Transfer alignment method and device suitable for long endurance

Abstract

The invention discloses a transfer alignment method and device suitable for long endurance, and relates to the technical field of navigation.The method comprises the following steps that navigation of a sub inertial navigation system is initialized based on position information, speed information and attitude information provided by a main inertial navigation system; carrying out inertial navigation on the basis of the apparent velocity increment and the angular increment of the sub inertial navigation system subjected to navigation initialization; establishing a state equation of a kalman filter, and performing time updating; establishing a measurement equation of a kalman filter, and utilizing speed information and attitude information provided by a main inertial navigation system to construct measurement and update the measurement; and after time updating and measurement updating are completed each time, the error covariance matrix P is constrained. According to the method, the error covariance matrix P is kept in symmetry and non-negative nature for a long time, so that the time requirement of rapid alignment is met, and the precision requirement of long-time alignment can also be met.

Description

Technical Field

[0001] The present invention relates to the technical field of navigation, and particularly relates to a transfer alignment method and device applicable to long endurance. Background Art

[0002] The transfer alignment technology refers to using a master inertial navigation system with higher precision to calibrate a slave inertial navigation system with lower precision. Its main task is to estimate the installation error between the master and slave inertial navigation systems, so as to solve the initial alignment problem of the slave inertial navigation system under dynamic base conditions.

[0003] The transfer alignment matching methods can usually be divided into two categories: one is computational parameter matching, and the other is measurement parameter matching. Among them, computational parameter matching means using navigation information such as position, velocity, and attitude calculated by the master and slave inertial navigation systems as the matching quantity; measurement parameter matching uses the original outputs of the inertial devices of the master and slave inertial navigation systems as the matching quantity, such as angular velocity, etc. Currently, the velocity and attitude matching method is still widely used in engineering.

[0004] In the traditional transfer alignment scheme based on velocity and attitude matching, after a long time of filtering calculation, due to the influence of cumulative errors, the error covariance matrix P may lose non-negativity, and the calculated gain matrix K gradually loses its proper weighting effect, resulting in divergence, which will affect the alignment accuracy.

[0005] Therefore, to meet the actual requirements, a transfer alignment technology applicable to long endurance is provided. Summary of the Invention

[0006] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a transfer alignment method and device applicable to long endurance, so that the error covariance matrix P maintains long-term symmetry and non-negativity, thereby meeting both the time requirements of rapid alignment and the accuracy requirements of long-term alignment.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present application provides a transfer alignment method applicable to long endurance, and the method includes the following steps:

[0009] Based on the position information, velocity information, and attitude information provided by the master inertial navigation system, initialize the navigation of the slave inertial navigation system;

[0010] Based on the apparent velocity increment and angular increment of the slave inertial navigation system after completing navigation initialization, perform inertial navigation;

[0011] Establish the state equation of the Kalman filter and perform time update;

[0012] Establish the measurement equation of the Kalman filter, and use the velocity information and the attitude information provided by the master inertial navigation system to construct the measured quantity and perform measurement update;

[0013] After each time update and measurement update are completed, the error covariance matrix P is constrained.

[0014] Based on the above technical solution, in the navigation initialization of the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system, the following steps are included:

[0015] Initialize the position information and velocity information of the slave inertial navigation system;

[0016] Perform quaternion initialization on the slave inertial navigation system.

[0017] Based on the above technical solution, in the inertial navigation based on the apparent velocity increment and angular increment of the slave inertial navigation system after completing navigation initialization, the following steps are included:

[0018] Perform attitude update on the slave inertial navigation system;

[0019] Perform velocity update on the slave inertial navigation system;

[0020] Perform position update on the slave inertial navigation system.

[0021] Based on the above technical solution, in the establishment of the state equation of the Kalman filter and the time update, the following steps are included:

[0022] Construct the state equation of the Kalman filter, and the state equation includes twelve-dimensional states;

[0023] Based on the state equation of the Kalman filter, perform time update.

[0024] Based on the above technical solution, in the establishment of the measurement equation of the Kalman filter, and using the velocity information and the attitude information provided by the master inertial navigation system to construct the measured quantity and perform measurement update, the following steps are included:

[0025] Calculate the velocity error caused by the lever arm effect;

[0026] Construct the measurement equation of the Kalman filter;

[0027] Based on the Kalman filter, perform measurement update;

[0028] Perform feedback correction on the velocity information and the attitude information.

[0029] Second aspect, the present application also provides a transfer alignment method applicable to long endurance, and the method includes the following steps:

[0030] S1. Initialize the navigation of the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system;

[0031] S2. Perform inertial navigation based on the apparent velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization;

[0032] S3. Establish the state equation of the Kalman filter and perform time update;

[0033] S4. Establish the measurement equation of the Kalman filter, and use the velocity information and attitude information provided by the master inertial navigation system to construct a measurement quantity for measurement update;

[0034] S5. After each completion of the time update and the measurement update, perform constraint on the error covariance matrix P;

[0035] S6. Repeat S2 to S5, and perform iterative calculation through the Kalman filter until the estimated value of the misalignment angle converges.

[0036] Third aspect, the present application also provides a transfer alignment device applicable to long endurance, and the device includes:

[0037] A navigation initialization module, which is used to initialize the navigation of the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system;

[0038] An inertial navigation module, which is used to perform inertial navigation based on the apparent velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization;

[0039] A time update module, which is used to establish the state equation of the Kalman filter and perform time update;

[0040] A measurement update module, which is used to establish the measurement equation of the Kalman filter, and use the velocity information and attitude information provided by the master inertial navigation system to construct a measurement quantity for measurement update;

[0041] A constraint module, which is used to perform constraint on the error covariance matrix P after each completion of the time update and the measurement update.

[0042] Based on the above technical solution, the navigation initialization module is further used to initialize the position information and velocity information of the slave inertial navigation system;

[0043] The navigation initialization module is further used to perform quaternion initialization on the slave inertial navigation system.

[0044] Based on the above technical solution, the inertial navigation module is further configured to update the attitude of the sub-inertial navigation system;

[0045] The inertial navigation module is further configured to update the speed of the sub-inertial navigation system;

[0046] The inertial navigation module is further configured to update the position of the sub-inertial navigation system.

[0047] Based on the above technical solution, the time update module is further configured to construct a state equation of a Kalman filter, and the state equation includes a twelve-dimensional state;

[0048] Based on the state equation of the Kalman filter, time update is performed.

[0049] Based on the above technical solution, the measurement update module is further configured to calculate the speed error caused by the lever arm effect;

[0050] Construct a measurement equation of a Kalman filter;

[0051] Based on the Kalman filter, measurement update is performed;

[0052] Perform feedback correction on the speed information and the attitude information.

[0053] Compared with the prior art, the advantages of the present invention are as follows:

[0054] The present invention enables the error covariance matrix P to maintain long-term symmetry and non-negativity, thereby meeting both the time requirements for rapid alignment and the accuracy requirements for long-term alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 It is a step flowchart of a transfer alignment method applicable to long endurance according to an embodiment of the present invention;

[0057] Figure 2 It is a structural block diagram of a transfer alignment device applicable to long endurance according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0059] The following further elaborates on the embodiments of the present invention with reference to the accompanying drawings.

[0060] The embodiments of this application provide a transfer alignment method and device applicable to long endurance, enabling the error covariance matrix P to maintain long-term symmetry and non-negativity, thereby meeting both the time requirements for rapid alignment and the accuracy requirements for long-term alignment.

[0061] To achieve the above technical effects, the general idea of this application is as follows:

[0062] A transfer alignment method applicable to long endurance, the transfer alignment method applicable to long endurance includes the steps of:

[0063] S1. Based on the position information, velocity information, and attitude information provided by the master inertial navigation system, initialize the navigation of the slave inertial navigation system;

[0064] S2. Based on the visual velocity increment and angular increment of the slave inertial navigation system after completing the navigation initialization, perform inertial navigation;

[0065] S3. Establish the state equation of the Kalman filter and perform time update;

[0066] S4. Establish the measurement equation of the Kalman filter and use the velocity information and attitude information provided by the master inertial navigation system to construct the measurement quantity and perform measurement update;

[0067] S5. After each completion of the time update and the measurement update, constrain the error covariance matrix P.

[0068] The following further elaborates on the embodiments of this application with reference to the accompanying drawings.

[0069] In the first aspect, as shown in Figure 1 the embodiments of this application provide a transfer alignment method applicable to long endurance, the method including the following steps:

[0070] S1. Based on the position information, velocity information, and attitude information provided by the master inertial navigation system, initialize the navigation of the slave inertial navigation system;

[0071] S2. Perform inertial navigation based on the apparent velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization;

[0072] S3. Establish the state equation of the Kalman filter and perform time update;

[0073] S4. Establish the measurement equation of the Kalman filter, and use the velocity information and attitude information provided by the master inertial navigation system to construct a measurement quantity and perform measurement update;

[0074] S5. After each completion of the time update and the measurement update, perform constraint on the error covariance matrix P.

[0075] The technical solution of the embodiment of the present application enables the error covariance matrix P to maintain long-term symmetry and non-negativity, thereby meeting both the time requirement of rapid alignment and the accuracy requirement of long-term alignment.

[0076] Generally speaking, compared with the prior art through the above technical solution conceived by the present invention, it can not only meet the time requirement of rapid alignment, but also meet the accuracy requirement of long-term alignment.

[0077] Further, in the navigation initialization of the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system, the following steps are included:

[0078] Initialize the position information and velocity information of the slave inertial navigation system;

[0079] Perform quaternion initialization on the slave inertial navigation system.

[0080] Further, in the inertial navigation based on the apparent velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization, the following steps are included:

[0081] Update the attitude of the slave inertial navigation system;

[0082] Update the velocity of the slave inertial navigation system;

[0083] Update the position of the slave inertial navigation system.

[0084] Further, in the establishment of the state equation of the Kalman filter and the performance of time update, the following steps are included:

[0085] Construct the state equation of the Kalman filter, and the state equation includes a twelve-dimensional state;

[0086] Based on the state equation of the Kalman filter, perform time update.

[0087] Further, in establishing the measurement equation of the Kalman filter and using the velocity information and the attitude information provided by the master inertial navigation system to construct the measured quantity and perform measurement update, the following steps are included:

[0088] Calculate the velocity error caused by the lever arm effect;

[0089] Construct the measurement equation of the Kalman filter;

[0090] Perform measurement update based on the Kalman filter;

[0091] Perform feedback correction on the velocity information and the attitude information.

[0092] Specifically, a transfer alignment method applicable to long endurance includes the following steps:

[0093] S1. Initialize the navigation of the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system;

[0094] S2. Perform inertial navigation based on the visual velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization;

[0095] S3. Establish the state equation of the Kalman filter and perform time update;

[0096] S4. Establish the measurement equation of the Kalman filter and use the velocity information and the attitude information provided by the master inertial navigation system to construct the measured quantity and perform measurement update;

[0097] S5. After each completion of the time update and the measurement update, perform constraint on the error covariance matrix P;

[0098] S6. Repeat S2 to S5, and perform iterative calculation through the Kalman filter until the estimated value of the misalignment angle converges.

[0099] In summary, for the traditional transfer alignment scheme, after a long time of filtering calculation, due to the influence of cumulative errors, the error covariance matrix P may lose non-negativity, and the calculated gain matrix K gradually loses its appropriate weighting effect, resulting in divergence. To solve this problem, the embodiment of the present application proposes a transfer alignment scheme applicable to long endurance, which enables the error covariance matrix P to maintain symmetry and non-negativity for a long time, thereby meeting both the time requirement for fast alignment and the accuracy requirement for long-term alignment.

[0100] Based on the technical solution of the embodiment of the present application, in specific implementation, the situation is as follows:

[0101] S1: Initialize the navigation of the slave inertial navigation system using the position, velocity, and attitude information provided by the master inertial navigation system.

[0102] S11: Initialize the position and velocity of the slave inertial navigation system.

[0103] B s0 = B m ,

[0104] L s0 = L m ,

[0105] h s0 = h m ,

[0106] v s n = v m n ; Wherein:

[0107] B m , L m , h m respectively correspond to the geodetic latitude, longitude, and altitude sent by the master inertial navigation system;

[0108] v m n is the velocity in the three directions of north-east-up sent by the master inertial navigation system.

[0109] S12: Initialize the attitude quaternion of the slave inertial navigation system.

[0110] Obtain the initial attitude quaternion q of the slave inertial navigation system from the attitude angles of the master inertial navigation system according to a certain rotation sequence 0 .

[0111] S2: Perform inertial navigation using the visual velocity increment and angular increment of the slave inertial navigation system.

[0112] In the embodiment of the present invention, the specific steps of S2 include:

[0113] S21: Perform attitude update as follows:

[0114] q k = [q 0 (t k )q 1 (t k )q 2 (t k ) q 3 (t k )] T ,

[0115] q k * = [q 0 (tk ) - q 1 (t k ) - q 2 (t k ) - q 3 (t k )] T ,

[0116]

[0117] In the formula:

[0118] q k+1 is the attitude quaternion after recursive update;

[0119] q k is the attitude quaternion before recursive update;

[0120] [Δθ x Δθ y Δθ y is the angular increment output by the gyro;

[0121] F v→q represents converting the vector v to the quaternion q, which is well - known in the art and will not be elaborated further;

[0122] F q×v represents multiplying the quaternion q by v, which is well - known in the art and will not be elaborated further.

[0123] S22: Perform velocity update as follows:

[0124]

[0125] In the formula:

[0126] is the velocity of the sub - inertial navigation system before update;

[0127] is the velocity of the sub - inertial navigation system before update;

[0128]

[0129] Δv sfm = F q×v (q k , Δv).

[0130] S23: Perform position update as follows:

[0131]

[0132] In the formula:

[0133] B k 、L k, h k are the latitude, longitude, and altitude before the update of the sub-inertial navigation system;

[0134] B k+1 , L k+1 , h k+1 are the latitude, longitude, and altitude before the update of the sub-inertial navigation system. The above pure inertial navigation is well-known in the art, and the specific calculations will not be described in detail. S3: Establish a Kalman state equation and perform time update.

[0135] In the embodiment of the present invention, the specific steps of S3 include:

[0136] S31: Construct the state equation of the Kalman filter, which includes a twelve-dimensional state,

[0137] X = [Φ n , δv n , ε b , Ψ] T ;

[0138] In the formula:

[0139] Φ n is the attitude misalignment angle of the sub-inertial navigation system;

[0140] δv n is the velocity error of the sub-inertial navigation system;

[0141] ε b is the three-axis gyro drift of the sub-inertial navigation system;

[0142] Ψ is the three-axis installation deviation angle of the sub-inertial navigation system.

[0143] The state equation is as follows:

[0144]

[0145]

[0146] ε b = 0;

[0147] Ψ = 0.

[0148] S32: Time update:

[0149] X k / k-1 = A k / k-1 X k-1 ;

[0150]

[0151] The above is the basic formula for the time update of the Kalman filter, which is well-known in the art, and the specific calculations will not be described in detail.

[0152] S4: Establish the Kalman measurement equation, construct the measurement quantity using the velocity and attitude information provided by the master inertial navigation, and perform measurement update.

[0153] In the embodiment of the present invention, the specific steps of S4 include:

[0154] S41: Calculate the velocity error caused by the lever arm effect as follows:

[0155]

[0156] In the formula:

[0157] r is the lever arm value between the master inertial navigation system and the slave inertial navigation system;

[0158] is the attitude matrix of the master inertial navigation system.

[0159] S42: Construct the measurement equation, adopting velocity plus attitude matching:

[0160]

[0161] In the formula:

[0162] is used to construct the attitude measurement quantity.

[0163] The measurement equation is as follows:

[0164]

[0165] S43: Measurement update:

[0166] The Kalman filter is updated:

[0167]

[0168] P k = (I - K k H k )P k / k-1 ;

[0169] X k = X k / k-1 + K k (Z k - H k X k / k-1 );

[0170] The above are the basic formulas for Kalman filter measurement update, which are well-known in the art, and the specific calculations will not be described in detail.

[0171] S44: Feedback correction

[0172] After the filtering update, feedback correction is performed on the system state variables, i.e., attitude error and velocity error, as follows:

[0173] Velocity correction:

[0174] Attitude correction:

[0175]

[0176] In the formula:

[0177] The superscript "-" represents the value of the corresponding element before correction, and "+" represents the value of the corresponding element after correction.

[0178] S5: Perform P k matrix constraint after each measurement update.

[0179] In the embodiment of the present invention, the specific steps of S5 include:

[0180] S51: Make P k maintain symmetry:

[0181]

[0182] S52: Enhance the non-negativity of P k :

[0183] if(P k(i，i) < P Min(i，i) ) then (P k(i，i) = P Min(i，i) );

[0184] if{|P k(i，j) P k(j，i) | > P k(i，i) P k(j，j)} then;

[0185]

[0186] S6: Repeat S2~S5, and through iterative calculation of the Kalman filter, when the misalignment angle of P- converges, the transfer alignment result is credible.

[0187] In a second aspect, as shown in Figure 2 , the embodiment of the present application provides a transfer alignment device applicable to long endurance, and the device includes:

[0188] A navigation initialization module, which is used to perform navigation initialization on the slave inertial navigation system based on the position information, velocity information, and attitude information provided by the master inertial navigation system;

[0189] An inertial navigation module, which is used to perform inertial navigation based on the visual velocity increment and angular increment of the slave inertial navigation system that has completed navigation initialization;

[0190] A time update module, which is used to establish the state equation of the Kalman filter and perform time update;

[0191] A measurement update module, which is used to establish the measurement equation of the Kalman filter, and construct a measurement quantity by using the velocity information and the attitude information provided by the master inertial navigation system, and perform measurement update;

[0192] A constraint module, which is used to constrain the error covariance matrix P each time the time update and the measurement update are completed.

[0193] The technical solution of the embodiment of the present application enables the error covariance matrix P to maintain long-term symmetry and non-negativity, so as to meet both the time requirement of rapid alignment and the accuracy requirement of long-term alignment.

[0194] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, it can not only meet the time requirement of rapid alignment, but also meet the accuracy requirement of long-term alignment.

[0195] Further, the navigation initialization module is also used to initialize the position information and velocity information of the slave inertial navigation system;

[0196] The navigation initialization module is also used to perform quaternion initialization on the slave inertial navigation system.

[0197] Further, the inertial navigation module is also used to perform attitude update on the slave inertial navigation system;

[0198] The inertial navigation module is also used to perform velocity update on the slave inertial navigation system;

[0199] The inertial navigation module is also used to perform position update on the slave inertial navigation system.

[0200] Further, the time update module is also used to construct the state equation of the Kalman filter, and the state equation includes a twelve-dimensional state;

[0201] Based on the state equation of the Kalman filter, time update is performed.

[0202] Further, the measurement update module is also used to calculate the velocity error caused by the lever arm effect;

[0203] Construct the measurement equation of the Kalman filter;

[0204] Based on the Kalman filter, measurement update is performed;

[0205] Perform feedback correction on the speed information and the attitude information.

[0206] It should be noted that the transfer alignment device applicable to long endurance mentioned in the second aspect is similar in terms of technical problems, technical means, and technical effects to the technical principle of the transfer alignment method applicable to long endurance mentioned in the first aspect, and will not be elaborated here.

[0207] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0208] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0209] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. 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 application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A transfer alignment method suitable for long-duration flight, characterized in that: The method comprises the following steps: Initialize the navigation of the sub-INS based on the position information, speed information and attitude information provided by the main INS; Perform inertial navigation based on the apparent velocity increment and angle increment of the sub-inertial navigation system that has completed navigation initialization; Establish the state equation of the Kalman filter and update it in time; Establishing a measurement equation of a Kalman filter, and using the speed information and the attitude information provided by the main inertial navigation system to construct a measurement and perform measurement update; After each completion of the time update and the measurement update, the error covariance matrix P is constrained.

2. The transfer alignment method suitable for long-distance flight as claimed in claim 1, characterized in that: The navigation initialization of the sub-inertial navigation system based on the position information, speed information and attitude information provided by the main inertial navigation system includes the following steps: Initializing the position information and speed information of the sub-inertial navigation system; The quaternion of the sub-inertial navigation system is initialized.

3. The transfer alignment method suitable for long-distance flight as claimed in claim 1, characterized in that: The inertial navigation based on the apparent velocity increment and the angular increment of the sub-inertial navigation system that has completed the navigation initialization comprises the following steps: Performing attitude update on the sub-inertial navigation system; updating the speed of the sub-inertial navigation system; The position of the sub-inertial navigation system is updated.

4. The transfer alignment method suitable for long-distance flight as claimed in claim 1, characterized in that: The state equation of the Kalman filter is established and time updated, including the following steps: Constructing a state equation of a Kalman filter, wherein the state equation includes a twelve-dimensional state; Based on the state equation of the Kalman filter, time updating is performed.

5. The transfer alignment method suitable for long-distance flight as claimed in claim 1, characterized in that: The step of establishing the measurement equation of the Kalman filter and using the speed information and the attitude information provided by the main inertial navigation system to construct the measurement and perform measurement update includes the following steps: Calculate velocity error due to lever arm effect; Construct the measurement equation of the Kalman filter; Performing measurement update based on the Kalman filter; Feedback correction is performed on the speed information and the posture information.

6. A transfer alignment method suitable for long-duration flight, characterized in that: The method comprises the following steps: S1. Initialize the navigation of the sub-inertial navigation system based on the position information, speed information and attitude information provided by the main inertial navigation system; S2, performing inertial navigation based on the apparent velocity increment and angle increment of the sub-inertial navigation system that has completed navigation initialization; S3, establish the state equation of the Kalman filter and perform time update; S4, establishing a measurement equation of a Kalman filter, and using the speed information and the attitude information provided by the main inertial navigation system to construct a measurement and perform measurement update; S5, constraining the error covariance matrix P after completing the time update and the measurement update each time; S6. Repeat S2 to S5 and iteratively calculate through the Kalman filter until the misalignment angle estimation value converges.

7. A transfer alignment device suitable for long-distance flight, characterized in that: The device comprises: A navigation initialization module is used to initialize the navigation of the sub-inertial navigation system based on the position information, speed information and attitude information provided by the main inertial navigation system; An inertial navigation module, which is used to perform inertial navigation based on the apparent velocity increment and angle increment of the sub-inertial navigation system that has completed navigation initialization; A time update module, which is used to establish the state equation of the Kalman filter and perform time update; A measurement update module, which is used to establish a measurement equation of a Kalman filter, and to construct a measurement using the speed information and the attitude information provided by the main inertial navigation system, and to perform measurement update; A constraint module is used to constrain the error covariance matrix P after completing the time update and the measurement update each time.

8. The transfer alignment device suitable for long-distance flight as claimed in claim 7, characterized in that: The navigation initialization module is also used to initialize the position information and speed information of the sub-inertial navigation system; The navigation initialization module is also used to perform quaternion initialization on the sub-inertial navigation system.

9. The transfer alignment device suitable for long-distance flight as claimed in claim 7, characterized in that: The inertial navigation module is also used to update the attitude of the sub-inertial navigation system; The inertial navigation module is also used to update the speed of the sub-inertial navigation system; The inertial navigation module is also used to update the position of the sub-inertial navigation system.

10. The transfer alignment device suitable for long-distance flight as claimed in claim 7, characterized in that: The time update module is also used to construct a state equation of the Kalman filter, wherein the state equation includes a twelve-dimensional state; Based on the state equation of the Kalman filter, time updating is performed.

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