Guidance law design method suitable for plane symmetry missile BTT control strategy
By designing a guidance law suitable for the BTT control strategy of symmetric missiles, the problem of the inapplicability of the traditional STT control strategy was solved, the coordination between the control system and the guidance system and the strike accuracy were improved, and efficient guidance law calculation was achieved.
Patent Information
- Application Number
- CN202511586590.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-02
- Publication Date
- 2026-02-06
AI Technical Summary
Traditional STT control strategies are not suitable for the aerodynamic shape of symmetrical missiles, and guidance law design needs to be improved to adapt to BTT control strategies in order to improve strike accuracy.
A guidance law method suitable for the BTT control strategy of symmetric missiles is designed. By designing coordinate system transformation and proportional guidance law, the overload command and roll angle command are optimized, and the coupling between the yaw channel and the roll channel is reduced.
It improves the coordination between the control and guidance systems, enhances strike accuracy, and has a simple algorithm that can be efficiently and quickly calculated by the onboard computer.
Smart Images
Figure CN121474948A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a design method, specifically a guidance law design method applicable to the BTT control strategy of symmetric missiles. Background Technology
[0002] Traditional tactical missiles, including surface-to-air missiles, anti-tank missiles, and rockets, mostly adopt an axisymmetric aerodynamic shape, have strong overload capacity and good maneuverability, and generally use the STT control strategy.
[0004] A key difference between symmetrical and axisymmetric missiles lies in their aerodynamic shapes. Axisymmetric missiles typically have a smooth body with aerodynamic fins at the tail, or sometimes aerodynamic fins in the middle of the body, but these are always symmetrically distributed. In contrast, symmetrical missiles have tail fins and a pair of ailerons. To increase the lift-to-drag ratio and improve range, the ailerons have a larger wingspan, with an aspect ratio of around 18. Under these aerodynamic configurations, the traditional STT (Standard Tolerance) control strategy is no longer applicable, and a BTT (Body Tolerance) control strategy is required.
[0005] To adapt to the BTT control strategy, the guidance law design method needs to be adapted and improved, changing from the normal / lateral overload command + zero roll angle command of STT control to the Y-axis overload command + roll angle command + zero Z-axis overload command of the projectile system of BTT control. Summary of the Invention
[0006] Unlike axisymmetric missiles, which employ a slide-to-turn (STT) control strategy, symmetric missiles, including cruise missiles and loitering munitions, mostly employ a bank-to-turn (BTT) control strategy. Based on the technical characteristics of the BTT control strategy, this invention proposes a guidance law design method suitable for the BTT control strategy of symmetric missiles by utilizing the transformation relationships between the launch coordinate system, the missile-target line-of-sight coordinate system, the quasi-missile coordinate system, and the missile body coordinate system. This method enhances the matching and coordination between the control system and the guidance system, thereby improving strike accuracy.
[0007] This invention is achieved through the following technical solutions:
[0008] A guidance law design method applicable to the BTT control strategy of symmetric missiles includes:
[0009] 1) Coordinate system transformation
[0010] 1.1) From the launch coordinate system to the target line-of-sight coordinate system
[0011] The transformation matrix from the launch coordinate system to the target line-of-sight coordinate system is:
[0012] (1)
[0013] in, and These are the tilt angle and deflection angle of the bullet's line of sight, respectively.
[0014] 1, 2) From launch coordinate system to projectile coordinate system
[0015] The transformation matrix from the launch coordinate system to the projectile coordinate system is:
[0016] (3)
[0017] 1, 3) From the quasi-projectile coordinate system to the projectile coordinate system
[0018] The transformation matrix from the quasi-projectile coordinate system to the projectile coordinate system is:
[0019] (4)
[0020] 2) Guidance law design process applicable to BTT control strategy for symmetric missiles
[0021] The components of the angular velocity along the Y / Z axes of the projectile-view line-of-sight coordinate system are:
[0022] (5)
[0023] The proportional guidance law is designed in the line-of-sight coordinate system as follows:
[0024] (6)
[0025] In equation (6), For navigation ratio, The rate of change of the relative distance between the projectile and the target;
[0026] Assuming the overload command on the X-axis of the projectile-target line-of-sight coordinate system is 0, based on the transformation relationship from the projectile-target line-of-sight coordinate system to the quasi-projectile coordinate system, the overload command in the quasi-projectile coordinate system can be obtained as follows:
[0027] (7)
[0028] Simplifying equation (7), we obtain the overload command for the Y / Z axes in the quasi-elastic system as follows:
[0029] (8)
[0030] Compensating for the gravity term, the overload command for the Y / Z axes in the corrected quasi-ballistic system is as follows:
[0031] (9)
[0032] The quasi-projectile coordinate system differs from the projectile coordinate system only by one roll motion along the X-axis. Therefore, the Y-axis overload command and roll angle command in the projectile coordinate system can be calculated as follows:
[0033] (10)
[0034] Based on the characteristics of the BTT (Body Tolerance) control strategy for symmetrical missiles, a portion of the missile's lift in the Y-axis direction is diverted to the yaw channel via roll to achieve turning. Therefore, the overload command on the Z-axis of the missile body should be set to zero to reduce the coupling between the yaw and roll channels. Thus, the guidance law suitable for the BTT control strategy is:
[0035] (11)
[0036] The beneficial effects of this invention are:
[0037] 1. The designed guidance law is suitable for the BTT control strategy of symmetrical missiles, with good coordination between the control system and the guidance system, and high guidance accuracy;
[0038] 2. The guidance law design process is rigorous, the physical meaning is clear, and the algorithm implementation is simple and intuitive. The algorithm is written as a C language function module, which can complete the calculation efficiently and quickly in the onboard computer. Attached Figure Description
[0039] Figure 1 Launch coordinate system and missile-target line-of-sight coordinate system;
[0040] Figure 2. Projectile coordinate system and quasi-projectile coordinate system. Detailed Implementation
[0041] This invention is a guidance law design method applicable to the BTT control strategy of symmetric missiles.
[0042] 1. Definition of coordinate system
[0043] 1.1 Launch coordinate system and missile-target line-of-sight coordinate system
[0044] Launch coordinate system The origin is usually chosen at the missile launch point. The axis direction can be defined arbitrarily, but it is generally chosen to be the direction of the target or due north in the local area. The shaft is pointing upwards along the plumb line. shaft and The plane is perpendicular and obeys the right-hand rule, launch coordinate system It is a coordinate system fixed to the Earth, and it rotates with the Earth's rotation.
[0045] Bullet line-of-sight coordinate system The origin is the missile's center of mass. The axis and the projectile's line of sight are aligned and pointed towards the target. The shaft is inside the plumb line and The axis is vertically upward. shaft and The plane is perpendicular and conforms to the right-hand rule; the coordinate system of the projectile-eye line of sight changes with the relative motion of the projectile and eye.
[0046] Launch coordinate system and missile-target line-of-sight coordinate system, as follows Figure 1 As shown.
[0047] 1.2 Projectile coordinate system and quasi-projectile coordinate system
[0048] like Figure 2 As shown, the projectile coordinate system The origin is taken at the missile's center of mass. The axis coincides with the longitudinal axis of the projectile, and the direction pointing towards the head of the projectile is positive; The axis is located within the longitudinal symmetry plane of the projectile and The axis is vertical, and pointing upwards is considered positive; Axis perpendicular to The plane and direction are determined by the right-hand rule. The missile's coordinate system is fixed to the missile and is a moving coordinate system.
[0049] Quasi-projectile coordinate system The origin is taken at the missile's center of mass. The axis coincides with the longitudinal axis of the projectile, and the direction pointing towards the head of the projectile is positive; The shaft is inside the plumb line and Vertical, pointing upwards, is positive; Axis perpendicular to The plane and direction are determined by the right-hand rule.
[0050] 2. Coordinate system transformation
[0051] 2.1 From the launch coordinate system to the target line-of-sight coordinate system
[0052] The transformation matrix from the launch coordinate system to the target line-of-sight coordinate system is:
[0053] (1)
[0054] in, and These are the tilt angle and deflection angle of the bullet's line of sight, respectively.
[0055] 2.2 From launch coordinate system to projectile coordinate system
[0056] The transformation matrix from the launch coordinate system to the projectile coordinate system is:
[0057] (3)
[0058] 2.3 From Quasi-projectile coordinate system to projectile coordinate system
[0059] The transformation matrix from the quasi-projectile coordinate system to the projectile coordinate system is:
[0060] (4)
[0061] 3. Guidance law design process applicable to BTT control strategy for symmetric missiles
[0062] The components of the angular velocity along the Y / Z axes of the projectile-view line-of-sight coordinate system are:
[0063] (5)
[0064] The proportional guidance law is designed in the line-of-sight coordinate system as follows:
[0065] (6)
[0066] In equation (6), For navigation ratio, This represents the rate of change of the relative distance between the projectile and the target.
[0067] Assuming the overload command on the X-axis of the projectile-viewpoint coordinate system is 0, based on the transformation relationship from the projectile-viewpoint coordinate system to the quasi-projectile coordinate system, the overload command in the quasi-projectile coordinate system can be obtained as follows:
[0068] (7)
[0069] Simplifying equation (7), we obtain the overload command for the Y / Z axes in the quasi-elastic system as follows:
[0070] (8)
[0071] Compensating for the gravity term, the overload command for the Y / Z axes in the corrected quasi-ballistic system is as follows:
[0072] (9)
[0073] The quasi-projectile coordinate system differs from the projectile coordinate system only by one roll motion along the X-axis. Therefore, the Y-axis overload command and roll angle command in the projectile coordinate system can be calculated as follows:
[0074] (10)
[0075] Based on the characteristics of the BTT (Body Tolerance) control strategy for symmetrical missiles, a portion of the missile's lift in the Y-axis direction is diverted to the yaw path via roll to achieve turning. Therefore, the overload command on the Z-axis of the missile body should be set to zero to reduce the coupling between the yaw and roll paths. Thus, the guidance law suitable for the BTT control strategy is:
[0076] (11).
Claims
1. A guidance law design method applicable to the BTT control strategy of symmetric missiles, characterized by: include: 1) Coordinate system transformation 1.1) From the launch coordinate system to the target line-of-sight coordinate system The transformation matrix from the launch coordinate system to the target line-of-sight coordinate system is: (1) in, and These are the tilt angle and deflection angle of the bullet's line of sight, respectively. 1, 2) From launch coordinate system to projectile coordinate system The transformation matrix from the launch coordinate system to the projectile coordinate system is: (3) 1, 3) From the quasi-projectile coordinate system to the projectile coordinate system The transformation matrix from the quasi-projectile coordinate system to the projectile coordinate system is: (4) 2) Guidance law design process applicable to BTT control strategy for symmetric missiles The components of the angular velocity along the Y / Z axes of the projectile-view line-of-sight coordinate system are: (5) The proportional guidance law is designed in the line-of-sight coordinate system as follows: (6) In equation (6), For navigation ratio, Rate of change of the relative distance between the projectile and the target; Assuming the overload command on the X-axis of the projectile-target line-of-sight coordinate system is 0, based on the transformation relationship from the projectile-target line-of-sight coordinate system to the quasi-projectile coordinate system, the overload command in the quasi-projectile coordinate system can be obtained as follows: (7) Simplifying equation (7), we obtain the overload command for the Y / Z axes in the quasi-elastic system as follows: (8) Compensating for the gravity term, the overload command for the Y / Z axes in the corrected quasi-ballistic system is as follows: (9) The quasi-projectile coordinate system differs from the projectile coordinate system only by one roll motion along the X-axis. Therefore, the Y-axis overload command and roll angle command in the projectile coordinate system can be calculated as follows: (10) Based on the characteristics of the BTT (Body Tolerance) control strategy for symmetrical missiles, a portion of the missile's lift in the Y-axis direction is diverted to the yaw channel via roll to achieve turning. Therefore, the overload command on the Z-axis of the missile body should be set to zero to reduce the coupling between the yaw and roll channels. Thus, the guidance law suitable for the BTT control strategy is: (11)。 2. The guidance law design method for a symmetric missile BTT control strategy according to claim 1, characterized in that: The algorithm is written as a C language function module, which can perform calculations efficiently and quickly on the onboard computer.