Mid-terminal stage handover guidance method based on laser semi-active strapdown guidance

Abstract

The application discloses a mid-terminal stage handover guiding method based on laser semi-active strapdown guidance, relates to the field of aircraft control and comprises the following steps: S1, according to the pitch misalignment angle and the azimuth misalignment angle output by a seeker, the target is quickly guided into a linear area of a field of view of the seeker; S2, a missile-target line-of-sight angle in an inertial space is calculated, and an initial value of the initial missile-target line-of-sight angle is recorded, the line-of-sight angle comprises a high-low angle and an azimuth angle; S3, a digital filter algorithm is used to filter the missile-target line-of-sight angle, a missile-target line-of-sight angle rate is obtained, and the filter initial value is set as the initial value of the missile-target line-of-sight angle, so that the filter convergence is accelerated; S4, a guidance instruction is generated; and S5, a linear transition method is used to complete smooth transition of a mid-terminal stage, a L1 guidance stage and a PN guidance stage. The method guarantees smooth transition of the guidance instruction of the missile in the mid-terminal stage, provides guarantee for accurate attack on the target in the terminal guidance stage, ensures that the missile accurately hits the target, and the design of the mid-terminal stage handover guiding algorithm based on the laser semi-active strapdown guidance is crucial.

Description

Technical Field

[0001] This invention relates to the field of aircraft control, and in particular to a mid-to-terminal handover guidance method based on laser semi-active strapdown guidance. Background Technology

[0002] Strapdown laser semi-active seekers, characterized by strong anti-jamming capabilities, simple structure, and easy miniaturization, have been widely used in air-to-ground missile systems. They mainly consist of an optical lens, a four-quadrant detector, a signal processing board, and a mechanical lens barrel. During guidance, the seeker receives diffuse reflection echoes generated by the laser designator illuminating the target, enabling functions such as echo focusing, photoelectric conversion, pattern recognition, and four-quadrant energy ratio calculation to obtain information such as the target misalignment angle.

[0003] Air-to-ground missiles employing strapdown laser semi-active homing typically consist of three phases: initial guidance, mid-course guidance, and terminal guidance. The initial guidance phase primarily stabilizes the missile upon launch. The mid-course guidance phase guides the missile to its intended target position until the seeker acquires the target. The terminal guidance phase utilizes the seeker's misalignment angle information and the control system to achieve precise engagement with the target. The handover between the mid-course and terminal phases is the most crucial stage in the missile's flight. Therefore, ensuring a smooth transition between these phases is of paramount importance. Summary of the Invention

[0004] The purpose of this invention is to design a mid-to-terminal handover guidance method based on laser semi-active strapdown guidance in order to solve the above problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] Mid-to-terminal handover guidance methods based on laser semi-active strapdown guidance include:

[0007] S1. Based on the pitch and azimuth offset angles output by the seeker, guide the target to quickly enter the linear zone of the seeker's field of view;

[0008] S2. Calculate the missile-eye line-of-sight angle in inertial space based on the pitch and azimuth misalignment angles, and record the initial value of the initial missile-eye line-of-sight angle. The line-of-sight angle includes the elevation angle and the azimuth angle.

[0009] S3. A digital filtering algorithm is used to filter the line-of-sight angle of the bullet to obtain the line-of-sight angle rate of the bullet. The initial value of the filter is set to the initial value of the line-of-sight angle of the bullet to accelerate the convergence of the filter.

[0010] S4. Generate guidance commands based on pitch and azimuth misalignment angles;

[0011] S5. A linear transition method is used to achieve a smooth transition between the mid-to-late guidance segment, the L1 guidance segment, and the PN guidance segment.

[0012] The beneficial effects of this invention are as follows: This method ensures a smooth transition of guidance commands during the mid- and terminal phases of the missile's guidance process, providing a guarantee for the accurate strike of the target in the terminal guidance phase and ensuring that the missile accurately hits the target. The design of the mid- and terminal phase handover guidance algorithm based on laser semi-active strapdown guidance is crucial. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the L1 guidance geometry in the terminal guidance phase.

[0014] Figure 2 This is a schematic diagram of the L1 total overload command decomposition in the final guidance phase;

[0015] Figure 3 This is a schematic diagram showing the change in the total misalignment angle during the final guidance phase and the guidance stages.

[0016] Figure 4 It is the logic of the connection of guidance laws in the mid-to-final guidance phase;

[0017] Figure 5 This is a simulation case of the mid-to-late stage handover guidance algorithm. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0023] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] Mid-to-terminal handover guidance methods based on laser semi-active strapdown guidance include:

[0026] S1. Based on the pitch and azimuth offset angles output by the seeker, guide the target quickly into the linear region of the seeker's field of view; specifically including:

[0027] S11. Based on the pitch offset angle output by the seeker head. and orientation misalignment angle Calculate the total misalignment angle, expressed as:

[0028]

[0029] S12, according to Figure 1 The schematic diagram of the three-dimensional L1 guidance geometry shown is used to obtain the total overload command using the three-dimensional L1 guidance algorithm, and is represented as follows:

[0030]

[0031] Where V is the missile velocity, L1 is an adjustable parameter representing the distance of the missile from the reference point on the line of sight; the smaller L1 is, the faster the missile's velocity. c The larger, The faster the convergence to zero, the better. Conversely, The convergence speed is slow; considering both the convergence speed and the bandwidth of the control system, its range is generally... g is the acceleration due to gravity;

[0032] S13, according to pitch misalignment angle and orientation misalignment angle The total overload is decomposed into normal and lateral overload commands for the missile system O-x1y1z1. The combined direction of these two commands ensures that the total overload direction points towards the target's azimuth. Figure 2 The diagram showing the total overload command decomposition, considering the longitudinal component of gravitational acceleration, yields the longitudinal and lateral overload commands, expressed as follows:

[0033]

[0034] in, For the normal overload command of the L1 guidance segment, This is a lateral overload command for the L1 guidance phase. This refers to the trajectory inclination angle.

[0035] S14. Make the target quickly enter the linear zone of the seeker's field of view.

[0036] S2. Calculate the missile-eye line-of-sight angle in inertial space based on the pitch and azimuth misalignment angles, and record the initial value of the initial missile-eye line-of-sight angle. The line-of-sight angle includes the elevation and azimuth angles; specifically:

[0037] Once the seeker locks onto the target, the relative distance between the missile and the target at a certain moment is r. The components of r in the O-x1y1z1 equation can be obtained from the elevation and azimuth misalignment angles. The line-of-sight angle can be used to determine the component of r in the launch system O. g -x g y g z g If the positional components are in the matrix, then the following relationship holds:

[0038]

[0039] in, For the elevation angle of the line of sight, The azimuth angle of the line of sight. From O-x1y1z1 to O g -x g y g z g The transformation matrix is ​​represented as:

[0040]

[0041] in, The pitch angle, It is the azimuth angle. For roll angle;

[0042] The elevation and azimuth angles are then expressed as:

[0043]

[0044] Among them, R m，n for The element in the m-th row and n-th column is used to denote the initial values ​​of the elevation angle and azimuth angle as follows: and .

[0045] S3. A digital filtering algorithm is used to filter the projectile-eye line-of-sight angle to obtain the projectile-eye line-of-sight angle rate. The initial value of the filter is set to the initial value of the projectile-eye line-of-sight angle to accelerate filter convergence; specifically including:

[0046] S31. Due to significant measurement noise in the offset angle and the inability to directly obtain the angular rate information required for the PN guidance law, a second-order digital filter is used to obtain the line-of-sight angle and line-of-sight angular rate filtered values. The filter form is as follows:

[0047]

[0048] Among them, T s The filter period is the same as the offset angle update period. G and H are the filter gains, both determined by parameters. Sure, Let n be the input value at time n. , The input estimates and differential estimates are respectively given at time n.

[0049] S32. To ensure fast filter convergence, on the one hand, reduce... Increasing the filter bandwidth will affect the filtering effect, which needs to be determined through actual simulation. On the other hand, the filter form shows that the estimated value at time n is related to the estimated value at time n-1. Therefore, it is necessary to set the initial value of the filter to start the filtering process. Thus, the initial value of the final line-of-sight angle is used as the initial value of the filter estimate to ensure rapid tracking of the original signal, expressed as:

[0050]

[0051] in, , , , These are the estimated values ​​of the line of sight elevation angle, elevation rate, azimuth angle, and azimuth rate at the initial moment;

[0052] S33. The initial values ​​are estimated using a filter and a summation filter to obtain estimated values ​​for the line-of-sight elevation angle, elevation rate, azimuth angle, and azimuth rate, denoted as follows: , , , .

[0053] S4. Generate guidance commands based on the pitch and azimuth misalignment angles; such as... Figure 3 As shown, it specifically includes:

[0054] S41. Let the field of view of the seeker be... Linear region field of view Total misalignment angle threshold design value ;

[0055] S42. Upon entering terminal guidance, the final values ​​of the normal overload and lateral overload commands and the guidance time during the mid-guided phase are respectively... , and T0;

[0056] S43. After entering the final guidance phase, calculate the L1 guidance phase normal overload command. Lateral overload command and guidance time T1;

[0057] S44. Determine whether the total misalignment angle is less than a predetermined threshold. If yes, proceed to S45; otherwise, return to S43.

[0058] S45. Enter the PN guidance phase and use guidance commands generated by proportional guidance; specifically:

[0059] ① Obtained from digital filters , , , Combined with the missile attitude angle, , Transforming to O-x1y1z1, it is represented as:

[0060]

[0061] in, , For the azimuth line-of-sight rate and pitch line-of-sight rate in O-x1y1z1, for Transpose of;

[0062] ② Calculate the PN guidance section overload command based on proportional guidance, expressed as:

[0063]

[0064] in, , These are the normal overload and lateral overload commands for the PN guidance segment in O-x1y1z1, respectively, and K. y K zThese are the normal and lateral guidance ratios, respectively.

[0065] S5. A linear transition method is used to achieve a smooth transition between the mid-to-late guidance segment, the L1 guidance segment, and the PN guidance segment, such as... Figure 4 As shown, specifically: line-of-sight angular rate filtering begins simultaneously upon entering the L1 guidance phase. Although the PN guidance phase has not yet been entered, the filter's pre-calculation allows for additional convergence time. Based on the guidance law connection logic of the mid-to-final guidance phases, the guidance command for the final guidance phase is obtained, expressed as:

[0066]

[0067] in, and The expression is:

[0068]

[0069] Where, in the formula and These represent the transition time from mid-course guidance to terminal guidance and the transition time from L1 guidance to PN guidance, respectively, where t is the guidance time.

[0070] Simulation verification:

[0071] Among the seeker parameters , ,but The L1 guidance parameter is set to L1=550m, and the digital filter parameters are... Filtering period T s =0.05s, PN guidance segment guidance ratio K y =4、K z =3.5, guidance segment switching time The guidance process includes the seeker's misalignment angle and total misalignment angle, normal overload and lateral overload commands and their tracking, and the filtering effects of line-of-sight elevation and azimuth angles, as shown below. Figure 5 As shown in the figure, the missile enters terminal guidance around T0=9.2s and PN guidance around T1=11.5s. L1 guidance occurs between [T0, T1). During this time period, the line-of-sight angular rate digital filter converges, achieving good guidance performance. The above simulation case verifies the mid-to-terminal handover guidance design algorithm.

[0072] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A mid-to-terminal handover guidance method based on laser semi-active strapdown guidance, characterized in that, include: S1. Based on the pitch offset angle output by the seeker head. and orientation misalignment angle This allows the target to quickly enter the linear region of the seeker's field of view; S2, based on pitch misalignment angle and orientation misalignment angle Calculate the missile-eye line-of-sight angle in inertial space and record the initial value of the initial missile-eye line-of-sight angle, which includes elevation and azimuth angles; S3. A digital filtering algorithm is used to filter the line-of-sight angle of the bullet to obtain the line-of-sight angle rate of the bullet. The initial value of the filter is set to the initial value of the line-of-sight angle of the bullet to accelerate the convergence of the filter. S4. Based on pitch misalignment angle and orientation misalignment angle Generate guidance commands; S5. A linear transition method is used to achieve a smooth transition between the mid-to-late guidance segment, the L1 guidance segment, and the PN guidance segment; specifically: Upon entering the L1 guidance phase, line-of-sight angular rate filtering begins. Although the PN guidance phase has not yet been entered, the pre-calculation of the filter allows for additional time for convergence. Based on the guidance law connection logic of the mid-to-final guidance phases, the guidance command for the final guidance phase is obtained, expressed as: ； in, and The expression is: ； Where, in the formula and These represent the transition time from mid-course guidance to terminal guidance and the transition time from L1 guidance to PN guidance, respectively, where t is the guidance time. , T0 and T1 represent the final values ​​of the normal and lateral overload commands and the guidance time, respectively, during the mid-course guidance phase. , These are the normal overload and lateral overload commands for the PN guidance segment in O-x1y1z1, respectively.

2. The mid-to-terminal handover guidance method based on laser semi-active strapdown guidance according to claim 1, characterized in that, S1 includes: S11. Calculate the total offset angle based on the pitch and azimuth offset angles output by the seeker. S12. The total overload command is obtained by using a three-dimensional L1 guidance algorithm; S13. Decompose the total overload into the normal overload and lateral overload commands of the missile system according to the pitch and azimuth misalignment angles; S14. Make the target quickly enter the linear zone of the seeker's field of view.

3. The mid-to-terminal handover guidance method based on laser semi-active strapdown guidance according to claim 1, characterized in that, Specifically in S2: According to pitch misalignment angle and orientation misalignment angle The components of r in O-x1y1z1 can be obtained. Based on the line-of-sight angle, the components of r in the emission system O can be obtained. g -x g y g z g If the positional components are in the matrix, then the following relationship holds: ； in, For the elevation angle of the line of sight, The azimuth angle of the line of sight. From O-x1y1z1 to O g -x g y g z g The transformation matrix is ​​represented as: ； in, The pitch angle, It is the azimuth angle. For roll angle; The elevation and azimuth angles are then expressed as: ； Among them, R m，n for The element in the m-th row and n-th column is used to denote the initial values ​​of the elevation angle and azimuth angle as follows: and .

4. The mid-to-terminal handover guidance method based on laser semi-active strapdown guidance according to claim 1, characterized in that, S3 includes: S31. Suppose a second-order digital filter is used to obtain the filtered values ​​of the line-of-sight angle and the line-of-sight angle rate. The filter form is: ； Among them, T s The filter period is the same as the offset angle update period. G and H are the filter gains, both determined by parameters. Sure, Let n be the input value at time n. , The input estimates and differential estimates are respectively given at time n. S32. The initial value of the final line-of-sight angle is used as the initial value for filter estimation, expressed as: ； in, , , , These are the estimated values ​​of the line of sight elevation angle, elevation rate, azimuth angle, and azimuth rate at the initial moment; S33. The initial values ​​are estimated using a filter and a summation filter to obtain estimated values ​​for the line-of-sight elevation angle, elevation rate, azimuth angle, and azimuth rate, denoted as follows: , , , .

5. The mid-to-terminal handover guidance method based on laser semi-active strapdown guidance according to claim 1, characterized in that, Specifically in S4: S41. Let the field of view of the seeker be... Linear region field of view Total misalignment angle threshold design value ; S42. Upon entering terminal guidance, the final values ​​of the normal overload and lateral overload commands and the guidance time during the mid-guided phase are respectively... , and T0; S43. After entering the final guidance phase, calculate the L1 guidance phase normal overload command. and lateral overload command ; S44. Determine whether the total misalignment angle is less than a predetermined threshold. If yes, proceed to S45; otherwise, return to S43. S45. Enter the PN guidance phase and use guidance commands generated by proportional guidance.

6. The mid-to-terminal handover guidance method based on laser semi-active strapdown guidance according to claim 1, characterized in that, Specifically in S45: ① Obtained from digital filters , , , Combined with the missile attitude angle, , Transforming to O-x1y1z1, it is represented as: ； in, , For the azimuth line-of-sight rate and pitch line-of-sight rate in O-x1y1z1, for transpose; ② Calculate the PN guidance section overload command based on proportional guidance, expressed as: ； in, , These are the normal overload and lateral overload commands for the PN guidance segment in O-x1y1z1, respectively, and K. y K z These are the normal and lateral guidance ratios, respectively.

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