Method and device for controlling spacecraft to avoid multistage collision

Abstract

The invention provides a method and device for controlling a spacecraft to avoid multistage collision, and belongs to the technical field of aerospace. According to the method, each collision object in a plurality of collision objects of the spacecraft is used as a repulsive force source, and according to a dynamic mapping matrix of the spacecraft and each collision object at a predicted collision moment, a repulsive force acceleration generated by each collision object to the spacecraft is calculated; and taking the sum of the repulsive force accelerations of the plurality of collision objects as a control acceleration for controlling the spacecraft to avoid the target collision object. The method not only can ensure that the spacecraft avoids the target collision object, but also can ensure that the spacecraft does not collide with other collision objects.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to a method and device for controlling a spacecraft to avoid multi-stage collisions. Background Art

[0002] During the process of a spacecraft operating in accordance with a set orbit to perform a space mission, there are collision objects such as space debris, defunct satellites, and other on-orbit targets in space. Moreover, with the development of technology, various satellite constellations (i.e., satellite clusters composed of multiple satellites, such as Starlink, etc.) are deployed in space, and the orbital space is becoming increasingly crowded. On this basis, during the process of a spacecraft performing a space mission, the possibility of the spacecraft colliding with multiple objects (i.e., multi-stage collisions) within a short period of time increases. Therefore, it is necessary to control the spacecraft to adjust its operating orbit so as to ensure that the spacecraft does not collide with other objects and enables the spacecraft to successfully complete the space mission.

[0003] However, the existing methods for controlling a spacecraft to avoid collisions can only perform collision avoidance control on the spacecraft for one collision object. During the process of controlling the spacecraft to avoid one collision object, there is a risk that the spacecraft collides with another collision object. Summary of the Invention

[0004] The present invention provides a method and device for controlling a spacecraft to avoid multi-stage collisions, which can control the spacecraft not to collide with other collision objects during the process of the spacecraft avoiding a target collision object, thereby avoiding multi-stage collisions of the spacecraft.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for controlling a spacecraft to avoid multi-stage collisions, which is used to avoid multi-stage collisions during the process of the spacecraft avoiding a target collision object. The method includes: during the process of controlling the spacecraft to avoid a target collision object among multiple collision objects, for each collision object among the multiple collision objects, determining the predicted collision time between the spacecraft and the collision object, and the distance between the spacecraft and the collision object at the predicted collision time. According to the predicted collision time and the distance, determining the dynamic mapping matrix of the spacecraft at the predicted collision time; wherein, the dynamic mapping matrix is used to describe the mapping relationship between the position change amount of the spacecraft and the control acceleration. Then, based on the dynamic mapping matrix of the spacecraft at the predicted collision time, determining the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source. And taking the sum of the repulsive accelerations generated by the multiple collision objects on the spacecraft as the control acceleration for the spacecraft to avoid the target collision object.

[0007] As can be seen from the above content, in the process of controlling the spacecraft to avoid the target collision object among multiple collision objects, for each collision object among the multiple collision objects of the spacecraft, each collision object is used as a repulsive force source of the spacecraft, and based on the dynamic mapping matrix of the spacecraft at the collision moment between the spacecraft and each collision object, the repulsive acceleration generated by each collision object on the spacecraft is determined, and then the sum of the repulsive accelerations of the multiple collision objects is used as the control acceleration for the spacecraft to avoid the target collision object. In the process of controlling the spacecraft to avoid the target collision object among multiple collision objects, each collision object among the multiple collision objects of the spacecraft is used as a repulsive force source, and according to the dynamic mapping matrix of the spacecraft and each collision object at the predicted collision moment, the repulsive acceleration generated by each collision object on the spacecraft is calculated, and then the sum of the repulsive accelerations of the multiple collision objects is used as the control acceleration for the spacecraft to avoid the target collision object. As can be seen from the above content, the embodiment of the present application utilizes the characteristic of mutual repulsion between objects in the repulsive force field, so that when the spacecraft is under the repulsive action (i.e., repulsive force) of multiple collision objects as repulsive force sources, the spacecraft does not collide with any of the above multiple collision objects. Therefore, using the sum of the repulsive accelerations generated by multiple repulsive force sources as the control acceleration of the spacecraft can not only ensure that the spacecraft avoids the target collision object, but also ensure that the spacecraft does not collide with other collision objects, thereby avoiding multi-stage collisions of the spacecraft and further ensuring the successful completion of the space mission by the spacecraft.

[0008] In one implementation manner of the first aspect, based on the dynamic mapping matrix of the spacecraft at the predicted collision moment, determining the repulsive acceleration generated by the collision object on the spacecraft when the collision object is used as a repulsive force source includes: predicting the distance between the spacecraft and the collision object at the predicted collision moment when the collision object is used as a repulsive force source based on the dynamic mapping matrix. Then, with the maximum distance between the predicted spacecraft and the collision object at the predicted collision moment as the optimization target, the direction of the repulsive acceleration is solved.

[0009] Wherein, when the collision object is represented as the i-th collision object among multiple collision objects, the direction v of the repulsive acceleration generated by the i-th collision object on the spacecraft opt,i Satisfies:

[0010] v opt,i = -(A i - λ opt,i I) + b i

[0011] A i = M i T QM i ,M i represents the dynamic mapping matrix of the spacecraft at the predicted collision moment, Mi T is the transpose of M i ,

[0012] λ opt,i represents the influence factor of the repulsive force of unit size on the predicted distance, λ opt,i satisfies:

[0013]

[0014] where, (*) T represents the transpose of a vector or matrix, (*)+ represents the pseudo-inverse of a matrix, λ1 represents the first non-zero eigenvalue of A i and λ2 represents the second non-zero eigenvalue of A i , s1 represents the eigenvector corresponding to λ1, and s2 represents the eigenvector corresponding to λ2;

[0015] I is the 3×3 identity matrix;

[0016] b i =(r e,i T QM i / Δv) -T , r e,i represents the rendezvous position vector of the spacecraft and the i-th collision object, and Δv represents the change in the velocity of the spacecraft;

[0017] According to the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, and the dynamic mapping matrix, the magnitude of the repulsive acceleration generated by the collision object on the spacecraft is solved according to the following formula:

[0018] The magnitude u of the repulsive acceleration generated by the i-th collision object on the spacecraft i satisfies:

[0019]

[0020] where, C r represents the safety redundancy factor of the spacecraft; D threshold represents the distance threshold; d i ' is used to indicate the distance between the spacecraft and the collision object at the predicted collision time; Δt i represents the time difference between the current time t and the predicted collision time TCA i ; t b represents the time threshold.

[0021] In the above implementation, multiple collision objects in multi-level collisions are used as repulsive force sources, and the sum of the repulsive force accelerations generated by multiple repulsive force sources on the spacecraft is used as the control acceleration of the spacecraft. Since the process of calculating the repulsive force acceleration based on the repulsive force source is relatively simple and the amount of calculation is small, therefore, the control acceleration of the spacecraft can be quickly calculated, and the above calculation process does not require the computing resources of ground equipment, which can improve the efficiency of the spacecraft avoiding multi-level collisions.

[0022] In one implementation of the first aspect, the predicted time to collision TCA i satisfies:

[0023]

[0024] where t 0,i represents the predicted time to collision between the spacecraft and the i-th collision object;

[0025] represents the velocity of the spacecraft at the predicted time to collision, represents the velocity of the i-th collision object at the predicted time to collision;

[0026] (x1, y1, z1) represents the position of the spacecraft at the predicted time to collision, and (x2, y2, z2) represents the position of the i-th collision object at the predicted time to collision.

[0027] In one implementation of the first aspect, the distance d between the spacecraft and the i-th collision object at the predicted time to collision i satisfies:

[0028]

[0029] where c i =(x1 - x2) 2 +(y1 - y2) 2 +(z1 - z2) 2 .

[0030] In one implementation of the first aspect, for the i-th collision object among multiple collision objects, the dynamic mapping matrix M of the spacecraft at the predicted time to collision i satisfies:

[0031] M i =R i K i D i

[0032] where,

[0033] β i represents The angle between and

[0034] v1 represents the magnitude of the velocity of the spacecraft at the warning collision moment, k1 ∈ (-1, +1), k2 ∈ (-1, +1);

[0035] Δθ i represents the true anomaly of the spacecraft relative to the i-th collision object at the current moment t, n1 represents the angular velocity of the spacecraft, and r1 represents the semi-major axis of the spacecraft's orbit.

[0036] In the above implementation, solving for the predicted collision moment TCA i and the distance d i is based on the reasonable assumption that the spacecraft and the collision object approach each other and collide at a uniform linear motion. By taking the square of both sides of the distance formula between the spacecraft and the i-th collision object and simplifying, the predicted collision moment TCA i and the distance d i are solved. Compared with the existing method of iteratively solving for the predicted collision moment TCA i and the distance d i , the above calculation process is simpler and more efficient.

[0037] In a second aspect, the present invention provides a device for controlling a spacecraft to avoid multi-stage collisions. The device is used to prevent multi-stage collisions from occurring during the process of the spacecraft avoiding a target collision object. The device includes a collision moment and distance determination module, a mapping matrix determination module, an acceleration determination module, and a control quantity determination module. The collision moment and distance determination module is used to determine, for each collision object among multiple collision objects, the predicted collision moment of the spacecraft and the collision object, and the distance between the spacecraft and the collision object at the predicted collision moment during the process of controlling the spacecraft to avoid the target collision object among multiple collision objects. The mapping matrix determination module is used to determine the dynamic mapping matrix of the spacecraft at the predicted collision moment according to the predicted collision moment and the distance; the dynamic mapping matrix is used to describe the mapping relationship between the position change amount of the spacecraft and the control acceleration. The acceleration determination module is used to determine the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source based on the dynamic mapping matrix of the spacecraft at the predicted collision moment. The control quantity determination module is used to take the sum of the repulsive accelerations generated by multiple collision objects on the spacecraft as the control acceleration for the spacecraft to avoid the target collision object.

[0038] In an implementation of the second aspect, the acceleration determination module is specifically configured to predict the distance between the spacecraft and the collision object at the predicted collision moment when the collision object is a repulsive force source based on the dynamic mapping matrix. Then, with the optimization objective of maximizing the predicted distance between the spacecraft and the collision object at the predicted collision moment, the direction of the repulsive acceleration is solved.

[0039] Where, when the collision object is represented as the i-th collision object among multiple collision objects, the direction v of the repulsive acceleration generated by the i-th collision object on the spacecraft opt,i Satisfies:

[0040] v opt,i = -(A i - λ opt,i I) + b i

[0041] A i = M i T QM i M i represents the dynamic mapping matrix of the spacecraft at the predicted collision moment, M i T is the transpose of M i ,

[0042] λ opt,i represents the influence factor of the repulsive force of unit magnitude on the predicted distance, λ opt,i Satisfies:

[0043]

[0044] Where, (*) T represents the transpose of a vector or matrix, (*)+ represents the pseudo-inverse of a matrix, λ1 represents the first non-zero eigenvalue of A i λ2 represents the second non-zero eigenvalue of A i , s1 represents the eigenvector corresponding to λ1, s2 represents the eigenvector corresponding to λ2;

[0045] I is a 3×3 identity matrix;

[0046] b i = (r e,i T QM i / Δv) -T r e,i represents the rendezvous position vector between the spacecraft and the i-th collision object, and Δv represents the velocity change of the spacecraft.

[0047] According to the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, and the dynamic mapping matrix, the magnitude of the repulsive acceleration generated by the collision object on the spacecraft is solved according to the following formula:

[0048] The magnitude u of the repulsive acceleration generated by the i-th collision object on the spacecraft i Satisfies:

[0049]

[0050] Among them, C r Represents the safety redundancy factor of the spacecraft; D threshold Represents the distance threshold; d i 'Is used to indicate the distance between the spacecraft and the collision object at the predicted collision time; Δt i Represents the time difference between the current time t and the predicted collision time TCA i ; t b Represents the time threshold.

[0051] In a third aspect, the present invention provides an electronic device, including a processor and a memory coupled to the processor; the memory is used to store computer instructions, and when the electronic device runs, the processor executes the computer instructions stored in the memory, so that the electronic device executes the method described in the first aspect or any one of its implementation manners above.

[0052] In a fourth aspect, the present invention provides a computer-readable storage medium, including computer program instructions, and when the computer program instructions are executed by a computer, the computer is caused to execute the method described in the first aspect or any one of its implementation manners above.

[0053] In a fifth aspect, the present invention provides a computer program product, including computer program instructions, and when the computer program instructions run on a computer, the computer is caused to execute the method described in the first aspect or any one of its implementation manners above.

[0054] For the technical effects corresponding to the second to fifth aspects and their possible implementation manners above, reference can be made to the description of the technical effects of the first aspect and its possible implementation manners above, and details are not described herein again. Description of the Drawings

[0055] Figure 1 Is a schematic diagram of a multi-level collision scenario of a spacecraft provided by an embodiment of the present application;

[0056] Figure 2 Is one of the schematic diagrams of a method for controlling a spacecraft to avoid multi-level collisions provided by an embodiment of the present application;

[0057] Figure 3It is a schematic diagram of the reference coordinate system provided by an embodiment of the present application;

[0058] Figure 4 It is the second schematic diagram of a method for controlling a spacecraft to avoid multi - stage collisions provided by an embodiment of the present application;

[0059] Figure 5 It is a schematic diagram of the relationship between the control acceleration and time provided by an embodiment of the present application;

[0060] Figure 6 It is a schematic diagram of the relationship between the distance between a satellite and debris and time provided by an embodiment of the present application;

[0061] Figure 7 It is a schematic structural diagram of a device for controlling a spacecraft to avoid multi - stage collisions provided by an embodiment of the present application. Detailed implementation manners

[0062] In the description of the present invention, terms such as "first" and "second" in the specification and claims are used to distinguish different objects, rather than to describe a specific order of the objects.

[0063] In the embodiments of the present application, "and / or" represents the relationship between objects. For example, A and / or B may represent the following three situations: A exists alone, B exists alone, and both A and B exist simultaneously.

[0064] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific manner.

[0065] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more. For example, a plurality of collision objects means two or more collision objects.

[0066] The methods and devices provided by the embodiments of the present application can be used to control a spacecraft to avoid multi - stage collisions. Specifically, by controlling the acceleration to adjust the operating orbit of the spacecraft (such as a satellite, etc.), collision avoidance control of the spacecraft for multiple collision objects (such as space debris, failed satellites, and other on - orbit targets, etc.) in multi - stage collisions is achieved.

[0067] It can be understood that, referring to Figure 1 , in the embodiments of the present application, multi - stage collision (Multiple Collision) refers to a spacecraft ( Figure 1During the process of a satellite in [[]] operating on a set orbit to perform a space mission, due to the change in the position of the spacecraft, there is a situation where the spacecraft collides with multiple collision objects ( Figure 1 space debris 1 to space debris n in [[]]) because they are too close.

[0068] Exemplarily, a scenario of multi-level collision is: during the process of controlling the spacecraft to avoid a target collision object, the spacecraft collides with other collision objects. It should be noted that the embodiments of the present application mainly describe in detail the method for controlling the spacecraft to avoid multi-level collision with this scenario as an example.

[0069] Based on the description of the background technology, it can be known that the existing methods for controlling a spacecraft to avoid collision can only perform collision avoidance control on the spacecraft for one collision object. Then, during the process of the spacecraft avoiding collision with one collision object, there is a risk that the spacecraft collides with another collision object. To solve this problem, the embodiments of the present application provide a method and device for controlling a spacecraft to avoid multi-level collision. During the process of controlling the spacecraft to avoid a target collision object among multiple collision objects, for each collision object among the multiple collision objects of the spacecraft, each collision object is used as a repulsive force source of the spacecraft. Based on the dynamic mapping matrix of the spacecraft at the collision moment between the spacecraft and each collision object, the repulsive acceleration generated by each collision object on the spacecraft is determined. Then, the sum of the repulsive accelerations of the multiple collision objects is used as the control acceleration for the spacecraft to avoid the target collision object. In this technical solution, applying the above control acceleration to the spacecraft can enable the spacecraft not to collide with other collision objects during the process of avoiding the target collision object, thereby avoiding multi-level collision of the spacecraft and further ensuring the successful completion of the space mission by the spacecraft.

[0070] Exemplarily, the method for controlling a spacecraft to avoid multi-level collision provided by the embodiments of the present invention can be executed by an electronic device with processing functions. For example, the electronic device can be a computer, a server, etc. The electronic device can be an electronic device on the spacecraft or an electronic device capable of communicating with the spacecraft, which is not limited in the embodiments of the present application.

[0071] Taking the electronic device as a computer as an example, the hardware part of the computer can include: a processor, a memory, a network interface, a user interface, a communication bus, etc.

[0072] Among them, the processor is used to control the electronic device to execute relevant processing and calculation tasks. For example, it is used to determine the predicted collision moment, the distance between the spacecraft and the collision object, the dynamic mapping matrix, the repulsive acceleration, and the control acceleration, etc. The processor can include a central processing unit (CPU) or other processors. The processor can be single-core or multi-core. For example, the processor can include multiple CPUs.

[0073] The memory is used to store computer instructions and related data. For example, it is used to store collision warning information, predicted collision time, distance between the spacecraft and the collision object at the predicted collision time, dynamic mapping matrix, repulsive acceleration, and control acceleration, etc. The memory can be a random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or optical memory, magnetic disk storage medium, or any other magnetic storage device, or any other medium capable of storing program code or data that can be accessed by a computer. Optionally, the memory can be integrated within the processor, or the memory can be independent of the processor.

[0074] The network interface is used for the computer to communicate with other devices or communication networks. For example, warning information sent by a ground measurement and control station can be obtained through the network interface. The network interface can be a transceiver with sending and receiving functions. Optionally, the network interface can include standard wired interfaces, wireless interfaces (such as WI-FI interfaces, Bluetooth interfaces, 5G interfaces).

[0075] The communication bus is used to realize connection and communication between various different components. For example, the above-mentioned processor, memory, network interface, and user interface can be interconnected through the communication bus.

[0076] The user interface can include a display screen, an input unit (such as a keyboard). Optionally, the user interface can also include standard wired interfaces, wireless interfaces.

[0077] Those skilled in the art can understand that the above computer may also include more or fewer components, or combine certain components, or have different component arrangements, and the embodiments of the present application do not limit this.

[0078] Combined with the above content, an embodiment of the present application provides a method for controlling a spacecraft to avoid multi-level collisions, and this method can be used to avoid multi-level collisions during the process of the spacecraft avoiding a target collision object. As Figure 2 shown, this method includes S101 - S104.

[0079] S101. During the process of controlling the spacecraft to avoid a target collision object among multiple collision objects, for each collision object among the multiple collision objects of the spacecraft, determine the predicted collision time between the spacecraft and the collision object, and the distance between the spacecraft and the collision object at the predicted collision time.

[0080] The above-mentioned multiple collision objects refer to multiple collision objects that the spacecraft may collide with during the execution of space missions on the set operating orbit in a future period of time (i.e., multiple collision objects in multi-stage collisions).

[0081] Optionally, the spacecraft receives early warning information sent by the ground TT&C station through a transmission link, and solves the predicted collision time between the spacecraft and each collision object among the multiple collision objects, as well as the distance between the spacecraft and the collision object at the predicted collision time, based on the early warning information.

[0082] The above-mentioned early warning information includes the predicted collision time of the spacecraft with each collision object, the position and velocity of the spacecraft at each predicted collision time, and the position and velocity of the collision object at each predicted collision time.

[0083] It can be understood that the ground TT&C station can generate early warning information based on the spatial target position and velocity prediction obtained from the comprehensive ground TT&C information and satellite GNSS information.

[0084] Taking one collision object as an example, the following details the process of solving the predicted collision time TCA between the spacecraft and the collision object, i as well as the distance d between the spacecraft and the collision object at the predicted collision time i .

[0085] The first step: Construct a reference coordinate system.

[0086] According to the velocity v1 of the spacecraft at the predicted collision time and the velocity v2 of the collision object at the predicted collision time in the above-mentioned early warning information, a three-dimensional reference coordinate system is constructed.

[0087] As Figure 3 shown, the three axes of the above-mentioned three-dimensional reference coordinate system are respectively denoted as the ξ-axis, η-axis, and ζ-axis. Specifically, the position of the collision object is taken as the origin O of the reference coordinate system, the direction of the common perpendicular line of the plane formed by v1 and v2 is taken as the positive direction of the ξ-axis of the reference coordinate system, the direction of v1 - v2 is taken as the positive direction of the η-axis of the reference coordinate system, and the positive direction of the ζ-axis, the positive direction of the ξ-axis, and the positive direction of the η-axis form a right-handed coordinate system. The unit vector u ξ of the ξ-axis, the unit vector u η of the η-axis, and the unit vector of the ζ-axis satisfy the relationship described by the following formula (1): ζ

[0088]

[0089] where ||*|| represents the modulus value of the vector.

[0090] ​Step 2: Based on the reference coordinate system, construct the distance formula between the spacecraft and the collision object.

[0091] Compared with the operating period of the spacecraft on the set operating orbit, the time for the spacecraft to collide with the collision object is very short. Based on this, it can be assumed that within a short period of time, both the spacecraft and the collision object move in a uniform straight line and approach each other and then collide. Based on the above assumption, the distance formula between the spacecraft and the collision object can be constructed through the warning collision time t 0,i in the warning information, the position r1 and velocity v1 of the spacecraft at the warning collision time, and the position r2 and velocity v2 of the collision object at the warning collision time.

[0092] Below, when representing a collision object as the i-th collision object among multiple collision objects, the distance formula between the above-mentioned spacecraft and the i-th collision object is the following formula (2):

[0093] d i (t) = ||r1 - r2 + (t - t 0,i )(v1 - v2)|| Formula (2)

[0094] where, d i (t) represents the distance between the spacecraft and the i-th collision object at the current time t; the position r1 of the spacecraft can be represented by the position coordinates of the spacecraft in three directions in the geocentric inertial coordinate system (the three coordinate axes are the x-axis, y-axis, and z-axis), that is, r1 = (x1, y1, z1), and the position r2 of the collision object can be represented by the position coordinates of the collision object in three directions in the geocentric inertial coordinate system, that is, r2 = (x2, y2, z2). Similarly, the velocity v1 of the spacecraft and the velocity v2 of the collision object can also be represented by the velocities in three directions in the geocentric inertial coordinate system, that is Since the geocentric inertial coordinate system is a common coordinate system in this field, it will not be elaborated here.

[0095] Step 3: According to the distance formula constructed in Step 2, solve the predicted collision time TCA i (TCA i is the time t when the distance d i takes the minimum value), and the distance d i between the spacecraft and the collision object at the predicted collision time.

[0096] Let Δt i = t - t 0,i , and the above formula (2) can be transformed into formula (3):

[0097] d i (Δt i + t) = ||r1 - r2 + Δt i(v1 - v2) || Equation (3)

[0098] Square the above Equation (3) to obtain:

[0099] d i (Δt i + t) 2 = ||r1 - r2 + Δt i (v1 - v2)|| 2 Equation (4)

[0100] Furthermore, substitute r1 = (x1, y1, z1), r2 = (x2, y2, z2), and into Equation (4) to obtain Equation (5):

[0101]

[0102] Perform the following transformations on the above Equation (5) successively according to Equations (6) to (8):

[0103]

[0104] Simplify Equation (8) to obtain:

[0105] d i (Δt i + t) 2 = a i Δt i 2 + b i Δt i + c i Equation (9)

[0106] where

[0107]

[0108] c i = (x1 - x2) 2 + (y1 - y2) 2 + (z1 - z2) 2 .

[0109] Since r1, r2, v1, and v2 are all known quantities obtained from the warning information, then a i , b i and c i are also known quantities.

[0110] In a i , b i and c iWhen the known quantity is given, the distance between the spacecraft and the collision object is minimized when formula (9) takes the minimum value (i.e., the two are most likely to collide). Then, it can be considered that the moment (t) corresponding to the minimum value of formula (9) is the predicted collision moment TCA between the spacecraft and the collision object. i The minimum value of formula (9) is the distance d between the spacecraft and the collision object at the predicted collision moment. i .

[0111] Using the solution method of a quadratic equation of one variable to solve the above formula (9), the predicted collision moment TCA between the spacecraft and the i-th collision object is obtained. i Satisfies the following formula;

[0112]

[0113] The distance d between the spacecraft and the i-th collision object at the predicted collision moment i Satisfies the following formula.

[0114]

[0115] The above process of solving the predicted collision moment between the spacecraft and a collision object and the distance between them at the predicted collision moment is based on the reasonable assumption that both the spacecraft and the collision object move towards each other in a uniform straight line and collide. By squaring both sides of the distance formula shown in formula (2), simplifying, and then solving, the predicted collision moment TCA is obtained. i and the distance d i , compared with the existing method of solving the early warning information by shortening the step size and approaching the collision moment by the dichotomy method to obtain the predicted collision moment TCA i and the distance d i , the calculation process of the method provided by the embodiment of the present application is simpler and more efficient.

[0116] Optionally, after obtaining the predicted collision moment between the spacecraft and each collision object, and the distance between the spacecraft and the corresponding collision object at each predicted collision moment, the motion state of the spacecraft can be adjusted multiple times to control the spacecraft to avoid the target collision object. Specifically, a control acceleration is designed for the spacecraft, and then the control acceleration is applied to adjust the motion state of the spacecraft.

[0117] In the process of avoiding the target collision object, the process of determining the control acceleration of the spacecraft includes the following S102 - S104.

[0118] S102. Determine the dynamic mapping matrix of the spacecraft at the predicted collision time based on the predicted collision time between the spacecraft and the collision object and the distance between the two predicted collision times. This dynamic mapping matrix is used to describe the mapping relationship between the position change of the spacecraft and the control acceleration.

[0119] It can be understood that usually, the operating orbit of the spacecraft is changed by maneuvering the spacecraft to avoid the target collision object. Specifically, a maneuvering control amount is applied to the spacecraft to achieve the maneuvering control of the spacecraft. The maneuvering control amount can be a maneuvering control force or a control acceleration, etc. In the embodiments of the present application, the control acceleration is used as the maneuvering control amount to describe the spacecraft avoiding the target collision object.

[0120] Taking one of the multiple collision objects (denoted as the i-th collision object) as an example, according to the collision avoidance dynamics linear equation proposed by Bombaredelli, the thrust acceleration vector u of the spacecraft (i.e., the control acceleration of the spacecraft) and the position change amount δr of the spacecraft in the reference coordinate system (the coordinate system shown above) Figure 3 can be obtained. i The linear relationship satisfies:

[0121] δr i =R i K i D i uδt=M i uδt Formula (12)

[0122] where δt represents the action time of the thrust acceleration vector u.

[0123] From the above formula (12), the dynamic mapping matrix M of the spacecraft at the predicted collision time can be derived i , M i satisfies:

[0124] M i =R i K i D i Formula (13)

[0125] where, β i represents the angle between ; v1 represents the speed magnitude of the spacecraft at the early warning collision time, k1∈(-1, +1), k2∈(-1, +1); Δθ i represents the true anomaly of the spacecraft relative to the i-th collision object at the current time t, n1 represents the angular velocity of the spacecraft, r1 represents the semi-major axis of the spacecraft's orbit, Δθ i =(TCAi -t) / n1, TCA i For the solution method of, refer to the above formula (10).

[0126] For the above K i There are four cases for the value of

[0127] When u ξ is in the same direction as r1, k1 = -1, k2 = -1;

[0128] When u ξ is in the opposite direction to r1, k1 = 1, k2 = 1.

[0129] S103. Based on the dynamic mapping matrix of the spacecraft at the predicted collision moment, determine the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source.

[0130] In the embodiments of the present application, multiple collision objects of the spacecraft are used as repulsive force sources to construct a repulsive force field of the spacecraft; then, the repulsive acceleration generated by each repulsive force source (i.e., the collision object) in the repulsive force field of the spacecraft on the spacecraft is calculated through the dynamic mapping matrix of the spacecraft at the predicted collision moment. Among them, the repulsive acceleration refers to the change in velocity generated by the spacecraft when the repulsive force exerted by the collision object on the spacecraft acts on the spacecraft.

[0131] It should be understood that determining the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source includes determining the direction and magnitude of the repulsive acceleration.

[0132] Optionally, in combination with Figure 2 , as Figure 4 shown, the above S103 includes S1031 - S1033. Among them, S1031 - S1032 describe the process of determining the direction of the repulsive acceleration, and S1033 describes the process of determining the magnitude of the repulsive acceleration.

[0133] S1031. Based on the prediction of the dynamic mapping matrix, predict the distance between the spacecraft and the collision object at the predicted collision moment when the collision object is a repulsive force source.

[0134] When the collision object is represented as the i-th collision object among multiple collision objects, the distance d im between the spacecraft and the collision object at the predicted collision moment when the i-th collision object is a repulsive force source satisfies the following formula.

[0135]

[0136] Among them, r e,i is the rendezvous position vector between the spacecraft and the i-th collision object; and r e,i = (ξ i , ζi ), ξ i is the projection of the distance between the spacecraft and the collision object at the predicted collision time on the ξ-axis of the reference coordinate system, ζ i is the projection of the distance between the spacecraft and the collision object at the predicted collision time on the ζ-axis of the reference coordinate system. ξ i and ζ i Satisfy:

[0137] ξ i = r rel,i · u ξ , ζ i = r rel,i · u ζ Formula (14)

[0138] Among them, r rel,i represents the position of the spacecraft relative to the collision object at the predicted collision time, r rel,i = r1 - r2 + (TCA i - t i,0 )(v1 - v2), u ζ and u ξ The solution method is shown in the above formula (1), and the solution method of TCA i is shown in the above formula (10).

[0139] S1032. With the maximum distance between the spacecraft and the collision object predicted based on the dynamic mapping matrix as the optimization objective, solve the direction of the repulsive acceleration.

[0140] It should be understood that during the process of controlling the spacecraft to avoid multi-level collisions, when a given velocity pulse amount Δv (Δv = uδt, u is the thrust acceleration vector of the spacecraft) is given, there is an optimal maneuvering direction, so that when the spacecraft is affected by the velocity pulse amount Δv in the optimal maneuvering direction, it can move away from the collision object to the greatest extent. Then, when the direction v opt,i of the repulsive acceleration generated by the collision object on the spacecraft is the same as this optimal maneuvering direction, the repulsive force generated by the collision object on the spacecraft can make the spacecraft move away from the collision object as much as possible, so that the distance between the spacecraft and the collision object at the predicted collision time is the largest.

[0141] According to the above content, optionally, take the square d 2 of the distance between the spacecraft and the collision object as the optimization objective, and solve the direction v opt,i of the repulsive acceleration generated by the collision object on the spacecraft when the distance between the spacecraft and the collision object is the largest.

[0142] In the above case, the optimization objective J satisfies the following formula.

[0143] J = dim 2 = (r e,i + M i Δv) T Q(r e,i + M i Δv) = r e,i T Qr e,i + ΔvA i Δv + 2r e,i T QM i Δv formula (15)

[0144] It can be understood that the above formula (15) is a quadratic programming problem. By solving formula (15) using the optimal gradient solution method of convex optimization, the direction v of the repulsive acceleration can be obtained. opt,i , v opt,i satisfies:

[0145] v opt,i = -(A i - λ opt,i I) + b i formula (16)

[0146] where A i = M i T QM i , M i represents the dynamic mapping matrix of the spacecraft, and M i T is the transpose of M i .

[0147] λ opt,i represents the influence factor of the repulsive force of unit magnitude on the predicted distance. λ opt,i satisfies:

[0148]

[0149] where, (*) T represents the transpose of a vector or matrix, (*)+ represents the pseudo-inverse of a matrix, λ1 represents the first non-zero eigenvalue of A i , and λ2 represents the second non-zero eigenvalue of A i . The eigenvectors s1 corresponding to λ1 and s2 corresponding to λ2 are well-known means in the art and will not be elaborated here.

[0150] I is a 3×3 identity matrix, and (*) + represents the pseudo-inverse of a matrix.

[0151] b i T = r e,i T QM i / Δv, where Δv represents the magnitude of the velocity pulse of the spacecraft (a known quantity).

[0152] S1033. Solve for the magnitude of the repulsive acceleration generated by the collision object on the spacecraft.

[0153] In the embodiments of the present application, according to the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, and the dynamic mapping matrix, the magnitude of the repulsive acceleration generated by the collision object on the spacecraft is solved according to the following formula.

[0154] The magnitude u of the repulsive acceleration generated by the i-th collision object on the spacecraft i satisfies:[[]]END]]

[0155]

[0156] where C r represents the safety redundancy factor of the spacecraft (a known quantity); D threshold represents the distance threshold (a known quantity); t b represents the time threshold (a known quantity); Δt i represents the time difference between the current time t and the predicted collision time TCA i Δt i = TCA i - t.

[0157] d i ' is used to indicate the distance between the spacecraft and the collision object at the predicted collision time. Specifically, d i ' is the projection of the distance between the spacecraft and the collision object at the predicted collision time in the <ξ, ζ> plane (i.e., the collision plane) of the reference coordinate system, and ξ i and ζ i can be calculated by the above formula (15).

[0158] It can be seen from the above formula (17) that in the process of controlling the spacecraft to avoid the target collision object, the repulsive acceleration generated by each collision object on the spacecraft needs to be considered.

[0159] When the projection d i ' of the distance between the spacecraft and the i-th collision object at the predicted collision time in the collision plane is less than the distance threshold D threshold , and, the time difference Δt i between the current time and the predicted collision time is greater than or equal to the time threshold t b at this time, the magnitude u of the repulsive accelerationi Determined by the size of the larger it is, the greater the magnitude u of the repulsive acceleration generated by the collision object on the spacecraft i will be.

[0160] When the projection d of the distance between the spacecraft and the i-th collision object at the predicted collision moment in the collision plane i is less than the distance threshold D threshold , and the time difference Δt between the current moment and the predicted collision moment i is less than the time threshold t b , the magnitude u of the repulsive acceleration i is determined by and the size of (i.e., the size of), the larger it is, the greater the magnitude u of the repulsive acceleration generated by the collision object on the spacecraft i will be.

[0161] When the projection d of the distance between the spacecraft and the i-th collision object at the predicted collision moment i is greater than or equal to the distance threshold D threshold , it indicates that the spacecraft will not collide with the i-th collision object at the predicted collision moment, or when the time difference Δt between the current moment and the predicted collision moment i is less than 0, it indicates that the current moment has exceeded the control time limit for the spacecraft to perform multi-level collision avoidance for the i-th collision object. In these two cases, the i-th collision object does not need to be used as the repulsive force source of the spacecraft, and the i-th collision object does not generate a repulsive acceleration on the spacecraft. At this time, the magnitude of the repulsive acceleration is expressed as 0.

[0162] S104. Use the sum of the repulsive accelerations generated by multiple collision objects on the spacecraft as the control acceleration for the spacecraft to avoid the target collision object.

[0163] The control acceleration u for controlling the spacecraft to avoid the target collision object sat satisfies:

[0164]

[0165] where n represents the number of multiple collision objects.

[0166] In one implementation, after calculating the above control acceleration u sat , apply the above control acceleration u sat to the spacecraft to change the motion state of the spacecraft, so that the position of the spacecraft relative to the collision object changes. Then, according to the action of the control acceleration satUpdate the position change of the spacecraft relative to the collision object, and update the position r of the spacecraft relative to the collision object at the predicted collision time. rel,i , and then, in the next control process, calculate a new repulsive acceleration according to the position r of the collision object. rel,i Calculate a new repulsive acceleration.

[0167] Optionally, the position change δr of the spacecraft relative to the collision object after the above control acceleration satisfies: i Satisfy:

[0168] δr i = M i u sat δt s

[0169] where δt s represents the maneuvering time of the spacecraft (i.e., the time when the control acceleration is applied).

[0170] Then the updated position r of the collision object satisfies: rel,i Satisfy:

[0171] r rel,i = r rel,i '+ δr i

[0172] where r rel,i ' represents the position of the spacecraft relative to the collision object at the predicted collision time before update.

[0173] It can be understood that in the embodiments of the present application, the operating orbit of the spacecraft is gradually adjusted by repeatedly executing the above S102 - S104 to avoid the target collision object.

[0174] In summary, a method for controlling a spacecraft to avoid multi-stage collisions provided by an embodiment of the present application is used to prevent multi-stage collisions from occurring during the process of the spacecraft avoiding a target collision object. During the process of controlling the spacecraft to avoid the target collision object among multiple collision objects, each collision object among the multiple collision objects of the spacecraft is used as a repulsive force source, and according to the dynamic mapping matrix between the spacecraft and each collision object at the predicted collision moment, the repulsive force acceleration generated by each collision object on the spacecraft is calculated, and then the sum of the repulsive force accelerations of the multiple collision objects is used as the control acceleration for the spacecraft to avoid the target collision object. As can be seen from the above content, the embodiment of the present application utilizes the characteristic of mutual repulsion between objects in the repulsive force field, so that when the spacecraft is under the repulsive action (i.e., repulsive force) of multiple collision objects acting as repulsive force sources, the spacecraft does not collide with any of the above multiple collision objects. Therefore, using the sum of the repulsive force accelerations generated by multiple repulsive force sources as the control acceleration of the spacecraft can not only ensure that the spacecraft avoids the target collision object, but also ensure that the spacecraft does not collide with other collision objects, thereby avoiding multi-stage collisions of the spacecraft and further ensuring the successful completion of the space mission by the spacecraft.

[0175] Furthermore, in the embodiment of the present application, multiple collision objects of multi-stage collisions are used as repulsive force sources, and the sum of the repulsive force accelerations generated by the multiple repulsive force sources on the spacecraft is used as the control acceleration of the spacecraft. Since the process of calculating the repulsive force acceleration based on the repulsive force source is relatively simple and the amount of calculation is small, therefore, the control acceleration of the spacecraft can be quickly calculated, and the above calculation process does not require the computing resources of ground equipment, which can improve the efficiency of the spacecraft to avoid multi-stage collisions.

[0176] Next, taking the spacecraft as a satellite and the collision object as space debris as an example, combined with the warning information provided in Table 1 and Table 2, the avoidance effect of the above method will be described.

[0177] The following Table 1 shows the positions and velocities of four space debris (Debris1, Debris2, Debris3, Debris4) at the predicted collision moment, and the duration from the current moment to the predicted collision moment (TCA-t); the following Table 2 shows the positions and velocities of the satellite (corresponding to SatRV1, SatRV2, SatRV3, SatRV4) at four predicted collision moments without avoiding multi-stage collisions, and the duration from the current moment to the predicted collision moment (TCA-t).

[0178] Table 1

[0179]

[0180] Table 2

[0181]

[0182] Based on the above Tables 1 and 2, the satellite is controlled by the method provided in the embodiments of the present application to avoid one of the above four space debris (i.e., the target collision object). During this process, the magnitude of the maneuvering control amount (i.e., the control force) of the satellite is as Figure 5 shown, and the position changes of the satellite and the four space debris are as Figure 6 shown. From Figure 6 it can be seen that during the process of controlling the satellite to avoid the above target collision object based on the method provided in the embodiments of the present application, the distances between the satellite and the four space debris are all greater than 500 m. It can be seen that through the above method, not only can the satellite be controlled to avoid the above target collision object, but also the satellite can be controlled not to collide with the other three space debris, thereby effectively eliminating the multi-stage collision risk of the spacecraft, so that the spacecraft does not have a multi-stage collision during the process of avoiding the target collision object.

[0183] Correspondingly, the embodiments of the present application provide a device for controlling a spacecraft to avoid multi-stage collisions. The above device is used to avoid multi-stage collisions during the process of the spacecraft avoiding a target collision object, as Figure 7 shown. The above device includes a collision time and distance determination module 701, a mapping matrix determination module 702, an acceleration determination module 703, and a control amount determination module 704.

[0184] Among them, the collision time and distance determination module 701 is used to determine, for each of the multiple collision objects during the process of controlling the spacecraft to avoid the target collision object among the multiple collision objects, the predicted collision time between the spacecraft and the collision object, and the distance between the spacecraft and the collision object at the predicted collision time. For example, the collision time and distance determination module 701 is used to implement S101 of the above method for avoiding multi-stage collisions of the spacecraft.

[0185] The mapping matrix determination module 702 is used to determine the dynamic mapping matrix of the spacecraft at the predicted collision time according to the predicted collision time and the distance; the dynamic mapping matrix is used to describe the mapping relationship between the position change amount of the spacecraft and the control acceleration. For example, the mapping matrix determination module 702 is used to implement S102 of the above method for avoiding multi-stage collisions of the spacecraft.

[0186] The acceleration determination module 703 is used to determine the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source based on the dynamic mapping matrix of the spacecraft at the predicted collision time. For example, the acceleration determination module 703 is used to implement S103 of the above method for avoiding multi-stage collisions of the spacecraft.

[0187] The control quantity determination module 704 is configured to use the sum of the repulsive acceleration generated by multiple collision objects on the spacecraft as the control acceleration for the spacecraft to avoid the target collision object. For example, the control quantity determination module 704 is configured to implement S104 of the above-mentioned avoidance control method for multi-stage collisions of the spacecraft.

[0188] Optionally, the acceleration determination module 703 is specifically configured to: based on the prediction of the dynamic mapping matrix, predict the distance between the spacecraft and the collision object at the collision moment when the collision object is a repulsive force source;

[0189] Taking the maximum distance between the predicted spacecraft and the collision object at the predicted collision moment as the optimization goal, solve the direction of the repulsive acceleration;

[0190] Where, when the collision object is represented as the i-th collision object among multiple collision objects, the direction v of the repulsive acceleration generated by the i-th collision object on the spacecraft opt,i Satisfies:

[0191] v opt,i = -(A i - λ opt,i I) + b i

[0192] A i = M i T QM i , M i represents the dynamic mapping matrix of the spacecraft at the predicted collision moment, M i T is the transpose of M i ,

[0193] λ opt,i represents the influence factor of the repulsive force of unit magnitude on the predicted distance, λ opt,i Satisfies:

[0194]

[0195] Where, (*) T represents the transpose of a vector or matrix, (*) + represents the pseudo-inverse of a matrix, λ1 represents the first non-zero eigenvalue of A i and λ2 represents the second non-zero eigenvalue of A i , s1 represents the eigenvector corresponding to λ1, and s2 represents the eigenvector corresponding to λ2;

[0196] I is a 3×3 identity matrix;

[0197] b i = (r e,iT QM i / Δv) -T ,r e,i represents the rendezvous position vector between the spacecraft and the i-th collision object, and Δv represents the change in the velocity of the spacecraft;

[0198] According to the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, and the dynamic mapping matrix, the magnitude of the repulsive acceleration generated by the collision object on the spacecraft is solved according to the following formula:

[0199] The magnitude u of the repulsive acceleration generated by the i-th collision object on the spacecraft i satisfies:

[0200]

[0201] where C r represents the safety redundancy factor of the spacecraft; D threshold represents the distance threshold; d i ' is used to indicate the distance between the spacecraft and the collision object at the predicted collision time; Δt i represents the time difference between the current time t and the predicted collision time TCA i ; t b represents the time threshold. For example, the acceleration determination module 703 is specifically used to implement S1031 - S1033 of the above-mentioned multi-level collision avoidance control method for spacecraft.

[0202] In one implementation, the above device further includes an update module 705.

[0203] The update module 705 is used to, for example, for each collision object among the multiple collision objects of the spacecraft, update the position of the spacecraft relative to the collision object at the predicted collision time according to the change in the position of the spacecraft relative to the collision object after the action of the control acceleration. The update module 705 is specifically used to implement S105 of the above-mentioned multi-level collision avoidance control method for spacecraft.

[0204] Each module of the above device for controlling the spacecraft to avoid multi-level collisions can also be used to execute other steps in the above method embodiments. All relevant contents involved in the above method embodiments can be cited in the function descriptions of the corresponding functional modules, and will not be elaborated here.

[0205] An embodiment of the present application further provides an electronic device, including: a processor and a memory coupled to the processor; the memory is used to store computer instructions, and when the electronic device runs, the processor executes the computer instructions stored in the memory so that the electronic device executes the method in the above embodiment. Among them, the processor can implement the above-mentioned collision time and distance determination module 701, mapping matrix determination module 702, acceleration determination module 703, control quantity determination module 704, and update module 705; the above-mentioned memory can also be used to store the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, the repulsive acceleration, and the control acceleration, etc.

[0206] An embodiment of the present application further provides a computer-readable storage medium, which includes a computer program. When the computer program runs on a computer, it executes the method described in the above embodiment.

[0207] An embodiment of the present application further provides a computer program product, which includes computer program instructions. When the computer program instructions run on a computer, they execute the method described in the above embodiment.

[0208] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0209] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for controlling a spacecraft to avoid multi-level collisions, characterized in that: The method is used to avoid multiple collisions during the process of the spacecraft avoiding a target collision object, and the method comprises: In a process of controlling the spacecraft to avoid a target collision object among a plurality of collision objects, for each of the plurality of collision objects, determining a predicted collision moment between the spacecraft and the collision object, and a distance between the spacecraft and the collision object at the predicted collision moment; Determine a dynamic mapping matrix of the spacecraft at the predicted collision moment according to the predicted collision moment and the distance; the dynamic mapping matrix is ​​used to describe a mapping relationship between a position change of the spacecraft and the control acceleration; Based on the dynamic mapping matrix of the spacecraft at the predicted collision moment, determining the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source; The sum of the repulsive accelerations generated by the multiple collision objects on the spacecraft is used as the control acceleration for the spacecraft to avoid the target collision object.

2. The method according to claim 1, characterized in that The determining, based on the dynamic mapping matrix of the spacecraft at the predicted collision moment, the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source, comprises: The distance between the spacecraft and the collision object at the predicted collision moment when the collision object is a repulsive force source is predicted based on the dynamic mapping matrix; Taking the maximum distance between the spacecraft and the collision object at the predicted collision moment as an optimization goal, solving the direction of the repulsive acceleration; Wherein, when the collision object is represented as the i-th collision object among the multiple collision objects, the direction v of the repulsive acceleration generated by the i-th collision object on the spacecraft is opt,i satisfy: v opt,i =-(A i -λ opt,i I) + b i A i =M i T QM i , M i represents the dynamic mapping matrix of the spacecraft at the predicted collision moment, M i T M i The transpose of λ opt,i represents the influence factor of the unit repulsion on the predicted distance, λ opt,i satisfy: in,(*) T represents the transpose of a vector or matrix, (*)+ represents the pseudo-inverse of a matrix, and λ1 represents A i The first non-zero eigenvalue of , λ2 represents A i The second non-zero eigenvalue of , s1 represents the eigenvector corresponding to λ1, and s2 represents the eigenvector corresponding to λ2; I is a 3×3 identity matrix; b i =(r e,i T QM i / Δv) -T , r e,i represents the intersection position vector between the spacecraft and the i-th collision object, Δv represents the velocity change of the spacecraft; According to the predicted collision time, the distance between the spacecraft and the collision object at the predicted collision time, and the dynamic mapping matrix, the magnitude of the repulsive acceleration generated by the collision object on the spacecraft is solved according to the following formula: The magnitude u of the repulsive acceleration generated by the i-th collision object on the spacecraft i satisfy: Among them, C r represents the safety redundancy factor of the spacecraft; D threshold Indicates the distance threshold; d i 'Used to indicate the distance between the spacecraft and the collision object at the predicted collision time; Δt i Represents the current time t and the predicted collision time TCA i The time difference; t b Indicates the time threshold.

3. The method according to claim 2, characterized in that The predicted collision time TCA i satisfy: Among them, t 0,i represents the warning collision time between the spacecraft and the i-th collision object; represents the speed of the spacecraft at the time of the warning collision, represents the speed of the i-th collision object at the warning collision moment; (x1, y1, z1) represents the position of the spacecraft at the warning collision moment, and (x2, y2, z2) represents the position of the i-th collision object at the warning collision moment.

4. The method according to claim 3, characterized in that The distance d between the spacecraft and the i-th collision object at the predicted collision time i satisfy: Among them, c i =(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2 .

5. The method according to claim 3, characterized in that For the ith collision object among the plurality of collision objects, the dynamic mapping matrix M of the spacecraft at the predicted collision time i satisfy: M i =R i K i D i in, β i express and The angle between v1 represents the velocity of the spacecraft at the time of the warning collision, k1∈(-1, +1), k2∈(-1, +1); Δθ i represents the anomaly angle of the spacecraft relative to the i-th collision object at the current time t, n1 represents the angular velocity of the spacecraft, and r1 represents the semi-major axis of the orbit of the spacecraft.

6. A device for controlling a spacecraft to avoid multi-level collisions, characterized in that: The device is used to avoid multi-level collisions when the spacecraft avoids a target collision object, and the device includes a collision time and distance determination module, a mapping matrix determination module, an acceleration determination module, and a control amount determination module; The collision time and distance determination module is used to determine, for each of the multiple collision objects, a predicted collision time between the spacecraft and the collision object and a distance between the spacecraft and the collision object at the predicted collision time in a process of controlling the spacecraft to avoid a target collision object among the multiple collision objects; The mapping matrix determination module is used to determine the dynamic mapping matrix of the spacecraft at the predicted collision moment according to the predicted collision moment and the distance; the dynamic mapping matrix is ​​used to describe the mapping relationship between the position change of the spacecraft and the control acceleration; The acceleration determination module is used to determine the repulsive acceleration generated by the collision object on the spacecraft when the collision object is a repulsive force source based on the dynamic mapping matrix of the spacecraft at the predicted collision moment; The control amount determination module is used to use the sum of the repulsive accelerations generated by the multiple collision objects on the spacecraft as the control acceleration for the spacecraft to avoid the target collision object.

7. An electronic device, characterized in that: It comprises a processor and a memory coupled to the processor; the memory is used to store computer instructions, and when the electronic device is running, the processor executes the computer instructions stored in the memory, so that the electronic device executes the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: The method comprises computer program instructions, which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 5.

9. A computer program product, characterized in that The method comprises computer program instructions, and when the computer program instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 5.

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