A universal air-to-air alignment method for gun-launched guided munitions navigation systems

Abstract

A universal air-to-air alignment method for gun-launched guided munitions navigation systems is proposed. Addressing the common problems of poor alignment accuracy and long convergence time in air-to-air alignment of both rotating and non-rotating guided munitions after firing, this invention proposes a two-step universal air-to-air alignment method. The first step employs an adaptive weighted coarse alignment method to calculate the initial roll angle of the guided munition. The second step uses an extended-dimensional observation filtering fine alignment method to accurately estimate the alignment errors of the three attitude angles, gyroscope constant errors, and accelerometer constant errors of the guided munition. Compared to traditional air-to-air alignment methods, this invention can adapt to various rotating guided munitions and various boosted or non-boosted trajectories, and features high alignment accuracy, short convergence time, and good trajectory adaptability.

Description

Technical Field

[0001] This invention relates to a universal air alignment method for a gun-launched guided munitions navigation system, belonging to the field of navigation technology. Background Technology

[0002] The harsh environment of high spin and high overload during shell launch renders ground-based static base alignment of the strapdown inertial navigation system ineffective before launch, necessitating in-flight alignment. Traditional in-flight initial roll angle alignment uses geomagnetic sensors to measure the roll angle; however, this method is highly susceptible to external interference and fails to function in environments with strong magnetic interference, rendering navigation information meaningless. Another method uses gyroscope signal modulation to calculate the roll angle, but this method suffers from poor observability, especially after launch without propulsion, slow convergence, large calculation errors, and is affected by accumulated gyroscope errors.

[0003] With the emergence of new guided munitions, the rate of fire is constantly increasing and the ballistic characteristics are becoming more diverse. The above-mentioned air-to-ground alignment methods are no longer able to meet the requirements in terms of alignment accuracy, alignment timeliness, ballistic adaptability, and versatility. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a universal air alignment method for artillery-launched guided munitions navigation systems to determine the initial attitude, position and velocity of the navigation system.

[0005] The technical solution of this invention is: a universal air alignment method for a gun-launched guided munition navigation system, comprising:

[0006] After the guided munition is fired from the gun barrel, its satellite navigation receiver begins to receive satellite navigation data, obtain the position and velocity of the navigation system as well as the pitch and heading angles, and calculates the roll angle of the guided munition in real time, and assigns the initial roll angle to the inertial navigation roll angle.

[0007] A filter is constructed, and the error terms in the unobserved variables of pitch, heading, and roll attitude angles of the guided munition are estimated based on the pitch angle, heading angle, roll angle of the navigation system and satellite navigation data. When the estimation process converges for a certain period of time or the fluctuation of the state variables is less than a certain threshold, the error terms are compensated on the corresponding measured values ​​to complete the air alignment. After that, the navigation system enters the navigation phase.

[0008] Furthermore, the calculation of the roll angle of the guided munition includes:

[0009] The roll angle is modulated and demodulated using the accelerometer measurement value of the inertial navigation system.

[0010] The roll angle is modulated and demodulated using the angular velocity measurement value of the inertial navigation system.

[0011] Based on the polarity and amplitude of the axial overload of the ammunition, the acceleration demodulation roll angle and the angular velocity demodulation roll angle are fused to generate an adaptive estimated roll angle.

[0012] Furthermore, the acceleration modulation and demodulation roll angle is... Wherein, the gravitational acceleration vector g' b =g b -f b g b f is the acceleration vector measured by the accelerometer in the body coordinate system. b The centrifugal force is measured by the accelerometer in the body coordinate system, where x, y, and z represent the axial directions and correspond to the front left upper coordinate axis, respectively.

[0013] Furthermore, the angular velocity modulation and demodulation roll angle is Where, ω b,y The measured value of the projectile's left-hand gyroscopic angular velocity, ω. b,z This is the measured value of the projectile's upward gyro angular velocity. Here, θ is the rate of change of the heading angle, and θ is the pitch angle. This represents the rate of change of the pitch angle.

[0014] Furthermore, the adaptively estimated roll angle is in, To modulate and demodulate the roll angle for angular velocity modulation. For acceleration modulation and demodulation, the roll angle k f Let be the adaptive coefficient, and the calculation formula is: In the formula f b,x f is the measured value from the axial accelerometer. th To set the threshold parameter.

[0015] Furthermore, the filter observation variable is obtained by subtracting the inertial measurement vector composed of the three-dimensional attitude, three-dimensional position, and three-dimensional velocity of the inertial navigation system from the observation reference vector composed of the trajectory pitch angle and trajectory heading angle resolved by satellite navigation velocity, the roll angle calculated by the adaptive weighted coarse alignment method, and the satellite navigation three-dimensional position and three-dimensional velocity, which is Z=[φ x φ y φ z δV E δV N δV U δP E δP N δP U ]; where attitude error Speed ​​error δV=V G -V INS Position error δP=P G -P INSThe state variables of the Kalman filter include attitude error, velocity error, position error, gyroscope constant error, accelerometer constant error, angle of attack, and sideslip angle, i.e.

[0016]

[0017] φ x φ y φ z These represent the attitude error of inertial navigation, θ. trace,G To calculate the pitch angle θ for satellite navigation tracks INS For inertial navigation pitch angle, To adaptively estimate the roll angle, γ INS For inertial navigation roll angle, ψ trace,G To calculate the heading angle for satellite navigation tracks, ψ INS For inertial navigation heading angle, V G Satellite navigation speed, V INS For inertial navigation speed, P G For satellite navigation positioning, P INS For inertial navigation position, δV E For the eastward velocity error, δV N For the northbound velocity error, δV U For the upward velocity error, δP E For the eastward position error, δP N For the northward position error, δP U For the celestial position error, ε b,x For forward gyroscope drift, ε b,y For left-hand gyroscope drift, ε b,z For upward gyroscope drift, To add zero bias to the forward table, To add zero bias to the left, The upward addition is zero bias, α is the angle of attack, and β is the sideslip angle.

[0018] Furthermore, the initial pitch and heading angles of the navigation system are provided by the track pitch and heading angles resolved from the satellite navigation velocity.

[0019] Furthermore, the initial position and velocity of the navigation system are provided by the satellite navigation receiver after power-on or obtained through binding.

[0020] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a general air alignment method for a gun-launched guided munition navigation system.

[0021] A universal air alignment device for a gun-launched guided munitions navigation system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the universal air alignment method for a gun-launched guided munitions navigation system.

[0022] The advantages of this invention compared to the prior art are:

[0023] (1) This invention addresses the common problems of poor alignment accuracy and long alignment convergence time in the air alignment of rotating and non-rotating guided munitions navigation systems that are powered on after gun firing. It designs an adaptive weighted roll angle estimation method with the axial accelerometer measurement value as the independent variable, realizing the adaptive estimation of the roll angle. It can adapt to various rotating guided munitions and various boosted or non-boosted trajectories, and has the characteristics of good trajectory adaptability. It eliminates the influence and constraints of trajectory maneuvering on air alignment.

[0024] (2) The present invention adopts a two-step general air alignment method for guided munitions. The first step adopts an adaptive weighted coarse alignment method to calculate the initial roll angle of the guided munitions. The second step adopts an extended dimension observation filtering fine alignment method to realize roll angle estimation and attitude alignment. Compared with the traditional alignment method, it can estimate more error terms such as instrument zero position error after overload. It has the advantages of high accuracy and short alignment convergence time. Attached Figure Description

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0026] Figure 1 The present invention provides a block diagram of the general aerial alignment method.

[0027] Figure 2 The flowchart illustrates the universal aerial alignment method proposed in this invention. Detailed Implementation

[0028] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0029] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of a universal air-to-air alignment method for a gun-launched guided munition navigation system provided by an embodiment of the present invention. Figure 1 Specific implementation methods may include:

[0030] The first step employs an adaptive weighted coarse alignment method to calculate the initial roll angle of the guided munition, which includes the following specific steps:

[0031] 1) The initial position and velocity of the navigation system are provided by the satellite navigation receiver after power-on or obtained through binding;

[0032] 2) The initial pitch and heading angles of the navigation system are provided by the track pitch and heading angles resolved by the satellite navigation velocity, or the initial firing angle and firing direction are obtained by binding.

[0033] 3) The initial roll angle of the navigation system is provided by an adaptive weighted roll angle estimation algorithm.

[0034] 4) The adaptive weighted roll angle estimation algorithm for rolling munitions comprises three parts: acceleration modulation and demodulation roll angle, angular velocity modulation and demodulation roll angle, and an adaptive weighting algorithm. The acceleration modulation and demodulation roll angle is calculated using accelerometer measurements from the inertial navigation system (INS), while the angular velocity modulation and demodulation roll angle is calculated using angular velocity measurements from the INS. The adaptive weighting algorithm, based on the polarity and amplitude of the axial overload of the munition, uses an adaptive calculation formula to fuse the acceleration demodulation roll angle and the angular velocity demodulation roll angle to generate an adaptively estimated roll angle. This adaptive weighting calculation method ensures good roll angle estimation accuracy in both the extended-range boost phase and the non-boost phase after guided munition launch, mitigating the impact of ballistic maneuvering on roll angle estimation accuracy.

[0035] The second step employs a dimension-expanded observation filtering fine alignment method to accurately estimate the three-way attitude angle alignment error, gyroscope constant error, and accelerometer constant error of the guided munition. This specifically includes the following steps:

[0036] 5) The extended-dimensional observation filtering fine alignment method uses a Kalman filter to estimate non-observed variables such as three-way attitude angle alignment errors, gyroscope constant errors, and accelerometer constant errors. The observed variables of the Kalman filter are obtained by subtracting the inertial measurement vector composed of the three-dimensional attitude, three-dimensional position, and three-dimensional velocity of the inertial navigation system from the observation reference vector composed of the trajectory pitch angle and trajectory heading angle of the satellite navigation velocity analysis, the roll angle calculated by the adaptive weighted coarse alignment method, and the satellite navigation three-dimensional position and three-dimensional velocity. The state variables of the Kalman filter include the attitude error, velocity error, position error, angle of attack, and sideslip angle of the inertial navigation system. By extending the dimension of the attitude observation variables, a fast and accurate estimation of the error terms in the non-observed variables is achieved.

[0037] In the solutions provided in the embodiments of the present invention, such as Figure 2 The steps include the following:

[0038] 1) After the guided munitions are fired from the gun barrel, the navigation system is powered on, and the inertial navigation measurement unit, satellite navigation receiver and other components inside the navigation system begin to work.

[0039] 2) After a few seconds of startup, the satellite navigation receiver begins receiving satellite navigation data, which includes the three-dimensional position vector P measured by satellite navigation. G =[P GE P GN P GU ] and three-dimensional velocity vector V G =[V GE V GN V GU ].

[0040] 3) Aerial alignment first step: adaptive weighted coarse alignment start.

[0041] 4) The initial position and velocity of the navigation system are provided by the satellite navigation receiver after power-on or obtained through binding. The initial position P of inertial navigation... INS =P G Initial velocity V INS =V G .

[0042] 5) The initial pitch and heading angles of the navigation system are provided by the track pitch and heading angles resolved from the satellite navigation velocity, while the initial pitch angle of inertial navigation... Inertial navigation initial heading angle The pitch angle of the flight path or the initial firing angle can also be obtained through binding.

[0043] 6) The initial roll angle of the navigation system is provided by an adaptive weighted roll angle estimation algorithm.

[0044] 7) The adaptive roll angle estimation algorithm for the rolling projectile consists of three parts: acceleration modulation and demodulation roll angle, angular velocity modulation and demodulation roll angle, and adaptive weighting algorithm. The acceleration modulation and demodulation roll angle uses the accelerometer measurement value of the inertial navigation system to modulate and demodulate the roll angle. The angular velocity modulation and demodulation roll angle uses the angular velocity measurement value of the inertial navigation system to modulate and demodulate the roll angle. The adaptive weighting algorithm uses an adaptive calculation formula based on the polarity and amplitude of the axial overload of the projectile to fuse the acceleration demodulation roll angle and the angular velocity demodulation roll angle to generate an adaptive estimated roll angle.

[0045] The above three parts run in parallel. The following is a detailed introduction to the algorithm implementation of the three parts.

[0046] The formula for calculating the roll angle of acceleration modulation and demodulation is: Where g' b =[g' b,x g' b,y g' b,z [g'] represents the periodic variation of the acceleration vector measured by the accelerometer in the body coordinate system. It exhibits periodic variation characteristics and is calculated using the formula g'. b =g b -f b , gb f is the acceleration vector measured by the accelerometer in the body coordinate system. b This represents the centrifugal force measured by the accelerometer in the body coordinate system. x, y, and z represent the axial directions, corresponding to the front left and upper coordinate axes, respectively.

[0047] The formula for calculating the roll angle of angular velocity modulation and demodulation is as follows: This formula is derived from the Euler equation, where ω b =[ω b,x ω b,x ω b,x ] represents the angular velocity vector of the gyroscope measured in the body coordinate system.

[0048] The formula for calculating the roll angle using the adaptive weighted algorithm is as follows: In the formula k f The adaptive coefficient is calculated using the following formula: In the formula f b,x f is the measured value from the axial accelerometer. th To set the threshold parameters, this adaptive weighted calculation method can ensure that the roll angle estimation accuracy is good in both the extended-range boost phase and the non-boost phase after the guided munition is launched, thus weakening the impact of the roll angle estimation accuracy of the ballistic maneuver.

[0049] 8) After obtaining the adaptive weighted estimated roll angle, it is assigned to the inertial navigation roll angle. The adaptive weighted coarse alignment algorithm continues to be executed, but the calculated roll angle is no longer assigned to the inertial navigation roll angle.

[0050] 9) The second step of the aerial alignment, the extended dimension observation and filtering fine alignment algorithm is started.

[0051] 10) The extended-dimensional observation filtering fine alignment method uses a Kalman filter to estimate non-observed variables such as the three-way attitude angle alignment error, gyroscope constant error, and accelerometer constant error. The observed variable of the Kalman filter is obtained by subtracting the inertial measurement vector composed of the three-dimensional attitude, three-dimensional position, and three-dimensional velocity of the inertial navigation system from the observation reference vector composed of the trajectory pitch angle and trajectory heading angle of the satellite navigation velocity analysis, the roll angle calculated by the adaptive weighted coarse alignment method, and the three-dimensional position and three-dimensional velocity of the satellite navigation system. That is, the observed variable Z = [φ x φ y φ z δV EδV N δV U δP E δP N δP U ], where attitude error Speed ​​error δV=V G -V INS Position error δP=P G -P INS The state variables of the Kalman filter include attitude error, velocity error, position error, gyroscope constant error, accelerometer constant error, angle of attack, and sideslip angle, i.e. The Kalman filter used can be designed in an open-loop or closed-loop manner to correct the cumulative error of inertial navigation. By expanding the dimensions of the observed variables, the error term in the unobserved variables can be estimated quickly and accurately.

[0052] 11) When the fine alignment algorithm converges for a certain period of time or the fluctuation of the state variable is less than a certain threshold, the three-way attitude angle alignment error, gyroscope constant error and accelerometer constant error of the fine alignment are compensated on the attitude angle of the inertial navigation, the measured value of the gyroscope and the measured value of the accelerometer respectively.

[0053] 12) The extended-dimensional observation filtering fine alignment algorithm ends, the entire air alignment process ends, and then the navigation system enters the navigation phase.

[0054] The present invention describes a general air alignment method for artillery-launched guided munitions navigation systems, wherein the adaptive weighted algorithm and roll angle estimation algorithm in the adaptive weighted coarse alignment, f th The threshold parameter can be set to [0.1g, g] based on the ballistic characteristics, where g is the local gravitational acceleration. Compared with traditional aerial alignment methods, the universal aerial alignment method proposed in this patent has advantages in alignment accuracy, alignment timeliness, ballistic adaptability, and versatility, and can overcome the problems existing in traditional aerial alignment methods.

[0055] This invention provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform... Figure 2 The method described.

[0056] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0057] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0058] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0059] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0061] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A universal air-to-air alignment method for a gun-launched guided munition navigation system, characterized in that, include: After the guided munition is fired from the gun barrel, its satellite navigation receiver begins to receive satellite navigation data, obtain the position and velocity of the navigation system as well as the pitch and heading angles, and calculates the roll angle of the guided munition in real time, and assigns the initial roll angle to the inertial navigation roll angle. Construct a filter and estimate the error terms in the unobserved variables of pitch, heading, and roll attitude angles of the guided munition based on the pitch angle, heading angle, roll angle of the navigation system and satellite navigation data; When the estimation process converges for a certain period of time or the fluctuation of the state variables is less than a certain threshold, the error terms are compensated on the corresponding measured values ​​to complete the air alignment. After that, the navigation system enters the navigation phase. The calculation of the roll angle of the guided munition includes: The roll angle is modulated and demodulated using the accelerometer measurement value of the inertial navigation system. The roll angle is modulated and demodulated using the angular velocity measurement value of the inertial navigation system. Based on the polarity and amplitude of the axial overload of the ammunition, the acceleration demodulation roll angle and the angular velocity demodulation roll angle are fused to generate an adaptive estimated roll angle.

2. The universal air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The acceleration modulation and demodulation roll angle is Among them, the gravitational acceleration vector , The acceleration vector measured by the accelerometer in the body coordinate system. The centrifugal force measured by the accelerometer in the body coordinate system. Indicates the axis, corresponding to the front left upper coordinate axis respectively.

3. The universal air-to-air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The angular velocity modulation and demodulation roll angle is ;in, This is the measured value of the projectile's left-hand gyro angular velocity. This is the measured value of the projectile's upward gyro angular velocity. For the heading angle transformation rate, The pitch angle, This represents the rate of change of the pitch angle.

4. The universal air-to-air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The adaptively estimated roll angle is ;in, To modulate and demodulate the roll angle for angular velocity modulation. Roll angle for acceleration modulation and demodulation Let be the adaptive coefficient, and the calculation formula is: In the formula The measured value is from the axial accelerometer. To set the threshold parameter.

5. A universal air-to-air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The filter observation variables are obtained by subtracting the inertial measurement vector composed of the three-dimensional attitude, three-dimensional position, and three-dimensional velocity of the inertial navigation system from the observation reference vector composed of the trajectory pitch and heading angles resolved by satellite navigation velocity analysis, the roll angle calculated by the adaptive weighted coarse alignment method, and the satellite navigation three-dimensional position and three-dimensional velocity. Among them, attitude error Speed ​​error Position error The state variables of the Kalman filter include attitude error, velocity error, position error, gyroscope constant error, accelerometer constant error, angle of attack, and sideslip angle, i.e. , , These represent the attitude error of inertial navigation. To calculate the pitch angle for satellite navigation tracks, For inertial navigation pitch angle, To adaptively estimate the roll angle, For inertial navigation roll angle, To calculate the heading angle for satellite navigation tracks, For inertial navigation heading angle, Satellite navigation speed, For inertial navigation speed, For satellite navigation position, For inertial navigation position, For eastward velocity error, For northbound velocity error, For the upward velocity error, This is the eastward position error. This is the northward position error. This is the celestial position error. For forward gyroscope drift, For left-hand gyroscope drift, For upward gyroscope drift, To add zero bias to the forward table, To add zero bias to the left, To add zero bias to the table, For the angle of attack, It is the sideslip angle.

6. A universal air-to-air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The initial pitch and heading angles of the navigation system are provided by the track pitch and heading angles resolved from the satellite navigation velocity.

7. A universal air-to-air alignment method for a gun-launched guided munitions navigation system according to claim 1, characterized in that, The initial position and velocity of the navigation system are provided by the satellite navigation receiver after power-on or obtained through binding.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

9. A universal air-to-air alignment device for a gun-launched guided munitions navigation system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 7.

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