Space debris environment quantification method based on risk entropy

Abstract

The invention relates to the technical field of aerospace, in particular to a space debris environment quantification method based on risk entropy, and the method comprises the steps: S1, discretizing an evaluation time range into a plurality of time periods, and recording the duration of each time period as delta t; any time period tj can be expressed as tj belongs to [(j-1) * delta t, j * delta t]; j < = N, where N represents the total number of time periods; simulation is carried out, and it is assumed that N + 1 possibilities exist in the in-orbit collision disintegration condition of the space object objk; specifically, if N time periods exist, there is N possibilities for the space object to collide and disintegrate; if the space object is still not disassembled at the end of simulation, judging that N + 1 possibilities exist in collision and disassembly of the space object; s2, calculating a collision probability in a time period; and S3, calculating a risk entropy according to the collision probability, and judging the influence of the space object on the space debris environment according to the risk entropy. The space debris environment quantification method based on the risk entropy can be used for quantification of uncertainty of the space debris environment.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to a space debris environment quantification method based on risk entropy. Background Art

[0002] With the development of human space activities, the amount of space debris is growing rapidly. The prediction of the evolution trend of the space debris environment is an important theoretical reference for the evaluation and optimization of space activities, and is also a theoretical support for space debris mitigation measures. Due to the large uncertainty in the time of future space collisions, the evolution of the space debris environment is also inevitably uncertain.

[0003] The existing technology is based on numerical methods, conducts multiple parallel numerical simulations, takes the average of the simulation results, and uses the average as the prediction result of the future evolution trend of the space debris environment. The main problem with this algorithm is that it cannot quantify the uncertainty of the prediction algorithm, and the results obtained are greatly affected by the randomness of the algorithm. Summary of the invention

[0004] Aiming at the problem that existing numerical algorithms are difficult to quantify the uncertainty of future space debris environment, the present invention proposes a risk-based quantitative assessment method for the stability of space debris environment.

[0005] The technical solution proposed by the present invention is: a method for quantifying space debris environment based on risk entropy, the method comprising:

[0006] S1. Discretize the evaluation time range into multiple time periods;

[0007] S2, calculate the collision probability within the time period;

[0008] S3. Calculate the risk entropy based on the collision probability, and determine the impact of the space object on the space debris environment based on the risk entropy.

[0009] Preferably, the S1 comprises the following steps:

[0010] The duration of each time period is recorded as Δt;

[0011] For any time period t j It can be expressed as t j ∈[(j-1)·Δt,j·Δt]; j≤N, where N represents the total number of time periods;

[0012] Perform simulation and set the space object obj k There are N+1 possible scenarios for the on-orbit collision and disintegration of the satellite; specifically:

[0013] If there are N time periods, then there are N possibilities for a space object to disintegrate in a collision;

[0014] If the space object has not disintegrated at the end of the simulation, it is determined that there are N+1 possibilities for the space object to collide and disintegrate.

[0015] Preferably, S2 comprises the following steps:

[0016] Calculate the density of a spatial unit;

[0017] Set the speed of the space object within the space unit;

[0018] Obtaining a total collision probability of the space object within the space unit;

[0019] Get the collision probability of space objects in all space units.

[0020] Preferably, S3 comprises the following steps:

[0021] Calculate and obtain the space object obj k In t j The probability of a collision within:

[0022]

[0023] Calculate the probability of a space object disintegrating due to collision:

[0024]

[0025] Calculate the risk entropy of space objects:

[0026]

[0027] The size of risk entropy is used as a quantitative indicator to measure the impact of space objects on the space debris environment.

[0028] Preferably, the calculating spatial density comprises the following steps:

[0029] Get j The volume of space unit i during the time period is V i , the orbital period of the space object T k and the residence time ΔT(i,k) in spatial unit i within a single cycle;

[0030] Bring in Get the spatial density.

[0031] Preferably, the setting of the speed of the space object in the space includes:

[0032] Assume that the speed of the space object in the space unit is

[0033] Among them, v x (i,k),vy (i,k),v z (i, k) represent the velocity of the space object k in the X-axis direction, the Y-axis direction and the Z-axis direction in the space unit i respectively.

[0034] Preferably, the obtaining of the total collision probability of the space object in the space unit includes:

[0035] The spatial density of space object k and space object k+1 in space unit i is obtained, that is:

[0036] ρ tj (i,k) and ρ tj (i,k2);

[0037] Get the speed of space object k and space object k+1 in space unit i, that is:

[0038] and

[0039] The total collision probability is then:

[0040] in,

[0041] σ=π(r k +r k2 ) 2 ;

[0042] Note the time period t j The total number of space objects in orbit is N obj , then time period t j Internal, spatial target obj k The total collision probability within spatial unit i is:

[0043]

[0044] Preferably, obtaining the collision probability of the space object in all space units includes:

[0045] The total number of Earth orbit space units is Ncell;

[0046] Then the spatial target obj k The collision probability in all spatial units is:

[0047]

[0048] Beneficial effects of the present invention:

[0049] 1. The present invention, the space debris environment quantification method based on risk entropy, can be used to quantify the uncertainty of the space debris environment. In addition to the overall phenomenon, it can provide in-depth analysis from the characteristics of a single debris. It can be used to evaluate the short-term or long-term impact caused by a large constellation system or only a specific space object. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flow chart of a method for quantifying space debris environment based on risk entropy. DETAILED DESCRIPTION

[0051] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0052] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0053] refer to Figure 1 The present invention provides a technical solution: a space debris environment quantification method based on risk entropy, comprising:

[0054] S1. First, the simulation time is discretized; specifically:

[0055] The duration of each time period is recorded as Δt;

[0056] For any time period t j It can be expressed as t j ∈[(j-1)·Δt,j·Δt]; j≤N, where N represents the total number of time periods;

[0057] Perform simulation and set the space object obj k There are N+1 possible scenarios for the on-orbit collision and disintegration of the satellite; specifically:

[0058] If there are N time periods, then there are N possibilities for a space object to disintegrate in a collision;

[0059] If the space object has not disintegrated at the end of the simulation, it is determined that there are N+1 possibilities for the space object to collide and disintegrate.

[0060] S2. Calculate the collision probability within the time period; specifically:

[0061] Calculate the density of a spatial unit;

[0062] Set the speed of the space object within the space unit;

[0063] Obtaining a total collision probability of the space object within the space unit;

[0064] Get the collision probability of space objects in all space units.

[0065] S3. Calculate the risk entropy based on the collision probability, and judge the impact of the space object on the space debris environment based on the risk entropy, specifically:

[0066] Calculate and obtain the space object obj k In t j The probability of a collision within:

[0067]

[0068] Calculate the probability of a space object disintegrating due to collision:

[0069]

[0070] Calculate the risk entropy of space objects:

[0071]

[0072] The size of risk entropy is used as a quantitative indicator to measure the impact of space objects on the space debris environment.

[0073] The calculation of spatial density comprises the following steps: obtaining t j The volume of space unit i during the time period is V i , the orbital period of the space object T k and the residence time ΔT(i,k) in spatial unit i within a single cycle;

[0074] Bring in Get the spatial density.

[0075] The step of setting the speed of the space object in the space comprises:

[0076] Assume that the speed of the space object in the space unit is

[0077] Among them, v x (i,k),v y (i,k),v z (i, k) represent the velocity of the space object k in the X-axis direction, the Y-axis direction and the Z-axis direction in the space unit i respectively.

[0078] The obtaining of the total collision probability of the space object in the space unit comprises:

[0079] The spatial density of space object k and space object k+1 in space unit i is obtained, that is:

[0080] ρ tj (i,k) and ρ tj (i,k2);

[0081] Get the speed of space object k and space object k+1 in space unit i, that is:

[0082] and

[0083] The total collision probability is:

[0084] in,

[0085] σ=π(r k +r k2 ) 2 ;

[0086] Note the time period t j The total number of space objects in orbit is N obj , then time period t j Internal, spatial target obj k The total collision probability within spatial unit i is:

[0087]

[0088] The obtaining of the collision probability of the space object in all space units includes:

[0089] The total number of Earth orbit space units is Ncell;

[0090] Then the spatial target obj k The collision probability in all spatial units is:

[0091]

[0092] Taking the 2023 TLE data publicly released by the US Space Surveillance Network as the data source, the risk entropy of the CZ-4C rocket body in the next five years is calculated.

[0093] The total collision probability of the CZ-4C rocket body year by year is:

[0094] years Total collision probability 2024 <![CDATA[6.276×10 -5 ]]> 2025 <![CDATA[5.8743×10 -5 ]]> 2026 <![CDATA[5.4410×10 -5 ]]> 2027 <![CDATA[5.2101×10 -5 ]]> 2028 <![CDATA[5.0963×10 -5 ]]>

[0095] The annual risk entropy of this target is:

[0096] years Risk Entropy 2024 <![CDATA[2.63×10 -4 ]]> 2025 <![CDATA[2.49×10 -4 ]]> 2026 <![CDATA[2.32×10 -4 ]]> 2027 <![CDATA[2.23×10 -4 ]]> 2028 <![CDATA[2.19×10 -4 ]]>

[0097] It can be seen that the risk entropy of this target decreases year by year, and its impact on the space debris environment also decreases year by year.

[0098] The embodiments disclosed by the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the module, program segment, or a part of a code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of the boxes in the block diagram and / or the flowchart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0099] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the principles, the implementation methods of the present invention may be deformed or modified in any way.

Claims

1. A space debris environment quantification method based on risk entropy, characterized in that: include: S1. Discretize the evaluation time range into multiple time periods; S2, calculate the collision probability within the time period; S3. Calculate the risk entropy based on the collision probability, and determine the impact of the space object on the space debris environment based on the risk entropy.

2. The method for quantifying space debris environment based on risk entropy according to claim 1, characterized in that: The S1 comprises the following steps: The duration of each time period is recorded as Δt; For any time period t j It can be expressed as t j ∈[(j-1)·Δt,j·Δt]; j≤N, where N represents the total number of time periods; Perform simulation and set the space object obj k There are N+1 possible scenarios for the on-orbit collision and disintegration of the satellite; specifically: If there are N time periods, then there are N possibilities for a space object to disintegrate in a collision; If the space object has not disintegrated at the end of the simulation, it is determined that there are N+1 possibilities for the space object to collide and disintegrate.

3. The method for quantifying space debris environment based on risk entropy according to claim 2, characterized in that: The S2 comprises the following steps: Calculate the density of a spatial unit; Set the speed of the space object within the space unit; Obtaining a total collision probability of the space object within the space unit; Get the collision probability of space objects in all space units.

4. The method for quantifying space debris environment based on risk entropy according to claim 3 is characterized in that: The S3 comprises the following steps: Calculate and obtain the space object obj k In t j The probability of a collision within: Calculate the probability of a space object disintegrating due to collision: Calculate the risk entropy of space objects: The size of risk entropy is used as a quantitative indicator to measure the impact of space objects on the space debris environment.

5. The method for quantifying space debris environment based on risk entropy according to claim 4, characterized in that: The calculation of spatial density comprises the following steps: Get j The volume of space unit i during the time period is V i , the orbital period of the space object T k and the residence time ΔT(i,k) in spatial unit i within a single cycle; Bring in Get the spatial density.

6. The method for quantifying space debris environment based on risk entropy according to claim 5, characterized in that: The step of setting the speed of the space object in the space comprises: Assume that the speed of the space object in the space unit is Among them, v x (i,k),v y (i,k),v z (i, k) represent the velocity of the space object k in the X-axis direction, the Y-axis direction and the Z-axis direction in the space unit i respectively.

7. The method for quantifying space debris environment based on risk entropy according to claim 6, characterized in that: The obtaining of the total collision probability of the space object in the space unit comprises: The spatial density of space object k and space object k+1 in space unit i is obtained, that is: ρ tj (i, k) and ρ tj (i, k2); Get the speed of space object k and space object k+1 in space unit i, that is: The total collision probability is then: in, σ=π(r k +r k2 ) 2 ; Note the time period t j The total number of space objects in orbit is N obj , then time period t j Internal, space target obj k The total collision probability within spatial unit i is:

8. The method for quantifying space debris environment based on risk entropy according to claim 7, characterized in that: The obtaining of the collision probability of the space object in all space units includes: The total number of Earth orbit space units is Ncell; Then the spatial target obj k The collision probability in all spatial units is:

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