A method and system for intercepting an in-atmosphere target based on a three-dimensional time constraint guidance law considering field-of-view constraints

Abstract

The application relates to the field of aircraft guidance control, and discloses a method and system for intercepting a target in the atmosphere based on a three-dimensional time constraint guidance law considering field of view constraints, which specifically comprises the following steps: firstly, a line-of-sight angular velocity profile composed of a striking time error is designed; secondly, a fixed-time striking time guidance law is designed; thirdly, a prediction algorithm for the future average speed of an aircraft is designed; and finally, a specified time striking on a non-maneuvering moving target can be realized by using a predicted intercept point technology.

Description

Technical Field

[0001] This invention relates to the field of aircraft guidance and control, specifically to a method and system for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that takes into account field-of-view constraints. Background Technology

[0002] Against the backdrop of rapid iteration in military technology, the performance indicators of anti-missile defense systems have shown a continuous upward trend. This has rendered traditional proportional guidance strategies based on terminal miss distance constraints inadequate in the face of new missile combat requirements. To address this, the academic community has proposed advanced guidance algorithm systems with multiple constraint characteristics, which have demonstrated significant strategic value in actual combat: time-controlled guidance strategies, through refined timing planning, achieve multi-missile coordinated strike capabilities, significantly improving the overall effectiveness of saturation attacks; angle-constrained guidance methods effectively enhance missile damage effects by optimizing the terminal hit angle; and field-of-view limited guidance schemes ensure the reliability of guidance throughout the entire course of the mission thanks to their stable target tracking capabilities. In particular, when considering the factor of varying aircraft velocity, the dual guidance algorithm that simultaneously achieves field-of-view constraints and time control is not only a key technology for improving combat effectiveness but has also become a significant technical bottleneck in the current guidance and control field.

[0003] Currently, research on strike time control has made significant progress. Based on different guidance law design principles, existing research can be divided into two main types: one is guidance laws that require estimation of remaining flight time, and the other is guidance laws that do not require calculation of remaining flight time. However, most existing guidance laws are designed based on the assumption of constant velocity. This simplification ignores the real-time velocity variations caused by factors such as gravity, thrust, and air resistance in actual combat environments. Therefore, three-dimensional time-constrained guidance laws that consider the time-varying characteristics of velocity remain a research direction that urgently needs further exploration.

[0004] Patent publication CN109614756B discloses a guidance law analysis method with attack time and seeker field-of-view constraints. This method achieves guidance law design through relative distance reshaping and can determine the feasible time domain under field-of-view constraints. However, this guidance law is only designed in a two-dimensional plane, which has significant limitations in practical applications. Patent publication CN114995495A discloses a three-dimensional sliding mode guidance law design method with time and angle constraints under uncontrollable speed conditions. It achieves guidance law design with attack time and angle constraints based on super-spiral sliding mode theory. However, the derivation process of this patent is based on the assumption of constant speed and does not consider the characteristics of real-time speed changes in actual combat scenarios. Patent publication CN15950310A discloses an attack time and angle constraint guidance method for time-varying speed aircraft. It generates a two-stage flight trajectory that satisfies flight time constraints through a second-order Bezier curve and uses a trajectory tracking algorithm to calculate guidance commands. However, this invention is limited to two-dimensional planar design, and its application effect in three-dimensional combat scenarios is limited. Patent publication number CN116414035A discloses a terminal guidance method for a loitering munition with controllable terminal time in a two-dimensional plane. By estimating the remaining flight time and using the error between the remaining flight time and the expected flight time to construct a guidance law, the strike time constraint is achieved. However, this invention patent also only targets the two-dimensional plane design and does not consider the real-time changes in missile speed caused by factors such as drag and gravity in actual scenarios.

[0005] The current state of development of strike-time guidance laws can be attributed to the following factors: First, designing guidance laws in a two-dimensional plane eliminates the need to consider the coupling relationship between pitch and yaw directions, greatly simplifying the design process. Second, while the assumption of constant aircraft velocity allows for the derivation of analytical expressions for remaining flight time, calculating remaining flight time under time-varying velocity conditions presents significant challenges. This results in most existing strike-time guidance laws being applicable only to aircraft with constant velocity. Given this current state of development, research into strike-time guidance laws that consider velocity variations and field-of-view constraints in three-dimensional engagement space is particularly necessary. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that takes into account field-of-view constraints, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, comprising the following steps:

[0008] Step 1: Based on the constructed strike time error, design the desired line-of-sight vector rotation angular rate profile that can achieve strike time and field-of-sight constraints;

[0009] Step 2: Based on fixed-time control technology, design a fixed-time guidance law so that the aircraft can track the desired line-of-sight vector rotation angular rate profile from Step 1 within a fixed time.

[0010] Step 3: Propose a numerical iterative algorithm for predicting the future average velocity, and then calculate the future average velocity of the aircraft in the atmosphere based on the three-dimensional time-constrained guidance law in Step 2.

[0011] Step 4: Use the predicted interception point technology to predict the location of the interception target, and then predict the missile-target distance and remaining flight distance; then use the future average speed prediction algorithm from Step 3 to calculate the aircraft's future average speed. Then according to With the three-dimensional time-constrained guidance law designed in step 2, the interception of non-maneuvering moving targets at a specified time can be achieved.

[0012] Preferably, the desired line-of-sight vector rotation angular rate profile in step 1 is designed in a vector coordinate system. The specific engagement model is described as follows: the aircraft's motion state can be represented by the velocity vector V. M and control acceleration vector A M The target's motion state is represented by the velocity vector V. T and control acceleration vector A T The description defines the line-of-sight vector between the aircraft and the target as R, where R = ||R|| is the distance between the aircraft and the target, and V... M =||V M ||and V T =||V T || are the speeds of the aircraft and the target, respectively, and let and For a unit vector, the following equations hold:

[0013]

[0014]

[0015] Ω in the formula L and These represent the rotational angular velocities of the line-of-sight vector and the aircraft velocity vector, respectively. Let represent the derivatives of the missile-target distance, the line-of-sight unit vector, and the missile velocity unit vector with respect to time, respectively; define the aircraft front as σ, and satisfy the following relationship:

[0016] cosσ=r·v M (4)

[0017] sinσk=r×v M (5)

[0018] Where k is known to be defined as k = r × v / ||r × v||, for the line-of-sight angular rate Ω L Taking the derivative, we have the following relationship:

[0019]

[0020] For an aircraft flying within the atmosphere, its speed is affected by gravity, air resistance, and thrust, as shown in the following equations:

[0021]

[0022] in, The vector represents the derivative of the missile's velocity with respect to time, i.e., the change in the magnitude of the missile's velocity; T is the vehicle thrust, Q is the aerodynamic pressure, s is the vehicle area, m is the vehicle mass, and g is the gravitational acceleration vector. n The component of gravity in the direction of the aircraft's velocity is given by the formula g. n =v M ×(g×v M ), C D0 K is the zero-lift drag coefficient. D This is the induced drag coefficient.

[0023] As a preferred embodiment: based on the constructed strike time error mentioned in step 1, a desired line-of-sight vector rotation angular rate profile is designed to achieve strike time and field-of-sight constraints. Specifically, the designed desired line-of-sight vector rotation angular rate profile is as follows:

[0024]

[0025] Where tanh(·) is the hyperbolic tangent function. For the desired line-of-sight vector rotation angular rate profile, To combat time errors, T represents the future average speed of the aircraft. d The specified attack time is t, where t is the time after the aircraft is released. go Let k1 be the remaining flight time of the aircraft, and k1 = cosσ. max , σ max For the maximum field of view,

[0026] Preferably, step 2 is based on fixed-time control technology, and the designed three-dimensional time-constrained guidance law is as follows:

[0027]

[0028] Where S = Ω L -ΩLd sig(S,p)=|S| p sign(S) and sign(·) are the sign functions, α>0, β>0, 0<p<1, and q>1 are adjustable controller parameters.

[0029] Preferably: after calculating the three-dimensional time-constrained guidance law in step 2... Afterwards, the control acceleration vector A of the aircraft M Calculated as,

[0030]

[0031] As a preferred embodiment, the specific algorithm flow for step 3 is as follows:

[0032] Step 3-1, when the impact time error When convergence is zero, the strike time constraint guidance law transforms into:

[0033]

[0034] Step 3-2: Define the aircraft state vector as follows:

[0035] x=[t,R,V M ] T (12)

[0036] Where the superscript T represents the transpose of the matrix;

[0037] Step 3-3: Adjust the aircraft state vector from Step 3-2 relative to the remaining flight distance D. go Taking the derivative, we get:

[0038]

[0039] in,

[0040]

[0041] Steps 3-4, iteration step size is Where the superscript C represents the current state of the aircraft, and H represents the number of numerical iterations, here... N is the proportional guidance coefficient, and the aircraft state vector x and remaining flight distance D are... go Let x be the discrete node. h and Where h = {0, 1, ..., H-1}, then the future average speed of the aircraft is... The following process is used to derive the following:

[0042] Step 3-4-1, Settings

[0043] Step 3-4-2: Set h = 0;

[0044] Step 3-4-3: When h < H, execute steps 2-4-4 to 2-4-7;

[0045] Step 3-4-4: Calculate according to formula (11)

[0046] Steps 3-4-5: Calculate f(x) according to formula (14). h );

[0047] Steps 3-4-6: Calculate x h+1 =x h +Δ h f(x h );

[0048] Steps 3-4-7: Calculate h = h + 1;

[0049] Steps 3-4-8: Calculation

[0050] Steps 3-4-9: Calculate the predicted future average speed

[0051] in, Indicates the predicted remaining flight time of the missile; x H This represents the state vector parameter of the H-th discrete node x; x C The state vector parameter x represents the state vector parameter at the current time; x h+1 This represents the state vector parameters of the (h+1)th discrete node x.

[0052] As a preferred embodiment, step 4 specifically involves:

[0053] Step 4-1: Using the predicted interception point technology, predict the location of the interception target point as follows:

[0054]

[0055] in For the target's real-time location, The predicted target location;

[0056] Step 4-2: Based on the target prediction and real-time aircraft position from Step 4-1, determine the interception location. The distance to the target can be predicted. The predicted remaining flight distance is

[0057] Step 4-3: Based on the target distance and remaining flight distance predicted in Step 4-2, the future average speed of the aircraft can be calculated using the future average speed prediction algorithm from Step 3.

[0058] Step 4-4: Based on the future average speed of the aircraft for striking non-maneuvering moving targets predicted in Step 4-3. Using the guidance law proposed in step 2, a time-limited strike can be achieved against a non-maneuverable moving target.

[0059] The guidance system based on the above-mentioned method for intercepting targets within the atmosphere using a three-dimensional time-constrained guidance law considering field-of-view constraints includes a vehicle kinematics and target kinematics calculation unit, a real-time guidance law calculation unit for the vehicle, a future average velocity calculation unit for the vehicle, and a vehicle guidance control unit, wherein:

[0060] The vehicle and target kinematics calculation unit calculates the position information of the vehicle and the target in real time based on the guidance control variables, providing accurate dynamic kinematic data support for subsequent guidance law calculation.

[0061] The aircraft real-time guidance law calculation unit calculates the guidance control quantities of the aircraft in real time based on the user-set specified strike time parameters (or expected strike time parameters) and the designed guidance law, ensuring that the aircraft can intercept the target at the predetermined time.

[0062] The aircraft's future average speed calculation unit takes the real-time remaining flight distance as input and estimates the aircraft's future average speed in real time through a designed future average speed prediction algorithm, providing key speed information for guidance law calculation.

[0063] The aircraft guidance control unit drives the aircraft's rudder control system based on the guidance commands output by the guidance law calculation unit, thereby achieving precise control of the aircraft and ensuring that the aircraft completes the interception of the target within a specified time.

[0064] Compared with the prior art, the beneficial effects of this invention are as follows:

[0065] This invention addresses atmospheric target interception missions by proposing a three-dimensional time-constrained guidance law and system that considers field-of-view constraints, and innovatively designing a vector line-of-sight angular rate tracking method. This method can intercept non-maneuvering targets within a specified strike time, while fully considering the effects of gravity and drag within the atmosphere. Based on the designed fixed-time strike guidance law, the aircraft can accurately track a preset line-of-sight angular rate profile, achieving precise interception of the target within the specified time, while ensuring that the guidance process consistently meets the field-of-sight constraints, guaranteeing continuous and stable target lock by the seeker. The guidance law design process is logically clear, possesses high operability and practicality, and can effectively solve the problem of time-constrained interception of non-maneuvering targets under atmospheric velocity variations. Attached Figure Description

[0066] Figure 1 This is the three-dimensional vector guidance coordinate system for the aircraft and target of this invention;

[0067] Figure 2 This is a flowchart of a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints;

[0068] Figure 3 This image shows the three-dimensional trajectory of the aircraft and the three-dimensional trajectory of the target in a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints.

[0069] Figure 4 A leading-edge diagram of a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints;

[0070] Figure 5 A missile-target range diagram for a method of intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints;

[0071] Figure 6 An overload diagram of a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints;

[0072] Figure 7 A velocity diagram of an aircraft for a method of intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints;

[0073] Figure 8 This is a predicted future average velocity map of an aircraft in a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that takes into account field-of-view constraints. Detailed Implementation

[0074] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] Example 1

[0076] Please see Figures 1-8 The diagram illustrates a method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law that considers field-of-view constraints, comprising the following steps:

[0077] Step 1: Based on the constructed strike time error, design the desired line-of-sight vector rotation angular rate profile that can achieve strike time and field-of-sight constraints;

[0078] Step 2: Based on fixed-time control technology, design a three-dimensional time-constrained guidance law so that the aircraft can track the desired line-of-sight vector rotation angular rate profile from Step 1 within a fixed time.

[0079] Step 3: Propose a numerical iterative algorithm for predicting the future average velocity, and then calculate the future average velocity of the aircraft in the atmosphere based on the three-dimensional time-constrained guidance law in Step 2.

[0080] Step 4: Use the predicted interception point technology to predict the location of the interception target, and then predict the missile-target distance and remaining flight distance; then use the future average speed prediction algorithm from Step 3 to calculate the aircraft's future average speed. Then according to With the three-dimensional time-constrained guidance law designed in step 2, the interception of non-maneuvering moving targets at a specified time can be achieved.

[0081] In this embodiment, Figure 1 This is the three-dimensional relative guidance coordinate system between the aircraft and the target of this invention, combined with... Figure 1 The specific description of the aircraft-target engagement model is as follows:

[0082] The motion state of an aircraft can be represented by its velocity vector V. M and control acceleration vector A M The target's motion state is represented by the velocity vector V. T and control acceleration vector A M The description defines the line-of-sight vector between the aircraft and the target as R, where R = ||R|| is the distance between the aircraft and the target, and V... M =||V M ||and V T =||V T || represent the velocities of the aircraft and the target, respectively, and set... and As a unit vector, further, the following equations exist:

[0083]

[0084] Ω in the formula L and These represent the rotational angular velocities of the line-of-sight vector and the aircraft velocity vector, respectively. These represent the derivatives of the missile-target distance, the line-of-sight unit vector, and the missile velocity unit vector with respect to time, respectively. For the guidance law required by this invention, the aircraft front is defined as σ, and satisfies the following relationship:

[0085] cosσ=r·v M (4)

[0086] sinσk=r×v M (5)

[0087] Where k is known to be defined as k = r × v / ||r × v||, for the line-of-sight angular rate Ω L Taking the derivative, we have the following relationship:

[0088]

[0089] For an aircraft flying within the atmosphere, its speed is affected by gravity, air resistance, and thrust, as shown in the following equations:

[0090]

[0091] in, The variable represents the derivative of the missile's velocity with respect to time, i.e., the change in the magnitude of the missile's velocity. T is the vehicle thrust, Q is the aerodynamic pressure, s is the vehicle area, m is the vehicle mass, and g is the gravitational acceleration vector. n The component of gravity in the direction of the aircraft's velocity is given by the formula g. n =v M ×(g×v M ), C D0 K is the zero-lift drag coefficient. D This is the induced drag coefficient.

[0092] Furthermore, based on the constructed strike time error described in step 1, a desired line-of-sight vector rotation angular rate profile capable of achieving strike time and field-of-sight constraints was designed. The specific steps are as follows:

[0093] Step 1-1: Design a new strike time error variable as follows:

[0094]

[0095] Where T d The specified time for the aircraft to strike is t, where t is the time after the aircraft is released. This represents the future average speed of the aircraft.

[0096] Step 1-2, the desired line-of-sight vector rotation angular rate profile is designed as follows:

[0097]

[0098] Where tanh(·) is the hyperbolic tangent function. For the desired line-of-sight vector rotation angular rate profile, To combat time errors, T represents the future average speed of the aircraft. d The specified attack time is t, where t is the time after the aircraft is released. go Let k1 be the remaining flight time of the aircraft, and k1 = cosσ. max , σ max For the maximum field of view,

[0099] Steps 1-3: Differentiating formula (8) yields:

[0100]

[0101] Steps 1-4: Assuming the aircraft can track the rotational angular rate profile of the designed line-of-sight angular rate vector over a finite time, then:

[0102]

[0103] According to geometric relations, we have:

[0104]

[0105] Combining formulas (51) and (52), we can obtain:

[0106] σ=atan(k1tanh(e)) (53)

[0107] Substituting (53) into (50), we get:

[0108]

[0109] According to (54), This holds true for all cases if and only if e = 0. It can bring the strike time error to zero and achieve strike time constraint.

[0110] Steps 1-5: According to (53), the maximum forward angle of the aircraft can be obtained as σ = atan(k1). Therefore, by adjusting the parameter k1, the maximum forward angle constraint of the aircraft can be guaranteed.

[0111] Steps 1-6: Based on the derivation process from Steps 1-1 to 1-5, it can be shown that the rotation angular rate vector profile of the line-of-sight vector designed in Step 1-1 can achieve the constraints of the time of impact and the field of view.

[0112] Furthermore, based on the fixed-time control technology described in step 2, a fixed-time guidance law was designed to enable the aircraft to track the desired line-of-sight vector rotation angular rate designed in step 1 within a fixed time period. The specific steps are as follows:

[0113] Step 2-1: Construct the tracking error of the rotational angular rate with the sliding surface as the line-of-sight angular rate vector, which is:

[0114] S = Ω L -Ω Ld (55)

[0115] Step 2-2: Differentiating formula (55), we can obtain:

[0116]

[0117] Steps 2-3: Using fixed-time control technology, the sliding surface S is made to converge within a fixed time. The guidance law is designed as follows:

[0118]

[0119] Where S=Ω L -Ω Ld sig(S,p)=|S| p sign(S) and sign(·) are the sign functions, α>0, β>0, 0<p<1, and q>1 are adjustable controller parameters.

[0120] Steps 2-4: Construct the Lyapunov function as follows

[0121] V1 = 0.5S T S (58)

[0122] Differentiating formula (58) and substituting it into guidance law (9), we can obtain:

[0123]

[0124] Among them, s i =S(i), i = 1, 2, 3.

[0125] Further, there are:

[0126]

[0127] Equation (60) is consistent with the fixed-time convergence lemma, so the tracking error S of the rotational angular rate of the line-of-sight vector can converge in a fixed time.

[0128] Further, in step 3, to calculate the future average velocity of the aircraft within the atmosphere used in step 2, a numerical iterative algorithm for predicting the future average velocity is proposed. The specific steps are as follows:

[0129] Step 3-1, when the impact time error When convergence is zero, the three-dimensional time-constrained guidance law transforms into:

[0130]

[0131] Step 3-2: Define the aircraft state vector as follows:

[0132] x=[t,R,V M ] T (12)

[0133] Step 3-3: Adjust the aircraft state vector from Step 3-2 relative to the remaining flight distance D. go Taking the derivative, we get:

[0134]

[0135] in,

[0136]

[0137] Steps 3-4, iteration step size is The superscript C represents the current state of the aircraft, and H represents the number of numerical iterations. N is the proportional guidance coefficient, and the aircraft state vector x and remaining flight distance D are... go Let x be the discrete node. h and Where h = {0, 1, ..., H-1}, then the future average speed of the aircraft is... The following process can be used to derive the following:

[0138] Step 3-4-1, Settings

[0139] Step 3-4-2: Set h = 0;

[0140] Step 3-4-3: When h < H, execute steps 3-4-4 to 3-4-7;

[0141] Step 3-4-4: Calculate according to formula (11)

[0142] Steps 3-4-5: Calculate f(x) according to formula (14). h );

[0143] Steps 3-4-6: Calculate x h+1 =x h +Δ h f(x h );

[0144] Steps 3-4-7: Calculate h = h + 1;

[0145] Steps 3-4-8: Calculation

[0146] Steps 3-4-9: Calculate the predicted future average speed of the aircraft.

[0147] in, Indicates the predicted remaining flight time of the missile; x H This represents the state vector parameter of the H-th discrete node x; x C The state vector parameter x represents the state vector parameter at the current time; x h+1 This represents the state vector parameters of the (h+1)th discrete node x.

[0148] Furthermore, in step 4, in order to apply the time-constrained guidance law designed in step 2 to non-maneuverable moving targets, predictive interception point technology is used, which enables the interception of non-maneuverable moving targets at a specified time. The specific steps are as follows:

[0149] Step 4-1: Using the predicted interception point technology, predict the location of the interception target point as follows:

[0150]

[0151] in, For the target's real-time location, The predicted target location;

[0152] Step 4-2: Based on the target prediction and real-time aircraft position from Step 4-1, determine the interception location. The distance to the target can be predicted. The predicted remaining flight distance is

[0153] Step 4-3: Based on the target distance and remaining flight distance predicted in Step 4-2, the future average speed of the aircraft can be calculated using the future average speed prediction algorithm described in Step 3.

[0154] Step 4-4: Based on the future average speed of the aircraft for striking non-maneuvering moving targets predicted in Step 4-3. By utilizing the guidance law proposed in step 2, it is possible to strike non-maneuverable moving targets at a specified time.

[0155] Furthermore, after calculating the guidance law in step 2... Afterwards, the control acceleration vector A of the aircraft M It can be calculated as follows:

[0156]

[0157] Example 2

[0158] A three-dimensional strike time system for intercepting targets within the atmosphere, considering field-of-view constraints and based on line-of-sight angular rate shaping, includes a vehicle kinematics and target kinematics calculation unit, a real-time guidance law calculation unit, a future average velocity calculation unit, and a vehicle guidance control unit, wherein:

[0159] The vehicle and target kinematics calculation unit calculates the position information of the vehicle and the target in real time based on the guidance control variables, providing accurate dynamic kinematic data support for subsequent guidance law calculation.

[0160] The aircraft real-time guidance law calculation unit calculates the guidance control quantities of the aircraft in real time based on the user-defined specified strike time parameters and the designed guidance law, ensuring that the aircraft can intercept the target at the predetermined time.

[0161] The aircraft's future average speed calculation unit takes the real-time remaining flight distance as input and estimates the aircraft's future average speed in real time through a designed future average speed prediction algorithm, providing key speed information for guidance law calculation.

[0162] The aircraft guidance control unit drives the aircraft's rudder control system based on the guidance commands output by the guidance law calculation unit, thereby achieving precise control of the aircraft and ensuring that the aircraft completes the interception of the target within a specified time.

[0163] The overall workflow is as follows: During the guidance process, the kinematics calculation unit of the aircraft and the target continuously updates the position information of the aircraft and the target, and transmits the data to the real-time guidance law calculation unit of the aircraft. The guidance law calculation unit combines the speed information provided by the specified strike time and the future average speed calculation unit to generate guidance commands in real time. The aircraft guidance control unit drives the rudder control system according to the guidance commands to adjust the attitude and trajectory of the aircraft, and finally achieves the precise interception of the target by the aircraft at the specified time.

[0164] Then, taking the interception of a stationary target by an aircraft as an example, the initial position of the aircraft is (-13.38km, 7.726km, 4.142km), the initial velocity is 300m / s, the initial trajectory inclination angle is 5.4768°, the initial trajectory deflection angle is -15.858°, the target position is (0km, 0km, 0km), the designed engagement time is 61s, the maximum lead angle is set to 45°, i.e., parameter k1 = 1 in the guidance law, and other parameters are set as follows: α = 1.2, β = 1.2, p = 0.6, q = 1.4. The aerodynamic drag parameters and aircraft parameters are: T = 0, C D0 =0.04, K D =0.1, air density ρ=1.2, m=200, s=0.4. This embodiment only provides a set of aerodynamic characteristics and desired impact settings for simulation. For other scenarios, only the corresponding parameters need to be replaced, and the impact time T needs to be changed. d That's all. Figures 5-8 The simulation results show that a single aircraft guided by a single aircraft can intercept a target within a specified time of 60 seconds, demonstrating the effectiveness of the strike time constraint guidance law proposed in this invention.

[0165] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0166] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, characterized in that, Includes the following steps: Step 1: Based on the constructed strike time error, design the desired line-of-sight vector rotation angular rate profile that can achieve strike time and field-of-sight constraints; Step 2: Based on fixed-time control technology, design a three-dimensional time-constrained guidance law so that the aircraft can track the desired line-of-sight vector rotation angular rate profile from Step 1 within a fixed time. Step 3: Propose a numerical iterative algorithm for predicting the future average velocity, and then calculate the future average velocity of the aircraft in the atmosphere based on the three-dimensional time-constrained guidance law in Step 2. Step 4: Use the predicted interception point technology to predict the location of the interception target, and then predict the missile-target distance and remaining flight distance; then use the future average speed prediction algorithm from Step 3 to calculate the aircraft's future average speed. Then according to With the three-dimensional time-constrained guidance law designed in step 2, the interception of non-maneuvering moving targets at a specified time can be achieved.

2. The method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 1, is characterized in that: The desired line-of-sight vector rotation angular rate profile in step 1 is designed in a vector coordinate system. The specific engagement model is described as follows: the aircraft's motion state can be represented by the velocity vector V. M and control acceleration vector A M The target's motion state is represented by the velocity vector V. T and control acceleration vector A T The description defines the line-of-sight vector between the aircraft and the target as R, where R = ||R|| is the distance between the aircraft and the target, and V... M =||V M ||and V T =||V T || are the speeds of the aircraft and the target, respectively, and let and For a unit vector, the following equations hold: Ω in the formula L and These represent the rotational angular velocities of the line-of-sight vector and the aircraft velocity vector, respectively. Let represent the derivatives of the missile-target distance, the line-of-sight unit vector, and the missile velocity unit vector with respect to time, respectively; define the aircraft front as σ, and satisfy the following relationship: cosσ=r·v M (4) sinσk=r×v M (5) Where k is known to be defined as k = r × v / ||r × v||, for the line-of-sight angular rate Ω L Taking the derivative, we have the following relationship: For an aircraft flying within the atmosphere, its speed is affected by gravity, air resistance, and thrust, as shown in the following equations: in, The velocity of the missile is represented by the derivative with respect to time; T is the thrust of the aircraft, Q is the aerodynamic pressure, s is the area of ​​the aircraft, m is the mass of the aircraft, and g is the gravitational acceleration vector. n The component of gravity in the direction of the aircraft's velocity is given by the formula g. n =v M ×(g×v M ), C D0 K is the zero-lift drag coefficient. D This is the induced drag coefficient.

3. The method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 2, is characterized in that: The step 1, based on the constructed strike time error, designs a desired line-of-sight vector rotation angular rate profile capable of achieving strike time and field-of-view constraints. Specifically, the designed desired line-of-sight vector rotation angular rate profile is as follows: Where tanh(·) is the hyperbolic tangent function. For the desired line-of-sight vector rotation angular rate profile, To combat time errors, T represents the future average speed of the aircraft. d The specified attack time is t, where t is the time after the aircraft is released. go Let k1 be the remaining flight time of the aircraft, and k1 = cosσ. max , σ max For the maximum field of view, 4. The method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 3, is characterized in that: The three-dimensional time-constrained guidance law designed in step 2 is specifically as follows: Where S=Ω L -Ω Ld sig(S,p)=|S| p sign(S) and sign(·) are the sign functions, α>0, β>0, 0<p<1, and q>1 are adjustable controller parameters.

5. A method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 4, is characterized in that: After calculating the three-dimensional time-constrained guidance law in step 2... Afterwards, the control acceleration vector A of the aircraft M Calculated as, 6. A method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 5, is characterized in that: The specific process of step 3 is as follows: Step 3-1, when the impact time error When convergence is zero, the three-dimensional time-constrained guidance law transforms into: Step 3-2: Define the aircraft state vector as follows: x=[t,R,V M ] T (12) Where the superscript T represents the transpose of the matrix; Step 3-3: Adjust the aircraft state vector from Step 3-2 relative to the remaining flight distance D. go Taking the derivative, we get: in, Steps 3-4, iteration step size is In this context, the superscript C represents the current state of the aircraft, and H represents the number of numerical iterations. N is the proportional guidance coefficient, and the aircraft state vector x and remaining flight distance D are... go Let x be the discrete node. h and Where h = {0, 1, ..., H-1}, then the future average speed of the aircraft is... The following process is used to derive the following: Step 3-4-1, Settings Step 3-4-2: Set h = 0; Step 3-4-3: When h < H, execute steps 3-4-4 to 3-4-7; Step 3-4-4: Calculate according to formula (11) Steps 3-4-5: Calculate f(x) according to formula (14). h ); Steps 3-4-6: Calculate x h+1 =x h +Δ h f(x h ); Steps 3-4-7: Calculate h = h + 1; Steps 3-4-8: Calculation Steps 3-4-9: Calculate the predicted future average speed of the aircraft. in, Indicates the predicted remaining flight time of the missile; x H This represents the state vector parameter of the H-th discrete node x; x C The state vector parameter x represents the state vector parameter at the current time; x h+1 This represents the state vector parameters of the (h+1)th discrete node x.

7. A method for intercepting targets within the atmosphere based on a three-dimensional time-constrained guidance law considering field-of-view constraints, as described in claim 6, is characterized in that: Step 4 specifically involves: Step 4-1: Using the predictive interception point technique, predict the location of the interception target point as follows: in For the target's real-time location, Predict the interception location for the target; Step 4-2: Based on the target prediction and real-time aircraft position from Step 4-1, determine the interception location. The distance to the target can be predicted. The predicted remaining flight distance is Step 4-3: Based on the target distance and remaining flight distance predicted in Step 4-2, the future average speed of the aircraft can be calculated using the future average speed prediction algorithm from Step 3. Step 4-4: Based on the future average speed of the aircraft for striking non-maneuvering moving targets predicted in Step 4-3. Using the guidance law proposed in step 2, a time-limited strike can be achieved against a non-maneuverable moving target.

8. A guidance system for the method of any one of claims 1-7, comprising an aircraft kinematics and target kinematics calculation unit, an aircraft real-time guidance law calculation unit, an aircraft future average velocity calculation unit, and an aircraft guidance control unit, characterized in that: The vehicle and target kinematics calculation unit calculates the position information of the vehicle and the target in real time based on the guidance control variables, providing accurate dynamic kinematic data support for subsequent guidance law calculation. The aircraft real-time guidance law calculation unit calculates the guidance control quantities of the aircraft in real time based on the user-defined specified strike time parameters and the designed guidance law, ensuring that the aircraft can intercept the target at the predetermined time. The aircraft's future average speed calculation unit takes the real-time remaining flight distance as input and estimates the aircraft's future average speed in real time through a designed future average speed prediction algorithm, providing key speed information for guidance law calculation. The aircraft guidance control unit drives the aircraft's rudder control system based on the guidance commands output by the guidance law calculation unit, thereby achieving precise control of the aircraft and ensuring that the aircraft completes the interception of the target within a specified time.

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