Missile-borne inertial navigation air coarse alignment method and system based on GNSS assistance

Abstract

The invention discloses a missile-borne inertial navigation air coarse alignment method and system based on GNSS assistance. The method belongs to the technical field of inertial navigation, and comprises the following steps: firstly, acquiring projectile body initial information provided by a GNSS receiver and real-time measurement data of an inertial navigation system, and initializing the inertial navigation system by combining the information to generate an initial attitude matrix of a projectile body; and then simplifying and decomposing the initial attitude matrix based on a matrix chain multiplication relationship, obtaining real-time information through a GNSS, and constructing an apparent position vector through an inertial navigation specific force equation and GNSS speed information to obtain an optimized and corrected real-time coarse alignment attitude matrix. And finally, further solving and verifying the real-time coarse alignment attitude matrix based on a dual-vector attitude determination algorithm of REQUEST. According to the invention, rapid and accurate coarse alignment of the inertial navigation system in the air is realized, and a solid foundation is provided for subsequent high-precision navigation and guidance tasks.

Description

Technical Field

[0001] The present invention relates to the field of inertial navigation technology, and more specifically to a missile-borne inertial navigation aerial coarse alignment method and system based on GNSS assistance. Background Art

[0002] The inertial navigation system (INS) is an autonomous navigation system that measures the acceleration and angular velocity of the carrier to infer information such as position, velocity and attitude. However, the inertial navigation system has the problem of error accumulation over time, and its accuracy will gradually decrease as the navigation time increases. This may lead to large navigation deviations in long-term flight missions, affecting the hit accuracy and combat effectiveness of the missile.

[0003] The Global Navigation Satellite System (GNSS) has the advantages of high positioning accuracy and global coverage. However, in some cases, such as when satellite signals are blocked or interfered with or in a high-dynamic environment, the GNSS receiver may not be able to receive satellite signals normally or the signal quality may degrade, resulting in failure of positioning and navigation functions. Moreover, the GNSS itself cannot directly provide the carrier's attitude information. For missiles that require precise attitude control, relying solely on GNSS cannot meet the requirements.

[0004] In order to overcome the limitations of inertial navigation systems and satellite navigation systems, the GNSS / INS combined navigation system has become a research hotspot and development trend in the current navigation field. By integrating the high-precision positioning information of GNSS and the autonomy and continuity of INS, the advantages can be complemented and the overall performance and reliability of the navigation system can be improved. It has been widely used in aviation, aerospace, navigation and other fields.

[0005] In missile-borne navigation systems, aerial alignment is a key link, which directly affects the subsequent navigation accuracy and combat effectiveness of the missile. Traditional ground alignment methods cannot meet the requirements of rapid response and high maneuverability in some cases, so it is necessary to study aerial rough alignment methods suitable for missile-borne inertial navigation. However, aerial rough alignment of missile-borne inertial navigation faces many challenges, such as high dynamics during flight, complex mechanical environment, and uncertainty of satellite signals. How to quickly and accurately achieve rough alignment of the inertial navigation system under these complex conditions is an urgent problem to be solved. Summary of the invention

[0006] In view of this, the present invention provides a method and system for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance, which realizes rapid and accurate rough alignment of the initial posture of the missile body in the air by combining the data of the GNSS receiver and the inertial navigation system, thereby improving the accuracy and reliability of the navigation system.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] On the one hand, the present invention discloses a method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance, comprising the following steps:

[0009] After the inertial navigation system is started, the initial information of the missile body provided by the GNSS receiver and the measurement data of the inertial navigation system are obtained;

[0010] Initializing the inertial navigation system according to the initial information of the projectile in combination with the measurement data to obtain an initial attitude matrix corresponding to the projectile;

[0011] Decompose the initial posture matrix based on the matrix chain multiplication relationship;

[0012] Obtaining the measurement data updated by the inertial navigation system;

[0013] The apparent position vector is constructed through the inertial navigation specific force equation and the measurement data to obtain the real-time rough alignment attitude matrix;

[0014] The REQUEST-based dual-vector attitude determination algorithm solves the attitude matrix of the rough alignment to obtain a rough alignment result.

[0015] Preferably, the initial posture matrix is ​​decomposed based on the matrix chain multiplication relationship as follows:

[0016]

[0017] in, Represents the attitude transformation matrix from n0 system to n system at time t; Represents the attitude transformation matrix from system n to system b at the initial moment; Represents the attitude transformation matrix from system b to system b0 at time t;

[0018] Further To break it down:

[0019]

[0020] in:

[0021]

[0022] λ0 and L0 represent the longitude and latitude of the start time of the aerial rough alignment, respectively. t and L t Respectively represent the real-time longitude and latitude of the carrier.

[0023] Preferably, the inertial navigation system is initialized according to the initial information of the projectile in combination with the measurement data to obtain an initial attitude matrix corresponding to the projectile, including:

[0024] The initial information of the projectile is converted into the navigation coordinate system by means of a coordinate conversion algorithm, and an initial vector of the projectile in the navigation coordinate system is determined;

[0025] Performing an integration operation on the measurement data to determine a change vector of the projectile in the inertial space;

[0026] The change vector is combined with the initial vector using a vector synthesis algorithm to construct an initial posture matrix of the corresponding projectile.

[0027] Preferably, after obtaining the initial information of the projectile provided by the GNSS receiver, it also includes: determining whether the current operating state of the GNSS is normal and whether the feedback information is true and valid based on the feedback information of the GNSS, and if so, determining that the GNSS is currently valid.

[0028] Preferably, the initial information of the projectile includes the initial position, initial velocity and initial attitude angle of the projectile; and the measurement data of the inertial navigation system includes the angular velocity measurement value of the gyroscope and the acceleration measurement value of the accelerometer.

[0029] On the other hand, the present invention discloses a missile-borne inertial navigation aerial coarse alignment system based on GNSS assistance, comprising:

[0030] The data acquisition module is used to obtain the initial information of the missile body provided by the GNSS receiver and the measurement data of the inertial navigation system after the inertial navigation system is started;

[0031] An initial module, used to initialize the inertial navigation system according to the initial information of the projectile in combination with the measurement data, and obtain an initial attitude matrix corresponding to the projectile;

[0032] A decomposition module, used to decompose the initial posture matrix based on the matrix chain multiplication relationship;

[0033] The attitude estimation module is used to construct the apparent position vector through the inertial force equation and the measurement data to obtain the real-time rough alignment attitude matrix;

[0034] The solution module is used to solve the rough alignment posture matrix based on the REQUEST dual-vector posture determination algorithm to obtain a rough alignment result.

[0035] It can be known from the above technical solution that compared with the prior art, the present invention discloses a method and system for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance. The present invention combines the data of GNSS receiver and inertial navigation system, constructs the apparent position vector through inertial navigation specific force equation and measurement data, obtains real-time rough alignment attitude matrix, and solves the rough alignment attitude matrix based on REQUEST dual vector attitude determination algorithm, thereby realizing rapid rough alignment of missile body in the air. Compared with traditional alignment methods, this method can significantly improve the alignment speed and accuracy, and ensure the timeliness and accuracy of missile-borne navigation system. In the rough alignment process, the covariance shaping adaptive adjustment process is introduced, which helps to enhance the robustness of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0037] Figure 1 A flow chart of the method provided by the present invention;

[0038] Figure 2 A schematic diagram of the structure of the system provided by the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The embodiment of the present invention discloses a method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance, such as Figure 1 As shown, the following steps are included:

[0041] After the inertial navigation system is started, the initial information of the projectile provided by the GNSS receiver and the measurement data of the inertial navigation system are obtained; the multi-dimensional initial information about the projectile transmitted by the GNSS receiver is obtained, covering the initial geographical location coordinates of the projectile, and its longitude and latitude data are accurate to extremely small units of measurement, providing a benchmark for subsequent positioning; the initial velocity information includes the initial velocity magnitude and direction vector of the projectile in all directions of three-dimensional space, clearly showing the dynamic trend of the projectile at the moment of startup; and the extremely critical initial attitude angle, detailed to the pitch angle, yaw angle and roll angle, accurately depicting the initial spatial orientation of the projectile. At the same time, various sensors inside the inertial navigation system are also running synchronously at high speed, collecting their own measurement data in real time. Among them, the gyroscope quickly and accurately captures the angular velocity measurement value, and records the instantaneous state of the projectile in terms of rotational motion at an extremely high frequency. The accelerometer closely follows up and accurately measures the component values ​​of the acceleration of the projectile in each axial direction.

[0042] The inertial navigation system is initialized according to the initial information of the projectile combined with the measurement data to obtain the initial attitude matrix of the corresponding projectile; through the coordinate conversion algorithm, the initial information of the projectile provided by GNSS is converted from its original coordinate system to the navigation coordinate system, so as to accurately determine the initial vector position of the projectile in the navigation coordinate system. Next, an integral operation is performed on the measurement data collected by the inertial navigation system to obtain the change vector generated by the projectile in the inertial space over time, so as to fully grasp the dynamic evolution trajectory of the projectile. Finally, the vector synthesis algorithm is used to perfectly integrate the change vector calculated in the early stage with the initial vector, so as to construct an initial attitude matrix that can accurately correspond to the current state of the projectile, laying a solid foundation for subsequent fine operations.

[0043] Decompose the initial posture matrix based on the matrix chain multiplication relationship;

[0044] Obtain updated measurement data from the inertial navigation system;

[0045] The apparent position vector is constructed through the inertial navigation specific force equation and the measurement data to obtain the real-time rough alignment attitude matrix;

[0046] The REQUEST-based dual-vector attitude determination algorithm solves the attitude matrix of coarse alignment and obtains the coarse alignment result.

[0047] Furthermore, based on the matrix chain multiplication relationship, the initial posture matrix is ​​decomposed into:

[0048]

[0049] in, Represents the attitude transformation matrix from n0 system to n system at time t; Represents the attitude transformation matrix from system n to system b at the initial moment; Represents the attitude transformation matrix from system b to system b0 at time t;

[0050] Further To break it down:

[0051]

[0052] in:

[0053]

[0054]

[0055] λ0 and L0 represent the longitude and latitude of the start time of the aerial rough alignment, respectively. t and L t Respectively represent the real-time longitude and latitude of the carrier.

[0056] For convenience The solution and derivation of The first-order differential form of for:

[0057]

[0058] According to the above formula, we can know that Only then can the real-time position information of the inertial navigation system be calculated, and the solution The key is the constant matrix Therefore, it is necessary to Construct a vector observation model.

[0059] Furthermore, the inertial navigation system is initialized according to the initial information of the missile body combined with the measurement data to obtain the initial attitude matrix of the corresponding missile body, including:

[0060] Through the coordinate conversion algorithm, the initial information of the missile body is converted to the navigation coordinate system, and the initial vector of the missile body in the navigation coordinate system is determined;

[0061] Integrate the measured data to determine the change vector of the projectile in the inertial space;

[0062] The vector synthesis algorithm is used to combine the change vector with the initial vector to construct the initial posture matrix of the corresponding projectile.

[0063] In another embodiment, after obtaining the initial information of the projectile provided by the GNSS receiver, it also includes: determining whether the current operating state of the GNSS is normal and whether the feedback information is true and valid based on the feedback information of the GNSS, and if so, determining that the GNSS is currently valid.

[0064] In another embodiment, the initial information of the projectile includes the initial position, initial velocity and initial attitude angle of the projectile; and the measurement data of the inertial navigation system includes the angular velocity measurement value of the gyroscope and the acceleration measurement value of the accelerometer.

[0065] The dual-vector attitude determination algorithm based on REQUEST solves the attitude matrix of the rough alignment and obtains the rough alignment result. Specifically, the inertial navigation specific force equation can be expressed as:

[0066]

[0067] according to and It can also be expressed as:

[0068]

[0069] You can get:

[0070]

[0071] Multiply both sides of the above equation We can get:

[0072]

[0073] Rearranging the above formula, we can get:

[0074]

[0075] Multiply both sides of the above equation We can get:

[0076]

[0077] Rearranging the above formula, we can get:

[0078]

[0079] Integrating both sides of the above equation, we can get:

[0080]

[0081] Rearranging the above formula, we can get:

[0082]

[0083] The first integral term on the left side of the above equation can be calculated as:

[0084]

[0085] We can get:

[0086]

[0087] According to the above formula, we can see that the constant matrix The solution to can be transformed into The solution of The solution can be completed by constructing a vector, constructing a vector α v (t) and β v (t) are as follows:

[0088]

[0089] Among them, since the aircraft does not produce lateral displacement during flight, v b It can be obtained through GNSS and written as:

[0090] v b =[0 v GNSS 0] T

[0091] where v GNSS The carrier forward speed provided for GNSS.

[0092] Therefore, the coarse alignment model can be reformulated as:

[0093]

[0094] Directly adopt α v (t) and β v (t) The optimal base rough alignment will inevitably introduce GNSS noise, thereby reducing the smoothness and accuracy of attitude and positioning navigation results. v (t) and β v (t) Perform another vector integration to obtain α p (t) and β p (t), that is:

[0095]

[0096] Therefore, based on the dual-vector pose determination method, The solution of can further obtain the real-time attitude matrix Complete the rough alignment of the inertial navigation system attitude.

[0097] The REQUEST algorithm does not have the problem of slow calculation speed caused by constructing multi-dimensional vectors, and its calculation speed is basically the same as that of the TRIDE algorithm. Therefore, the REQUEST algorithm has advantages in both observation information utilization and computational efficiency, and has strong engineering applicability. The implementation process of the REQUEST algorithm is introduced in three aspects.

[0098] a. Initialization

[0099] Initialize M = 1, K(0) = 0 4×4 , where M is the number of recursive steps and K(0) is the initial 4×4 dimensional recursive matrix.

[0100] b. Recursive matrix K(M) solution

[0101] The Mth calculation cycle is recursively deduced as follows:

[0102] B=β p (M)[α p (M)] T

[0103] δS=B+B T

[0104] δz=[B 23 -B 32 B 31 -B 13 B 12 -B 21 ] T

[0105] δσ=tr(B)

[0106]

[0107] Among them, B, δS and δz have no specific physical meanings and are matrix variables of the operation process; δσ represents the trace of the matrix B; K(M) represents the 4×4 dimensional recursive matrix of the Mth step; K(M-1) represents the 4×4 dimensional recursive matrix of the M-1th step; δK represents the 4×4 dimensional incremental matrix; ρ is the attenuation factor, which usually takes a value of 0.950~0.999. The purpose of introducing the attenuation factor is to reduce the weight of the recent observation information, weaken the negative impact caused by the accumulation of device errors during the iterative operation, and improve the speed and accuracy of the alignment.

[0108] c. Constant Matrix Solution

[0109] Solve the eigenvector corresponding to the maximum eigenvalue of the recursive matrix K(M) to obtain the constant matrix with error The corresponding quaternion Then converting the quaternion into a direction cosine matrix gives Finally, the number of recursive steps M is increased by 1. The process is shown in the following formula:

[0110]

[0111] M=M+1

[0112] Among them, max is the maximum eigenvalue of the recursive matrix K(M).

[0113] On the other hand, the present invention discloses a missile-borne inertial navigation aerial coarse alignment system based on GNSS assistance, such as Figure 2 As shown, including:

[0114] The data acquisition module is used to obtain the initial information of the missile body provided by the GNSS receiver and the measurement data of the inertial navigation system after the inertial navigation system is started;

[0115] The initial module is used to initialize the inertial navigation system according to the initial information of the missile body combined with the measurement data to obtain the initial attitude matrix of the corresponding missile body;

[0116] A decomposition module, used to decompose the initial posture matrix based on the matrix chain multiplication relationship;

[0117] The attitude estimation module is used to construct the apparent position vector through the inertial force equation and the measurement data to obtain the real-time rough alignment attitude matrix;

[0118] The solution module is used to solve the rough alignment attitude matrix based on the REQUEST dual-vector attitude determination algorithm to obtain the rough alignment result.

[0119] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0120] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may 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 rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance, characterized in that: The following steps are involved: After the inertial navigation system is started, the initial information of the missile body provided by the GNSS receiver and the measurement data of the inertial navigation system are obtained; Initializing the inertial navigation system according to the initial information of the projectile in combination with the measurement data to obtain an initial attitude matrix corresponding to the projectile; Decompose the initial posture matrix based on the matrix chain multiplication relationship; Obtaining the measurement data updated by the inertial navigation system; The apparent position vector is constructed through the inertial navigation specific force equation and the measurement data to obtain the real-time rough alignment attitude matrix; The REQUEST-based dual-vector attitude determination algorithm solves the attitude matrix of the rough alignment to obtain a rough alignment result.

2. The method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance according to claim 1 is characterized in that: Based on the matrix chain multiplication relationship, the initial posture matrix is ​​decomposed into: in, Represents the attitude transformation matrix from n0 system to n system at time t; Represents the attitude transformation matrix from system n to system b at the initial moment; Represents the attitude transformation matrix from system b to system b0 at time t; Further To break it down: in: λ0 and L0 represent the longitude and latitude of the start time of the aerial rough alignment, respectively. t and L t Respectively represent the real-time longitude and latitude of the carrier.

3. The method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance according to claim 1 is characterized in that: Initializing the inertial navigation system according to the initial information of the projectile in combination with the measurement data to obtain an initial attitude matrix corresponding to the projectile, including: The initial information of the projectile is converted into the navigation coordinate system by means of a coordinate conversion algorithm, and an initial vector of the projectile in the navigation coordinate system is determined; Performing an integration operation on the measurement data to determine a change vector of the projectile in the inertial space; The change vector is combined with the initial vector using a vector synthesis algorithm to construct an initial posture matrix of the corresponding projectile.

4. The method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance according to claim 1 is characterized in that: After obtaining the initial information of the projectile provided by the GNSS receiver, it also includes: determining whether the current operating state of the GNSS is normal and whether the feedback information is true and valid based on the feedback information of the GNSS, and if so, determining that the GNSS is currently valid.

5. The method for rough alignment of missile-borne inertial navigation in the air based on GNSS assistance according to claim 1, characterized in that: The initial information of the projectile includes the initial position, initial velocity and initial attitude angle of the projectile; the measurement data of the inertial navigation system includes the angular velocity measurement value of the gyroscope and the acceleration measurement value of the accelerometer.

6. A missile-borne inertial navigation aerial coarse alignment system based on GNSS assistance, characterized in that: include: The data acquisition module is used to obtain the initial information of the missile body provided by the GNSS receiver and the measurement data of the inertial navigation system after the inertial navigation system is started; An initial module, used to initialize the inertial navigation system according to the initial information of the projectile in combination with the measurement data, and obtain an initial attitude matrix corresponding to the projectile; A decomposition module, used to decompose the initial posture matrix based on the matrix chain multiplication relationship; The attitude estimation module is used to construct the apparent position vector through the inertial force equation and the measurement data to obtain the real-time rough alignment attitude matrix; The solution module is used to solve the rough alignment posture matrix based on the REQUEST dual-vector posture determination algorithm to obtain a rough alignment result.

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