Rocket final stage off-orbit attitude angle optimization method and device, equipment and medium

Abstract

The application discloses a rocket final stage off-orbit attitude angle optimization method, device, equipment and medium. The method comprises the following steps: acquiring a first position and a first velocity vector of a rocket final stage when the rocket final stage is off-orbit, and a target off-orbit time length; predicting the rocket final stage to be off-orbit at the first position with the first velocity vector and different target attitude angles, and a second position and a second velocity vector of the rocket final stage in a ground-fixed coordinate system when the off-orbit time length reaches the target off-orbit time length; determining a first first-circle perigee height of the rocket final stage after off-orbit according to the corresponding second position and the corresponding second velocity vector under each target attitude angle; respectively determining a difference value of each first first-circle perigee height and a preset height threshold value, and determining a target attitude angle corresponding to a difference value less than or equal to a difference threshold value as a candidate attitude angle; and determining an optimal attitude angle from the candidate attitude angles that meet a measurement and control condition and a far-field safety condition. The optimal attitude angle determined by the method has better off-orbit effect.

Description

Technical Field

[0001] This invention relates to the field of guidance and control technology, and in particular to a method, apparatus, equipment and medium for optimizing the deorbit attitude angle of the final stage of a rocket. Background Technology

[0002] Developing and implementing space debris mitigation technologies is a primary means of protecting the future space environment, and deorbit control technology is a crucial component of space debris mitigation. The deorbiting of the final stage of a launch vehicle includes two methods: active deorbiting and passive deorbiting. Compared to passive deorbiting technology, active deorbiting technology achieves the spacecraft's deorbiting by consuming its own energy.

[0003] In related technologies, active deorbiting technology is used to reduce space debris and achieve the deorbiting of the rocket's final stage. The attitude angle of the rocket's final stage during deorbiting directly affects the deorbiting effect; therefore, finding the optimal attitude angle for the rocket's final stage during deorbiting is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a method, apparatus, device and medium for optimizing the deorbit attitude angle of the rocket's final stage to solve the above problems. It can predict the optimal attitude angle that meets the telemetry and control conditions and far-field safety conditions based on the first position and first velocity vector of the rocket's final stage in the orbital coordinate system when it deorbits, as well as the target deorbit time, so as to ensure that the rocket's final stage can have a better deorbit effect when deorbiting with the optimal attitude angle.

[0005] In a first aspect, the present invention provides a method for optimizing the deorbit attitude angle of a rocket's final stage, the method comprising:

[0006] The first position and first velocity vector of the rocket's final stage in the launch coordinate system when it deorbits, as well as the target deorbit time of the rocket's final stage, are obtained; the launch coordinate system is a coordinate system established with the launch point where the rocket's final stage deorbits as the origin and the launch direction as the horizontal axis.

[0007] The system predicts that the rocket's final stage will deorbit from its first position with the first velocity vector and different target attitude angles, and that when the deorbiting time reaches the target deorbiting time, the rocket's final stage will have a second position and a second velocity vector in the Earth-fixed coordinate system. The target attitude angles are referenced to the orbital coordinate system and include the target yaw angle, target roll angle, and target pitch angle. The orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis. The Earth-fixed coordinate system is established with the Earth's center of mass as the origin.

[0008] The altitude of the first perigee after the rocket's final stage deorbits is determined based on the second position and the corresponding second velocity vector at each target attitude angle.

[0009] The difference between the perigee height of each first orbit and a preset height threshold is determined, and the target attitude angle corresponding to the difference being less than or equal to the preset difference threshold is determined to identify the candidate attitude angle.

[0010] The optimal attitude angle is determined from the candidate attitude angles that meet the preset measurement and control conditions and far-field safety conditions.

[0011] Optionally, before obtaining the first position and first velocity vector of the rocket's final stage in the launch coordinate system at the time of deorbiting, and the target deorbiting time of the rocket's final stage, the method further includes:

[0012] Obtain the remaining propellant charge at the time of the rocket's final stage deorbiting and the amount of propellant consumed per unit time during the deorbiting process;

[0013] The ratio of the remaining amount of explosive to the amount of explosive consumed is determined as the target deorbit duration.

[0014] Optionally, predicting the rocket's final stage deorbiting at the first position with the first velocity vector and different target attitude angles, and determining the second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time, includes:

[0015] Assign initial attitude angles to the rocket's final stage upon deorbiting; the initial attitude angles include initial yaw angle, initial roll angle, and initial pitch angle, with the initial pitch angle being 180°; the initial attitude angles are referenced to the orbital coordinate system.

[0016] The rocket's final stage is predicted to deorbit at the first position with the initial attitude angle and the first velocity vector, and the rocket's final stage will be at the third position and third velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0017] Based on the third position and the third velocity vector, determine the altitude of the second perigee after the rocket's final stage deorbits;

[0018] If the second perigee height is less than the height threshold, the rocket's final stage is predicted to deorbit at the first position with the first velocity vector and a different target attitude angle, and the rocket's final stage will be in the second position and second velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0019] Optionally, after determining the perigee altitude of the second first orbit after the rocket's final stage deorbits based on the third position and the third velocity vector, the method further includes:

[0020] If the perigee height of the second first orbit is greater than or equal to the height threshold, then the remaining propellant charge at the time of deorbiting of the rocket's final stage is increased.

[0021] Optionally, the telemetry and control conditions are that after the rocket's final stage leaves orbit, the angle between the direction of the space-based antenna on the rocket's final stage and the target straight line is less than or equal to a preset space-based beam angle, and the target straight line is the line connecting the rocket's final stage and the Tianlian satellite.

[0022] Optionally, the far-field safety condition is that after the rocket's final stage leaves orbit, the minimum distance between the rocket's final stage and the target satellite is greater than or equal to a preset distance threshold, and the target satellite is the satellite sent into a predetermined orbit by the rocket's final stage.

[0023] Optionally, determining the optimal attitude angle from candidate attitude angles that satisfy preset measurement and control conditions and far-field safety conditions includes:

[0024] The historical attitude angles of the rocket's final stage before deorbiting are obtained; the historical attitude angles are referenced to the orbital coordinate system.

[0025] Calculate the angle difference between the historical attitude angle and the preferred attitude angle, wherein the preferred attitude angle is a candidate attitude angle that satisfies the preset measurement and control conditions and far-field safety conditions;

[0026] The preferred attitude angle corresponding to the smallest angle difference is determined as the optimal attitude angle.

[0027] Secondly, the present invention provides a device for optimizing the deorbit attitude angle of a rocket's final stage, the device comprising:

[0028] The acquisition module is used to acquire the first position and first velocity vector of the rocket's final stage in the launch coordinate system when it deorbits, as well as the target deorbit time of the rocket's final stage; the launch coordinate system is a coordinate system established with the launch point where the rocket's final stage deorbits as the origin and the launch direction as the horizontal axis.

[0029] The prediction module is used to predict the rocket's final stage's deorbiting from the first position with the first velocity vector and different target attitude angles, and the second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time; the target attitude angle is based on the orbital coordinate system and includes the target yaw angle, target roll angle, and target pitch angle; the orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis; the Earth-fixed coordinate system is established with the Earth's center of mass as the origin.

[0030] The first determining module is used to determine the altitude of the first perigee of the rocket's final stage after deorbiting, based on the second position and the corresponding second velocity vector at each target attitude angle.

[0031] The second determining module is used to determine the difference between the perigee height of each of the first first laps and a preset height threshold, and to determine the candidate attitude angle by setting the target attitude angle corresponding to the difference being less than or equal to the preset difference threshold.

[0032] The third determining module is used to determine the optimal attitude angle from candidate attitude angles that meet preset measurement and control conditions and far-field safety conditions.

[0033] Thirdly, the present invention provides an electronic device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the method as described in the first aspect.

[0034] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing the computer to perform the method as described in the first aspect.

[0035] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0036] This invention provides a method, apparatus, device, and medium for optimizing the deorbit attitude angle of a rocket's final stage. It obtains the first position and first velocity vector of the rocket's final stage in the launch coordinate system during deorbit, as well as the target deorbit duration, and understands the initial deorbit conditions. It predicts that the rocket's final stage will deorbit from the first position with the first velocity vector and different target attitude angles, and determines the second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbit duration reaches the target deorbit duration. This yields the position and velocity vector of the rocket's final stage after deorbiting at different target attitude angles. Based on the second position and velocity vector corresponding to each target attitude angle... The corresponding second velocity vector determines the first perigee altitude after the rocket's final stage deorbits, reflecting its post-deorbit trajectory. The difference between each first perigee altitude and a preset altitude threshold is determined, and the target attitude angle corresponding to a difference less than or equal to the preset threshold is used to determine candidate attitude angles. Only candidate attitude angles will result in first perigee altitudes near the required altitude threshold. The optimal attitude angle is then determined from the candidate attitude angles that meet preset telemetry and control conditions and far-field safety conditions. The optimal attitude angle must at least satisfy the first perigee altitude requirement, telemetry and control conditions, and far-field safety conditions. The optimal attitude angle determined by this method allows the rocket's final stage to achieve better deorbit performance.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0039] Figure 1 This is a flowchart of a method for optimizing the deorbit attitude angle of a rocket's final stage, provided by an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the trajectory of a rocket's final stage before and after deorbiting, provided by an embodiment of the present invention;

[0041] Figure 3 This is a structural block diagram of a rocket final stage deorbit attitude angle optimization device provided in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. Unless otherwise specified, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0043] Figure 1 This is a flowchart of a method for optimizing the deorbit attitude angle of a rocket's final stage, provided by an embodiment of the present invention. This method can be used in the design of the rocket's final stage deorbit attitude scheme, which is used to pre-design the attitude angle of the rocket's final stage upon deorbit. Figure 1 As shown, the method includes:

[0044] Step S110: Obtain the first position and first velocity vector of the rocket's final stage in the launch coordinate system when it leaves orbit, as well as the target departure time of the rocket's final stage.

[0045] The launch coordinate system is established with the launch point where the rocket's final stage de-orbits as the origin and the launch direction as the horizontal axis; its vertical axis is perpendicular to the launch point and points upwards, and its vertical axis forms a right-handed rectangular coordinate system with its horizontal and vertical axes.

[0046] In this embodiment, the first position and the first velocity vector are pre-designed, and the previously designed first position and the first velocity vector can be directly used when designing the rocket's final stage deorbiting attitude scheme.

[0047] Optionally, before step S110, a method for calculating the target's off-orbit duration is also included, specifically including:

[0048] Obtain the remaining propellant charge at the time of rocket deorbit and the amount of propellant consumed per unit time during the deorbit process; determine the ratio of the remaining propellant charge to the consumed propellant charge as the target deorbit duration.

[0049] In this embodiment, the remaining propellant and the propellant consumption are also pre-designed. To avoid pollution and other impacts caused by residual fuel in the rocket engine, the remaining propellant is consumed as much as possible during deorbiting. Therefore, the time required to consume the remaining propellant is the target deorbiting time. Let the remaining propellant be denoted as m and the propellant consumption as k, then the target deorbiting time t = m / k.

[0050] Step S120: Predict the rocket's final stage deorbiting at the first position with a first velocity vector and different target attitude angles, and determine the rocket's final stage's second position and second velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0051] The target attitude angles are defined with the orbital coordinate system as the reference coordinate system and include the target yaw angle, target roll angle, and target pitch angle. The orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis. Its vertical axis is located outside the orbit pointing towards deorbiting and is perpendicular to its horizontal axis. Its vertical axis is perpendicular to both its horizontal and vertical axes, and its establishment satisfies the right-hand rule. Instantaneous orbital plane.

[0052] The target pitch angle is the angle between the projection of the rocket's X-axis (horizontal axis) onto the instantaneous orbital plane and the X-axis of the orbital coordinate system; the target yaw angle is the angle between the rocket's X-axis and the instantaneous orbital plane; the target roll angle is the rotation angle of the rocket about the X-axis of the orbital coordinate system. When the target roll angle = 0, the rocket's Y-axis (vertical axis) lies within the instantaneous orbital plane. The instantaneous orbital plane is the plane formed by the horizontal and vertical axes of the orbital coordinate system.

[0053] The target yaw angle, target roll angle, and target pitch angle all range from -180° to 180°. This range can be divided into multiple equally spaced sub-ranges, with different attitude angles taking values ​​from different sub-ranges. The number of sub-ranges for the target yaw angle is denoted as m, and the target yaw angle psi = -180 + [360 / (m×i)], where i = 0, 1, 2, 3..., 360 / (m-1). The number of sub-ranges for the target roll angle is denoted as n, and the target yaw angle gam = -180 + [360 / (n×j)], where j = 0, 1, 2, 3..., 360 / (n-1).

[0054] It should be noted that two different attitude angles can refer to at least one of the target yaw angle, target roll angle, and target pitch angle being different.

[0055] The Earth-fixed coordinate system is a coordinate system established with the Earth's center of mass as the origin.

[0056] In this embodiment, it is assumed that the rocket's final stage begins deorbiting from a first position, with the velocity vector at deorbiting being the first velocity vector and the attitude angle being the target attitude angle. The second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system are predicted when the deorbiting time reaches the target deorbiting time (at the end of deorbiting). Then, while keeping the first position and first velocity vector unchanged, the target attitude angle is changed, and the deorbiting at the changed target attitude angle is predicted again. The second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system at the end of deorbiting are then obtained. Thus, the second position and second velocity vector at different target attitude angles under the same first position and the same first velocity vector are obtained.

[0057] The Runge-Kutta integration method is generally used to calculate the velocity and position of the rocket's final stage during deorbiting. By integrating the forces acting on the final stage and combining this with the first position and velocity vectors, the final position and velocity vector of the final stage in the launch coordinate system at the end of deorbiting can be calculated. Then, determine the final position and final velocity vector of the rocket's final stage in the launch coordinate system. Convert to Earth-fixed coordinate system for the second position and second velocity vector of the rocket's final stage During deorbiting, the velocity increment ΔV of the rocket's final stage can be a fixed value, and the magnitude of ΔV can be designed in advance.

[0058] Step S130: Determine the altitude of the first perigee after the rocket's final stage deorbits based on the second position and the corresponding second velocity vector at each target attitude angle.

[0059] In this embodiment, the rocket's final stage deorbiting involves entering an elliptical orbit from its initial orbit before deorbiting. Within this elliptical orbit, there is a point closest to Earth, called the perigee. The distance between this perigee and Earth is called the perigee altitude. The perigee altitude of the first elliptical orbit entered after the rocket's final stage deorbiting is called the first orbit perigee altitude.

[0060] In this embodiment of the application, the perigee altitude of the first orbit after deorbiting is calculated by numerical integration. Step S130 includes:

[0061] The first step is to calculate the semi-major axis of the elliptical orbit according to formula (1).

[0062]

[0063] Where a represents the semi-major axis of the elliptical orbit, μ represents the Earth's gravitational constant, V1 represents the magnitude of the second velocity vector, R represents the magnitude of the distance vector from the Earth's center to the rocket's final stage at the second position when deorbiting ends, and E represents the orbital energy.

[0064] The second step is to calculate the angular momentum of the elliptical orbit according to formula (2).

[0065]

[0066] in, Represents angular momentum. This represents the distance vector from the Earth's center when the rocket's final stage is in its second position at the end of deorbiting. This represents the second velocity vector.

[0067] The third step is to calculate the eccentricity according to formula (3).

[0068]

[0069] Where e represents the eccentricity.

[0070] The fourth step is to calculate the perigee height of the first lap according to formula (4).

[0071] h = a × (1 - e) - R e ; Formula (4)

[0072] Where h represents the perigee altitude of the first lap, R e This represents the Earth's radius.

[0073] Therefore, based on the second position and the corresponding second velocity vector at each target attitude angle, the altitude of the first perigee after the rocket's final stage deorbits can be determined using the above four formulas, thus obtaining the altitude of the first perigee at all target attitude angles.

[0074] Step S140: Determine the difference between the perigee height of each first orbit and the preset height threshold, and determine the candidate attitude angle by setting the target attitude angle corresponding to the difference that is less than or equal to the preset difference threshold.

[0075] In this embodiment, candidate attitude angles are first selected from all target attitude angles. The candidate attitude angles are the target attitude angles whose first perigee height is near the height threshold. Using the candidate attitude angles for deorbiting can ensure that the first perigee height after deorbiting meets the requirements.

[0076] Step S150: Determine the optimal attitude angle from the candidate attitude angles that meet the preset measurement and control conditions and far-field safety conditions.

[0077] In this embodiment, candidate attitude angles that meet preset telemetry and control conditions and far-field safety conditions are determined as preferred attitude angles, and then the optimal attitude angle is determined from the preferred attitude angles. Finally, deorbiting with the optimal attitude angle ensures that the perigee altitude of the rocket's final stage after deorbiting meets the requirements, as well as the telemetry and control conditions and far-field safety conditions, thus achieving the best deorbiting effect.

[0078] Optionally, the telemetry and control conditions are that after the rocket's final stage leaves orbit, the angle between the direction of the space-based antenna on the final stage and the target line is less than or equal to the preset space-based beam angle, and the target line is the line connecting the rocket's final stage and the Tianlian satellite.

[0079] In this embodiment, the angle between the pointing direction of the space-based antenna and the target straight line can be calculated based on the position of the rocket's final stage, the installation angle of the space-based antenna, and the position of the Tianlian satellite at different times after deorbiting. Then, it is determined whether this angle meets the constraint requirements of the space-based beam angle. Candidate attitude angles that do not meet the constraint requirements are eliminated, leaving only those that do. In other words, deorbiting with candidate attitude angles that meet the space-based beam angle constraint requirements allows the rocket's final stage to transmit data normally after deorbiting. Specifically, the line connecting the rocket's final stage and the Tianlian satellite, i.e., the target straight line, can be determined based on the position of the rocket's final stage and the position of the Tianlian satellite.

[0080] The space-based antenna is used to transmit data to the Tianlian satellite, which is China's tracking and data relay satellite.

[0081] Optionally, the far-field safety condition is that after the rocket's final stage deorbits, the minimum distance between the rocket's final stage and the target satellite is greater than or equal to a preset distance threshold.

[0082] The target satellite is the satellite that the rocket's final stage sends into its predetermined orbit.

[0083] In this embodiment of the application, the distance between the rocket's final stage and the target satellite is calculated based on their positions at different times after deorbiting. Candidate attitude angles with a minimum distance less than a preset distance threshold are eliminated, and candidate attitude angles with a minimum distance greater than or equal to the preset distance threshold are retained. In other words, candidate attitude angles that meet the far-field safety requirements between the rocket's final stage and the target satellite are retained.

[0084] After the rocket's final stage begins deorbiting, the distance between the final stage and the satellite may either monotonically increase or decrease over a period of time. If the distance monotonically increases, the distance will become larger, and the far-field safety requirements can be considered met. If the distance decreases over a period of time, and the minimum distance after the decrease is less than the distance threshold L0, the far-field safety requirements are considered not met. If the minimum distance after the decrease is greater than or equal to the distance threshold L0, the far-field safety requirements are considered met. The distance threshold L0 can be set according to the actual situation and the satellite's requirements.

[0085] Optionally, step S120 includes:

[0086] The first step is to assign the initial attitude angle to the rocket's final stage upon deorbiting.

[0087] The initial attitude angles include the initial yaw angle, initial roll angle, and initial pitch angle, with the initial pitch angle being 180°. The initial attitude angles are referenced to the orbital coordinate system.

[0088] In this embodiment, as shown in formula (1), the semi-major axis decreases as the second velocity vector decreases. When the semi-major axis decreases, the corresponding first orbit perigee height will decrease. Therefore, the smaller the second velocity vector, the lower the first orbit perigee height will be. Thus, theoretically, if the rocket's final stage ignites completely in the opposite direction of the first velocity vector when deorbiting, the rocket's final stage velocity can be minimized, thus maximizing the reduction of the first orbit perigee height after deorbiting. However, igniting completely in the opposite direction of the first velocity vector requires the rocket's pitch angle to reach 180°. Therefore, an initial pitch angle of 180° is first assigned, and then it is assumed that the rocket's final stage deorbits with a pitch angle of 180°.

[0089] The second step is to predict the rocket's final stage's deorbiting from its first position with its initial attitude angle and first velocity vector, and the rocket's final stage's third position and third velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0090] In this embodiment of the application, it is assumed that the rocket's final stage de-orbits at the first position with a first velocity vector, and the pitch angle at the time of de-orbiting is the initial pitch angle, which is 180°. Then, the third position and the third velocity vector of the rocket's final stage in the Earth-fixed coordinate system at the end of the de-orbiting are determined.

[0091] The third step is to determine the perigee altitude of the second orbit after the rocket's final stage deorbits, based on the third position and the third velocity vector.

[0092] Based on the method described above, the altitude of the second first orbit after the rocket's final stage deorbits is calculated under the third position and the third velocity vector, thus obtaining the minimum altitude of the first orbit after the rocket's final stage deorbits.

[0093] Fourth step: If the perigee altitude of the second orbit is less than the altitude threshold, then predict that the rocket's final stage will deorbit at the first position with the first velocity vector and different target attitude angles, and when the deorbiting time reaches the target deorbiting time, the rocket's final stage will be at the second position and second velocity vector in the Earth-fixed coordinate system.

[0094] In this embodiment, if the altitude of the second first orbit's perigee is less than the altitude threshold, it means that regardless of the pitch angle chosen during deorbiting, the altitude of the first orbit's perigee after deorbiting will always be less than the altitude threshold, thus meeting the altitude requirement. In this case, the target attitude angle is continuously changed during the deorbiting assumption to obtain the rocket's final stage's second position and second velocity vector in the Earth-fixed coordinate system at different target attitude angles during deorbiting. The altitude threshold can be 100 km.

[0095] Figure 2 This is a schematic diagram of the trajectory of a rocket's final stage before and after deorbiting, provided by an embodiment of the present invention. Figure 2As shown, the orbit 1 before the rocket's final stage deorbits is the initial orbit of the final stage. The minimum altitude (first perigee altitude) of the first orbit after deorbiting is the same as the orbits at the same altitude, including the first elliptical orbit 3 and the second elliptical orbit 4. Therefore, for the same target yaw angle and the same target roll angle, there are two target pitch angles when the first perigee altitude is the same. That is to say, the direction of the velocity V0 before the rocket's final stage deorbits is forward, and the direction of the velocity V at deorbiting can be upward or downward relative to the direction of the velocity before deorbiting. The velocity variable ΔV during the deorbiting process also has two directions. Therefore, the deorbiting methods include upward deorbiting and downward deorbiting, and the corresponding target pitch angles have two sets of solutions. These two sets of solutions are called the "upward solution" and the "downward solution," respectively. At the same time, the perigee altitude is lowest when the angle between ΔV and the direction of the first velocity vector at the moment of deorbiting is 180°. As the angle approaches 0°, the perigee altitude increases.

[0096] Therefore, if the perigee height of the second first orbit is less than the altitude threshold, it means that there is a solution for the target pitch angle. When designing the rocket's final stage deorbit attitude scheme, in order to improve design efficiency, candidate attitude angles can be tested little by little, without needing to determine the perigee height of the first orbit under all target attitude angles.

[0097] Therefore, the fourth step includes: iteratively calculating the target pitch angle according to the upward and downward deorbiting methods respectively, until the calculated perigee height of the first orbit after deorbiting reaches near the required altitude threshold.

[0098] Specifically, from the previously defined small range of different values ​​for the target yaw angle and roll angle, different target yaw angles and roll angles are determined based on different values ​​of i and j. The target pitch angle that meets the deorbiting requirements is then solved through ballistic integral iteration. The target pitch angle iteration starts from 180°.

[0099] First, select a suitable target yaw angle and target roll angle. Determine the first perigee altitude corresponding to an initial target pitch angle of 180°. Then, determine if the difference between this first perigee altitude and an altitude threshold is less than or equal to the difference threshold. If the difference is less than or equal to the difference threshold, then the target yaw angle, target roll angle, and the 180° target pitch angle are selected as candidate attitude angles. However, if the target pitch angle changes to other angles (not 180°) while the target yaw angle and target roll angle remain unchanged, the first perigee altitude will increase, leading to a larger difference. Therefore, target pitch angles at other angles will not meet the first perigee altitude requirement and will not be selected as candidate attitude angles. Thus, it is unnecessary to determine the first perigee altitude under other target pitch angles.

[0100] If the difference is greater than the difference threshold, it means that the altitude of the first perigee is not near the altitude threshold, and the target pitch angle of 180° does not meet the requirements. Therefore, the target pitch angle needs to be changed. The adjustment amount of the target pitch angle can be determined based on the difference. So, the adjusted target pitch angle is the target pitch angle before adjustment ± the adjustment amount. The target pitch angle before adjustment + the adjustment amount gives the "upward solution" of the adjusted target pitch angle, and the target pitch angle before adjustment - the adjustment amount gives the "downward solution" of the adjusted target pitch angle. Keeping the target yaw angle and target roll angle unchanged, the target pitch angle after the first adjustment becomes 180° ± the adjustment amount. Calculate the altitude of the first perigee under the first adjusted target pitch angle, and then determine whether the difference between the altitude of the first perigee and the altitude threshold is less than or equal to the difference threshold. If yes, the target yaw angle, target roll angle, and the first adjusted target pitch angle are determined as candidate attitude angles. If not, the same iterative method is used to adjust the target pitch angle until the difference between the first perigee altitude and the altitude threshold under the adjusted target pitch angle is less than or equal to the difference threshold. The iteration stops then, and the up and down solutions for the target pitch angle are obtained. The corresponding target pitch angle, the corresponding target yaw angle, and the corresponding target roll angle are determined as candidate attitude angles. Alternatively, the iteration stops when the adjusted target pitch angle is 0, and no candidate attitude angle is obtained in this iteration. Ultimately, under the same target yaw angle and the same target roll angle, at most one up target pitch angle and one down target pitch angle can be determined, i.e., two sets of candidate attitude angles.

[0101] Then, the target yaw angle or target roll angle is adjusted. With a new combination of target yaw and roll angles, a new round of iteration is performed to determine a new set of target pitch angles, resulting in two new sets of candidate attitude angles. This process is repeated iteratively to select the target yaw, roll, and pitch angles that meet the requirements under different target yaw, roll, and pitch angles, resulting in multiple sets of candidate attitude angles. Using this method to iteratively determine all candidate attitude angles that meet the requirements can reduce design time.

[0102] For example, the formula for calculating the adjustment amount of the target pitch angle is:

[0103] Δα=(H1-H) / 10000; Formula (5)

[0104] Where Δα represents the adjustment amount, H1 represents the perigee height of the first lap, and H represents the height threshold.

[0105] Optionally, a fifth step is included after the third step:

[0106] If the perigee altitude of the second first orbit is greater than or equal to the altitude threshold, the remaining propellant charge at the time of deorbiting of the rocket's final stage will be increased.

[0107] In this embodiment of the application, if the second first orbit perigee height is greater than or equal to the height threshold, it means that no matter what attitude angle the rocket's final stage is at when it deorbits, the first orbit perigee height after deorbiting will not meet the requirements. Therefore, the remaining propellant charge of the rocket's final stage is increased when it deorbits, thereby increasing the target deorbiting time and increasing the distance between the rocket's final stage and the Earth after deorbiting, so that the first orbit perigee height after deorbiting meets the requirements.

[0108] Optionally, step S150 includes:

[0109] Obtain the historical attitude angles of the rocket's final stage before deorbiting; calculate the angle difference between the historical attitude angles and the preferred attitude angles; and determine the preferred attitude angle corresponding to the smallest angle difference as the optimal attitude angle.

[0110] The historical attitude angles can be the attitude angles of the rocket's final stage at the moment before deorbiting, with the preferred attitude angles being candidate attitude angles that meet preset telemetry and control conditions and far-field safety conditions. The historical attitude angles are referenced to the orbital coordinate system.

[0111] This can be understood as, combining the standard of minimizing the derailment attitude adjustment angle, selecting the optimal attitude angle from the preferred attitude angles with the smallest change in angle as the optimal attitude angle. That is, selecting the preferred attitude angle with the smallest change from the moment of derailment to the moment before derailment as the optimal attitude angle, because this optimal attitude angle requires the least adjustment and is more conducive to derailment operation.

[0112] In this embodiment of the application, when designing the deorbit attitude scheme, the scheme is automatically screened by combining the measurement and control requirements, far-field safety requirements and attitude adjustment angle minimization standard, so as to quickly obtain the optimal rocket deorbit attitude scheme, reduce the difficulty and workload of manual design, and improve design efficiency.

[0113] Based on the same inventive concept, this invention also provides a device for optimizing the deorbit attitude angle of the rocket's final stage. Figure 3 This is a structural block diagram of a rocket final stage deorbit attitude angle optimization device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the device 300 includes an acquisition module 301, a prediction module 302, a first determination module 303, a second determination module 304, and a third determination module 305.

[0114] The acquisition module 301 is used to acquire the first position and first velocity vector of the rocket's final stage in the launch coordinate system when it deorbits, as well as the target deorbit time of the rocket's final stage; the launch coordinate system is based on...

[0115] The established coordinate system;

[0116] The prediction module 302 is used to predict the rocket's final stage deorbiting from its first position with a first velocity vector and different target attitude angles, and the second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time; the target attitude angle is based on the orbital coordinate system and includes the target yaw angle, target roll angle, and target pitch angle; the orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis; the Earth-fixed coordinate system is established with the Earth's center of mass as the origin.

[0117] The first determining module 303 is used to determine the altitude of the first perigee after the rocket's final stage deorbits based on the second position and the corresponding second velocity vector at each target attitude angle.

[0118] The second determining module 304 is used to determine the difference between the perigee height of each first lap and the preset height threshold, and to determine the candidate attitude angle by setting the target attitude angle corresponding to the difference that is less than or equal to the preset difference threshold.

[0119] The third determining module 305 is used to determine the optimal attitude angle from candidate attitude angles that meet preset measurement and control conditions and far-field safety conditions.

[0120] Optionally, the device 300 further includes a fourth determining module for:

[0121] Obtain the remaining propellant charge at the time of rocket deorbiting and the amount of propellant consumed per unit time during the deorbiting process;

[0122] The ratio of remaining propellant to consumed propellant is determined as the target deorbit time.

[0123] Optionally, the prediction module 302 includes:

[0124] The allocation unit is used to allocate the initial attitude angles to the rocket's final stage upon deorbiting. The initial attitude angles include the initial yaw angle, initial roll angle, and initial pitch angle, with the initial pitch angle being 180°. The initial attitude angles are referenced to the orbital coordinate system.

[0125] The first prediction unit is used to predict the rocket's final stage deorbiting at the first position with an initial attitude angle and a first velocity vector, and the rocket's final stage's third position and third velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0126] The determination unit is used to determine the perigee altitude of the second orbit after the rocket's final stage deorbits, based on the third position and the third velocity vector.

[0127] The second prediction unit is used to predict the rocket's final stage deorbiting at a first position with a first velocity vector and different target attitude angles if the altitude of the second first orbit perigee is less than the altitude threshold, and to predict the rocket's final stage's second position and second velocity vector in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time.

[0128] Optionally, the prediction module 302 further includes an addition unit for:

[0129] If the perigee altitude of the second first orbit is greater than or equal to the altitude threshold, the remaining propellant charge at the time of deorbiting of the rocket's final stage will be increased.

[0130] Optionally, the telemetry and control conditions are that after the rocket's final stage leaves orbit, the angle between the direction of the space-based antenna on the final stage and the target line is less than or equal to the preset space-based beam angle, and the target line is the line connecting the rocket's final stage and the Tianlian satellite.

[0131] Optionally, the far-field safety condition is that after the rocket's final stage leaves orbit, the minimum distance between the rocket's final stage and the target satellite is greater than or equal to a preset distance threshold, and the target satellite is the satellite sent into a predetermined orbit by the rocket's final stage.

[0132] Optionally, the third determining module 305 is also used for:

[0133] Obtain the historical attitude angles of the rocket's final stage before deorbiting; the historical attitude angles are referenced to the orbital coordinate system.

[0134] Calculate the angle difference between the historical attitude angle and the preferred attitude angle. The preferred attitude angle is the candidate attitude angle that meets the preset measurement and control conditions and far-field safety conditions.

[0135] The preferred attitude angle corresponding to the smallest angle difference is determined as the optimal attitude angle.

[0136] It is understood that the device provided in the above embodiments is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0137] This invention also provides an electronic device that may include a processor and a memory, wherein the processor and the memory may be interconnected via a bus or other means.

[0138] The processor can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. It can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or other chips, or combinations of the above types of chips.

[0139] Memory may include mass storage for data or instructions. For example, and not limitingly, memory may include hard disk drives (HDDs), floppy disk drives, flash memory, optical disks, magneto-optical disks, magnetic tape, or Universal Serial Bus (USB) drives, or combinations of two or more of these. Where appropriate, memory may include removable or non-removable (or fixed) media. Where appropriate, memory may be internal or external to an electronic device. In a particular embodiment, memory may be non-volatile solid-state memory.

[0140] In one instance, the memory may be read-only memory (ROM). In one instance, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0141] The processor reads and executes computer program instructions stored in the memory to implement any of the methods for optimizing the deorbit attitude angle of the rocket's final stage in the above embodiments.

[0142] In one example, the electronic device may further include a communication interface and a bus. The processor, memory, and communication interface are connected via the bus to communicate with each other. The communication interface is primarily used to enable communication between the various modules, devices, units, and / or equipment in the embodiments of this application. Where appropriate, the bus may include one or more buses.

[0143] Furthermore, in conjunction with the rocket final stage deorbit attitude angle optimization method in the above embodiments, this invention can be implemented using a computer-readable storage medium. This computer-readable storage medium stores computer program instructions; when executed by a processor, these computer program instructions implement any of the rocket final stage deorbit attitude angle optimization methods in the above embodiments.

[0144] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0145] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0146] This invention provides a method, apparatus, device, and medium for optimizing the deorbit attitude angle of a rocket's final stage. It obtains the first position and first velocity vector of the rocket's final stage in the launch coordinate system during deorbit, as well as the target deorbit duration, and understands the initial deorbit conditions. It predicts that the rocket's final stage will deorbit from the first position with the first velocity vector and different target attitude angles, and determines the second position and second velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbit duration reaches the target deorbit duration. This yields the position and velocity vector of the rocket's final stage after deorbiting at different target attitude angles. Based on the second position and velocity vector corresponding to each target attitude angle... The corresponding second velocity vector determines the first perigee altitude after the rocket's final stage deorbits, reflecting its post-deorbit trajectory. The difference between each first perigee altitude and a preset altitude threshold is determined, and the target attitude angle corresponding to a difference less than or equal to the preset threshold is used to determine candidate attitude angles. Only candidate attitude angles will result in first perigee altitudes near the required altitude threshold. The optimal attitude angle is then determined from the candidate attitude angles that meet preset telemetry and control conditions and far-field safety conditions. The optimal attitude angle must at least satisfy the first perigee altitude requirement, telemetry and control conditions, and far-field safety conditions. The optimal attitude angle determined by this method allows the rocket's final stage to achieve better deorbit performance.

[0147] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0148] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0149] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A method for optimizing the deorbit attitude angle of a rocket's final stage, characterized in that, The method includes: The first position and first velocity vector of the rocket's final stage in the launch coordinate system at the time of deorbiting are obtained, as well as the target deorbiting time of the rocket's final stage; the launch coordinate system is a coordinate system established with the launch point of the rocket's final stage deorbiting as the origin and the launch direction as the horizontal axis; the first position and the first velocity vector are pre-designed; Assign an initial attitude angle to the rocket's final stage upon deorbiting; the initial attitude angle includes an initial yaw angle, an initial roll angle, and an initial pitch angle, with the initial pitch angle being 180°; the initial attitude angle is referenced to the orbital coordinate system; predict that the rocket's final stage will deorbit at the first position with the initial attitude angle and the first velocity vector, and determine the third position and third velocity vector of the rocket's final stage in the Earth-fixed coordinate system when the deorbiting time reaches the target deorbiting time; determine the second perigee altitude of the rocket's final stage after deorbiting based on the third position and the third velocity vector; if the second perigee altitude... If the altitude of the location is less than a preset altitude threshold, it is predicted that the rocket's final stage will deorbit at the first position with the first velocity vector and different target attitude angles. When the deorbiting time reaches the target deorbiting time, the rocket's final stage will be at a second position and with the second velocity vector in the Earth-fixed coordinate system. The target attitude angles are referenced to the orbital coordinate system and include the target yaw angle, target roll angle, and target pitch angle. The orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis. The Earth-fixed coordinate system is established with the Earth's center of mass as the origin. The altitude of the first perigee after the rocket's final stage deorbits is determined based on the second position and the corresponding second velocity vector at each target attitude angle. The difference between the perigee height of each first orbit and the height threshold is determined, and the target attitude angle corresponding to the difference being less than or equal to the preset difference threshold is determined to identify the candidate attitude angle. The optimal attitude angle is determined from the candidate attitude angles that meet the preset measurement and control conditions and far-field safety conditions; The process of determining the optimal attitude angle from candidate attitude angles that satisfy preset measurement and control conditions and far-field safety conditions includes: The historical attitude angles of the rocket's final stage before deorbiting are obtained; the historical attitude angles are referenced to the orbital coordinate system. Calculate the angle difference between the historical attitude angle and the preferred attitude angle, wherein the preferred attitude angle is a candidate attitude angle that satisfies the preset measurement and control conditions and far-field safety conditions; The preferred attitude angle corresponding to the smallest angle difference is determined as the optimal attitude angle.

2. The method for optimizing the deorbit attitude angle of the rocket's final stage according to claim 1, characterized in that, Before obtaining the first position and first velocity vector of the rocket's final stage in the launch coordinate system at the time of deorbiting, and the target deorbiting time of the rocket's final stage, the method further includes: Obtain the remaining propellant charge at the time of the rocket's final stage deorbiting and the amount of propellant consumed per unit time during the deorbiting process; The ratio of the remaining amount of explosive to the amount of explosive consumed is determined as the target deorbit duration.

3. The method for optimizing the deorbit attitude angle of the rocket's final stage according to claim 1, characterized in that, After determining the perigee altitude of the second first orbit after the rocket's final stage deorbits based on the third position and the third velocity vector, the method further includes: If the perigee height of the second first orbit is greater than or equal to the height threshold, then the remaining propellant charge at the time of deorbiting of the rocket's final stage is increased.

4. The method for optimizing the deorbit attitude angle of the rocket's final stage according to claim 1, characterized in that, The telemetry and control conditions are that after the rocket's final stage leaves orbit, the angle between the direction of the space-based antenna on the rocket's final stage and the target straight line is less than or equal to the preset space-based beam angle, and the target straight line is the line connecting the rocket's final stage and the Tianlian satellite.

5. The method for optimizing the deorbit attitude angle of the rocket's final stage according to claim 1, characterized in that, The far-field safety condition is that after the rocket's final stage leaves orbit, the minimum distance between the rocket's final stage and the target satellite is greater than or equal to a preset distance threshold, and the target satellite is the satellite that the rocket's final stage sends into a predetermined orbit.

6. A device for optimizing the deorbit attitude angle of a rocket's final stage, characterized in that, The device includes: The acquisition module is used to acquire the first position and first velocity vector of the rocket's final stage in the launch coordinate system when it deorbits, as well as the target deorbit time of the rocket's final stage; the launch coordinate system is a coordinate system established with the launch point where the rocket's final stage deorbits as the origin and the launch direction as the horizontal axis. The prediction module is used to assign an initial attitude angle to the rocket's final stage upon deorbiting; the initial attitude angle includes an initial yaw angle, an initial roll angle, and an initial pitch angle, with the initial pitch angle being 180°; the initial attitude angle uses the orbital coordinate system as a reference coordinate system; it predicts that the rocket's final stage will deorbit at the first position with the initial attitude angle and the first velocity vector, and that when the deorbiting time reaches the target deorbiting time, the rocket's final stage will have a third position and a third velocity vector in the Earth-fixed coordinate system; based on the third position and the third velocity vector, it determines the altitude of the rocket's second perigee after deorbiting; if the second... If the perigee altitude of the first orbit is less than a preset altitude threshold, it is predicted that the rocket's final stage will deorbit at the first position with the first velocity vector and different target attitude angles. When the deorbiting time reaches the target deorbiting time, the rocket's final stage will be at a second position and with the second velocity vector in the Earth-fixed coordinate system. The target attitude angles are referenced to the orbital coordinate system and include the target yaw angle, target roll angle, and target pitch angle. The orbital coordinate system is established with the center of mass of the rocket's final stage as the origin and the direction of the first velocity vector as the horizontal axis. The Earth-fixed coordinate system is established with the Earth's center of mass as the origin. The first determining module is used to determine the altitude of the first perigee of the rocket's final stage after deorbiting, based on the second position and the corresponding second velocity vector at each target attitude angle. The second determining module is used to determine the difference between the perigee height of each of the first first laps and the height threshold, and to determine the candidate attitude angle by setting the difference to be less than or equal to the target attitude angle corresponding to the preset difference threshold. The third determining module is used to determine the optimal attitude angle from the candidate attitude angles that meet the preset measurement and control conditions and far-field safety conditions; The process of determining the optimal attitude angle from candidate attitude angles that satisfy preset measurement and control conditions and far-field safety conditions includes: The historical attitude angles of the rocket's final stage before deorbiting are obtained; the historical attitude angles are referenced to the orbital coordinate system. Calculate the angle difference between the historical attitude angle and the preferred attitude angle, wherein the preferred attitude angle is a candidate attitude angle that satisfies the preset measurement and control conditions and far-field safety conditions; The preferred attitude angle corresponding to the smallest angle difference is determined as the optimal attitude angle.

7. An electronic device, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method of any one of claims 1-5.

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