A front angle-based adaptive gravity compensation trajectory correction method

Abstract

The application discloses a self-adaptive gravity compensation trajectory correction method based on a lead angle and belongs to the technical field of aircraft guidance control. The application constructs a dynamic mapping relation between a trajectory deviation and a gravity compensation amount by using the real-time measured lead angle information of the aircraft, adaptively adjusts a gravity compensation coefficient to correct the trajectory, reduces the compensation amount to inhibit the trajectory lifting when attacking a short-distance target, enhances the compensation to offset the falling effect when attacking a long-distance target, improves the problem that the gravity compensation is fixed and does not affect the guidance effect in the traditional method when attacking targets with different distances, reduces the dependence on the difficult-to-measure parameters such as the remaining time in other methods, and improves the striking precision and the shooting range of the aircraft on different targets.

Description

Technical Field

[0001] This invention belongs to the field of aircraft guidance and control technology, specifically relating to an adaptive gravity compensation trajectory correction method based on lead angle. Background Technology

[0002] In aircraft guidance and control, gravity compensation is a core means of suppressing ballistic drop and improving accuracy. Traditional gravity compensation methods are typically based on a fixed proportional coefficient, using a preset gravitational acceleration component to statically correct the trajectory. For example, the classic gravity compensation proportional guidance law corrects the trajectory by offsetting the gravity component. However, such methods have significant limitations in practical applications: when there is a large deviation between the attack distance and the preset trajectory, the fixed compensation coefficient is difficult to adapt to the dynamic changes in the relative motion of the projectile and the target. For example, in close-range attack scenarios, fixed compensation can cause the trajectory to rise and become inaccurate due to excessive offsetting of the gravity component; while in long-range attacks, insufficient compensation exacerbates the trajectory drop, ultimately leading to a larger miss distance. This fixed compensation strategy severely limits the strike effectiveness of aircraft.

[0003] Existing improvement schemes attempt to enhance adaptability by dynamically adjusting the gravity compensation coefficient. For example, they employ a phased coefficient switching strategy or adjust the compensation amount based on a ballistic height threshold. However, such methods suffer from limitations due to their reliance on parameters that are difficult to obtain accurately in real time, such as remaining time, leading to complex engineering implementation. Furthermore, they rely on limited feedback information, adjusting the compensation amount solely based on the projectile-eye line-of-sight angular velocity or ballistic height information, failing to fully utilize the multi-dimensional information measured in real time by onboard sensors, resulting in correction lag. Adaptability is also limited; existing compensation strategies largely depend on preset conditions or theoretical trajectory predictions, failing to generate compensation amounts in real time based on actual trajectory deviations. Some methods compensate by proactively correcting the theoretical trajectory, but these rely on offline calculation models and are ill-suited to handle real-time dynamic errors.

[0004] Therefore, there is an urgent need for a method that can autonomously adjust the amount of gravity compensation based on the real-time status of the aircraft, thereby breaking through the limitations of traditional methods on the attack range and achieving a flexible correction effect of "shooting at close range and correcting at long range, and shooting at long range and correcting at close range". Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an adaptive gravity compensation ballistic correction method based on the lead angle. By constructing an adjustment strategy for the gravity compensation amount through the lead angle information, the gravity compensation amount is adaptively adjusted in real time to achieve the ballistic correction effect of "correcting the distance when hitting a target and correcting the distance when hitting a target", which significantly improves the target range and accuracy of the aircraft.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An adaptive gravity compensation ballistic correction method based on lead angle includes the following steps:

[0008] S1. Measure the aircraft's velocity V in the northeast-northeast coordinate system in real time using the aircraft's integrated navigation system. e V n V s and position x n ,y n ,z n Furthermore, the projectile-eye line-of-sight angle q is obtained by measuring and filtering through the seeker. g and the angular velocity of the bullet's line of sight

[0009] S2, based on position x n ,y n ,z n The latitude φ and altitude h information are used to calculate the gravitational acceleration g in real time; then, based on x... n and y n Calculate the transformation matrix L from the navigation coordinate system to the ground coordinate system, and then use the velocity V. e V n V s The velocity V of the aircraft in the ground coordinate system is calculated using the transformation matrix L. x V y V z Relative velocity V between projectile and target xr V yr V zr And according to V x V y The trajectory inclination angle θ is calculated, and based on the projectile-target line-of-sight angle q... g Calculate the lead angle η of the vehicle's velocity vector based on the trajectory inclination angle θ, and then calculate the relative velocity V between the projectile and the target. xr V yr V zr The relative velocity V between the aircraft and the target was calculated. m ;

[0010] S3. Based on the current relative speed V between the aircraft and the target. m and the angular velocity of the bullet's line of sight Calculate the proportional guidance command a in the guidance command calculation yc ;

[0011] S4. Calculate the adaptive gravity compensation command a based on the real-time changes in the trajectory inclination angle θ and the lead angle η. g And through the adaptive gravity compensation command a g And proportional guidance instruction a yc Calculation of comprehensive guidance instructions a y This is done to achieve the purpose of ballistic correction.

[0012] As a further preferred embodiment of the present invention, S2 specifically includes:

[0013] Based on position x n ,y n ,z n Using the latitude φ and altitude h information, the gravitational acceleration g is calculated in real time using the following formula:

[0014]

[0015] Where R = 6378137;

[0016] The transformation matrix L from the navigation coordinate system to the ground coordinate system is calculated using the following formula:

[0017]

[0018] Where ψ is the yaw rotation angle between the northeast celestial coordinate system and the ground coordinate system.

[0019] Reusing speed V e V n V s The velocity V of the aircraft in the ground coordinate system is calculated using the transformation matrix L. x V y V z Relative velocity V between projectile and target xr V yr V zr The formula is as follows:

[0020] [V x V y V z ] T =L[V e V n V s ] T

[0021] [V xr V yr V zr ] T =L[V e -V et V n -V nt V s -V st ] T

[0022] Among them, V e V n V s These represent the eastward, northward, and celestial velocities of the spacecraft in the northeast-northeast coordinate system, respectively. x V y Vz These represent the x, y, and z velocities of the aircraft in the ground coordinate system, respectively, V. xr V yr V zr V represents the relative velocities of the aircraft with the target in the x, y, and z directions, respectively. et V nt V st The target's northward velocity, eastward velocity, and celestial velocity in the northeast-to-sky coordinate system;

[0023] And according to V x V y The trajectory inclination angle θ is calculated using the following formula:

[0024]

[0025] After the aircraft enters the terminal guidance phase, the aircraft velocity vector lead angle η is calculated every m frames of data. The formula for the aircraft velocity vector lead angle η is as follows:

[0026] η = q g -θ

[0027] Where, q g The line of sight for bullets;

[0028] Based on the relative velocity V of the projectile and the target xr V yr V zr The relative velocity V between the aircraft and the target was calculated. m The formula is as follows:

[0029]

[0030] As a further preferred embodiment of the present invention, the formula for calculating S3 is:

[0031]

[0032] Where N represents the proportionality coefficient, and 2 <N<6,a yc For proportional guidance instructions, V m The relative speed between the aircraft and the target is currently [value missing]. The angular velocity is the line-of-sight velocity of the projectile.

[0033] As a further preferred embodiment of the present invention, the adaptive gravity compensation command a is calculated in S4. g The formula is as follows:

[0034]

[0035] Where, k gθ This is a gravity compensation coefficient related to the trajectory inclination of the aircraft. k is the gravity compensation coefficient related to the attack angle when the seeker acquires the target. gη This is the gravity compensation coefficient related to the aircraft's leading angle;

[0036] Calculate the gravity compensation coefficient k based on the ballistic inclination angle θ. gθ The formula is as follows:

[0037] k gθ =cosθ

[0038] Determine the threshold range of the trajectory inclination angle θ0 when the aircraft enters the terminal guidance phase, and then determine the gravity compensation coefficient related to the attack angle when the seeker acquires the target. The formula is as follows:

[0039]

[0040] Where, k g1 k g2 and k g3 θ1 and θ2 are gravity compensation coefficients for different intervals, and θ1 and θ2 are ballistic inclination angle thresholds;

[0041] Determine the threshold range and sign of the amplitude of the aircraft's lead angle η, and then adaptively adjust the gravity compensation coefficient k related to the aircraft's lead angle. gη ,

[0042] The formula is as follows:

[0043]

[0044] Where, k gη11 k gη12 k gη21 k gη22 k gη31 k gη32 and k gη4 These are the gravity compensation coefficients for different intervals, and η1, η2, and η3 are the pre-angle thresholds.

[0045] As a further preferred embodiment of the present invention, in S4, the adaptive gravity compensation command a g And proportional guidance instruction a yc Calculation of comprehensive guidance instructions a y The formula is as follows:

[0046]

[0047] As a further preferred embodiment of the present invention, the proportionality coefficient N in S3 is 4.

[0048] As a further preferred embodiment of the present invention, in S2, the aircraft velocity vector advance angle η is calculated once after measuring m frames of data, where m is 20°.

[0049] As a further preferred embodiment of the present invention, k in S4 g1 =1.3, k g2 =1,k g3 =0.7, θ1=-20, θ2=-35.

[0050] As a further preferred embodiment of the present invention, k in S4 gη11 =0.7, k gη12 =-0.5, k gη21 =0.4, k gη22 =-0.3, k gη31 =0.3, k gη32 =-0.2, k gη4 =0, eta1=10, eta2=5, eta3=3.

[0051] The beneficial effects of this invention are as follows:

[0052] This invention dynamically and adaptively adjusts the gravity compensation amount by measuring the lead angle information in real time, effectively solving the problem of "under-compensation at long range and over-compensation at close range" in traditional fixed gravity compensation methods when attacking targets at different distances. Based on the strong correlation between the lead angle and the ballistic deviation, an adaptive correction relationship is constructed. When attacking close-range targets, the gravity compensation coefficient is reduced by the lead angle information to avoid excessive ballistic rise. When attacking long-range targets, the compensation amount is adaptively increased to suppress ballistic drop, significantly improving the accuracy and range of attacking targets at different ranges.

[0053] Compared to traditional compensation strategies that rely on indirect parameters such as remaining time, this invention directly utilizes the lead angle to map real-time ballistic deviations, reducing parameter dependence and simplifying the calculation process. Combined with proportional guidance laws, it achieves flexible control effects of "shooting close and correcting long distances, and shooting long distances and correcting close distances," expanding the aircraft's strike capabilities in different scenarios. At the same time, it optimizes computational efficiency, avoids the computational burden caused by multi-dimensional parameter calculations, meets the stringent real-time requirements of ballistic correction, and improves the aircraft's multi-mission adaptability.

[0054] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0055] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0056] Figure 1 This is a geometric diagram showing the intersection of an aircraft and a target in the longitudinal plane.

[0057] Figure 2 The curves showing the change in the forward angle for different target distance deviations;

[0058] Figure 3 A comparison of the longitudinal ballistic trajectory throughout the entire flight path under a certain launch condition, along with a magnified view of a portion thereof;

[0059] Figure 4 A comparison curve of the lead angle in the final guidance phase under a certain deployment condition;

[0060] Figure 5 A comparison curve of gravity compensation commands during the final guidance phase under a certain deployment condition;

[0061] Figure 6 A comparison curve of overload commands in the terminal guidance phase under a certain deployment condition;

[0062] Figure 7 This is a schematic diagram of the overall process of an adaptive gravity compensation ballistic correction method based on the lead angle according to the present invention. Detailed Implementation

[0063] like Figures 1-7 As shown, this invention discloses an adaptive gravity compensation ballistic correction method based on the lead angle, and the specific implementation steps are as follows:

[0064] Taking a certain type of axisymmetric aircraft as an example, the rendezvous relationship between the aircraft and the target in the longitudinal plane is as follows: Figure 1 As shown, where n m For the normal overload of the aircraft, y m The implementation process of this invention is described using the longitudinal altitude of the aircraft as an example:

[0065] S1. Utilize the integrated navigation system of the axisymmetric aircraft to measure the aircraft's velocity V in the northeast-northeast coordinate system in real time. e V n V s and position x n ,y n ,z n The aircraft's seeker measures and filters to obtain the missile's line-of-sight angle q. g and the angular velocity of the bullet's line of sight

[0066] Among them, V e V n V s These represent the eastward, northward, and celestial velocities of the spacecraft in the northeast-northeast coordinate system, respectively. n ,y n ,z n These represent the spacecraft's eastward, northward, and celestial positions in the northeast-northeast coordinate system.

[0067] S2. Using the real-time measured position and velocity information of the aircraft, information such as gravitational acceleration, velocity, and trajectory inclination angle are calculated. Specifically:

[0068] S21. Based on the latitude φ and altitude h of the aircraft, calculate the precise gravitational acceleration g in real time.

[0069]

[0070] Where R = 6378137;

[0071] S22. Calculate the transformation matrix L from the navigation coordinate system to the ground coordinate system.

[0072]

[0073] Where ψ is the yaw rotation angle between the northeast celestial coordinate system and the ground coordinate system.

[0074] S23. Using the information obtained in real time from the integrated navigation system and the transformation relationship between the northeast celestial coordinate system and the ground coordinate system, the velocity V of the aircraft in the ground system is calculated. x V y V z Relative velocity V between projectile and target xr V yr V zr .

[0075] [V x V y V z ] T =L[V e V n V s ] T

[0076] [V xr V yr V zr ] T =L[V e -V et V n -V nt V s -V st ] T

[0077] Among them, V x V y V z These represent the x, y, and z velocities of the aircraft in the ground coordinate system, respectively, V. xr V yr Vzr V represents the relative velocities of the aircraft with the target in the x, y, and z directions, respectively. et V nt V st The northward velocity, eastward velocity, and celestial velocity of the target in the northeast-sky coordinate system.

[0078] Then, using the information obtained from the above steps, the ballistic tilt angle θ and the current relative velocity V between the aircraft and the target are calculated. m .

[0079]

[0080] After the axisymmetric vehicle enters the terminal guidance phase, the vehicle velocity vector advance angle η is calculated every 20 frames of data.

[0081] η = q g -θ

[0082] The magnitude and sign of the leading angle η differ depending on the target distance, such as... Figure 2 As shown, the dashed line represents shooting close and repairing far, while the solid line represents shooting far and repairing close.

[0083] S3. Based on the obtained relative speed V between the current aircraft and the target. m and line-of-sight angular velocity Calculate the proportional guidance term a in the guidance command yc , usually 2 <N<6。

[0084]

[0085] N represents the scaling factor, and the scaling factor N is chosen to be 4.

[0086] S4. Based on the real-time changes in the trajectory inclination angle θ and lead angle η obtained in the above steps, adaptive gravity compensation is performed on the guidance command. The gravity compensation coefficients mainly include:

[0087] Gravity compensation coefficient k related to the trajectory inclination of the aircraft gθ Gravity compensation coefficient related to the attack angle when the seeker acquires the target The gravity compensation coefficient k related to the aircraft's lead angle gη .

[0088] Calculate the gravity compensation coefficient k based on the ballistic inclination angle θ. gθ .

[0089] k gθ =cosθ

[0090] Determine the threshold range of the trajectory inclination angle θ0 when the aircraft enters the terminal guidance phase, and then determine the gravity compensation coefficient related to the attack angle when the seeker acquires the target.

[0091]

[0092] Determine the threshold range and sign of the amplitude of the aircraft's lead angle η, and then adaptively adjust the gravity compensation coefficient k related to the aircraft's lead angle. gη .

[0093]

[0094] Gravity compensation term a in guidance commands g for:

[0095]

[0096] The integrated guidance command consists of proportional guidance command and adaptive gravity compensation command.

[0097]

[0098] The adaptive guidance command calculated through the above steps can adjust the compensation terms according to the changes in the aircraft's lead angle, make full use of gravity factors for trajectory correction, improve the guidance control loop's ability to resist uncertainties, is easy to implement in engineering, and significantly expands the aircraft's combat effectiveness and applicability.

[0099] A simulation was conducted for a scenario where the target is 18km horizontally from the launch point. Two identical aircraft were launched at a launch velocity of 600m / s, a launch angle of 45°, no off-axis angle, and an aerodynamic pull of 1.1. The horizontal distance at which the target was acquired increased by 800m compared to the initial target acquisition time, which falls under the "close-range target acquisition, long-range target acquisition" scenario. The results are as follows: Figure 3 The two ballistic curves shown are shown.

[0100] The first spacecraft employs a proportional guidance law for guidance during the mid-course guidance phase and an adaptive gravity-compensated trajectory correction guidance law as described in this invention during the terminal guidance phase. The mid-course and terminal guidance transition ensures that the seeker acquires the target and the trajectory smoothly transitions, with its trajectory curve as shown below. Figure 3 As shown in the "Adaptive Gravity Compensation" section.

[0101] The second spacecraft employs a proportional guidance law for guidance during the mid-course phase and a traditional fixed overgravity compensation guidance law for guidance during the terminal phase. The mid-course and terminal guidance transition ensures that the seeker acquires the target and the trajectory smoothly transitions, with its trajectory curve as shown below. Figure 3 As shown in the "Fixed Overgravity Compensation" section.

[0102] The traditional fixed overload compensation guidance law used is as follows:

[0103]

[0104] from Figure 3 The two flight trajectories show that the miss distance of the aircraft using the adaptive gravity compensation guidance law of this invention is 0.26m, which is better than the 4.2m of the traditional overgravity compensation guidance law. This indicates that the adaptive adjustment of the gravity compensation term can improve guidance accuracy and expand the attack range.

[0105] from Figure 4 As can be seen from the two lead angle change curves, the lead angle of the aircraft using the adaptive gravity compensation guidance law of this invention converges to 0 faster, while the traditional overweight compensation guidance law converges slowly and ultimately does not converge to 0.

[0106] from Figure 5 and Figure 6 A comparison of the gravity compensation command curve and the overload command curve shows that the gravity compensation command and overload command of the aircraft using the adaptive gravity compensation guidance law of this invention are adaptively adjusted according to the change of the lead angle.

[0107] This invention dynamically and adaptively adjusts the gravity compensation amount by measuring the lead angle information in real time, effectively solving the problem of "under-compensation at long range and over-compensation at close range" in traditional fixed gravity compensation methods when attacking targets at different distances. Based on the strong correlation between the lead angle and the ballistic deviation, an adaptive correction relationship is constructed. When attacking close-range targets, the gravity compensation coefficient is reduced by the lead angle information to avoid excessive ballistic rise. When attacking long-range targets, the compensation amount is adaptively increased to suppress ballistic drop, significantly improving the accuracy and range of attacking targets at different ranges.

[0108] Compared to traditional compensation strategies that rely on indirect parameters such as remaining time, this invention directly utilizes the lead angle to map real-time ballistic deviations, reducing parameter dependence and simplifying the calculation process. Combined with proportional guidance laws, it achieves flexible control effects of "shooting close and correcting long distances, and shooting long distances and correcting close distances," expanding the aircraft's strike capabilities in different scenarios. At the same time, it optimizes computational efficiency, avoids the computational burden caused by multi-dimensional parameter calculations, meets the stringent real-time requirements of ballistic correction, and improves the aircraft's multi-mission adaptability.

[0109] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. An adaptive gravity compensation ballistic correction method based on lead angle, characterized in that: Includes the following steps: S1. Measure the aircraft's velocity in the northeast-northeast coordinate system in real time using the aircraft's integrated navigation system. and location Furthermore, the projectile-eye line-of-sight angle is obtained by measuring and filtering through the seeker. and the angular velocity of the bullet's line of sight ; S2, based on position latitude and height Information, calculate gravitational acceleration g in real time; and then according to Calculate the transformation matrix from the navigation coordinate system to the ground coordinate system. , then utilize speed and transformation matrix The velocity of the aircraft in the ground coordinate system was calculated. Relative velocity between projectile and target and according to The calculated trajectory inclination angle And according to the line of sight of the bullet. and ballistic inclination angle Calculate the lead angle of the aircraft velocity vector And based on the relative velocity of the projectile and the target The relative speed between the aircraft and the target was calculated. ;in These represent the eastward, northward, and celestial velocities of the spacecraft in the northeast-northeast coordinate system. These represent the x-axis, y-axis, and z-axis velocities of the aircraft in the ground coordinate system. These represent the relative velocities of the aircraft with respect to the target in the x, y, and z directions, respectively. S3. Based on the current relative speed between the aircraft and the target. and the angular velocity of the bullet's line of sight Calculate the proportional guidance command in the guidance command. ; S4. Based on the ballistic inclination angle and front angle Real-time changes, calculate adaptive gravity compensation commands And through adaptive gravity compensation commands Scaling and proportional guidance instructions Calculation of comprehensive guidance instructions This is done to achieve ballistic correction. Calculate adaptive gravity compensation command in S4 The formula is as follows: in, This is a gravity compensation coefficient related to the trajectory inclination of the aircraft. This is a gravity compensation coefficient related to the attack angle when the seeker acquires the target. This is the gravity compensation coefficient related to the aircraft's leading angle; According to the ballistic inclination angle Calculate the gravity compensation coefficient The formula is as follows: Determine the trajectory inclination angle of the aircraft when it enters the terminal guidance phase. The threshold range in which it falls is used to determine the gravity compensation coefficient related to the attack angle when the seeker acquires the target. The formula is as follows: in, , and These are the gravity compensation coefficients for different intervals. and This is the threshold for the ballistic inclination angle; Determine the aircraft's leading angle The threshold range and sign of the amplitude are determined, thereby adaptively adjusting the gravity compensation coefficient related to the aircraft's forward angle. , The formula is as follows: in, , , , , , and These represent the gravity compensation coefficients for different intervals. , and This is the leading angle threshold.

2. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 1, characterized in that: S2 specifically includes: According to location latitude and height Information, real-time calculation of gravitational acceleration g, the formula is as follows: Where R = 6378137; Calculate the transformation matrix from the navigation coordinate system to the ground coordinate system. The formula is as follows: in, This represents the yaw rotation angle between the northeast celestial coordinate system and the ground coordinate system. ; Reuse speed and transformation matrix The velocity of the aircraft in the ground coordinate system was calculated. Relative velocity between projectile and target The formula is as follows: in, The target's northward velocity, eastward velocity, and celestial velocity in the northeast-to-sky coordinate system; And according to The calculated trajectory inclination angle The formula is as follows: After the spacecraft enters the terminal guidance phase, each measurement Calculate the aircraft velocity vector advance angle once after frame data. Aircraft velocity vector lead angle The formula is as follows: in, The line of sight for bullets; Based on the relative velocity of the projectile and the target The relative speed between the aircraft and the target was calculated. The formula is as follows: 。 3. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 1, characterized in that: The formula for calculating S3 is: in, This represents the proportionality constant, and 2 <N<6, This is a proportional guidance instruction. The relative speed between the aircraft and the target is currently [value missing]. The angular velocity is the line-of-sight velocity of the projectile.

4. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 1, characterized in that: S4 uses adaptive gravity compensation commands Scaling and proportional guidance instructions Calculation of comprehensive guidance instructions The formula is as follows: 。 5. The adaptive gravity compensation ballistic correction method based on the lead angle according to claim 3, characterized in that: The proportionality coefficient in S3 The value is 4.

6. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 2, characterized in that: Each measurement in S2 Calculate the aircraft velocity vector advance angle once after frame data. , where m is 20.

7. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 1, characterized in that: S4 , , , , .

8. The adaptive gravity compensation ballistic correction method based on lead angle according to claim 1, characterized in that: S4 , , , , , , , , , .

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