate of the velocity error in the navigation coordinate system e; Represents the velocity change rate of the sub-inertial navigation coordinate system s in the navigation coordinate system e; Represents the velocity change rate of the sub-inertial navigation coordinate system s in the inertial coordinate system i; Represents the relative attitude matrix The estimated value in the navigation coordinate system e; Represents the estimated value of the force vector in the navigation coordinate system e; Represents the relative attitude matrix The true value in the navigation coordinate system e; Represents the true force vector in the navigation coordinate system e; φ represents the attitude error angle; I 3 Represents the 3x3 identity matrix; (·×) represents the skew-symmetric matrix operator.

[0041] A non-singular linear transfer alignment system based on the relative attitude matrix, comprising:

[0042] Initialization module: used to obtain the carrier coordinate system of the strapdown inertial navigation system and determine the main inertial navigation attitude matrix;

[0043] Model establishment module: used to establish a transfer alignment error model based on the main inertial navigation attitude matrix and adopt the relative attitude matrix;

[0044] Model optimization module: used to obtain the flexible lever arm state information and optimize the transfer alignment error model;

[0045] Transfer alignment module: used to implement the transfer alignment of a strapdown inertial navigation system based on the optimized transfer alignment error model.

[0046] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a non-singular linear transfer alignment method and system based on a relative attitude matrix. Starting from obtaining the carrier coordinate system of the strapdown inertial navigation system, it gradually progresses to establishing a transfer alignment error model, and then optimizing the model to consider the flexible lever arm effect, and finally achieving accurate transfer alignment. Each step is closely connected, forming a complete process, ensuring the logic and coherence of the solution. In addition, by introducing advanced mathematical modeling and real-time error compensation mechanisms, the alignment accuracy and reliability of the strapdown inertial navigation system are significantly improved, having broad application prospects and practical value. Brief Description of the Drawings

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0048] Figure 1 It is a schematic flowchart of the method of the present invention;

[0049] Figure 2 It is a schematic structural diagram of the system of the present invention. Detailed Embodiments

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] The object of the present invention is to provide a non-singular linear transfer alignment method and system based on a relative attitude matrix. The method includes: obtaining the carrier coordinate system of the strapdown inertial navigation system and determining the main inertial navigation attitude matrix; establishing a transfer alignment error model using the relative attitude matrix based on the main inertial navigation attitude matrix; obtaining the flexible lever arm state information and optimizing the transfer alignment error model; and implementing the transfer alignment of the strapdown inertial navigation system based on the optimized transfer alignment error model. The present invention solves the problems caused by installation errors, additional acceleration sensitivity caused by flexible lever arms, and time-varying factors, providing a solution for improving alignment accuracy and system robustness.

[0052] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] See Figure 1 , an embodiment of the present invention discloses a non-singular linear transfer alignment method based on a relative attitude matrix, including the following steps:

[0054] Obtain the carrier coordinate system of the strapdown inertial navigation system and determine the master inertial navigation attitude matrix; based on the master inertial navigation attitude matrix, establish a transfer alignment error model using the relative attitude matrix; obtain the flexible rod arm state information and optimize the transfer alignment error model; and achieve the transfer alignment of the strapdown inertial navigation system based on the optimized transfer alignment error model.

[0055] Specifically, by optimizing the transfer alignment error model, the present invention significantly improves the alignment accuracy and can still maintain a stable and reliable alignment result under a large installation error angle or a complex dynamic environment, enhancing the robustness and accuracy of the transfer alignment model.

[0056] In a specific embodiment, the obtaining of the carrier coordinate system of the strapdown inertial navigation system and determining the master inertial navigation attitude matrix includes:

[0057] When the carrier of the strapdown inertial navigation system is in a stationary state, use gravity and the geomagnetic field as references to calculate the initial attitude matrix;

[0058] When the carrier of the strapdown inertial navigation system is in a moving state, obtain angular velocity data and update the attitude matrix based on the angular velocity data using a differential equation, thereby determining the master inertial navigation attitude matrix.

[0059] In a specific embodiment, when the carrier of the strapdown inertial navigation system is in a moving state, obtain angular velocity data and update the attitude matrix based on the angular velocity data using a differential equation, and the expression is:

[0060]

[0061] In the formula, is the angular velocity vector transformed into the navigation coordinate system (the rotation speed of the carrier coordinate system relative to the reference coordinate system), (·×) is used to convert the angular velocity vector ω into an anti-symmetric matrix (also called a cross product matrix) to represent the rotation effect, is the master inertial navigation attitude matrix, is the updated master inertial navigation attitude matrix.

[0062] Specifically, when the strapdown inertial navigation system is started, an accurate initial alignment process is required to determine the initial attitude of the MINS. This is usually completed through static or dynamic initialization methods.

[0063] When the vehicle is in a stationary state, the initial attitude matrix is calculated using gravity and the geomagnetic field as references.

[0064] If the vehicle is in motion, auxiliary information such as GPS and vision sensors can be used for more complex dynamic initialization.

[0065] In a specific embodiment, based on the master inertial navigation attitude matrix, a transfer alignment error model is established using the relative attitude matrix, including:

[0066]

[0067] In the formula, is the updated master inertial navigation attitude matrix, is the slave inertial navigation attitude matrix, is the relative attitude matrix;

[0068] Specifically, the relative attitude matrix describes the relative attitude between the master inertial navigation coordinate system m and the slave inertial navigation coordinate system s;

[0069] Specifically, in order to extract the attitude error from the relative attitude matrix as a state variable, it can be processed by the chain decomposition method. In particular, when considering the time-varying deformation angle, the relative attitude matrix can be decomposed into a constant part and a time-varying part.

[0070] For the relative attitude matrix perform chain decomposition. When considering the time-varying deformation angle, the relative attitude matrix is a time-varying matrix, and the chain decomposition gives:

[0071]

[0072] In the formula, is the constant attitude matrix, where m 0 and s 0 respectively represent the inertial coordinate systems obtained by freezing the master and slave inertial body coordinate systems at the initial moment;

[0073] Among them, the time-varying attitude matrix and are obtained by integrating the angular velocities output by the master and slave inertial navigation gyroscopes using the attitude matrix differential equation:

[0074]

[0075] In the formula, is the master inertial navigation angular velocity, is the slave inertial navigation angular velocity;

[0076] Specifically, since the accuracy of the slave inertial navigation is relatively low, so is error-containing, that is results in also being error-containing, denoted as whose error angle φ s , can be modeled as a linear differential equation, that is, taking the attitude matrix and the error angle as state variables, to establish a non-singular linear transfer alignment error model under any installation error angle:

[0077]

[0078] In the formula, is the angular velocity of the slave inertial navigation, the error of is the time-varying attitude matrix the error of, φ s is the error angle.

[0079] Specifically, through the chain decomposition method, the relative attitude matrix is decomposed into a constant part and a time-varying part. The attitude matrix is updated using the angular velocity output by the gyroscope. Considering the error of the slave inertial navigation angular velocity and modeling it as a linear differential equation. Through these steps, the state information of the flexible lever arm can be effectively obtained and the transfer alignment error model can be optimized.

[0080] In a specific embodiment, obtaining the state information of the flexible lever arm and optimizing the transfer alignment error model includes:

[0081] Establishing the vector representation form from the inertial coordinate system i to the slave inertial navigation coordinate system s:

[0082]

[0083] In the formula, represents the vector from the inertial coordinate system i to the master inertial navigation coordinate system m; represents the vector from the master inertial navigation coordinate system m to the slave inertial navigation coordinate system s; represents the rotation matrix from the master inertial navigation coordinate system m to the inertial coordinate system i; represents the vector from the inertial coordinate system i to the slave inertial navigation coordinate system s.

[0084] Establishing the vector representation form from the navigation coordinate system e to the slave inertial navigation coordinate system s:

[0085]

[0086] In the formula, represents the vector from the navigation coordinate system e to the master inertial navigation coordinate system m, represents the rotation matrix from the master inertial navigation coordinate system m to the navigation coordinate system e; represents the vector from the master inertial navigation coordinate system m to the slave inertial navigation coordinate system s; the vector from the navigation coordinate system e to the slave inertial navigation coordinate system s.

[0087] While considering the time-varying nature of the flexible boom, taking the derivative of the vector representation form, we have:

[0088]

[0089] And define the boom velocity in the i-frame as:

[0090]

[0091] Similarly, we can obtain:

[0092]

[0093] Since and the projection coordinate system and the reference coordinate system in are the same, so it can be denoted as and where, and are called the absolute velocity, and are called the navigation velocity in the e-frame and the relative velocity. To sum up, the velocity linear differential equation in the navigation coordinate system can be obtained as:

[0094] Expressed as:

[0095]

[0096] In the formula, represents the change rate of the navigation coordinate system e velocity error; represents the velocity change rate of the local inertial coordinate system s in the navigation coordinate system e; represents the velocity change rate of the local inertial coordinate system s in the inertial coordinate system i; represents the estimated value of the relative attitude matrix in the navigation coordinate system e; represents the estimated value of the force vector in the navigation coordinate system e; represents the relative attitude matrix the true value in the navigation coordinate system e; represents the true force vector in the navigation coordinate system e; φ represents the attitude error angle; I 3 represents the 3x3 identity matrix; (·×) represents the skew-symmetric matrix operator.

[0097] Specifically, in this embodiment, the velocities in each coordinate system are first defined:

[0098] The velocity of the local inertial in the inertial coordinate system i;

[0099] The velocity of the local inertial in the navigation coordinate system e.

[0100] According to the vector relationship and the definition of velocity, it can be obtained that:

[0101]

[0102]

[0103] Furthermore, in order to establish a velocity error model, this embodiment needs to consider the rate of change of velocity error That is, the velocity error of the slave inertial navigation system in the navigation coordinate system e. The velocity error model can be expressed as:

[0104]

[0105] Further expansion gives:

[0106]

[0107] Where is the estimated value of the relative attitude matrix in the navigation coordinate system e; is the estimated value of the force vector in the navigation coordinate system e; is the true value of the relative attitude matrix in the navigation coordinate system e; is the true force vector in the navigation coordinate system e.

[0108] The final linear differential equation of velocity in the navigation coordinate system can be expressed as:

[0109]

[0110] After simplification, it is obtained:

[0111]

[0112] Specifically, through the above steps, the present invention can systematically derive the linear differential equation of velocity in the navigation coordinate system for optimizing the transfer alignment error model.

[0113] In a specific embodiment, by implementing all the above steps, the accuracy, stability, and reliability of the model are ensured. Including:

[0114] First, obtain the body coordinate system of the strapdown inertial navigation system, and determine the initial positions and attitudes of the master inertial navigation system (MINS) and the slave inertial navigation system (SINS). The specific implementation method is to use a high-precision initialization process, such as static or dynamic initialization, to determine the initial states of the body coordinate system i and the navigation coordinate system e. Determine the initial positions and attitudes of the master inertial navigation coordinate system m and the slave inertial navigation coordinate system s.

[0115] Then determine the main inertial navigation attitude matrix and select the accurate main inertial navigation attitude matrix. Specifically, measure the angular velocity using a high-precision gyroscope and update the attitude matrix through a differential equation. Combine Kalman filtering or other estimation methods, and use the external observations provided by auxiliary sensors (such as accelerometers, magnetometers, GPS) for error compensation and correction. Ensure the real-time update of the attitude matrix to reflect the current most accurate attitude information.

[0116] Secondly, based on the main inertial navigation attitude matrix, establish a transfer alignment error model using the relative attitude matrix, and construct a transfer alignment error model that can handle installation error angles of any size and ensure non-singularity. Specifically: Define the relative attitude matrix to describe the relative attitude between the main inertial navigation and the slave inertial navigation. Perform a chain decomposition on the relative attitude matrix, dividing it into a constant part and a time-varying part. List the error angles of the attitude matrix as one of the state variables and establish a linear differential equation to ensure the non-singularity of the model.

[0117] Thirdly, obtain the flexible lever arm state information and optimize the transfer alignment error model. Consider the existence of the flexible lever arm and its dynamic changes, and optimize the velocity error equation. Specifically: Define the representation form of the vector from the main inertial navigation to the slave inertial navigation in the inertial coordinate system i. Considering the time-varying nature of the flexible lever arm, define the lever arm velocity. Construct a linear differential equation of velocity in the navigation coordinate system, and combine the navigation velocity definition and the velocity error equation to update the velocity vector of the slave inertial navigation in real time. Specifically, it also includes obtaining information affecting the deformation of the mechanical structure through environmental monitoring devices (such as temperature sensors) and developing a real-time monitoring system for compensation.

[0118] Finally, based on the optimized transfer alignment error model, achieve the transfer alignment of the strapdown inertial navigation system. Apply the optimized transfer alignment error model to improve the alignment accuracy and robustness of the strapdown inertial navigation system.

[0119] On the other hand, referring to Figure 2 , the embodiment of the present invention also discloses a non-singular linear transfer alignment system based on the relative attitude matrix, including:

[0120] Initialization module: Obtain the carrier coordinate system of the strapdown inertial navigation system and determine the main inertial navigation attitude matrix;

[0121] Model establishment module: Based on the main inertial navigation attitude matrix, establish a transfer alignment error model using the relative attitude matrix;

[0122] Model optimization module: Obtain the flexible lever arm state information and optimize the transfer alignment error model;

[0123] Transfer alignment module: Based on the optimized transfer alignment error model, achieve the transfer alignment of the strapdown inertial navigation system.

[0124] The robustness and accuracy of the transfer alignment model are enhanced by the present invention, ensuring stable and reliable alignment results even in the face of large installation error angles or complex dynamic environments; the accuracy of speed error estimation is improved, and an effective solution is provided especially for the additional challenges brought by flexible connection structures; the algorithm design is simplified, the computational complexity is reduced, which is beneficial to rapid deployment and implementation in engineering practice; the anti-interference ability and long-term stability of the overall system are improved, providing a solid foundation for multi-sensor fusion.

[0125] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description of the method part for the relevant parts.

[0126] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A non-singular linear transfer alignment method based on relative posture matrix, characterized in that: The following steps are involved: Obtain the strapdown inertial navigation system carrier coordinate system and determine the main inertial navigation attitude matrix; Based on the main inertial navigation attitude matrix, the transfer alignment error model is established using the relative attitude matrix; the flexible arm state information is obtained to optimize the transfer alignment error model; and the transfer alignment of the strapdown inertial navigation system is realized based on the optimized transfer alignment error model.

2. A non-singular linear transfer alignment method based on relative posture matrix according to claim 1, characterized in that: The step of obtaining the strapdown inertial navigation system carrier coordinate system and determining the main inertial navigation attitude matrix includes: When the strapdown inertial navigation system carrier is at rest, the initial attitude matrix is ​​calculated using gravity and geomagnetic field as references; When the strapdown inertial navigation system carrier is in motion, angular velocity data is acquired, and the attitude matrix is ​​updated using a differential equation based on the angular velocity data, thereby determining the main inertial navigation attitude matrix.

3. A non-singular linear transfer alignment method based on relative posture matrix according to claim 2, characterized in that: When the strapdown inertial navigation system carrier is in motion, the angular velocity data is obtained, and based on the angular velocity data, the differential equation is used to calculate the To update the posture matrix, is the angular velocity vector converted to the navigation coordinate system, (·×) represents the rotation effect, is the main inertial navigation attitude matrix, is the updated main inertial navigation attitude matrix.

4. The non-singular linear transfer alignment method based on relative posture matrix according to claim 1, characterized in that: Based on the master inertial navigation attitude matrix, the transfer alignment error model is established using the relative attitude matrix, including: In the formula, is the updated master inertial navigation attitude matrix, is the sub-INS attitude matrix, is the relative posture matrix; Relative attitude matrix Do chain decomposition, when considering the time-varying deformation angle, the relative attitude matrix is a time-varying matrix, and the chain decomposition is: In the formula, m0 and s0 represent the inertial coordinate systems obtained by solidifying the main and sub-inertial body coordinate systems at the initial moment respectively; Among them, the time-varying attitude matrix and According to the angular velocity output by the main and sub inertial navigation gyroscopes, the attitude matrix differential equation is integrated to obtain: In the formula, is the main inertial navigation angular velocity, is the sub-inertial angular velocity; The attitude matrix and error angle are listed as state quantities, and a non-singular linear transfer alignment error model under any installation error angle is established: in, is the time-varying attitude matrix The error, is the error angle.

5. The non-singular linear transfer alignment method based on relative posture matrix according to claim 1, characterized in that: Obtain the state information of the flexible lever arm and optimize the transmission alignment error model, including: Establish a vector representation from the inertial coordinate system i to the sub-inertial navigation coordinate system s; Establish a vector representation from the navigation coordinate system e to the sub-inertial navigation coordinate system s; The vector representation is differentiated while taking into account the time-varying nature of the flexible lever arm; Define the speed in each coordinate system and establish the speed and vector relationship; The velocity and vector relationship establishes the velocity error model; Based on the velocity error model, the velocity linear differential equation in the final navigation coordinate system is obtained, which is the optimized transfer alignment error model.

6. The non-singular linear transfer alignment method based on relative posture matrix according to claim 5, characterized in that: The vector representation from the inertial coordinate system i to the sub-inertial navigation coordinate system s is established as: In the formula, represents the vector from the inertial coordinate system i to the main inertial navigation coordinate system m; Represents the vector from the main inertial navigation coordinate system m to the sub-inertial navigation coordinate system s; represents the rotation matrix from the main inertial navigation coordinate system m to the inertial coordinate system i; Represents the vector from the inertial coordinate system i to the sub-inertial navigation coordinate system s.

7. The non-singular linear transfer alignment method based on relative posture matrix according to claim 6, characterized in that: The vector representation from the navigation coordinate system e to the sub-inertial navigation coordinate system s is established as: In the formula, represents the vector from the navigation coordinate system e to the main inertial navigation coordinate system m, Represents the rotation matrix from the main inertial navigation coordinate system m to the navigation coordinate system e; Represents the vector from the main inertial navigation coordinate system m to the sub-inertial navigation coordinate system s; The vector from the navigation coordinate system e to the sub-INS coordinate system s.

8. The non-singular linear transfer alignment method based on relative posture matrix according to claim 7, characterized in that: Based on the velocity error model, the velocity linear differential equation in the final navigation coordinate system is expressed as: In the formula, It represents the rate of change of velocity error of navigation coordinate system e; It represents the velocity change rate of the sub-INS coordinate system s in the navigation coordinate system e; It represents the velocity change rate of the sub-inertial navigation coordinate system s in the inertial coordinate system i; Represents the relative posture matrix Estimated value in navigation coordinate system e; represents the estimated value of the force vector in the navigation coordinate system e; Represents the relative posture matrix The true value in the navigation coordinate system e; represents the true force vector in the navigation coordinate system e; φ represents the attitude error angle; I3 represents the 3x3 unit matrix; (·×) represents the antisymmetric matrix operator.

9. The system according to any one of claims 1 to 8, characterized in that: include: Initialization module: used to obtain the strapdown inertial navigation system carrier coordinate system and determine the main inertial navigation attitude matrix; Model building module: used to build the transfer alignment error model based on the main inertial navigation attitude matrix and the relative attitude matrix; Model optimization module: used to obtain the state information of the flexible lever arm and optimize the transmission alignment error model; Transfer alignment module: used to realize the transfer alignment of strapdown inertial navigation system based on the optimized transfer alignment error model.

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