Hypersonic speed interception missile multi-constraint mid-guidance method system considering information loss

Abstract

The invention discloses a hypersonic speed interception missile multi-constraint mid-guidance method system considering information loss, and belongs to the technical field of interception missiles. According to the method, firstly, an interception missile mathematical model is established under a ground trajectory system, and then the end attack angle constraint is converted into a terminal sight line constraint tracking problem, so that the problem difficulty is simplified; the method comprises the following steps: acquiring information of a target aircraft, estimating the acquired information by using a design filter, designing a trajectory classifier based on a long-short memory neural network, training to obtain a trajectory prediction database, performing trajectory prediction by using the database as support for guidance rate design, and finally designing an expected direction angle design through estimated target aircraft information to derive the guidance rate. And MATLAB simulation software is used for carrying out method verification, and the effectiveness of the method is judged.

Description

Technical Field

[0001] The invention belongs to the technical field of interceptor missiles and relates to a multi-constraint mid-course guidance method system for a hypersonic interceptor missile taking into account information loss. Background Art

[0002] Many aircraft basically have the capabilities of supersonic speed and stealth, and near-space hypersonic aircraft have extremely high flight altitudes and extremely fast flight speeds.

[0003] When conducting an interception, near-space hypersonic interceptors may often face the problem of missing enemy information during the interception process. During the interception process, accurately acquiring and processing target aircraft information is the key to achieving effective guidance. However, the characteristics of near-space hypersonic aircraft result in a small radar cross-sectional area and strong maneuverability. In addition, under hypersonic flight conditions, the difficulty of radar detection and tracking increases significantly, and information loss or delay is very likely to occur. This information loss may not only include the lag in updating basic parameters such as the position and speed of the target aircraft, but may also involve the loss of advanced information such as the target aircraft's flight trajectory prediction and maneuvering intention recognition, thus posing a severe test to the real-time and accuracy of the interception guidance system. Therefore, the hypersonic interception guidance problem considering information loss has become a difficult problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a multi-constraint mid-course guidance method system for a hypersonic interceptor missile taking into account information loss, so as to solve the problem in the prior art that near-space hypersonic interceptor missiles may often face information loss of the target aircraft during the interception process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A multi-constraint mid-course guidance method for a hypersonic interceptor missile considering information loss comprises the following steps:

[0007] S1, establishing an interceptor missile motion model, and setting multiple constraints for the motion model, the constraints including maximum stagnation point heat flux density constraint, maximum dynamic pressure constraint, maximum overload constraint, control amount constraint and attack angle constraint; the attack angle constraint is converted into simple terminal line of sight tracking;

[0008] S2, obtain the position of the target aircraft in the observation coordinate system through the tracking filter;

[0009] S3, based on the position of the target aircraft in the observation coordinate system, obtain the position, speed and trajectory category of the target aircraft in the geocentric rectangular coordinate system through a trajectory recognition classifier; the trajectory recognition classifier is obtained through LSTM network training;

[0010] S4: When the target aircraft information is missing, the ballistic category of the target aircraft in the geocentric rectangular coordinate system obtained in S3 is used to obtain the firing angles of the interceptor missile and the target aircraft, and the expected speed of the interceptor missile is further obtained, and the expected trajectory deviation angle is obtained through the expected speed. Based on the simple tracking of the terminal line of sight, a lateral tracking guidance law is designed, and the mid-course guidance correction of the interceptor missile is performed in the lateral plane through the lateral tracking guidance law. The mid-course guidance correction is to eliminate the trajectory deviation angle error through the sideslip angle instruction, and the interceptor missile is introduced to the target aircraft through the mid-course guidance.

[0011] A further improvement of the present invention is:

[0012] Preferably, in S1, the maximum stagnation point heat flux density constraint is:

[0013]

[0014] Among them, Q max is the maximum heat flux density allowed for the interceptor missile, k is the proportional coefficient for an interceptor missile of a certain shape, and ρ is the atmospheric density.

[0015] Preferably, in S1, the maximum dynamic pressure constraint is:

[0016] q=0.5ρv 2 ≤q max (6)

[0017] In the formula, q max Indicates the maximum dynamic pressure allowed by the interceptor missile, the unit is P a , ρ is the atmospheric density, and v is the aircraft speed.

[0018] Preferably, the maximum overload constraint is:

[0019]

[0020] Where L and D represent the lift and drag of the interceptor missile, α is the angle of attack, m is the mass of the interceptor missile, g0 is the gravitational acceleration at sea level, and n ymax Indicates the maximum overload value allowed for the interceptor missile;

[0021] The control quantity constraint is:

[0022] α min ≤α≤α max (8)

[0023] Where α is the angle of attack, α min is the minimum attack angle allowed for the interceptor missile, α max The maximum angle of attack allowed for the interceptor missile.

[0024] Preferably, in S1, the formula for converting the attack angle constraint into simple tracking of the terminal line of sight is:

[0025]

[0026] Among them, q f is the sight angle at the end of guidance, is the heading angle of the target aircraft at the end of terminal guidance, is the missile’s attack angle, V t , V m are the velocity vectors of the target aircraft and the missile respectively.

[0027] Preferably, in S2, the tracking filter is:

[0028]

[0029] Where X∈R 9 , Y∈R 3 is the measured output of the filter, W and V are the system noise and measurement noise respectively.

[0030] Preferably, in S2, the position of the target in the observation coordinate system is:

[0031]

[0032] Where R is the distance measurement value of the observation device; ε and κ are the angle measurement values ​​of the observation device.

[0033] Preferably, in S4, the desired trajectory deviation angle is:

[0034]

[0035] Among them, V G is the interceptor missile speed in the launch coordinate system.

[0036] Preferably, in S4, the sideslip angle instruction is:

[0037]

[0038] Among them, F aero,z is the aerodynamic force in the velocity coordinate system, The lateral force coefficient affected by the sideslip angle, q is the dynamic pressure, and S is the reference area of ​​the interceptor missile.

[0039] A multi-constraint mid-course guidance system for a hypersonic interceptor missile taking into account information loss, comprising:

[0040] A motion model unit is used to establish a motion model of the interceptor missile and set multiple constraints for the motion model, wherein the constraints include a maximum stagnation point heat flux constraint, a maximum dynamic pressure constraint, a maximum overload constraint, a control amount constraint, and an attack angle constraint; the attack angle constraint is converted into a simple terminal line of sight tracking;

[0041] A tracking unit, used for obtaining the position of the target aircraft in the observation coordinate system through a tracking filter;

[0042] A classification unit, for obtaining the position, velocity and trajectory category of the target aircraft in a geocentric rectangular coordinate system based on the position of the target aircraft in the observation coordinate system through a trajectory recognition classifier; the trajectory recognition classifier is obtained through LSTM network training;

[0043] The guidance unit is used to obtain the interceptor missile and the target aircraft's firing angle based on the trajectory category of the target aircraft in the geocentric rectangular coordinate system obtained by the classification unit when enemy information is missing, and further obtain the expected speed of the interceptor missile, and obtain the expected trajectory deviation angle through the expected speed; based on simple terminal line of sight tracking, a lateral tracking guidance law is designed, and the mid-course guidance correction of the interceptor missile is performed in the lateral plane through the lateral tracking guidance law, wherein the mid-course guidance correction is to eliminate the trajectory deviation angle error through the sideslip angle instruction, and the interceptor missile is introduced into the target aircraft through the mid-course guidance.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention discloses a multi-constraint mid-range guidance method for a hypersonic interceptor missile considering information loss. The method first establishes a mathematical model of the interceptor missile under a ground trajectory system; secondly, the process constraint, control quantity constraint, initial state constraint, and terminal state constraint are considered and a specific mathematical description is given, and the terminal attack angle constraint is converted into a terminal line of sight constraint tracking problem, which simplifies the difficulty of the problem; the acquired information is estimated by using a design filter, and then a trajectory classifier is designed based on a long short-term memory neural network and trained to obtain a trajectory prediction database, and the database is used for trajectory prediction as a support for guidance rate design, and finally the expected firing angle is designed and deduced through the estimated target aircraft information to obtain the guidance rate, thereby improving the accuracy of the guidance. The method is verified by using MATLAB simulation software to determine the effectiveness of the method.

[0046] Furthermore, the trajectory recognition classifier is obtained through LSTM network training. A data library of different trajectory forms is established through a large amount of training. When information is missing, the method of calling data for trajectory prediction is used to design guidance instructions. Simulation verification shows that this scheme can effectively solve the interception problem of missing information and has a good guidance effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A network model training graph of the present invention;

[0048] Figure 2 A diagram of a multi-constraint mid-course guidance method for a hypersonic interceptor missile according to the present invention;

[0049] Figure 3 It is a schematic diagram of the guided strike of the interceptor missile of the present invention. DETAILED DESCRIPTION

[0050] In the following, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features.

[0051] The co-shooting method provided in the embodiment of the present application can be applied to terminal devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptop computers, ultra-mobile personal computers (UMPC), netbooks, personal digital assistants (PDA), etc. The embodiment of the present application does not impose any restrictions on the specific type of the terminal device.

[0052] It should be noted that the terms "first", "second", etc. in the specification and drawings of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] The first aspect of the present invention discloses a multi-constraint mid-course guidance method for a hypersonic interceptor missile considering information loss, the method specifically comprising the following steps:

[0054] Step 1: Establish a mathematical model of interceptor missile motion

[0055] The kinematic and dynamic models of the interceptor missile center of mass are established in the ballistic coordinate system as follows:

[0056]

[0057] Where: P—angle of attack; α B — angle of attack; β B —sideslip angle; γ v —speed inclination angle; X—air resistance; Y—lift; Z—lateral force; m—missile mass; g—gravitational acceleration.

[0058] Among them, X and Y can usually be described as

[0059]

[0060] in, represents dynamic pressure; ρ—atmospheric density at the flight altitude; v—air velocity of the interceptor missile; S—reference area of ​​the interceptor missile; C x ,C y ,C z are the aerodynamic coefficients, representing the drag coefficient, lift coefficient and lateral force coefficient respectively.

[0061] The dynamic and kinematic models of the interceptor missile rotating around the center of mass are established as follows:

[0062]

[0063] The torque model is as follows:

[0064]

[0065] Among them, M x ,M y ,M z is the triaxial moment;

[0066] ω x ω y ω z The attitude angular velocity information of the three axes of the interceptor missile;

[0067] J x J y J z is the three-axis moment of inertia;

[0068] is the rolling moment coefficient caused by the rudder deflection angle;

[0069] is the yaw moment coefficient caused by the rudder deflection angle;

[0070] is the pitching moment coefficient caused by the rudder deflection angle.

[0071] Step 2: Establish a multi-constraint mathematical model

[0072] After re-entering the atmosphere, a hypersonic interceptor missile will be decelerated by strong resistance, and the surface temperature will rise sharply. Therefore, when designing the trajectory of the re-entry phase, it is necessary to consider a series of constraints such as process constraints, control quantity constraints, initial state constraints, and terminal state constraints. The mathematical descriptions of these constraints are given below.

[0073] a) Maximum stagnation point heat flux constraint

[0074] During the reentry process, the mechanical energy of the interceptor missile is converted into heat energy through braking. The huge amount of energy is transferred from the atmosphere to the surface of the aircraft, causing the aircraft structure to suffer high-temperature ablation. In particular, the stagnation point heat flux density at the head of the aircraft is high, and the ablation is more serious. Therefore, the structure of the interceptor missile can be protected by limiting the stagnation point heat flux density. The following empirical formula is used to calculate the value of the stagnation point heat flux density:

[0075]

[0076] Among them, Q max represents the maximum heat flux density allowed by the interceptor missile, and k is the proportional coefficient for a certain shape of the interceptor missile. In this invention, it is 5.5×10 -8 ; ρ is the atmospheric density.

[0077] b) Maximum dynamic pressure constraint

[0078] In order to protect the structural safety of the interceptor missile, it is necessary to limit the maximum dynamic pressure during flight to limit the aerodynamic force and aerodynamic moment during reentry. Let q represent the dynamic pressure during flight, which can be obtained by the following formula:

[0079] q=0.5ρv 2 ≤q max (6)

[0080] In the formula, q max Indicates the maximum dynamic pressure allowed by the interceptor missile, the unit is P a

[0081] c) Maximum overload constraint

[0082] During the reentry process, the maximum overload amplitude needs to be limited to protect the interceptor missile's structure from being damaged by aerodynamic forces and aerodynamic moments. When performing engineering design, constraints are generally imposed on the normal overload or total overload of the interceptor missile. The present invention imposes constraints on the total overload, and its calculation formula is:

[0083]

[0084] Where L and D represent the lift and drag of the interceptor missile, α is the angle of attack, m is the mass of the interceptor missile, g0 is the gravitational acceleration at sea level, and n ymax Indicates the maximum overload value allowed for the interceptor missile.

[0085] d) Control quantity constraints

[0086] During the reentry process, the interceptor missile mainly controls the aerodynamic force and aerodynamic torque through the angle of attack command and the roll angle command, thereby controlling the flight trajectory of the interceptor missile. While protecting the structural safety of the interceptor missile, in order to ensure that the actuator generates reliable aerodynamic force, the amplitude of the angle of attack must be constrained. Let α max represents the maximum attack angle allowed by the interceptor missile, and the control quantity constraint can be expressed as:

[0087] α min ≤α≤α max (8)

[0088] e) Angle of attack constraint

[0089] Constraining the attack angle meets the need to adjust the sight angle of the interceptor missile to ensure good side window detection conditions during the operation of intercepting high-speed maneuvering target aircraft. In order to facilitate solving the problem, modeling is mainly carried out here mainly for the longitudinal plane.

[0090] Since there are three definitions of the angle of attack, the definition used here is that the angle of attack is defined as the angle between the missile velocity vector and the target aircraft velocity vector when the interceptor missile hits the target aircraft.

[0091] The guidance law is designed based on the idea of ​​zeroing the line-of-sight angular velocity, that is, the missile-to-line-of-sight angular velocity is 0 when the missile hits the target aircraft.

[0092]

[0093] in, and They represent the heading angle of the target aircraft and the ballistic inclination angle of the interceptor missile at the end of terminal guidance, respectively. f is the sight angle at the end of guidance.

[0094] Defining Angle of Attack is the angle between the velocity vectors of the missile and the target aircraft when the missile hits the target aircraft, that is,

[0095]

[0096] Available

[0097]

[0098] Assume V t <V m , the final sight angle after trigonometric operation of the above formula is:

[0099]

[0100] if It is known that for a given angle of attack It can be obtained. Then it can be seen from the above formula that there is always a q f Correspondingly, the terminal attack angle constraint problem can be converted into a simple terminal line of sight tracking problem.

[0101] Step 3: Design of tracking filter on interceptor missile

[0102] Define the observation coordinate system as (ox g ,y g ,z g ), the origin is the observation radar point, oy g Direction in the vertical plane, pointing to the sky is positive. g In the attack plane formed by the origin and the target aircraft detected by the radar, and with oy g Vertical, pointing towards the target aircraft is positive. g Determined using the right-hand rule.

[0103] In the observation coordinate system, the following three state variables are defined:

[0104]

[0105] Among them, C x , C y , C z is the aerodynamic coefficient; m t is the mass of the target aircraft; S is the equivalent reference area of ​​the target aircraft. Select the state variables and establish the following state equation:

[0106]

[0107] in:

[0108]

[0109] Where ρ is the air density; is the speed of the target aircraft; μ = 3.98199 × 10 14 ; R e is the radius of the Earth; It is the transformation matrix from the velocity coordinate system to the observation coordinate system, which is specifically expressed as follows:

[0110]

[0111] The following EKF model is established:

[0112]

[0113] Where X∈R 9 , Y∈R 3 is the measured output of the filter, W and V are the system noise and measurement noise respectively, both are zero-mean Gaussian white noise. This model is a hybrid system with continuous state and discrete output.

[0114]

[0115] In actual situations, radar and other detection devices can only obtain the distance information and angle information of the target aircraft in the observation coordinate system. Let ε and κ represent the altitude angle and direction angle respectively. Then, in the observation coordinate system, the measured position coordinates of the target aircraft are It can be obtained by the following formula:

[0116]

[0117] In the formula, The distance measurement value of the observation device; and is the angle measurement value of the observation device. The variance of the distance measurement of the known measuring device is E(ΔR) 2 and the variance of the angle measurement E(Δε) 2 、E(Δκ) 2 , the distance measurement noise and the high and low angle noise and azimuth noise are independent of each other, that is, the measurable noise variance matrix R n .

[0118] Step 4: LSTM-based trajectory prediction

[0119] There are many possible modes for unpowered reentry gliding of hypersonic target aircraft, mainly including balanced gliding and balanced jump gliding. They represent two typical flight trajectories. Balanced gliding refers to approximately maintaining the iso-altitude flight condition as a balanced equation, and the typical trajectory is the famous Qian Xuesen trajectory. Balanced jump gliding can be figuratively compared to a water skipping ballistics, also known as the Sanger trajectory.

[0120] Since the unpowered reentry glide trajectory of a hypersonic vehicle is much more complex than the inertial trajectory, it is necessary to first identify the trajectory category based on the measurement data. A trajectory identification classifier is constructed. The input of the trajectory identification classifier is the target aircraft information, and the output is the trajectory type. The main body of the trajectory identification classifier is the LSTM network.

[0121] The reentry trajectory data of the hypersonic glide vehicle is divided into balanced glide and balanced jump glide, which are respectively denoted as Glide and Jump. The total trajectory data set can be expressed as:

[0122] DATA={TD_glide,TD_jump} (23)

[0123] Where TD_glide and TD_jump represent the data sets of various trajectories respectively.

[0124] TD={tra 1 ,tra 2 ,…,tra N} (twenty four)

[0125] In the formula, tra N It is a trajectory sample, a complete trajectory of the target aircraft, and a trajectory time series.

[0126] tra={D x ,D y ,D z ,D Vx ,D Vy ,D Vz ,flag} (25)

[0127] Where D x ,D y ,D z ,D Vx ,D Vy ,D Vz , flag respectively represent the position, velocity and trajectory category identification of the target aircraft trajectory in the geocentric rectangular coordinate system; the geocentric rectangular coordinate system is defined as: the x-axis is consistent with the earth's rotation axis, the y-axis points to the intersection of the launch point meridian and the equator in the equatorial plane, and the z-axis and the two axes form a right-handed rectangular coordinate system.

[0128] The preprocessing normalizes the possible value range of the trajectory data roots, reduces the amplitude range, and manually assigns label information to become a formal network training sample set.

[0129] After constructing the trajectory recognition classifier, the network is trained through the network training sample set to obtain the trained trajectory recognition classifier.

[0130] After completing the network construction of the trajectory identification classifier as mentioned above, it is also necessary to classify the trajectory according to the current situation during application to provide support for the design of the maneuverability and guidance rate of the interceptor missile.

[0131] Step 5: Design of mid-range guidance rate based on firing direction

[0132] When the target aircraft information is missing, the predicted position information of the target aircraft is obtained through the trajectory category in step 4, and the guidance design is performed based on the predicted position information as the imaginary position of the target aircraft. Assuming that the attack angle constraint is met, the aforementioned attack angle constraint has already processed the vertical plane, and the subsequent design process is mainly aimed at the lateral plane. Therefore, the missile's mid-range guidance problem is transformed into a guidance correction problem in the lateral plane. The main task of the lateral guidance is to eliminate the heading angle error by designing the sideslip angle command β and guide the interceptor to the target aircraft. The trajectory deviation angle is defined as: the angle between the projection of the missile velocity vector on the horizontal plane (i.e., the Oxz plane of the ground coordinate system) and the ox axis of the ground coordinate.

[0133] In the above process, the predicted position information of the target aircraft can be obtained by the ballistic category based on the existing method.

[0134] See also Figure 3 , the guidance law design process includes the following steps:

[0135] Define the coordinates of the interceptor missile's current position A as The longitude and latitude coordinates of the target aircraft T are Then the angle Ad from the current point A to the target aircraft T can be calculated. It is easy to know that when the interceptor missile's velocity direction coincides with the current direction, the interceptor missile can accurately strike the target aircraft. Therefore, this velocity direction is defined as the expected velocity direction, and a North Celestial East coordinate system is established at point A to represent this velocity, as shown below:

[0136]

[0137] The conversion process of converting this velocity to the original emission system is as follows:

[0138]

[0139] In the formula, R ET-NRE The transformation matrix from the North Celestial East coordinate system to the geocentric rectangular coordinate system is expressed as follows:

[0140]

[0141] R G-ET The transformation matrix from the geocentric rectangular coordinate system to the launch coordinate system is expressed as follows:

[0142]

[0143] Therefore, the desired trajectory deviation angle σ d It can be expressed as follows:

[0144]

[0145] The lateral tracking guidance law is designed using the idea of ​​proportional feedback control, as shown in the following equation (37), where the tracking error is defined as e σ =σ-σ d . Then, the expected rate of change of tracking error is:

[0146]

[0147] The dynamic equation of the known reentry trajectory angle is:

[0148]

[0149] Among them, subscript 3 represents the ballistic coordinate system, F aero is the aerodynamic force. Then the actual tracking error change rate is:

[0150]

[0151] Considering It can be simplified to:

[0152]

[0153] The required aerodynamic force can be calculated as:

[0154] F aero,z3 =k1e σ mVcosθ-mg z3 (35)

[0155] Under BTT control conditions, when the roll angle is 0, the trajectory coordinate system coincides with the velocity coordinate system, so:

[0156]

[0157] The sideslip angle command at the next moment can be solved as follows:

[0158]

[0159] The second aspect of the present invention discloses a multi-constraint mid-course guidance system for a hypersonic interceptor missile taking into account information loss, comprising:

[0160] A motion model unit is used to establish a motion model of the interceptor missile and set multiple constraints for the motion model, wherein the constraints include a maximum stagnation point heat flux constraint, a maximum dynamic pressure constraint, a maximum overload constraint, a control amount constraint, and an attack angle constraint; the attack angle constraint is converted into a simple terminal line of sight tracking;

[0161] A tracking unit, used for obtaining the position of the target aircraft in the observation coordinate system through a tracking filter;

[0162] A classification unit, for obtaining the position, velocity and trajectory category of the target aircraft in a geocentric rectangular coordinate system based on the position of the target aircraft in the observation coordinate system through a trajectory recognition classifier; the trajectory recognition classifier is obtained through LSTM network training;

[0163] The guidance unit is used to obtain the interceptor missile and the target aircraft's firing angle based on the trajectory category of the target aircraft in the geocentric rectangular coordinate system obtained by the classification unit when enemy information is missing, and further obtain the expected speed of the interceptor missile, and obtain the expected trajectory deviation angle through the expected speed; based on simple terminal line of sight tracking, a lateral tracking guidance law is designed, and the mid-course guidance correction of the interceptor missile is performed in the lateral plane through the lateral tracking guidance law, wherein the mid-course guidance correction is to eliminate the trajectory deviation angle error through the sideslip angle instruction, and the interceptor missile is introduced into the target aircraft through the mid-course guidance.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-constraint mid-course guidance method for a hypersonic interceptor missile considering information loss, characterized in that: The following steps are involved: S1, establishing an interceptor missile motion model, setting multiple constraints for the motion model, the constraints including maximum stagnation point heat flux density constraint, maximum dynamic pressure constraint, maximum overload constraint, control amount constraint and attack angle constraint; the attack angle constraint is converted into simple terminal line of sight tracking; S2, obtain the position of the target aircraft in the observation coordinate system through the tracking filter; S3, based on the position of the target aircraft in the observation coordinate system, obtain the position, speed and trajectory category of the target aircraft in the geocentric rectangular coordinate system through a trajectory recognition classifier; the trajectory recognition classifier is obtained through LSTM network training; S4: When the target aircraft information is missing, the ballistic category of the target aircraft in the geocentric rectangular coordinate system obtained in S3 is used to obtain the firing angles of the interceptor missile and the target aircraft, and the expected speed of the interceptor missile is further obtained, and the expected trajectory deviation angle is obtained through the expected speed. Based on the simple tracking of the terminal line of sight, a lateral tracking guidance law is designed, and the mid-course guidance correction of the interceptor missile is performed in the lateral plane through the lateral tracking guidance law. The mid-course guidance correction is to eliminate the trajectory deviation angle error through the sideslip angle instruction, and the interceptor missile is introduced to the target aircraft through the mid-course guidance.

2. According to the method of multi-constraint mid-course guidance of a hypersonic interceptor missile considering information loss according to claim 1, it is characterized in that: In S1, the maximum stagnation point heat flux density constraint is: Among them, Q max is the maximum heat flux density allowed for the interceptor missile, k is the proportional coefficient for an interceptor missile of a certain shape, and ρ is the atmospheric density.

3. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile considering information loss according to claim 1, characterized in that: In S1, the maximum dynamic pressure constraint is: q=0.5ρv 2 ≤q max (6) In the formula, q max Indicates the maximum dynamic pressure allowed by the interceptor missile, the unit is P a , ρ is the atmospheric density, and v is the aircraft speed.

4. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile considering information loss according to claim 1, characterized in that: The maximum overload constraint is: Where L and D represent the lift and drag of the interceptor missile, α is the angle of attack, m is the mass of the interceptor missile, g0 is the gravitational acceleration at sea level, and n ymax Indicates the maximum overload value allowed for the interceptor missile; The control quantity constraint is: α min ≤α≤α max (8) Where α is the angle of attack, α min is the minimum attack angle allowed for the interceptor missile, α max The maximum angle of attack allowed for the interceptor missile.

5. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile taking into account information loss according to claim 1, characterized in that: In S1, the formula for converting the attack angle constraint into simple tracking of the terminal line of sight is: Among them, q f is the sight angle at the end of guidance, is the heading angle of the target aircraft at the end of terminal guidance, θ is the attack angle of the missile, V t , V m are the velocity vectors of the target aircraft and the missile respectively.

6. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile taking into account information loss according to claim 1, characterized in that: In S2, the tracking filter is: Where X∈R 9 , Y∈R 3 is the measured output of the filter, W and V are the system noise and measurement noise respectively.

7. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile taking into account information loss according to claim 1, characterized in that: In S2, the position of the target in the observation coordinate system is: In the formula, The distance measurement value of the observation device; and is the angle measured by the observation device.

8. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile taking into account information loss according to claim 1, characterized in that: In S4, the desired trajectory deviation angle is: Among them, V G is the interceptor missile speed in the launch coordinate system.

9. The method for multi-constraint mid-course guidance of a hypersonic interceptor missile taking into account information loss according to claim 1, characterized in that: In S4, the sideslip angle instruction is: Among them, F aero,z is the aerodynamic force in the velocity coordinate system, The lateral force coefficient affected by the sideslip angle, q is the dynamic pressure, and S is the reference area of ​​the interceptor missile.

10. A multi-constraint mid-course guidance system for a hypersonic interceptor missile taking into account information loss, characterized in that: include: A motion model unit is used to establish a motion model of the interceptor missile and set multiple constraints for the motion model, wherein the constraints include a maximum stagnation point heat flux constraint, a maximum dynamic pressure constraint, a maximum overload constraint, a control amount constraint, and an attack angle constraint; the attack angle constraint is converted into a simple terminal line of sight tracking; A tracking unit, used for obtaining the position of the target aircraft in the observation coordinate system through a tracking filter; A classification unit, for obtaining the position, velocity and trajectory category of the target aircraft in a geocentric rectangular coordinate system based on the position of the target aircraft in the observation coordinate system through a trajectory recognition classifier; the trajectory recognition classifier is obtained through LSTM network training; The guidance unit is used to obtain the interceptor missile and the target aircraft's firing angle based on the trajectory category of the target aircraft in the geocentric rectangular coordinate system obtained by the classification unit when enemy information is missing, and further obtain the expected speed of the interceptor missile, and obtain the expected trajectory deviation angle through the expected speed; based on simple terminal line of sight tracking, a lateral tracking guidance law is designed, and the mid-course guidance correction of the interceptor missile is performed in the lateral plane through the lateral tracking guidance law, wherein the mid-course guidance correction is to eliminate the trajectory deviation angle error through the sideslip angle instruction, and the interceptor missile is introduced into the target aircraft through the mid-course guidance.

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