Constellation economic availability evaluation method and device

Abstract

The invention discloses a constellation economic availability evaluation method and device. The method comprises the following steps: acquiring a preset satellite set; the preset satellite set comprises N satellites and SP standby satellites; processing the preset satellite set to obtain a constellation complementary network model; and processing the constellation complementary network model to obtain the constellation state transition probability. According to the method, the two-dimensional Markov chain model is embedded into the global optimization model, and the probability that a given number of satellites have faults is determined, so that a constellation availability evaluation result is obtained, and the life cycle cost of a satellite system is reduced to the maximum extent from the perspective of global optimization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of availability evaluation, in particular to a constellation economic availability evaluation method and device. BACKGROUND

[0002] In recent years, with the continuous expansion of satellite application fields, many tasks have been unable to be completed by relying on a single satellite. Compared with a single satellite, the coverage of a satellite constellation is significantly increased. Coverage refers to whether there is a clear line of sight between the satellite and the user being served. The coverage range will be affected when a satellite fails, and in order to maintain the coverage range when a failure occurs, a backup satellite is usually used.

[0003] It is becoming more and more frequent to provide communication, navigation, environmental monitoring and other civilian and military services by deploying a satellite constellation (a group of satellites that collectively provide services). Under the pressure of low cost sustainability, it is increasingly urgent for constellation design and operation management agencies to provide corresponding services at the lowest possible cost. As pointed out in early literature, the planning, design, deployment and operation of many constellation systems rarely consider economic issues. Usually, when considering costs, only the acquisition cost is focused on, which is only a small part of the total life cycle cost. Therefore, it is crucial to consider the use and maintenance costs and performance models comprehensively in the system life cycle phase. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a constellation economic availability evaluation method and device, which maximally reduces the life cycle cost of a satellite system from the perspective of global optimization, including satellite replacement cost, launch cost, satellite on-orbit cost, launch vehicle cost and operation cost, and establishes a close correspondence with the performance model that determines service availability. The further goal is to identify the best optimization method and determine how much cost can be saved compared with the current practice.

[0005] To solve the above technical problems, a first aspect of an embodiment of the present application discloses a constellation economic availability evaluation method, which comprises:

[0006] S1, acquiring a preset satellite set; the preset satellite set comprises N satellites, S P backup satellites;

[0007] S2, processing the preset satellite set to obtain a constellation network supplement model;

[0008] S3, processing the constellation network supplement model to obtain a constellation state transition probability.

[0009] As an optional implementation, in the first aspect of the embodiment of the present application, the constellation network supplement model comprises a state space a finite Markov chain {Y t : t∈Γ n} on a finite index set Γ n ={0, 1, …, n}, where S t is the total number of states in the state space, n is an arbitrary given positive integer, Y t =(u, v) represents that u running satellites in the constellation are failed and v standby satellites in the constellation are in the used state at the t time, and the horizontal axis of the constellation network supplement model represents the number of failed satellites, and the vertical axis represents the number of used standby satellites.

[0010] As an optional implementation, in the first aspect of the embodiment of the present application, the constellation network supplement model is processed to obtain constellation state transition probability, and the processing includes:

[0011] S31, the constellation network supplement model is initialized to obtain initialization parameters;

[0012] S32, the initialization parameters are processed to obtain constellation state transition probability.

[0013] As an optional implementation, in the first aspect of the embodiment of the present application, the constellation network supplement model is initialized to obtain initialization parameters, and the initialization includes:

[0014] S311, the constellation network supplement model is initialized to obtain constraint parameter information; the constraint parameter information expression is:

[0015] 0≤u≤N, 0≤v≤S p

[0016] Wherein, u is the number of running failed satellites in the constellation, N is the number of satellites in the constellation, v is the number of standby satellites entering the used state, and S P is the number of standby satellites;

[0017] S312, the number of satellites in the constellation and the number of standby satellites are processed to obtain the total number of states in the state space;

[0018] The total number of states expression is:

[0019] S t =(N+1)(S p +1)

[0020] Wherein, S t is the total number of states;

[0021] S313, the constraint parameter information and the total number of states are integrated to obtain initialization parameters.

[0022] As an optional implementation, in the first aspect of the present invention, processing the initialization parameters to obtain the constellation state transition probability includes:

[0023] S321, When the operating satellite enters a fault state, the initialization parameters are processed to obtain the first transfer probability information;

[0024] S322, When the backup satellite enters a fault state, the initialization parameters are processed to obtain the second transfer probability information;

[0025] S323, When using an on-orbit backup satellite to replace a faulty satellite, the initialization parameters are processed to obtain third transfer probability information;

[0026] S324, When replacing a faulty satellite by launching a ground backup satellite, the initialization parameters are processed to obtain the fourth transfer probability information;

[0027] S325, integrate the first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information to obtain the constellation state transition probability.

[0028] As an optional implementation, in the first aspect of the present invention, the expression for the first transition probability information is:

[0029] P[Y t =(u+1,v)|Y t-1 =(u,v)]=μ

[0030] Where u < N, the first transition probability information P[Y] t =(u+1,v)|Y t-1 =(u,v)] is to make the constellation change from state Y t-1 = (u,v) transitions to state Y t = (u+1,v), where μ is the probability of satellite failure;

[0031] The expression for the second transition probability information is:

[0032] P[Y t =(u,v+1)|Y t-1 =(u,v)]=μ

[0033] Where, v < S p The second transition probability information is to make the constellation transition from state Y. t-1 = (u,v) transitions to state Y t The probability of (u, v+1).

[0034] As an optional implementation, in the first aspect of the embodiment of the present application, the expression of the third transition probability information is:

[0035] P[Y t =(u,v+1)|Y t-1 =(u,v)]=λ r η t

[0036] wherein u>0 and v p t-1 The third transition probability information is the probability of transition from state Y t =(u,v) to state Y t =(u-1,v+1).

[0037] The expression of the fourth transition probability information is:

[0038] P[Y t =(u-1,v)|Y t-1 =(u,v)]=P S P LV P SV λ l

[0039] wherein u>0, the fourth transition probability information is the probability of transition from state Y t-1 =(u,v) to state Y t =(u-1,v).

[0040] The second aspect of the embodiment of the present application discloses a constellation economic usability evaluation device, which comprises:

[0041] a satellite set acquisition module, which acquires a preset satellite set; the preset satellite set comprises N satellites and S P backup satellites;

[0042] a constellation network supplement model construction module, which is used for processing the preset satellite set to obtain a constellation network supplement model;

[0043] a constellation state transition probability calculation module, which is used for processing the constellation network supplement model to obtain a constellation state transition probability.

[0044] As an optional implementation, in the second aspect of the embodiment of the present application, the constellation network supplement model comprises a finite Markov chain {Y t :t∈Γ n} on a state space n wherein Γ t ={0,1,…,n} is a finite index set, S t is the total number of states in the state space, and n is an arbitrary given positive integer, Yt = (u,v) indicates that at time t, u operational satellites in the constellation fail and v backup satellites enter the used state. The horizontal axis of the constellation network model represents the number of failed satellites, and the vertical axis represents the number of backup satellites in use.

[0045] As an optional implementation, in the second aspect of the present invention, processing the constellation network model to obtain the constellation state transition probabilities includes:

[0046] S31, Initialize the constellation mesh model to obtain initialization parameters;

[0047] S32, process the initialization parameters to obtain the constellation state transition probability.

[0048] As an optional implementation, in the second aspect of the present invention, the constellation mesh model is initialized to obtain initialization parameters, including the envelope:

[0049] S311, Initialize the constellation mesh model to obtain constraint parameter information; the expression for the constraint parameter information is:

[0050] 0≤u≤N, 0≤v≤S p

[0051] Where u is the number of operationally faulty satellites in the constellation, N is the total number of satellites in the constellation, v is the number of spare satellites that have entered the usage state, and S P Number of backup satellites;

[0052] S312, Process the number of satellites in the constellation and the number of spare satellites to obtain the total number of states in the state space;

[0053] The total number of states is expressed as follows:

[0054] S t =(N+1)(S p +1)

[0055] Among them, S t The total number of states;

[0056] S313, integrate the constraint parameter information and the total number of states to obtain the initialization parameters.

[0057] As an optional implementation, in a second aspect of the present invention, processing the initialization parameters to obtain the constellation state transition probability includes:

[0058] S321, When the operating satellite enters a fault state, the initialization parameters are processed to obtain the first transfer probability information;

[0059] S322, when the standby satellite enters a failure state, processing the initialization parameter to obtain second transition probability information;

[0060] S323, when replacing the failed satellite with an on-orbit standby satellite, processing the initialization parameter to obtain third transition probability information;

[0061] S324, when replacing the failed satellite with a launched ground backup satellite, processing the initialization parameter to obtain fourth transition probability information;

[0062] S325, integrating the first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information to obtain constellation state transition probability.

[0063] As an optional implementation, in the second aspect of the embodiment of the application, the expression of the first transition probability information is:

[0064] P[Y t =(u+1,v)|Y t-1 =(u,v)]=μ

[0065] wherein, u t =(u+1,v)|Y t-1 =(u,v)] is the probability of the constellation transferring from state Y t-1 =(u,v) to state Y t =(u+1,v), and μ is the satellite failure probability.

[0066] The expression of the second transition probability information is:

[0067] P[Y t =(u,v+1)|Y t-1 =(u,v)]=μ

[0068] wherein, v p =(u,v+1)|Y t-1 =(u,v) is the probability of the constellation transferring from state Y t =(u,v) to state Y

[0069] As an optional implementation, in the second aspect of the embodiment of the application, the expression of the third transition probability information is:

[0070] P[Y t =(u-1,v+1)|Y t-1 =(u,v)]=λ r η t

[0071] wherein u>0 and v p The third transition probability information is a probability of transitioning from a constellation state Y t-1 =(u,v) to a constellation state Y t =(u-1,v+1).

[0072] The expression of the fourth transition probability information is:

[0073] P[Y t =(u-1,v)|Y t-1 =(u,v)]=P S P LV P SV λ l

[0074] wherein u>0, the fourth transition probability information is a probability of transitioning from a constellation state Y t-1 =(u,v) to a constellation state Y t =(u-1,v).

[0075] The third aspect of the present application discloses another constellation economic usability evaluation device, which comprises:

[0076] a memory storing executable program codes;

[0077] a processor coupled with the memory;

[0078] The processor invokes the executable program codes stored in the memory to execute part or all steps of the constellation economic usability evaluation method disclosed in the first aspect of the present application.

[0079] The fourth aspect of the present application discloses a computer storage medium storing computer instructions, which are invoked to execute part or all steps of the constellation economic usability evaluation method disclosed in the first aspect of the present application.

[0080] Compared with the prior art, the present application has the following beneficial effects:

[0081] The present application proposes a constellation economic usability evaluation method, which calculates the sum of costs involved in each transition probability for each transition probability. The life cycle cost of the satellite system is reduced to the maximum extent from the perspective of global optimization, including satellite replacement cost, launch cost, satellite on-orbit cost, launch vehicle cost and operation cost, and a close corresponding relationship is established with the performance model determining service usability. BRIEF DESCRIPTION OF DRAWINGS

[0082] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort.

[0083] Figure 1 is a flow diagram of a constellation economic usability evaluation method disclosed by an embodiment of the present application;

[0084] Figure 2 is a constellation network supplementing model based on a two-dimensional Markov chain disclosed by an embodiment of the present application;

[0085] Figure 3 is a structural diagram of a constellation economic usability evaluation device disclosed by an embodiment of the present application;

[0086] Figure 4 is a structural diagram of another constellation economic usability evaluation device disclosed by an embodiment of the present application. DETAILED DESCRIPTION

[0087] In order to make the personnel in the technical field better understand the present application scheme, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of the present application.

[0088] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish different objects, not to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or equipment.

[0089] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The phrase appears in the specification at various places does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0090] The application discloses a constellation economic availability evaluation method and device, and the method comprises the following steps: acquiring a preset satellite set; the preset satellite set comprises N satellites and S backup satellites; P processing the preset satellite set to obtain a constellation network supplement model; and processing the constellation network supplement model to obtain constellation state transition probability.The method embeds a two-dimensional Markov chain model into a global optimization model, determines the probability of failure of a given number of satellites, and thus obtains a constellation availability evaluation result, so that the life cycle cost of a satellite system is maximally reduced from the perspective of global optimization.

[0091] Embodiment one

[0092] Please refer to Figure 1 , Figure 1 is a flowchart of a constellation economic availability evaluation method disclosed by the embodiment of the application. Figure 1 The described constellation economic availability evaluation method is applied to the technical field of availability evaluation, and the embodiment of the application is not limited. Figure 1 As shown in the figure, the constellation economic availability evaluation method can comprise the following operations:

[0093] S1, acquiring a preset satellite set; the preset satellite set comprises N satellites and S backup satellites; P

[0094] S2, processing the preset satellite set to obtain a constellation network supplement model;

[0095] S3, processing the constellation network supplement model to obtain constellation state transition probability.

[0096] Optionally, the constellation network supplement model comprises a finite Markov chain {Y :t∈Γ t} on a state space n , wherein Γ n ={0, 1,..., n} is a finite index set, S t is the total number of states in the state space, n is any given positive integer, Y t =(u, v) represents that u running satellites in the constellation fail and v backup satellites enter the used state at t time, and the constellation network supplement model indicates the number of failed satellites on the horizontal axis and the number of used backup satellites on the vertical axis.

[0097] Optionally, the processing of the constellation network supplement model to obtain constellation state transition probability comprises the following steps:

[0098] S31, initializing the constellation network supplement model to obtain initialization parameters;

[0099] S32, processing the initialization parameter to obtain constellation state transition probability.

[0100] Optionally, the constellation network supplement model is initialized to obtain the initialization parameter, and the initialization parameter comprises:

[0101] S311, the constellation network supplement model is initialized to obtain constraint parameter information; the constraint parameter information is expressed as:

[0102] 0≤u≤N, 0≤v≤S p

[0103] Wherein, u is the number of satellites running in failure in the constellation, N is the number of satellites in the constellation, v is the number of standby satellites entering the used state, S P is the number of standby satellites;

[0104] S312, the number of satellites in the constellation and the number of standby satellites are processed to obtain the total number of states in the state space;

[0105] The total number of states is expressed as:

[0106] S t =(N+1)(S p +1)

[0107] Wherein, S t is the total number of states;

[0108] S313, the constraint parameter information and the total number of states are integrated to obtain the initialization parameter.

[0109] Optionally, the initialization parameter is processed to obtain the constellation state transition probability, comprising:

[0110] S321, when the running satellite enters the failure state, the initialization parameter is processed to obtain first transition probability information;

[0111] S322, when the standby satellite enters the failure state, the initialization parameter is processed to obtain second transition probability information;

[0112] S323, when the on-orbit standby satellite is used to replace the failed satellite, the initialization parameter is processed to obtain third transition probability information;

[0113] S324, when the ground backup satellite is launched to replace the failed satellite, the initialization parameter is processed to obtain fourth transition probability information;

[0114] S325, integrate the first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information to obtain the constellation state transition probability.

[0115] Optionally, the expression for the first transition probability information is:

[0116] P[Y t =(u+1,v)|Y t-1 =(u,v)]=μ

[0117] Where u < N, the first transition probability information P[Y] t =(u+1,v)|Y t-1 =(u,v)] is to make the constellation change from state Y t-1 = (u,v) transitions to state Y t = (u+1,v), where μ is the probability of satellite failure;

[0118] The expression for the second transition probability information is:

[0119] P[Y t =(u,v+1)|Y t-1 =(u,v)]=μ

[0120] Among them, v p The second transition probability information is to make the constellation transition from state Y. t-1 = (u,v) transitions to state Y t The probability of (u, v+1).

[0121] Optionally, the expression for the third transition probability information is:

[0122] P[Y t = (u-1, v+1)|Y t-1 =(u,v)]=λ r η t

[0123] Where u > 0 and v < S p The third transition probability information is to make the constellation transition from state Y. t-1 = (u,v) transitions to state Y t The probability of (u-1, v+1);

[0124] The expression for the fourth transition probability information is:

[0125] P[Y t =(u-1,v)|Y t-1 =(u,v)]=P S P LV P SV λ​l

[0126] Where u>0, the fourth transition probability information is to make the constellation transition from state Y. t-1 = (u,v) transitions to state Y t The probability of (u-1,v).

[0127] When a satellite malfunctions, the malfunctioning satellite itself represents an economic loss. This cost is related to the satellite's value and the probability of failure. If a backup satellite in orbit is used as a replacement, the backup satellite also has its own costs. These costs include the initial launch cost, as well as fuel and lifespan losses during its time in orbit. These costs are related to its own probability of failure. If there are no backups in orbit, a relaunch from the ground will involve the launch cost of the launch vehicle itself, the cost of the backup satellite on the ground (including inventory costs and the cost of the satellite itself), satellite-rocket transfer costs, waiting costs, etc. These costs are also related to the probability of a successful launch, the probability of available satellite inventory, and the probability of available rocket inventory.

[0128] After obtaining the first, second, third, and fourth transition probability information, for each transition probability, calculate the sum of the costs involved under each transition probability, and then compare the sums to see which has the lowest total cost. The costs involved include:

[0129] Total cost of a constellation's lifespan C total Including the entire lifespan of the constellation system (T) L The costs of satellite replacement, launch, on-orbit satellite, launch vehicle, and operation are as follows:

[0130] C total = (Cost of satellite replacement + Launch cost + On-orbit cost of satellite + Launch vehicle cost + Operating cost)T L .

[0131] Formula for calculating the total cost of satellite replacement

[0132] Total cost of star replacement (C) = C1 + C2 + C3 + C4 + C5 + C6

[0133] The meanings and contents of each variable are as follows:

[0134] 1. Satellite development cost (C1)

[0135] The cost of designing, manufacturing, and testing a replacement satellite is one of the core costs of satellite replacement.

[0136] This includes: solution design fees, component / load procurement fees (such as chips, antennas, power supplies, etc.), final assembly and integration fees, environmental testing fees (vibration, high and low temperatures, radiation, etc.), and ground testing fees.

[0137] Special case: If a backup satellite is used, C1 is the maintenance activation cost of the backup satellite (such as detection during storage, battery activation, etc.), not the full development cost.

[0138] 2. Launch cost (C2)

[0139] The total cost of sending an alternative satellite into the planned orbit is affected by the type of rocket, launch site, orbital altitude, etc.

[0140] Includes: launch vehicle procurement costs (such as Long March series, Falcon 9, etc.), launch site service fees (site usage, fueling, etc.), launch and control fees (tracking and measurement, orbital correction, etc.), rocket and satellite interface testing fees.

[0141] Additional items: If "urgent launch" is required (such as shortening the launch period), a premium may be charged (usually 10-30% of the base launch cost).

[0142] 3. Ground system adaptation cost (C3)

[0143] The cost of adjusting the ground control and application system to adapt to the new satellite.

[0144] Includes: ground station software upgrade fees (such as orbital parameter updates, data interface adaptation), hardware modification fees (such as antenna tracking range adjustment), operator training fees, and testing fees for new satellites and existing constellation coordination, etc.

[0145] 4. Emergency planning and management cost (C4)

[0146] Fault response and task scheduling costs before the satellite replacement mission.

[0147] Includes: fault satellite diagnosis fees (orbital analysis, telemetry data interpretation), satellite replacement mission planning fees (orbital selection, launch window calculation), cross-department coordination fees (such as interface with launch site, control center, etc.).

[0148] 5. Insurance cost (C5)

[0149] Insurance cost to avoid risks during development and launch phase, usually calculated on a percentage basis.

[0150] Calculation formula: C5 = (C1 + C2) x insurance rate (usually 5-20%, depending on satellite type, launch risk level, higher rate for high-orbit satellites or new rockets).

[0151] 6. Other additional costs (C6)

[0152] Miscellaneous expenses during the satellite replacement process, added or reduced according to actual scenarios.

[0153] Satellite transportation (from manufacturer to launch site), temporary storage, international coordination (e.g. airspace crossing fees), extended operations (additional maintenance costs for existing systems due to constellation replenishment delays), etc.

[0154] Satellite on-orbit costs

[0155] Satellite on-orbit costs refer to the costs that occur each month for a satellite. The costs of a satellite are related to the number of satellites, the type of service provided, the orbit altitude, and the failure rate of the satellite. The failure rate of a satellite directly impacts the state of the constellation and increases the cost of the satellite through the need for more subsystem redundancy, larger solar arrays, etc. The development costs should also be included if a new satellite design is assumed each time an order is placed.

[0156] Launch vehicle costs

[0157] Launch vehicle costs typically assume that the launch vehicle is an existing, off-the-shelf product and do not include development costs. The costs are primarily determined by the mass of the satellite being placed into orbit, the orbit altitude, and the orbit inclination.

[0158] Operations costs

[0159] Operations costs refer to the infrastructure costs needed each month to maintain the satellite constellation. The costs of facilities such as office space, ground antenna sites to communicate with the satellites, etc. are fixed, while the personnel costs to monitor and troubleshoot satellite failures are variable. Even with a high degree of automation, it is estimated that 2 to 5 people per satellite are needed to maintain a constellation.

[0160] Optionally, after obtaining the first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information, the first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information are processed to obtain a failure prediction result, and total cost calculation is performed according to the failure prediction result.

[0161] Specifically, the method comprises the following steps:

[0162] The first transition probability information, the second transition probability information, the third transition probability information and the fourth transition probability information are fused to obtain failure prediction fusion information, and the failure prediction fusion information is input into a preset failure prediction model to obtain a failure prediction result.

[0163] The structure of the failure prediction model comprises a data embedding layer, a space-time encoder layer and a decoder.

[0164] The data embedding layer: first, the original input is converted into a fixed-length vector through a fully connected layer to where d is the embedding dimension, and by fusing the spatial graph Laplacian embedding, the time period embedding and the position encoding, the explicit modeling of the multi-dimensional features of the failure prediction fusion information is realized, and T x N represents the size of the data, T is the row, and N is the column:

[0165] (1) Spatial graph Laplacian embedding: a normalized Laplacian matrix Δ is constructed, where A is the adjacency matrix, D is the degree matrix, and I is the identity matrix, which reflects the connection weight and degree information between nodes:

[0166]

[0167] The eigenvalue matrix Λ and the eigenvector matrix U are obtained by eigenvalue decomposition of Δ, the first k smallest non-zero eigenvectors are selected (corresponding to low frequency signals, retaining global structure), and the spatial graph Laplacian embedding is generated by linear projection The Laplacian eigenvector embeds the graph into the Euclidean space and retains the global graph structure information.

[0168] Time period embedding: map the time t to the week index and the minute-level index through w(t) and d(t) And the period embedding of all T time slices is spliced to obtain , respectively representing the week period and the day period time sequence features, w(t) and d(t) are mapping functions, and C is the dimension after splicing.

[0169] (2) Time position encoding: if the embedding vector dimension is d, the position encoding is :

[0170]

[0171] pos is the original position information; after obtaining the above-mentioned various embeddings, the output of the data embedding layer is obtained by linearly superimposing each component , which is the initial input tensor of the space-time encoding layer. This fusion process unifies the spatial structure, time period, position information and original feature encoding into a high-dimensional vector, providing multi-dimensional input for the subsequent space-time encoder:

[0172]

[0173] Space-time encoder layer: including spatial self-attention module (SSA), delay perception feature transformation module (DFT) and time self-attention module (TSA), and the joint optimization of space-time features is realized through multi-head attention fusion, wherein the space-time encoding layer is stacked L layers, the layers are connected through the skip connection, the residual connection and layer normalization are introduced between the layers, and finally the spatial and temporal dependence captured by the SSA module and the TSA module is output as the space-time dependence features extracted by the space-time encoding layer after the L-layer space-time encoder.

[0174] Encoder: First, perform temporally coupled convolution on the output of the spatiotemporal encoder layer to fully couple the output results of the spatiotemporal encoder. The model identifies temporal dependencies and enhances information interaction between adjacent time slices. Then, it uses two 1×1 gated convolutions on the output of the temporally coupled convolution. Each convolutional layer fully integrates information from the corresponding channels and maps those channels to the dimension of the output. Furthermore, it adaptively filters out anomalous fluctuations in the prediction results using gated masks and enhances the model's ability to fuse multi-scale spatiotemporal features.

[0175] Optionally, after obtaining the first, second, third, and fourth transition probability information, these information are processed to obtain the number of operating satellites and the number of backup satellites for each transition probability information. This allows the construction of a first evaluation index A, a second evaluation index D, and a third evaluation index C. If the system has n states, then A is an n-dimensional vector, i.e., A = [a1 a2 a3…a…]. n ], where a i Let be the probability of the system being in state i when it starts executing the task, and

[0176] For example:

[0177] Assume the system has two operational satellites and one backup satellite, referred to as subsystem 1, subsystem 2, and subsystem 3, respectively. The initial state is divided as follows:

[0178] (1) State 1: Subsystem 1, Subsystem 2, and Subsystem 3 are all operating normally;

[0179] (2) State 2: Subsystem 1 is working normally, subsystem 2 is working normally, subsystem 3 is faulty;

[0180] (3) State 3: Subsystem 1 is working normally, Subsystem 3 is working normally, Subsystem 2 is faulty;

[0181] (4) Status 4: Subsystem 2 is working normally, Subsystem 3 is working normally, Subsystem 1 is faulty;

[0182] (5) Status 5: Subsystem 1 is working normally, subsystem 2 is faulty, and subsystem 3 is faulty;

[0183] (6) Status 6: Subsystem 2 is working normally, Subsystem 1 is faulty, Subsystem 3 is faulty;

[0184] (7) Status 7: Subsystem 3 is working normally, subsystem 1 is faulty, and subsystem 2 is faulty;

[0185] (8) State 8: Subsystem 1, Subsystem 2, Subsystem 3 are all failed.

[0186] Let b1, b2, b3 represent the probability of Subsystem 1, Subsystem 2, Subsystem 3 working normally respectively.

[0187]

[0188] The second evaluation index D is represented as:

[0189]

[0190] The reliability of each subsystem P i (P i The reliability of the ith subsystem) and the mean time between failures M i (M i The mean time between failures of the ith subsystem), i = 1, 2, 3, the relationship is:

[0191]

[0192] The third evaluation index C is the basic performance index (orbital characteristic index: orbital type, orbital height, orbital inclination, orbital period; system performance index: pointing accuracy, attitude stability, orbital maneuvering ability; basic performance index: thermal control efficiency, battery capacity, total fuel quantity) of Subsystem 1, Subsystem 2, Subsystem 3, which is comprehensively evaluated and processed using the analytic hierarchy process, and the evaluation matrix C is obtained and calculated:

[0193] E = A·D·C·(1-H)

[0194] Wherein, H is the environmental factor matrix, E is obtained by calculation, and E is the availability evaluation result of the constellation availability model.

[0195] Example Two

[0196] The purpose of this study is to propose a model that maximizes the reduction of satellite system life cycle costs, including replacement satellite costs, launch costs, satellite on-orbit costs, launch vehicle costs, and operating costs, from a global optimization perspective, and to establish a close correspondence with the performance model that determines service availability. The further goal is to identify the best optimization method and determine how much cost can be saved compared to current practices.

[0197] 1. Constellation configuration design

[0198] A reasonable constellation configuration can achieve global continuous coverage or global multiple continuous coverage, which has a unique advantage in global communication or navigation tasks, and its overall function is much greater than the sum of the functions of individual satellites. At present, the commonly used constellation configurations are as follows: star constellation, Walker-Delta constellation, Rosette constellation, etc. Among them:

[0199] Walker-Delta configuration emphasizes the phase difference configuration of satellites between different orbital planes to ensure global or wide-area continuous coverage. Delta refers to its specific phase distribution, aiming to minimize coverage gaps and repeated coverage. This constellation is suitable for global communication, earth observation, especially when global continuous coverage is required, and this paper takes this constellation configuration as the main research object.

[0200] In the design of Walker constellation, the three parameters T, P, and F jointly determine the coverage performance and operational efficiency of the satellite system. These parameters are defined as follows:

[0201] (1) T: Total number of satellites

[0202] T represents the total number of satellites in the constellation. Its main role is to control the size of the constellation, which will directly affect the system cost, coverage range, coverage frequency, and system redundancy. The increase of the number of satellites can improve the robustness and continuity of the service of the system, but at the same time, it will increase the initial investment and the complexity and cost of subsequent operation and maintenance.

[0203] (2) P: Number of orbital planes

[0204] P is the total number of different orbital planes to which satellites are assigned. It will affect the spatial layout of the constellation and the uniformity of ground coverage. Increasing the number of orbital planes can improve the uniformity of global or specified area coverage, helping to reduce the blind area of communication between ground stations and satellites.

[0205] (3) F: Phasing factor

[0206] F is the phase difference of satellites in adjacent orbital planes, that is, the angular difference between corresponding satellites on adjacent orbital planes. Its role is to determine how satellites on different orbital planes are positioned relative to each other, which is crucial for optimizing satellite field-of-view coverage and minimizing signal coverage overlap. A suitable phase difference can ensure effective continuous coverage of the global or specific region, avoiding waste of satellite resources.

[0207] In Walker constellation design, orbital planes are one of the key structural elements that make up the constellation. Each orbital plane contains a set of satellites that are at the same inclination and right ascension of the ascending node, but at different phase angle positions. The configuration of the orbital planes is critical to achieving the overall constellation's coverage objectives and communication continuity. Key characteristics of the orbital planes include:

[0208] (1) Inclination: All satellites in the same orbital plane share the same inclination. The inclination determines the highest dimension that the satellites can cover, thus affecting the coverage area.

[0209] (2) Right Ascension of the Ascending Node (RAAN): The spatial positioning of the orbital plane is primarily defined by the right ascension of the ascending node, which is the geographical position of the satellite when it crosses the equator going north. The RAAN of different orbital planes is usually different to ensure that the satellites can evenly cover the entire Earth.

[0210] (3) Phasing: The phasing difference between the orbital planes is adjusted by the phasing factor F of the Walker constellation, which ensures that the satellites on different orbital planes are relatively staggered in their positions on their orbits to optimize coverage of the Earth's surface.

[0211] The configuration of the Walker constellation can be designed through the following steps:

[0212] (1) Determine the total number of satellites T: Based on mission requirements, determine how many satellites are needed;

[0213] (2) Select the number of orbital planes P: Based on coverage requirements and cost considerations, select the appropriate number of orbital planes;

[0214] (3) Calculate the phasing factor F: Determine the phase stagger between adjacent orbital planes to ensure uniformity of coverage;

[0215] (4) Assign the right ascension of the ascending node and the inclination: According to the geographical coverage requirements and orbital dynamics, assign appropriate inclination and RAAN to each orbital plane.

[0216] 2 Constellation Inherent Availability / Constellation Redundancy Configuration

[0217] For constellations that provide services such as communication, navigation, etc., in order to avoid the degradation of service quality provided to users, the constellation system often has "backup" satellites running within the constellation, i.e., constellation redundancy configuration.

[0218] There are two main types of constellation redundancy configuration:

[0219] (1) Single satellite redundancy. An extra satellite is added to each orbital plane of the constellation, which can replace a failed satellite in time. Even if one satellite in an orbital plane fails, the constellation can continue to operate at full capacity without interruption. Communication constellations often use single satellite redundancy strategy.

[0220] (2) Double satellite redundancy. In cases where reliability and availability of the constellation are of utmost importance, two satellites can be used in redundancy in each orbital plane to ensure 99.99% or more service availability and reliability in most failure cases. Only if three or more satellites in the same orbital plane fail at the same time, the reliability and availability of the constellation is interrupted. Navigation constellations where signal reliability and availability are of utmost importance often use double satellite redundancy strategy.

[0221] Other types of constellations allow service capacity to degrade to a lower level in a shorter time, so they can use one of the three backup replacement strategies: on-orbit backup replacement, parking orbit backup replacement, or ground backup replacement.

[0222] 3. Constellation backup replacement strategies and their cost drivers

[0223] There are three main ways of satellite backup replacement strategies:

[0224] (1) On-orbit backup replacement

[0225] To avoid uncontrolled backup satellites colliding with operational satellites, backup satellites are not precisely located at the operational altitude of the constellation. A small difference in altitude means that the inclination between the backup satellite and the operational satellite's orbital planes is different, to counteract the difference in perturbations caused by the Earth's gravity and keep the orbital nodes at the same value.

[0226] To send the backup satellite to the correct orbital position, two Hohmann transfers can be performed to regain the nominal performance level. The first arrives at a phasing orbit, and the second returns to the operational altitude. The phasing orbit is usually a circular orbit at a different altitude from the constellation to eliminate the phase difference between the backup satellite and the operational satellite.

[0227] Replacing a failed satellite with this method usually takes a few days (typically one to two days). Cost drivers include, but are not limited to, the number of backup satellites, the velocity increment ΔV (total and per satellite) required for repositioning, the time required, and the performance level.

[0228] Communication constellations often use this strategy to replace failed satellites.

[0229] (2) Parking orbit backup replacement

[0230] Another satellite backup method is to use a "spare" satellite in a parking orbit. Cost drivers include, but are not limited to:

[0231] ●The velocity increment ΔV required to transfer from the parking orbit to any orbital plane of the constellation;

[0232] ●The velocity increment ΔV required for a satellite to reposition itself within its constellation;

[0233] ●The time delay between satellite malfunction and constellation orbit restoration.

[0234] The replacement time for a faulty satellite using this method is typically one to two months. Communication constellations often employ this strategy or use on-orbit backup satellites to replace faulty ones.

[0235] (3) Ground backup replacement

[0236] The final satellite backup method involves leaving one or more "spare" satellites in the constellation on the ground, replacing faulty satellites through on-demand launches. This involves two scenarios. One scenario is that there is a ground inventory of satellites, and available and suitable launch vehicles and launch sites, allowing for launch whenever needed. The other scenario is that there is no inventory of satellites, but production can be organized, and a successful launch can be ensured to replace the faulty satellite.

[0237] Earth-based constellations sometimes employ this strategy. Other types of constellations sometimes use this strategy as a backup to their primary alternative strategy.

[0238] This replacement strategy involves launching a backup satellite only to replace the faulty satellite in the event of a failure. For this strategy to be feasible for a particular mission, two conditions must be met: there must be a launch vehicle with the mass and volume to carry a single satellite, and there must be an agreement between the launch vehicle provider, the launch site provider, and the agency operating the constellation to ensure launch priority and availability.

[0239] For these reasons, the time required to replace a faulty satellite via on-demand launches is typically several months to a year. Cost drivers include, but are not limited to, waiting time, launch vehicle availability and reliability, launch site availability, satellite manufacturing plant availability, and so on.

[0240] Lifecycle Costs of the 4 Zodiac Signs

[0241] Total cost of a constellation's lifespan C total Including the entire lifespan of the constellation system (T) L The costs of satellite replacement, launch, on-orbit satellite, launch vehicle, and operation are as follows:

[0242] C total= (Satellite replenishment cost + Launch cost + Satellite on-orbit cost + Launch vehicle cost + Operations cost) T L .

[0243] Satellite replenishment cost is the cost of ordering satellites and launch vehicles each month. Satellite replenishment cost is related to the performance model because if there is no inventory of satellites or launch vehicles, it will result in a lower launch rate. Since the cost of satellites and launch vehicles is a function of service type and orbit type, satellite replenishment cost can only consider capital cost and ordering cost in the estimation process.

[0244] Launch cost is the cost of personnel and facilities needed to prepare and launch satellites and launch vehicles each month. It is linked to the performance model by increasing or decreasing the launch rate. At the cost of running more launch shifts and personnel overtime, the launch rate can be increased to increase the probability of being in a state of fewer satellite failures, thereby increasing the availability of the service.

[0245] Satellite on-orbit cost is the cost of satellites occurring each month. The cost of satellites is related to the following variables: number of satellites, type of service provided, orbit altitude, and failure rate of satellites. The failure rate of satellites directly affects the state of the constellation of satellites and increases the cost of satellites by requiring more subsystem redundancy, larger solar arrays, etc. The development cost should also be included if each order is assumed to be a new design.

[0246] Operations cost is the cost of infrastructure needed to maintain the constellation of satellites each month. Among them, the cost of facilities such as office space, ground antenna sites in communication with satellites, etc. is fixed, while the cost of personnel for monitoring and excluding satellite failures is variable. Even with a high degree of automation, it is estimated that 2 to 5 people are needed per satellite to maintain a constellation.

[0247] Launch vehicle cost usually assumes that the launch vehicle is an existing shelf product and does not include development costs. Its cost is mainly determined by the mass of satellites sent into orbit, orbit altitude, and orbit inclination.

[0248] The cost of each type can be estimated by the cost data of historical models or similar models at the initial stage of constellation design, and the estimation model can be optimized and improved by actual cost accounting at the later stage of constellation construction, which is convenient for cost analysis of subsequent related construction tasks.

[0249] 5 Constellation availability model

[0250] Constellation availability is a function of the number of failed satellites. In order to determine the probability of a given number of satellites failing, a two-dimensional Markov chain model can be embedded into the global optimization model. Figure 2This example illustrates a constellation replenishment configuration with 4 satellites and 2 spare satellites in two orbital planes. The horizontal axis represents the number of faulty satellites, and the vertical axis represents the number of spare satellites in use. State 1 represents all 4 operational satellites in the nominal constellation that have failed, and both spare satellites are also in use, which can be represented as a two-dimensional Markov state (4, 2). State 2 represents 3 operational satellites in the nominal constellation that have failed, and both spare satellites are in use, which can be represented as (3, 2). Similarly, State 15 represents 0 operational satellites in the nominal constellation that have failed, and both spare satellites are in an unused state, which can be represented as (0, 0). It is assumed here that the constellation does not launch new satellites when all spare satellites are in an unused state, i.e., it prioritizes using in-orbit spare satellites for fault replacement.

[0251] Abstracted into mathematical language, a finite state space can be defined. Finite Markov chain {Y} on t :t∈Γ n}, where Γ n = {0,1,…,n} is a finite set of indices, S t Let Y be the total number of states in the state space, and n be any given positive integer. t = (u,v), representing the situation at time t, assuming u operational satellites in the constellation fail and v backup satellites enter the operational state, assuming the number of orbital planes is P and the number of backup satellites is S. P The nominal number of satellites in the constellation is N, the satellite failure probability is μ, and the launch site launch rate is λ. l The probability of a successful launch of a carrier rocket is P. S The probability that the launch vehicle's ground inventory is available is P. LV The probability that the ground-based backup satellite inventory is available is P. SV The probability of a backup satellite successfully entering a phased orbit is λ. r The probability of a backup satellite successfully re-phased after entering phased orbit is η. t .

[0252] Then we have:

[0253] (1) 0 ≤ u ≤ N, 0 ≤ v ≤ S p

[0254] (2) The total number of states in the state space is

[0255] S t =(N+1)(S p +1)

[0256] (3) When u < N, and the operating satellite enters a fault state, the constellation is moved from state Y. t-1 = (u,v) transitions to state Yt = (u + 1, v) is

[0257] P[Y t = (u + 1, v) | Y t-1 = (u, v)] = μ

[0258] (4) When v < S p , the constellation is transferred from state Y t-1 = (u, v) to state Y t = (u, v + 1) with probability

[0259] P[Y t = (u, v + 1) | Y t-1 = (u, v)] = μ

[0260] (5) When u > 0 and v < S p , the constellation is transferred from state Y t-1 = (u, v) to state Y t = (u - 1, v + 1) with probability

[0261] P[Y t = (u - 1, v + 1) | Y t-1 = (u, v)] = λ r η t

[0262] (6) When u > 0, the constellation is transferred from state Y t-1 = (u, v) to state Y t = (u - 1, v) with probability

[0263] P[Y t = (u - 1, v) | Y t-1 = (u, v)] = P S P LV P SV λ l

[0264] With the one-step transition probabilities, from any initial state, one can enter any state at the current time after n steps, and then combine the corresponding cost data to perform economic analysis and scheme trade-off.

[0265] In summary, in order to achieve the goal of cost and availability synergy, the cost model for calculating the life cycle cost of a satellite system must consider all factors that affect performance, and each part that affects the availability model must have a related cost, including the supply chain, inventory, launch, operation, and disposal of satellites when they fail to provide services and launch vehicles.

[0266] Embodiment three

[0267] Please refer to Figure 3 , Figure 3 is a structural schematic diagram of a constellation economic availability evaluation device disclosed by an embodiment of the application. Wherein, Figure 3 The constellation economic availability evaluation device described is applied to the technical field of availability evaluation, and embodiments of the application are not limited. As Figure 3 shown, the constellation economic availability evaluation device can include the following operations:

[0268] S301, a satellite set acquisition module acquires a preset satellite set; the preset satellite set includes N satellites, S P satellites, and S

[0269] S302, a constellation network supplement model construction module, for processing the preset satellite set to obtain a constellation network supplement model;

[0270] S303, a constellation state transition probability calculation module, for processing the constellation network supplement model to obtain a constellation state transition probability.

[0271] Embodiment four

[0272] Please refer to Figure 4 , Figure 4 is a structural schematic diagram of another constellation economic availability evaluation device disclosed by an embodiment of the application. Wherein, Figure 4 The constellation economic availability evaluation device described is applied to the technical field of availability evaluation, and embodiments of the application are not limited. As Figure 4 shown, the constellation economic availability evaluation device can include the following operations:

[0273] The memory 401 stores executable program codes;

[0274] The processor 402 is coupled to the memory 401;

[0275] The processor 402 calls the executable program codes stored in the memory 401, for executing the steps in the constellation economic availability evaluation method described in embodiment one and embodiment two.

[0276] Embodiment five

[0277] The embodiment of the present application discloses a computer readable storage medium, which stores a computer program for electronic data exchange, wherein the computer program makes a computer execute steps in a constellation economy availability evaluation method described in embodiment one and embodiment two.

[0278] The above described device embodiments are only illustrative, wherein the modules illustrated as separate components can or can not be physically separated, and the components shown as modules can or can not be physical modules, i.e., can be located in one place or distributed to multiple network modules. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0279] Through the specific description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and the necessary general hardware platform, and of course, can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, including a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage, a magnetic tape storage, or any other computer readable medium that can be used to carry or store data.

[0280] It should be pointed out finally that: the constellation economy availability evaluation method and device disclosed by the embodiment of the application are only the preferred embodiment of the application, and are used for describing the technical solutions of the application, but not for limiting the application; although the application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features therein can be replaced equivalently; and the modification or replacement does not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A constellation economic availability evaluation method, characterized in that, The method comprises: S1, acquiring a preset satellite set; the preset satellite set includes N satellites, S P a spare satellite; S2, processing the preset satellite set to obtain a constellation supplementary network model; S3, processing the constellation supplementary network model to obtain constellation state transition probability.

2. The constellation economic usability evaluation method according to claim 1, characterized by, The constellation repair model comprises a finite Markov chain {Y t :t∈Γ n} on a state space n , where Γ t ={0, 1, …, n} is a finite index set, S t is the total number of states in the state space, n is an arbitrary given positive integer, Y p =(u, v) represents that u satellites in the constellation are in failure and v standby satellites are in use at time t, and the horizontal axis of the constellation repair model represents the number of failed satellites, and the vertical axis represents the number of standby satellites in use.

3. The constellation economic usability evaluation method according to claim 1, characterized by, The processing of the constellation supplementary network model to obtain constellation state transition probability comprises: S31, initializing the constellation supplementary network model to obtain initialization parameters; S32, processing the initialization parameters to obtain constellation state transition probability.

4. The constellation economic usability evaluation method according to claim 3, characterized by, The initialization of the constellation supplementary network model to obtain initialization parameters comprises: S311, initializing the constellation supplementary network model to obtain constraint parameter information; the constraint parameter information expression is: 0 < u < N, 0 < v < S p wherein u is the number of satellites in the constellation that are operating with a fault, N is the number of satellites in the constellation, v is the number of spare satellites that have entered an in-use state, S is the number of spare satellites in the constellation P is the number of spare satellites. S312, processing the number of satellites in the constellation and the number of backup satellites to obtain the total number of states in the state space; The total number of states expression is: S t = (N+1)(S p +1) where S t is the total number of states; S313, integrating the constraint parameter information and the total number of states to obtain initialization parameters.

5. The constellation economic usability evaluation method according to claim 1, characterized by, The processing of the initialization parameters to obtain constellation state transition probability comprises: S321, when a running satellite enters a failure state, processing the initialization parameters to obtain first transition probability information; S322, when a backup satellite enters a failure state, processing the initialization parameters to obtain second transition probability information; S323, when an on-orbit backup satellite is used to replace a failed satellite, processing the initialization parameters to obtain third transition probability information; S324, when a ground backup satellite is launched to replace a failed satellite, processing the initialization parameters to obtain fourth transition probability information; S325, integrating the first transition probability information, the second transition probability information, the third transition probability information, and the fourth transition probability information to obtain constellation state transition probability.

6. The constellation economic usability evaluation method according to claim 5, wherein The first transition probability information expression is: P[Y t = (u + 1, v) | Y t-1 = (u, v)] = μ where u < N, the first transition probability information P[Y t = (u + 1, v) | Y t-1 = (u, v) is the probability of the constellation transferring from the state Y t-1 = (u, v) to the state Y t = (u + 1, v), and μ is the satellite failure probability. The second transition probability information expression is: P[Y t = (u, v + 1) | Y t-1 = (u, v)] = μ where v < S p The second transition probability information is the probability of transitioning from state Y t-1 = (u, v) to state Y t = (u, v + 1).

7. The constellation economic usability evaluation method according to claim 5, wherein The third transition probability information expression is: P[Y t = (u - 1, v + 1) | Y t-1 = (u, v)] = λ r η t where u > 0 and v < S p The third transition probability information is the probability of transitioning from state Y t-1 = (u, v) to state Y t = (u - 1, v + 1). The fourth transition probability information expression is: P[Y t = (u - 1, v) | Y t-1 = (u, v)] = P S P LV P SV λ l where u > 0, the fourth transition probability information is a probability of making the constellation transition from a state Y t-1 = (u, v) to a state Y t = (u - 1, v).

8. A constellation economic usability evaluation apparatus characterized by comprising: The device comprises: The satellite set obtaining module obtains a preset satellite set; the preset satellite set includes N satellites, S P backup satellites; A constellation supplementary network model construction module for processing the preset satellite set to obtain a constellation supplementary network model; A constellation state transition probability calculation module for processing the constellation supplementary network model to obtain constellation state transition probability.

9. A constellation economic usability evaluation apparatus characterized by comprising: The device comprises: A memory storing executable program codes; A processor coupled with the memory; The processor invokes the executable program codes stored in the memory to execute the constellation economic availability evaluation method according to any one of claims 1-7.

10. A computer storable medium, characterized by The computer storage medium stores computer instructions, which are invoked to execute the constellation economic availability evaluation method according to any one of claims 1-7.

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