Aircraft trajectory shaping guidance method suitable for various spatiotemporal constraint couplings

Abstract

The application discloses a flight vehicle trajectory shaping guidance method suitable for various space-time constraint coupling, and belongs to the field of flight vehicle guidance and control. The method is realized by adopting a polynomial trajectory fitting mode, setting a polynomial function of a line-of-sight angle to a missile-target distance, establishing an algebraic equation of multiple constraint conditions, greatly simplifying parameter solving of a multiple constraint trajectory, converting a multiple constraint trajectory calculation problem into a single variable nonlinear equation solving problem, analytically solving n+1 constraint conditions, significantly reducing the solving difficulty of the multiple constraint trajectory calculation problem, and improving the solving efficiency. According to the trajectory shaping function determined according to the obtained parameters, a lead angle state tracking method is adopted to track a reference trajectory, time-space constraint guidance is realized under the condition of ensuring that a target miss distance is minimum, and the tracking precision and efficiency of the flight vehicle on the reference trajectory can be improved. The application can be used to solve the attack angle, time, terminal speed and acceleration constraint coupling problems in the flight vehicle guidance process.

Description

Technical Field

[0001] This invention relates to a precise terminal guidance method for aircraft, and more particularly to a trajectory shaping guidance method for aircraft applicable to various spatiotemporal constraint couplings, belonging to the field of aircraft guidance and control. Background Technology

[0002] With the development of modern battlefield situations and the deepening research on guidance problems, aircraft guidance technology is gradually developing towards collaboration, multi-constraint coupling, and intelligence. To achieve complex guidance missions under the performance limitations of weapon platforms, it is necessary to design guidance laws that can satisfy multi-constraint coupling conditions.

[0003] Although there is a great deal of research on the guidance problem of aircraft under attack angle, attack time and multiple constraints, most guidance methods with attack time constraints adopt the velocity steady assumption. In addition, the aircraft may also need to consider velocity and acceleration constraints in one step.

[0004] Therefore, it is necessary to design a more general multi-constraint coupling guidance method that can consider multiple constraints and has an intuitive design process for the guidance problem of aircraft under multi-constraint coupling. Summary of the Invention

[0005] To address the problems existing in the prior art, the main objective of this invention is to provide a trajectory shaping guidance method for aircraft applicable to various spatiotemporal constraints. By setting a polynomial function of the line-of-sight angle with respect to the target distance and an algebraic equation with multiple constraints, the parameter solution for multi-constraint trajectories is greatly simplified, transforming the multi-constraint trajectory calculation problem into a single-variable nonlinear equation solution problem, thus reducing the difficulty and improving the solution efficiency. Furthermore, by employing a finite-time guided trajectory tracking command, and through trajectory shaping guidance of aircraft under various spatiotemporal constraints, spatiotemporal constraint guidance is achieved while ensuring the target miss distance is minimized.

[0006] The objective of this invention is achieved through the following technical solution.

[0007] This invention discloses a trajectory shaping guidance method for aircraft applicable to various spatiotemporal constraints. The method employs a polynomial trajectory fitting approach, setting a polynomial function of the line-of-sight angle with respect to the target distance, and establishing algebraic equations for multiple constraints. This greatly simplifies the parameter solving of multi-constraint trajectories, transforming the multi-constraint trajectory calculation problem into a single-variable nonlinear equation solving problem, significantly reducing the difficulty of solving multi-constraint trajectory calculation problems and improving solution efficiency. By designing a finite-time guided trajectory tracking algorithm, spatiotemporal constraint guidance is achieved while ensuring minimal target miss distance. This invention can be used to solve the problem of constraint coupling between attack angle, time, terminal velocity, and acceleration in the aircraft guidance process.

[0008] The present invention discloses a ballistic shaping guidance method for aircraft applicable to various spatiotemporal constraint couplings, comprising the following steps:

[0009] Step 1: Construct the trajectory shaping fitting function of the aircraft by setting a polynomial function of the line-of-sight angle with respect to the distance between the missile and the target. The trajectory shaping fitting function of the aircraft is an nth-degree polynomial containing n+1 undetermined parameters. The n+1 undetermined parameters characterize the n+1 constraints in the guided missile trajectory.

[0010] By setting a polynomial function of the line-of-sight angle with respect to the target distance, the trajectory shaping function is designed as an nth-order polynomial function of the line-of-sight azimuth angle with respect to the target distance, as shown in formula (1).

[0011]

[0012] Where q is the line-of-sight angle, The ratio of the relative distance between the projectile and the target to the initial relative distance between the projectile and the target, k0~k n These are undetermined coefficients. The trajectory shaping fitting function of the aircraft is an nth-degree polynomial containing n+1 undetermined parameters, which characterize the n+1 constraints in the guided trajectory.

[0013] Step 2: Determine the actual constraints of the multi-constraint coupled aircraft guidance problem. Based on the aircraft trajectory shaping fitting function constructed in Step 1, the multi-constraint trajectory planning problem is transformed into a single-variable nonlinear equation solving problem. This simplifies the parameter solving problem of the multi-constraint trajectory, significantly reduces the difficulty of solving the multi-constraint trajectory planning problem, improves the efficiency of solving the multi-constraint trajectory planning problem, and thus obtains the trajectory shaping function after the parameters are determined.

[0014] The multiple constraints include initial position constraints, initial lead angle constraints, attack angle constraints, attack time constraints, terminal velocity constraints, and terminal acceleration constraints. General problems typically include initial position and initial lead angle constraints; attack angle and attack time constraints can be considered depending on the actual mission requirements; furthermore, terminal velocity and terminal acceleration constraints are considered to increase the complexity of the multi-temporal constraint coupled guidance problem and expand its application scope.

[0015] Step 2.1: Determine the constraints for the actual multi-constraint coupled aircraft guidance problem.

[0016] Constraint ① is the initial position of the aircraft. The constraint equation for equation (1) is as follows:

[0017] q(r0)=k0+k1+k2+…+k n =q0 (2)

[0018] Where r0 is the initial target distance and q0 is the initial line-of-sight azimuth.

[0019] Constraint condition ② is the initial lead angle of the aircraft. The constraint equation for equation (1) is as follows:

[0020]

[0021] Where σ0 is the initial leading angle.

[0022] Constraint ③: Attack angle constraint. The constraint equation for equation (1) is:

[0023] q(0)=θ M,f (4)

[0024] Where θ M,f This refers to the angle of attack at the terminal stage.

[0025] Constraint ④ is an attack time constraint. The constraint equation for equation (1) is as follows:

[0026]

[0027] Where r0 is the initial target distance, r f v represents the terminal target distance. m For the speed of the aircraft, σ m This refers to the aircraft's leading angle. t f t0 is the terminal time, and t0 is the initial time.

[0028] As shown in Equation (5), the attack time constraint is transformed into the ballistic length constraint as shown in Equation (6) when t0 = 0 under the condition of steady velocity, which further reduces the difficulty of solving the attack time constraint.

[0029]

[0030] Constraint ⑤ is the terminal velocity constraint, which is the desired control of the aircraft when q→0 under the aircraft velocity control condition.

[0031] v M (t f ) = v M,f (7)

[0032] Constraint ⑥ is the terminal acceleration constraint, which is the desired control of the aircraft when q→0 under the aircraft acceleration control condition.

[0033]

[0034] Step 2.2: Based on the nth-order polynomial function of the line-of-sight azimuth angle with respect to the target distance as shown in formula (1), and combined with the constraints of the actual multi-constraint coupled aircraft guidance problem determined in step 2.1, the initial position constraint and initial lead angle constraint equations shown in (2) to (3), and the attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equations in formulas (4) to (8) according to the actual multi-constraint requirements, establish n+1 equal constraint equations for multi-constraint coupled aircraft guidance, transform the multi-constraint ballistic planning problem into a single-variable nonlinear equation solving problem, simplify the parameter solving problem of the multi-constraint ballistics, significantly reduce the difficulty of solving the multi-constraint ballistic planning problem, and improve the efficiency of solving the multi-constraint ballistic planning problem.

[0035] Step 2.3: For the case where the attack time constraint is considered and the aircraft velocity is steady, by combining the initial position constraint and initial lead angle constraint equations shown in (2) to (3), and the attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equations in (4) to (8) according to the actual multiple constraints, the n+1 equal constraint equations in step 2.2 can be solved analytically to obtain the definite coefficients of the polynomial function of the line of sight angle with respect to the target distance under multiple constraints, that is, to obtain the trajectory shaping function after the parameters are determined.

[0036] For the remaining cases, by combining the initial position constraint and initial lead angle constraint equations shown in (2) to (3), and the attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equations in (4) to (8) according to the actual multi-constraint requirements, the n+1 equal constraint equations in step 2.2 can be solved analytically and numerically to obtain the definite coefficients of the polynomial function of the line-of-sight angle with respect to the target distance under multi-constraint conditions, that is, to obtain the trajectory shaping function after the parameters are determined.

[0037] Step 3: Based on the trajectory shaping function obtained in Step 2, the reference trajectory is tracked using the forward angle state tracking method. This achieves spatiotemporal constraint guidance while ensuring the target miss distance is minimized, and can improve the tracking accuracy and efficiency of the aircraft for the reference trajectory.

[0038] The leading angle state tracking method is adopted, and the leading angle is designed as follows:

[0039]

[0040] The preceding angular velocity is

[0041]

[0042] The design guidance command is

[0043]

[0044] Where k t >0 represents the feedback error gain.

[0045] By converting guidance commands...

[0046]

[0047] The reference trajectory is tracked according to the guidance command described in formula (12), thereby improving the tracking accuracy and efficiency of the aircraft.

[0048] Beneficial effects:

[0049] 1. The present invention discloses a vehicle trajectory shaping guidance method applicable to various spatiotemporal constraint couplings. By setting a polynomial function of the line-of-sight angle with respect to the target distance, an nth-degree polynomial vehicle trajectory shaping fitting function is constructed. The n+1 undetermined parameters characterize the n+1 constraints in the guided trajectory. The actual constraints of the multi-constraint coupled vehicle guidance problem are determined. Based on the constructed vehicle trajectory shaping fitting function, the multi-constraint trajectory planning problem is transformed into a single-variable nonlinear equation solving problem, simplifying the parameter solving problem of the multi-constraint trajectory, significantly reducing the difficulty of solving the multi-constraint trajectory planning problem, and improving the efficiency of solving the multi-constraint trajectory planning problem.

[0050] 2. The present invention discloses a ballistic shaping guidance method for aircraft applicable to various spatiotemporal constraints. These multiple constraints include initial position constraints, initial lead angle constraints, attack angle constraints, attack time constraints, terminal velocity constraints, and terminal acceleration constraints. General problems typically include initial position and initial lead angle constraints; attack angle and attack time constraints can be considered based on actual mission requirements; furthermore, considering terminal velocity and terminal acceleration constraints can solve the coupling problem of attack angle, time, terminal velocity, and acceleration constraints during aircraft guidance, thus broadening the application scope.

[0051] 3. The ballistic shaping guidance method for aircraft disclosed in this invention, applicable to various spatiotemporal constraints, for cases considering attack time constraints and steady aircraft velocity, transforms the attack time constraint into a range constraint, analytically solves the simultaneous n+1 constraint conditions, and obtains a definite ballistic shaping function; for other cases, an analytical + numerical method is used to solve the simultaneous n+1 constraint conditions, significantly reducing the difficulty of solving multi-constraint ballistic planning problems and improving the efficiency of solving multi-constraint ballistic planning problems.

[0052] 4. The trajectory shaping guidance method for aircraft disclosed in this invention is applicable to various spatiotemporal constraint couplings. Based on the trajectory shaping function after parameter determination, a leading angle state tracking method is used to track the reference trajectory, thereby improving the tracking accuracy and efficiency of the aircraft to the reference trajectory. Attached Figure Description

[0053] Figure 1 This is a flowchart of the ballistic shaping and guidance method for aircraft applicable to various spatiotemporal constraint couplings according to the present invention;

[0054] Figure 2 This is a schematic diagram of the geometric relationship of the guidance problem in Embodiment 1 of the present invention;

[0055] Figure 3 This is a flight trajectory diagram of an aircraft according to Embodiment 1 of the present invention;

[0056] Figure 4 This is a diagram showing the change in the relative distance between the aircraft and the target in Embodiment 1 of the present invention;

[0057] Figure 5 This is a graph showing the change in flight speed of an aircraft according to Embodiment 1 of the present invention;

[0058] Figure 6 This is a schematic diagram of the geometric relationship of the guidance problem in Embodiment 2 of the present invention;

[0059] Figure 7 This is a flight trajectory diagram of the aircraft according to Embodiment 2 of the present invention;

[0060] Figure 8 This is a diagram showing the change in the relative distance between the aircraft and the target in Embodiment 2 of the present invention;

[0061] Figure 9 This is a diagram showing the change in the forward angle of the aircraft according to Embodiment 2 of the present invention;

[0062] Figure 10 This is a diagram showing the trajectory inclination of an aircraft according to Embodiment 2 of the present invention;

[0063] Figure 11 This is a graph showing the acceleration variation of an aircraft according to Embodiment 2 of the present invention. Detailed Implementation

[0064] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0065] like Figure 1 As shown, the implementation method of this invention is as follows: A polynomial function of the line-of-sight angle with respect to the distance between the projectile and the target is set, and an algebraic equation with multiple constraints is established. This transforms the multi-constraint ballistic calculation problem into a single-variable nonlinear equation solving problem. Specific implementation steps are illustrated below:

[0066] Example 1: Design of a ballistic shaping guidance law for an unpowered aircraft under constraints of attack angle, terminal velocity, and acceleration.

[0067] The specific embodiment model is as follows: Figure 2 As shown, the terminal attack angle, velocity, and acceleration constraint guidance problem considered includes five constraints: initial position of the aircraft, lead angle, terminal attack angle, velocity, and acceleration.

[0068] To verify the feasibility of the algorithm design involved in this embodiment, the algorithm is validated in an autonomous landing scenario of an unmanned aerial vehicle (UAV). Consider three UAVs landing at the desired location (0,0)m with the same initial state. The UAV dynamic coefficient is m = 30kg. S ref =0.5m 2 K = 1. UAV1 uses proportional guidance with a coefficient of 3, UAV2 uses the optimal attack angle constraint guidance law, and UAV3 uses the method designed in this specific embodiment. The initial flight conditions are: initial distance 10km, speed 150m / s, line-of-sight angle -45°, and trajectory inclination angle 0°. Guidance constraints and trajectory parameters are shown in Table 1. Finally, the simulation results and landing conditions are shown in Table 2 and... Figures 3-5 As shown.

[0069] Step 1: Construct the trajectory shaping fitting function of the aircraft by setting a polynomial function of the line-of-sight angle with respect to the distance between the missile and the target.

[0070] The line-of-sight azimuth angle is designed as a fourth-order polynomial function of the missile-target distance to fit the trajectory, such as...

[0071]

[0072] It can be found that equation (13) contains five undetermined parameters, which can be solved by combining the five constraints with a simultaneous equation.

[0073] Step 2: Determine the constraints for the actual multi-constraint coupled aircraft guidance problem.

[0074] Step 2.1: Analysis of the boundary conditions shows that constraint condition ①, the initial position of the aircraft, has the following constraint equation for equation (13):

[0075] k0+k1+k2+k3+k4=q0 (14)

[0076] Where r0 is the initial target distance and q0 is the initial line-of-sight azimuth.

[0077] In addition, the trajectory must also satisfy constraint condition ②, the initial lead angle constraint. The constraint equation for the initial lead angle of the aircraft with respect to equation (13) is as follows:

[0078] k1+2k2+3k3+4k4=tanσ0 (15)

[0079] Where σ0 is the initial leading angle.

[0080] On the other hand, constraint condition ③ is the requirement for the attack angle at the end of the trajectory. The constraint equation for the attack angle in equation (13) is as follows:

[0081] k0=θ M,f (16)

[0082] Where θ M,f This refers to the angle of attack at the terminal stage.

[0083] When the target distance approaches 0, the aircraft speed also needs to reach the desired value, i.e., constraint condition ⑤. The constraint equation for the aircraft speed in equation (13) is as follows:

[0084] v M (t f ) = v M,f (17)

[0085] Terminal velocity cannot be simply expressed analytically, but it is a function of the initial guidance state, the projectile model, and the guidance law.

[0086] v m (t f )=F(K) (18)

[0087] The function F(·) is determined by the initial guidance state and the projectile model, with the independent variable K = [k0, k1, k2, k3, k4]. T .

[0088] Constraint ⑥ End-of-flight acceleration constraint, i.e., the desired control of the aircraft when q→0 under acceleration control conditions, is...

[0089]

[0090] From the ballistic fitting function, we can know

[0091]

[0092] Further, we can obtain

[0093]

[0094] When the spacecraft is in the terminal phase, r→0, σ m →0, ultimately resulting in

[0095]

[0096] The lift coefficient can be expressed as

[0097]

[0098] Where α is the angle of attack. With zero angle of attack lift coefficient, This is the induced lift coefficient. In addition, there is...

[0099]

[0100] in This refers to the pitch angle. Under controlled terminal velocity and trajectory angle conditions, there is...

[0101]

[0102] Step 2.2: Based on the polynomial function of the line-of-sight azimuth angle with respect to the target distance shown in formula (1), and combined with the constraints of the actual multi-constraint coupled aircraft guidance problem determined in step 2.1, it can be seen from the above formula that...

[0103]

[0104] According to the projectile dynamics model, we can obtain

[0105]

[0106] The ballistic shaping function is further obtained

[0107]

[0108] Considering the characteristics of the projectile, the drag is

[0109]

[0110] The acceleration can be obtained from the ballistic shaping fitting function.

[0111]

[0112] By adjusting equation (27) The final velocity is obtained by integrating over (r0,0), and it can be seen that this integral is F(k4). Therefore, the final velocity constraint can be expressed as a nonlinear equation.

[0113] F(k4)=v m,f (31)

[0114] Step 2.3: Numerical methods can be used to obtain the solution for this variable. Finally, the ballistic parameters k0 to k4 are obtained.

[0115] Step 3: Based on the ballistic shaping function with determined parameters obtained in Step 2, the lead angle state tracking method is adopted, with the lead angle designed as follows:

[0116]

[0117] The preceding angular velocity is

[0118]

[0119] The design guidance command is

[0120]

[0121] Where k t >0 represents the feedback error gain.

[0122] By converting the guidance commands, we can obtain...

[0123]

[0124] Table 1 Guidance constraints and ballistic parameters

[0125]

[0126]

[0127] Table 2 Landing Status

[0128]

[0129] from Figures 3-5 As shown in Table 2, in autonomous landing scenarios, unmanned aerial vehicles (UAVs) with the same initial state and projectile dynamics exhibit significant differences in their landing states under different guidance laws. Proportional guidance can only guarantee that the UAV reaches the landing position, but cannot guarantee the speed and direction during landing, which can easily lead to damage to the UAV. Attack angle constraint guidance laws can guarantee the speed and direction of the UAV during landing, but cannot guarantee the speed and attitude angle during landing, which can also easily lead to dangerous situations such as large landing impact force and nose-to-ground collision. In contrast, guidance laws that comprehensively constrain the attack angle, terminal velocity, and acceleration can guarantee multiple constraints during the landing process, ensuring a safe autonomous landing.

[0130] Example 2: Design of a ballistic shaping guidance law for an aircraft considering attack angle and time constraints:

[0131] To verify the feasibility of the algorithm design involved in this embodiment, simulation verification was performed considering the proposed attack angle and time control guidance law under varying aircraft velocity conditions. An aircraft with the same type of projectile dynamics was used to attack a target under different conditions, with the target position set to (0,0)m. The aircraft dynamic coefficients were m = 200kg and C... D0 =0.1, S ref =0.2m 2 K = 0.3, ρ = 1.2 kg / m 3 The initial state is shown in Table 3, and the constraints are shown in Table 4.

[0132] The spatiotemporal constraint-coupled guidance problem model considered in this specific embodiment is as follows: Figure 6 As shown, the constraints covered include four conditions: initial position of the aircraft, initial trajectory inclination, terminal trajectory inclination, and attack time.

[0133] Step 1: Construct the trajectory shaping fitting function of the aircraft by setting a polynomial function of the line-of-sight angle with respect to the distance between the missile and the target.

[0134] The ballistic shaping function is designed as a third-order polynomial function of the line-of-sight azimuth angle with respect to the target distance, such as...

[0135]

[0136] Where q is the line-of-sight angle, The ratio of the relative distance between the projectile and the target to the initial relative distance between the projectile and the target is given, and k0 to k3 are undetermined coefficients.

[0137] Step 2: Determine the constraints for the actual multi-constraint coupled aircraft guidance problem.

[0138] Step 2.1: Constraints ① The initial position of the aircraft is constrained by equation (36) as follows:

[0139] q(r0)=k0+k1+k2+k3=q0 (37)

[0140] Where r0 is the initial target distance and q0 is the initial line-of-sight azimuth.

[0141] Constraint condition ② The initial lead angle of the aircraft is given by the constraint equation of equation (36) as follows:

[0142] k1+2k2+3k3=tanσ0 (38)

[0143] Where σ0 is the initial leading angle.

[0144] Constraint ③ Attack Angle Constraint The constraint equation for equation (36) is as follows:

[0145] k0=θ M,f (39)

[0146] Where θ M,f This refers to the angle of attack at the terminal stage.

[0147] Constraint ④ Attack time constraint The constraint equation for equation (36) is as follows:

[0148]

[0149] Where r0 is the initial target distance, r f v represents the terminal target distance. m For the speed of the aircraft, σm This refers to the aircraft's leading angle. t f t0 is the terminal time, and t0 is the initial time.

[0150] Under the assumption of constant velocity, this can be transformed into a distance constraint. Let t0 = 0, then equation (40) can be transformed into

[0151]

[0152] Step 2.2: Based on the third-order polynomial function of the line of sight azimuth angle with respect to the distance between the missile and the target as shown in formula (37), and combined with the constraints determined in step 2.1 for the actual multi-constraint coupled aircraft guidance problem, solve equations (37) to (41) to obtain the constraint equations for the polynomial coefficients.

[0153] Step 2.3: For the case considering velocity constraints and where the aircraft velocity is steady, the solution for this variable is obtained analytically. Finally, the solution is...

[0154]

[0155] in,

[0156]

[0157]

[0158] Furthermore, when the aircraft speed is uncontrollable, the ballistic parameters can be directly solved using equation (40). Finally, the ballistic parameters k0~k3 are obtained.

[0159] Step 3: Based on the ballistic shaping function with determined parameters obtained in Step 2, the lead angle state tracking method is adopted, with the lead angle designed as follows:

[0160]

[0161] The preceding angular velocity is

[0162]

[0163] The design guidance command is

[0164]

[0165] Where k t >0 represents the feedback error gain.

[0166] By converting the guidance commands, we can obtain...

[0167]

[0168] Table 3 Initial State

[0169]

[0170]

[0171] Table 4 Constraints

[0172]

[0173] The obtained ballistic parameters are shown in Table 5.

[0174] Table 5 Initial State

[0175]

[0176] All ballistic tracking parameters are set to k. t =5. Simulation results are shown in Table 6 and Figures 7-11 As shown.

[0177] Table 6. Guidance Terminal Status

[0178]

[0179] Depend on Figure 7 It can be seen that the aircraft successfully hit the target in all four scenarios, and Table 6 further verifies that the aircraft struck the target at the set attack time. Figure 8 As can be seen, the target range of the aircraft eventually converges to 0 in all four cases. Figure 9 As can be seen, as the target distance converges to 0, the lead angle also converges to 0. Figure 10 As shown in Table 6, the aircraft successfully hit the target at the specified angle and time under four initial conditions. Figure 11 Figure showing the acceleration variation of the spacecraft.

[0180] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention.

Claims

1. A method for trajectory shaping guidance of a vehicle under multiple spatiotemporal constraints, characterized in that: Comprising the following steps, Step one, by setting the line of sight angle for the polynomial function of the distance of the projectile, the aircraft trajectory shaping fitting function is constructed, the aircraft trajectory shaping fitting function is n order polynomial, contains n+1 undetermined parameters, through n+1 undetermined parameters to characterize n+1 constraint conditions in guided trajectory; The implementation method of step one is, By setting the line of sight angle for the polynomial function of the distance of the projectile, the trajectory shaping function is designed as the n order polynomial function of the line of sight azimuth angle for the distance of the projectile as shown in formula (1) where q is a line-of-sight angle, is a ratio of the relative distance of the projectile and the initial relative distance of the projectile, k0~k n is a to-be-determined coefficient; the flight trajectory shaping fitting function is an n-th order polynomial, contains n+1 to-be-determined parameters, and n+1 to-be-determined parameters represent n+1 constraint conditions in the guided trajectory. Step two, determine the actual multi-constraint coupled aircraft guidance problem constraint condition, according to the aircraft trajectory shaping fitting function constructed in step one, the multi-constraint trajectory planning problem is converted into a single variable nonlinear equation solving problem, the parameter solving problem of multi-constraint trajectory is simplified, the solving difficulty of multi-constraint trajectory planning problem is significantly reduced, the solving efficiency of multi-constraint trajectory planning problem is improved, and then the trajectory shaping function after parameter determination is obtained; The implementation method of step two is, Step 2.1: determine the actual multi-constraint coupled aircraft guidance problem constraint condition; Constraint condition ① is the constraint equation of the initial position of the aircraft for formula (1) q(r0) = k0+ k1+ k2+... + k n = q0 (2) Wherein r0 is the initial relative distance of the projectile, q0 is the initial line of sight azimuth angle; Constraint condition ② is the constraint equation of the initial pre-angle of the aircraft for formula (1) Wherein σ0 is the initial pre-angle; Constraint condition ③: the constraint equation of the attack angle constraint for formula (1) is q(0) = θ M,f (4) where θ M,f is the end attack angle; Constraint condition ④ is the constraint equation of the attack time constraint for formula (1) where r0 is the initial missile-terminal relative distance, r f is the terminal-missile distance, v M is the vehicle velocity, σ M is the vehicle forward angle; t f is the terminal time, and t0 is the initial time. The attack time constraint as shown in formula (5) is t0=0 under the condition of constant velocity, formula (5) is converted into the trajectory length constraint as shown in formula (6), which further reduces the solving difficulty of the attack time constraint; Constraint condition ⑤ is the terminal velocity constraint, that is, the expected control of the aircraft when q→0 under the condition of aircraft speed control, which is v M (t f )=v M,f (7) Constraint condition ⑥ is the terminal acceleration constraint, that is, the expected control of the aircraft when q→0 under the condition of aircraft acceleration control, which is Step 2.2: according to the n order polynomial function of the line of sight azimuth angle for the distance of the projectile as shown in formula (1), combined with the actual multi-constraint coupled aircraft guidance problem constraint condition determined in step 2.1, the initial position constraint equation and the initial pre-angle constraint equation as shown in formula (2)~(3), and the attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equation according to the actual multi-constraint required to be considered in formula (4)~(8), n+1 equality constraint equations for multi-constraint coupled aircraft guidance are established, the multi-constraint trajectory planning problem is converted into a single variable nonlinear equation solving problem, the parameter solving problem of multi-constraint trajectory is simplified, the solving difficulty of multi-constraint trajectory planning problem is significantly reduced, the solving efficiency of multi-constraint trajectory planning problem is improved; Step 2.3: For the case of considering attack time constraint and constant speed of the aircraft, the n+1 equality constraint equations of step 2.2 can be analytically solved by simultaneously solving the initial position constraint, initial lead angle constraint equations as shown in (2)-(3), and attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equations according to actual multi-constraints as shown in (4)-(8), to obtain the determination coefficients of the polynomial function of the line-of-sight angle with respect to the missile-target distance under the multi-constraint condition, that is, the parameter-determined trajectory shaping function; For the remaining cases, the n+1 equality constraint equations of step 2.2 can be analytically and numerically solved by simultaneously solving the initial position constraint, initial lead angle constraint equations as shown in (2)-(3), and attack angle constraint, attack time constraint, terminal velocity constraint and terminal acceleration constraint equations according to actual multi-constraints as shown in (4)-(8), to obtain the determination coefficients of the polynomial function of the line-of-sight angle with respect to the missile-target distance under the multi-constraint condition, that is, the parameter-determined trajectory shaping function; Step three, according to the parameter-determined trajectory shaping function obtained in step two, the lead angle state tracking method is used to track the reference trajectory, to realize time and space constraint guidance under the condition of ensuring the minimum target miss distance, and to improve the tracking accuracy and efficiency of the aircraft on the reference trajectory; The implementation method of step three is, The reference lead angle is designed as The lead angle rate is The designed guidance command is where k t > 0 is the feedback error gain; The guidance command is obtained by transforming the guidance command The reference trajectory is tracked according to the guidance command as shown in formula (12), to improve the tracking accuracy and efficiency of the aircraft on the reference trajectory.

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