Aerodynamic capture maneuvering guidance method based on sideslip correction

Abstract

The invention discloses an aerodynamic capture maneuvering guidance method based on sideslip correction, and relates to the field of orbit braking energy consumption optimization, and the method comprises the steps: building a maneuvering dynamics model of a spacecraft in an atmospheric flight section in an atmospheric capture maneuvering process; s2, performing profile analysis on the maneuvering and dynamical model based on a saturation function, and designing a target aerodynamic capture heeling angle reference trajectory; basic parameters of the saturation function are set through the rolling maneuvering capability of the spacecraft, and guidance parameters with the heeling angle as modulation in the aerodynamic capture process are determined. According to the method, through a saturation function approximation step type heeling angle time sequence profile, the sensitivity of guidance parameters can be remarkably reduced, and the robustness of a guidance system is enhanced.

Description

Technical Field

[0001] The invention relates to the field of track braking energy consumption optimization, in particular to an aerodynamic capture maneuver guidance method based on sideslip correction. Background Art

[0002] Low-energy orbital braking in space missions such as planetary exploration and lunar return is a key link in mission implementation. How to reduce the spacecraft's own fuel consumption is the main issue in the overall mission design. Considering that the capture braking process belongs to the process of spacecraft kinetic energy attenuation, the application of atmospheric ablation deceleration is a potential, low-fuel capture method. This aerodynamic capture method can not only decelerate by replacing engine thrust with aerodynamic overload, but also has stronger maneuverability and can enhance the reach of the spacecraft's terminal state. It is considered to be a high-speed spacecraft capture method that can be widely used in the future.

[0003] To this end, many scholars have studied this issue, especially focusing on the corresponding guidance algorithm. At present, in the research of aerodynamic capture guidance algorithms, the optimal aerodynamic capture guidance algorithm proposed by American scholar Lu Ping has the best performance in terms of robustness and optimality. He proposed an optimal aerodynamic capture algorithm by converting the guidance trajectory design problem into a target shooting problem of individual parameters and combining it with the optimal control profile.

[0004] However, a significant disadvantage of this method is that the algorithm performance is heavily dependent on the spacecraft's ability to roll and maneuver during atmospheric flight, which makes it easy for control parameter saturation to occur during atmospheric flight. This control saturation will significantly reduce the maneuvering fuel consumption of the spacecraft to re-enter orbit after capture, thereby affecting the aerodynamic capture efficiency.

[0005] Therefore, an aerodynamic capture maneuver guidance method based on sideslip correction is urgently needed to improve the above problems. Summary of the invention

[0006] To solve the above problems, the present application proposes an aerodynamic capture maneuver guidance method based on sideslip correction, comprising the following steps:

[0007] S1. Based on the polar coordinate system of the spacecraft in the atmospheric flight process, a maneuvering dynamics model of the spacecraft in the atmospheric flight phase during the atmospheric capture maneuver is established;

[0008] S2, profile analysis of the maneuvering dynamics model based on the saturation function and design of the target aerodynamic capture roll angle reference trajectory;

[0009] The basic parameters of the saturation function are set by the spacecraft's rolling maneuverability, and the guidance parameters modulated by the roll angle during the aerodynamic capture process are determined according to the mapping relationship between the roll angle bang-bang optimal profile and the saturation function. The basic parameters include switching time and amplitude.

[0010] Preferably, the maneuvering dynamics model of the atmospheric flight phase during the aerodynamic capture process of the spacecraft in S1 is:

[0011]

[0012] In the above formula, They represent the rate of change of position radial vector, latitude, velocity, longitude, track angle and heading angle, respectively. r , g φ Represent the radial and tangential gravitational accelerations of the spacecraft, g r , g φ The expression is:

[0013]

[0014] Among them, r is the distance between the center of mass of the spacecraft and the center of the central celestial body; V is the velocity; γ is the track angle of the spacecraft, ψ is the heading angle of the spacecraft; σ is the flight roll angle, which is the control quantity; θ and φ are longitude and latitude respectively; ω is the angular velocity of the planet's rotation; μ is the planet's gravitational constant, R is the planet's radius; J2 is the planet's second-order spherical harmonic coefficient; the lift acceleration L, drag acceleration D and lateral force acceleration Q are respectively:

[0015]

[0016] Where S is the reference area of ​​the spacecraft; C L , C D and C Q are the lift coefficient, drag coefficient and sideslip coefficient respectively; ρ is the atmosphere density; m is the mass of the spacecraft.

[0017] Preferably, the specific contents of performing profile analysis on the maneuvering dynamics model based on the saturation function and designing the target aerodynamic capture roll angle reference trajectory in S2 are:

[0018] S201, based on the roll angle modulation, a sideslip correction component is added to the saturation function with the sideslip acceleration coefficient as the design parameter, and the aerodynamic capture guidance process is integrated into the first serial parameter target execution stage and the second serial parameter target execution stage through the sideslip correction component;

[0019] S202, constructing a mapping relationship between guidance parameters and aerodynamic capture effectiveness characterization quantities of the spacecraft during the atmospheric capture maneuver, and determining the target shooting parameters of the first serial parameter target shooting execution phase and the second serial parameter target shooting execution phase according to the mapping relationship;

[0020] S203, determining basic parameters of a saturation function based on a roll angle and guidance parameters through single-objective optimization, and providing an orbital velocity pulse representing aerodynamic capture effectiveness calculated based on a terminal state;

[0021] S204. According to the guidance parameters and terminal state obtained in S203, the trajectory, the time series profile of the roll angle and the time series profile of the sideslip force coefficient of the spacecraft during the atmospheric flight in the guidance period can be obtained.

[0022] Preferably, the specific content of the tilt angle modulation in S201 is:

[0023] The time-series profile of the roll angle is the time-varying trajectory of the roll angle, which is a reference profile based on a single-jump bang-bang structure. The expression of the reference profile is:

[0024]

[0025] Where t is the current moment, ts is the step moment of the roll angle without considering the change rate limit, σ min is the lower limit of the roll angle, σ max The upper limit of the roll angle, k is the smooth jump coefficient after considering the roll angle change rate, and the expression of k is:

[0026]

[0027] The upper limit of the roll angle change rate is s max ,Right now

[0028] in is the rate of change of the roll angle, s max is the boundary value of the roll angle change rate;

[0029] The first step in the open-loop guidance process of the guidance parameters is to determine ts by target shooting.

[0030] Preferably, in S201, the sideslip acceleration coefficient is used as a design parameter to add a sideslip correction component to the saturation function, and the specific content is:

[0031] The sideslip coefficient is unbounded, and C Q Set to:

[0032]

[0033] Among them, C Qmin and C Qmax They are the sideslip force coefficient C Q The lower and upper bounds of

[0034] Through the above expression, the side slip force coefficient C of the boundary limit is Q Mapped to the unconstrained variable C b .

[0035] Preferably, in S201, the first serial parameter targeting execution phase is performed with CQ As a guided target shooting parameter;

[0036] The second serial parameter shooting execution phase is the side slip correction phase. b As a guided target parameter.

[0037] Preferably, in S203, basic parameters of the saturation function based on the roll angle and guidance parameters are determined by single-objective optimization, and an orbital velocity pulse representing the aerodynamic capture efficiency calculated based on the terminal state is given. Specifically, the content is:

[0038] The effectiveness of the aerodynamic capture process is characterized by the post-atmospheric orbital maneuver pulse;

[0039] After the spacecraft flies out of the atmosphere, it enters the target orbit through the first pulse and the second pulse maneuvers;

[0040] The first pulse ΔV1 is collinear with the velocity at the apogee, raising the perigee to the target orbit radius, and the second pulse ΔV2 raises or lowers the new apogee to the target orbit apogee at the perigee;

[0041] The sum of the magnitudes of the first pulse and the second pulse is:

[0042]

[0043] Among them, r atgt , r ptgt are the apogee radius and perigee radius of the target orbit, r a0 and r p0 are the apogee and perigee radii of the orbit after aerodynamic capture, respectively;

[0044]

[0045] where a is the semi-major axis of the trajectory after aerodynamic capture, r EI 、V exit and γ exit is the position radial vector size, velocity and track angle under atmospheric exit conditions;

[0046] The semi-major axis of the trajectory after aerodynamic capture is:

[0047]

[0048] Preferably, in the guidance part of the roll angle modulation, the guidance parameter is ts, and the guidance parameter is solved as follows:

[0049] ts→minΔV(ts);

[0050] In the guidance part of the sideslip correction, the guidance parameter is C b , that is, the guidance parameter is solved as

[0051] C b →minΔV(C b );

[0052] The guidance parameters ts and C of the target are quickly searched by numerical Newton method or gradient descent method. b .

[0053] Given the guidance parameters ts and C of the target b Finally, the optimal aerodynamic capture orbit velocity pulse size minΔV is obtained.

[0054] Preferably, according to the guidance parameters and terminal state obtained in S203, the specific contents of the trajectory, the time series profile of the roll angle and the time series profile of the sideslip force coefficient of the spacecraft during the atmospheric flight process under the guidance period can be obtained as follows:

[0055] Given the guidance parameters ts and C of the target b After that, the roll angle σ and sideslip force coefficient C from the current moment to the final moment are obtained. Q , the roll angle σ forms a roll angle time series profile, the sideslip force coefficient C Q Construct the time series profile of the sideslip force coefficient;

[0056] Given the time series profile of the roll angle and the time series profile of the sideslip force coefficient, the trajectory of the spacecraft's atmospheric flight process in one guidance cycle is obtained by integrating the dynamic equations.

[0057] The orbital dynamics equation is

[0058] Starting from the current time t, the integral to the atmospheric inlet is expressed as:

[0059]

[0060] Among them, x EI , t exit ,x,g(), are the state vector of the atmospheric outlet, the time of the atmospheric outlet, the time-varying state vector, the differential expression of the state quantity, and the differential vector of the state quantity, respectively. The cutoff condition of the orbital integral is Γ0=r EI -r atm =0, and the integral trajectory, roll angle time-varying profile, and sideslip acceleration coefficient time-varying profile in one guidance cycle are obtained.

[0061] In summary, the aerodynamic capture maneuver guidance method based on sideslip correction of the present invention has the following advantages compared with the traditional technology:

[0062] (1) The aerodynamic capture maneuver guidance method based on sideslip correction proposed in the present invention can approximate the step-type roll angle time series profile through a saturation function, which can significantly reduce the sensitivity of the guidance parameters and enhance the robustness of the guidance system;

[0063] (2) The sideslip correction proposed by the present invention can significantly improve the problem of limited control ability caused by roll angle saturation, and fully utilize the effect of sideslip force to enhance the effectiveness of the guidance system;

[0064] (3) The guidance method proposed in the present invention converts the calculation of guidance parameters into an unconstrained single-objective optimization problem, so the calculation efficiency is high and the convergence is strong.

[0065] The technical method of the present invention is further described in detail below through the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a schematic diagram of the overall process of an embodiment of the present invention;

[0067] Figure 2 A schematic diagram of the trajectory of the aerodynamic capture maneuver process according to an embodiment of the present invention;

[0068] Figure 3 is a time series profile of the roll angle according to an embodiment of the present invention;

[0069] Figure 4 is a time series profile of the sideslip force coefficient according to an embodiment of the present invention;

[0070] Figure 5 This is the trajectory of the aerodynamic capture atmospheric flight process of an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The technical method of the present invention is further described below by means of the accompanying drawings and embodiments. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present application.

[0072] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0073] Technologies, systems, and devices known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, systems, and devices should be considered part of the specification.

[0074] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0075] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0076] The present invention provides an aerodynamic capture maneuver guidance method based on sideslip correction, comprising the following steps:

[0077] S1. Based on the polar coordinate system of the spacecraft in the atmospheric flight process, a maneuvering dynamics model of the spacecraft in the atmospheric flight phase during the atmospheric capture maneuver is established;

[0078] Preferably, the maneuvering dynamics model of the atmospheric flight phase during the aerodynamic capture process of the spacecraft in S1 is:

[0079]

[0080] In the above formula, They represent the rate of change of position radial vector, latitude, velocity, longitude, track angle and heading angle, respectively. r , g φ Represent the radial and tangential gravitational accelerations of the spacecraft, g r , g φ The expression is:

[0081]

[0082] Among them, r is the distance between the center of mass of the spacecraft and the center of the central celestial body; V is the velocity; γ is the track angle of the spacecraft, ψ is the heading angle of the spacecraft; σ is the flight roll angle, which is the control quantity; θ and φ are longitude and latitude respectively; ω is the angular velocity of the planet's rotation; μ is the planet's gravitational constant, R is the planet's radius; J2 is the planet's second-order spherical harmonic coefficient; the lift acceleration L, drag acceleration D and lateral force acceleration Q are respectively:

[0083]

[0084] Where S is the reference area of ​​the spacecraft; C L , C D and C Q are the lift coefficient, drag coefficient and sideslip coefficient respectively; ρ is the atmosphere density; m is the mass of the spacecraft.

[0085] S2, profile analysis of the maneuvering dynamics model based on the saturation function and design of the target aerodynamic capture roll angle reference trajectory;

[0086] The basic parameters of the saturation function are set by the spacecraft's rolling maneuverability, and the guidance parameters modulated by the roll angle during the aerodynamic capture process are determined according to the mapping relationship between the roll angle bang-bang optimal profile and the saturation function. The basic parameters include switching time and amplitude.

[0087] Existing technology has proven that the optimal roll angle timing profile is a single-jump bang-bang structure, so the designed roll angle timing profile will be based on this structure. However, since the ability of a spacecraft to perform attitude maneuvers is always limited, there is an upper limit to the rate of change of the roll angle of the spacecraft, and there are also upper and lower limits on the roll angle itself, that is, there is a lower limit σ min and the upper limit σ max .

[0088] The roll angle time series profile is the time-varying trajectory of the roll angle, which is given based on the bang-bang structure of optimal aerodynamic capture of atmospheric flight characteristics.

[0089] Preferably, the specific content of the tilt angle modulation in S201 is:

[0090] The time-series profile of the roll angle is the time-varying trajectory of the roll angle, which is a reference profile based on a single-jump bang-bang structure. The expression of the reference profile is:

[0091]

[0092] Where t is the current moment, ts is the step moment of the roll angle without considering the change rate limit, σ min is the lower limit of the roll angle, σ max The upper limit of the roll angle, k is the smooth jump coefficient after considering the roll angle change rate, and the expression of k is:

[0093]

[0094] The upper limit of the roll angle change rate is s max ,Right now

[0095] in is the rate of change of the roll angle, s max is the boundary value of the roll angle change rate;

[0096] The only thing left to determine the guidance profile is the step time ts. Therefore, the first step in the open-loop guidance process with the roll angle as the guidance parameter is to determine ts by target shooting.

[0097] Preferably, the specific contents of performing profile analysis on the maneuvering dynamics model based on the saturation function and designing the target aerodynamic capture roll angle reference trajectory in S2 are:

[0098] In order to overcome the boundary saturation problem, a sideslip correction is added here. S201, based on the roll angle modulation, a sideslip correction component is added to the saturation function with the sideslip acceleration coefficient as the design parameter. The aerodynamic capture guidance process is integrated into the first serial parameter targeting execution stage and the second serial parameter targeting execution stage through the sideslip correction component.

[0099] The sideslip correction component is added to the sideslip acceleration part of the dynamics. If the sideslip correction component is added in the dynamics, the corresponding sideslip acceleration will no longer be 0.

[0100] Preferably, in S201, the sideslip acceleration coefficient is used as a design parameter to add a sideslip correction component to the saturation function, and the specific content is:

[0101] The magnitude of the sideslip acceleration is completely controlled by the sideslip coefficient C Q Therefore, it is used as the target parameter in the guidance link of sideslip correction. Considering that the sideslip control ability is limited, and the control ability is reflected in the sideslip force coefficient C Q , so here we need to set a boundary limit on the sideslip correction. Assume that the sideslip force coefficient C Q There is a lower bound and an upper bound, namely C Qmin and C Qmax At this time, in order to make the guidance parameters as a single variable easy to converge during the target shooting process, the sideslip coefficient is unbounded, and C Q Set to:

[0102]

[0103] Among them, C Qmin and C Qmax They are the sideslip force coefficient C Q The lower and upper bounds of

[0104] Through the above expression, the side slip force coefficient C of the boundary limit is Q Mapped to the unconstrained variable C b .

[0105] The side slip coefficient C Q Mapped to the unconstrained variable C b The side slip correction link is based on C b As a guided target parameter.

[0106] S202, constructing a mapping relationship between guidance parameters and aerodynamic capture effectiveness characterization quantities of the spacecraft during the atmospheric capture maneuver, and determining the target shooting parameters of the first serial parameter target shooting execution phase and the second serial parameter target shooting execution phase according to the mapping relationship;

[0107] Preferably, in S201, the first serial parameter targeting execution phase is performed with C QAs a guided target shooting parameter;

[0108] The second serial parameter shooting execution phase is the side slip correction phase. b As a guided target parameter.

[0109] S203, determining basic parameters of a saturation function based on a roll angle and guidance parameters through single-objective optimization, and providing an orbital velocity pulse representing aerodynamic capture effectiveness calculated based on a terminal state;

[0110] The terminal state is obtained through the predictive open loop of each guidance. The termination condition of the predictive open loop is that the aircraft flies out of the edge of the atmosphere. The state at this time is the terminal state.

[0111] Preferably, in S203, the basic parameters of the saturation function based on the roll angle and the guidance parameters are determined by single-objective optimization, and the orbital velocity pulse representing the aerodynamic capture efficiency calculated based on the terminal state is given. The specific content is:

[0112] The effectiveness of the aerodynamic capture process is characterized by the post-atmospheric orbital maneuver pulse;

[0113] After the spacecraft flies out of the atmosphere, it enters the target orbit through the first pulse and the second pulse maneuvers;

[0114] The first pulse ΔV1 is collinear with the velocity at the apogee, raising the perigee to the target orbit radius, and the second pulse ΔV2 raises or lowers the new apogee to the target orbit apogee at the perigee;

[0115] like Figure 2 As shown, for the aerodynamic capture process, its effectiveness is characterized by the post-atmospheric orbital maneuver pulse. After the spacecraft flies out of the atmosphere, a double-pulse maneuver is required to finally enter the target orbit. The first pulse ΔV1 (colinear with the velocity at the apogee) increases the perigee to the target orbit radius, and the second pulse ΔV2 (at the perigee) raises or lowers the new apogee to the apogee of the target orbit.

[0116] The sum of the magnitudes of the first pulse and the second pulse is:

[0117]

[0118] Among them, r atgt , r ptgt are the apogee radius and perigee radius of the target orbit, r a0 and r p0 are the apogee and perigee radii of the orbit after aerodynamic capture, respectively;

[0119] in,

[0120] where a is the semi-major axis of the trajectory after aerodynamic capture, r EI 、V exit and γ exit is the position radial vector size, velocity and track angle under atmospheric exit conditions;

[0121] The semi-major axis of the trajectory after aerodynamic capture is:

[0122]

[0123] Preferably, in the guidance part of the roll angle modulation, the guidance parameter is ts, the guidance target is to minimize ΔV, and the guidance parameter is solved as follows:

[0124] ts→minΔV(ts);

[0125] In the guidance part of the sideslip correction, the guidance parameter is C b , the guidance target is to minimize ΔV. At this time, the mapping relationship between the guidance parameters and the aerodynamic capture efficiency characterization quantity is also a single-objective optimization problem, that is, the guidance parameter solution is

[0126] C b →minΔV(C b );

[0127] Whether it is the guidance part of the roll angle modulation or the guidance part of the sideslip correction, the solution process of the above single target is similar. The guidance parameters ts and C of the target are quickly searched by the numerical Newton method or gradient descent method. b .

[0128] Given the guidance parameters ts and C of the target b Finally, the optimal aerodynamic capture orbit velocity pulse size minΔV is obtained.

[0129] S204. According to the guidance parameters and terminal state obtained in S203, the trajectory, the time series profile of the roll angle and the time series profile of the sideslip force coefficient of the spacecraft during the atmospheric flight in the guidance period can be obtained.

[0130] Preferably, according to the guidance parameters and terminal state obtained in S203, the specific contents of the trajectory, the time series profile of the roll angle and the time series profile of the sideslip force coefficient of the spacecraft during the atmospheric flight process under the guidance period can be obtained as follows:

[0131] Given the guidance parameters ts and C of the target b After that, the roll angle σ and sideslip force coefficient C from the current moment to the final moment are obtained. Q , the roll angle σ forms a roll angle time series profile, the sideslip force coefficient C Q Construct the time series profile of the sideslip force coefficient;

[0132] Given the time series profile of the roll angle and the time series profile of the sideslip force coefficient, the trajectory of the spacecraft's atmospheric flight process in one guidance cycle is obtained by integrating the dynamic equations.

[0133] The orbital dynamics equation is

[0134] Starting from the current time t, the integral to the atmospheric inlet is expressed as:

[0135]

[0136] Among them, x EI , t exit ,x,g(), are the state vector of the atmospheric outlet, the time of the atmospheric outlet, the time-varying state vector, the differential expression of the state quantity, and the differential vector of the state quantity, respectively. The cutoff condition of the orbital integral is Γ0=r EI -r atm =0, and the integral trajectory, roll angle time-varying profile, and sideslip acceleration coefficient time-varying profile in one guidance cycle are obtained.

[0137] The specific embodiments are as follows:

[0138] The spacecraft used in the aerodynamic capture mission embodiment is the NASA "Orion" spacecraft, which has a mass of 10387 kg and a nominal lift-to-drag ratio of 0.27. The Earth's gravitational constant μ = 398600 km 3 / s 2 , the radius of the earth is R = 6378km, and the atmospheric height is 121.9km. The mission scenario is the aerodynamic capture of a spacecraft returning to Earth for one month, and the corresponding initial values ​​of the state quantities are shown in the following table.

[0139] Table 1 Nominal inertia entry conditions

[0140]

[0141] The target orbit is h aim 200km high circular orbit. The calculated time series profiles of the full-course roll angle, the time series profiles of the sideslip force coefficient, and the trajectory of the aerodynamic capture atmospheric flight process are shown as follows: Figure 3 , 4 As shown in , and 5, the orbital velocity increment ΔV is 47.29 m / s;

[0142] Therefore, the present invention adopts the aerodynamic capture maneuver guidance method based on sideslip correction proposed by the present invention, which can approximate the step-type roll angle time series profile through the saturation function, which can significantly reduce the sensitivity of the guidance parameters and enhance the robustness of the guidance system; at the same time, it can significantly enhance the problem of limited control ability caused by roll angle saturation, and make full use of the effect of sideslip force to enhance the effectiveness of the guidance system; in addition, when calculating the guidance parameters, they are converted into unconstrained single-objective optimization problems, so the calculation efficiency is high and the convergence is strong.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical method of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical method to deviate from the spirit and scope of the technical method of the present invention.

Claims

1. An aerodynamic capture maneuver guidance method based on sideslip correction, characterized in that: The following steps are involved: S1. Based on the polar coordinate system of the spacecraft in the atmospheric flight process, a maneuvering dynamics model of the spacecraft in the atmospheric flight phase during the atmospheric capture maneuver is established; S2, profile analysis of the maneuvering dynamics model based on the saturation function and design of the target aerodynamic capture roll angle reference trajectory; The basic parameters of the saturation function are set by the spacecraft's rolling maneuverability, and the guidance parameters modulated by the roll angle during the aerodynamic capture process are determined according to the mapping relationship between the roll angle bang-bang optimal profile and the saturation function. The basic parameters include switching time and amplitude.

2. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 1 is characterized in that: The maneuvering dynamics model of the atmospheric flight phase during the aerodynamic capture process of the spacecraft in S1 is: In the above formula, They represent the rate of change of position radial vector, latitude, velocity, longitude, track angle and heading angle, respectively. r , g φ Represent the radial and tangential gravitational accelerations of the spacecraft, g r , g φ The expression is: Among them, r is the distance between the center of mass of the spacecraft and the center of the central celestial body; V is the velocity; γ is the track angle of the spacecraft, ψ is the heading angle of the spacecraft; σ is the flight roll angle, which is the control quantity; θ and φ are longitude and latitude respectively; ω is the angular velocity of the planet's rotation; μ is the planet's gravitational constant, R is the planet's radius; J2 is the planet's second-order spherical harmonic coefficient; the lift acceleration L, drag acceleration D and lateral force acceleration Q are respectively: Where S is the reference area of ​​the spacecraft; C L , C D and C Q are the lift coefficient, drag coefficient and sideslip coefficient respectively; ρ is the atmosphere density; m is the mass of the spacecraft.

3. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 2 is characterized in that: In S2, the profile analysis of the maneuvering dynamics model based on the saturation function and the design of the target aerodynamic capture roll angle reference trajectory are as follows: S201, based on the roll angle modulation, a sideslip correction component is added to the saturation function with the sideslip acceleration coefficient as the design parameter, and the aerodynamic capture guidance process is integrated into the first serial parameter target execution stage and the second serial parameter target execution stage through the sideslip correction component; S202, constructing a mapping relationship between guidance parameters and aerodynamic capture effectiveness characterization quantities of the spacecraft during the atmospheric capture maneuver, and determining the target shooting parameters of the first serial parameter target shooting execution phase and the second serial parameter target shooting execution phase according to the mapping relationship; S203, determining basic parameters of a saturation function based on a roll angle and guidance parameters through single-objective optimization, and providing an orbital velocity pulse representing aerodynamic capture effectiveness calculated based on a terminal state; S204. According to the guidance parameters and terminal state obtained in S203, the trajectory, the time series profile of the roll angle, and the time series profile of the sideslip force coefficient of the spacecraft during the atmospheric flight process in the guidance period are obtained.

4. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 3 is characterized in that: The specific contents of the roll angle modulation in S201 are: The time-series profile of the roll angle is the time-varying trajectory of the roll angle, which is a reference profile based on a single-jump bang-bang structure. The expression of the reference profile is: Where t is the current moment, ts is the step moment of the roll angle without considering the change rate limit, σ min is the lower limit of the roll angle, σ max The upper limit of the roll angle, k is the smooth jump coefficient after considering the roll angle change rate, and the expression of k is: The upper limit of the roll angle change rate is s max ,Right now in is the rate of change of the roll angle, s max is the boundary value of the rate of change of the roll angle; The first step in the open-loop guidance process of the guidance parameters is to determine ts by target shooting.

5. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 4 is characterized in that: In S201, the sideslip acceleration coefficient is used as a design parameter to add a sideslip correction component to the saturation function. The specific content is: The sideslip coefficient is unbounded, and C Q Set to: Among them, C Qmin and C Qmax They are the sideslip force coefficient C Q The lower and upper bounds of Through the above expression, the side slip force coefficient C of the boundary limit is Q Mapped to the unconstrained variable C b .

6. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 5 is characterized in that: In S201, the first serial parameter targeting execution phase is performed with C Q As a guided target shooting parameter; The second serial parameter shooting execution phase is the side slip correction phase. b As a guided target parameter.

7. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 6 is characterized in that: In S203, the basic parameters of the saturation function based on the roll angle and the guidance parameters are determined by single-objective optimization, and the orbital velocity pulse representing the aerodynamic capture efficiency calculated based on the terminal state is given. The specific contents are: The effectiveness of the aerodynamic capture process is characterized by the post-atmospheric orbital maneuver pulse; After the spacecraft flies out of the atmosphere, it enters the target orbit through the first pulse and the second pulse maneuvers; The first pulse ΔV1 is collinear with the velocity at the apogee, raising the perigee to the target orbit radius, and the second pulse ΔV2 raises or lowers the new apogee to the target orbit apogee at the perigee; The sum of the magnitudes of the first pulse and the second pulse is: Among them, r atgt , r ptgt are the apogee radius and perigee radius of the target orbit, r a0 and r p0 are the apogee and perigee radii of the orbit after aerodynamic capture, respectively; in, where a is the semi-major axis of the trajectory after aerodynamic capture, r EI 、V exit and γ exit is the position radial vector size, velocity and track angle under atmospheric exit conditions; The semi-major axis of the trajectory after aerodynamic capture is:

8. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 7 is characterized in that: In the guidance part of the roll angle modulation, the guidance parameter is ts, and the guidance parameter solution is: ts→minΔV(ts); In the guidance part of the sideslip correction, the guidance parameter is C b , that is, the guidance parameter is solved as C b →minΔV(C b ); The guidance parameters ts and C of the target are quickly searched by numerical Newton method or gradient descent method. b ; Given the guidance parameters ts and C of the target b Finally, the optimal aerodynamic capture orbit velocity pulse size minΔV is obtained.

9. The aerodynamic capture maneuver guidance method based on sideslip correction according to claim 8, characterized in that: According to the guidance parameters and terminal state obtained in S203, the trajectory of the spacecraft during the atmospheric flight in the guidance period, the time series profile of the roll angle, and the time series profile of the sideslip force coefficient can be obtained as follows: Given the guidance parameters ts and C of the target b After that, the roll angle σ and sideslip force coefficient C from the current moment to the final moment are obtained. Q , the roll angle σ forms a roll angle time series profile, the sideslip force coefficient C Q Construct the time series profile of the sideslip force coefficient; Given the time series profile of the roll angle and the time series profile of the sideslip force coefficient, the trajectory of the spacecraft's atmospheric flight process in one guidance cycle is obtained by integrating the dynamic equations. The orbital dynamics equation is Starting from the current time t, the integral to the atmospheric inlet is expressed as: Among them, x EI , t exit ,x,g(), are the state vector of the atmospheric outlet, the time of the atmospheric outlet, the time-varying state vector, the differential expression of the state quantity, and the differential vector of the state quantity, respectively. The cutoff condition of the orbital integral is Γ0=r EI -r atm =0, and the integral trajectory, roll angle time-varying profile, and sideslip acceleration coefficient time-varying profile in one guidance cycle are obtained.

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