Remote sensing satellite relay transmission demand calculation method and system

Abstract

The invention relates to a remote sensing satellite relay transmission demand calculation method and system. The method comprises the following steps: S1, obtaining remote sensing satellite earth observation task parameters; s2, setting relay transmission basic task parameters according to the remote sensing satellite earth observation task parameters; s3, performing relay transmission link optimization according to the set relay transmission basic task parameters; s4, performing link delay analysis and calculation according to the optimized relay transmission link; and S5, calculating the link transmission rate according to the optimized relay transmission link. According to the method, the requirements of multi-load means, high-concurrency tasks and strong real-time requirements can be met, analysis and calculation of massive complex remote sensing satellite earth observation tasks through relay transmission requirements are achieved, and scientific and reasonable input is provided for subsequent relay satellite task planning.

Description

Technical Field

[0001] The present invention relates to the technical field of remote sensing satellite earth observation mission planning, and particularly to a method and system for calculating the relay transmission requirements of remote sensing satellites. Background Art

[0002] With the rapid development of space technology and space application fields, the number of on-orbit spacecraft is increasing, resulting in a geometric growth in the amount of remote sensing satellite data. The requirements for transmitting remote sensing satellite earth observation data with multiple payload means, high-concurrency tasks, and strong real-time requirements are becoming more and more complex. Currently, traditional methods for calculating the transmission requirements of remote sensing satellite earth observation data are difficult to handle complex scenarios such as sudden data transmission and high-concurrency tasks, resulting in inaccurate planning of relay transmission links and affecting the efficiency and success rate of data transmission.

[0003] Therefore, there is an urgent need for a scientific, reasonable, and intuitive way to calculate and display the relay transmission requirements of remote sensing satellites to address the above problems. Summary of the Invention

[0004] To solve the above technical problems existing in the prior art, the purpose of the present invention is to provide a method and system for calculating the relay transmission requirements of remote sensing satellites, which are used to calculate the requirements for transmitting remote sensing satellite earth observation data through relay transmission.

[0005] To achieve the above invention purpose, the present invention provides a method for calculating the relay transmission requirements of remote sensing satellites, including the following steps:

[0006] Step S1: Obtain the parameters of the remote sensing satellite earth observation mission;

[0007] Step S2: Set the basic task parameters of relay transmission according to the parameters of the remote sensing satellite earth observation mission;

[0008] Step S3: Optimize the relay transmission link according to the set basic task parameters of relay transmission;

[0009] Step S4: Analyze and calculate the link delay according to the optimized relay transmission link;

[0010] Step S5: Calculate the link transmission rate according to the optimized relay transmission link.

[0011] According to a technical solution of the present invention, it further includes:

[0012] Step S6: Display the results of the relay transmission link optimization, the link delay analysis calculation, and the link transmission rate calculation. The forms of display include two-dimensional maps and data charts.

[0013] According to a technical solution of the present invention, in the step S3, the relay transmission link preferably specifically includes:

[0014] Step S31: Conduct an inter-satellite node visibility analysis, calculate the visible arc segments of the inter-satellite nodes, and based on the calculated visible arc segments of the inter-satellite nodes, perform forecast reading, time slice selection, and link establishment information statistics to generate an inter-satellite visibility matrix;

[0015] Step S32: According to the inter-satellite link working mode and mission scenario configuration, use the minimum delay link establishment method to complete the inter-satellite link time slot planning and generate an inter-satellite link time slot table;

[0016] Step S33: According to the inter-satellite link time slot table generated in step S32, the inter-satellite link routing planning algorithm, the routing planning principle, or the configured routing table, complete the inter-satellite link routing planning, perform link optimization, and generate an inter-satellite link routing table.

[0017] According to a technical solution of the present invention, in the step S3, the inter-satellite link routing planning algorithm specifically includes:

[0018] Step S331: Define the network topology model of the satellite network. The network topology model is in the form of a directed graph G(V, E) of the inter-satellite link network, which is a periodic repetition sequence of several topological snapshots of the satellite positions within a period, where V represents the set of satellite nodes and E represents the set of ISLs of the entire network;

[0019] Step S332: According to the network topology model, perform optimization by restricting the number of hops, and screen to obtain an optimal feasible path set;

[0020] Step S333: Select the preferred principle attribute parameters and formulate a multi-attribute decision matrix for the paths;

[0021] Step S334: Set the weights of the preferred principle attribute parameters in the multi-attribute decision matrix for the paths by the information entropy method, and define the preference function by the Gaussian evaluation function method. Construct a preference index matrix according to the preference function and the weights of the preferred principle attribute parameters;

[0022] Step S335: According to the preference index matrix, evaluate the net advantage of the paths and obtain the optimal path.

[0023] According to a technical solution of the present invention, in step S332, it specifically includes:

[0024] Define (v S , v D ) to represent the source-destination satellite node pair in the satellite network. From the source satellite node v S to the destination satellite node v DA sequence of alternating points and edges is called a path, denoted as p = {v0e 1 v1e 2 …e m v m}, where v0 = v S , v m = v b , and e m is the m-th inter-satellite link in path p, and v m is the m-th satellite node passed by path p; e ∈ p represents that e is an inter-satellite link in path p, and v ∈ p represents that v is a satellite node in path p; P represents the set of feasible paths from the source satellite node v S to the destination satellite node v D , P = {p1, p2, …, p k}, and k represents the total number of paths in the set of feasible paths;

[0025] It is optimized by restricting the number of hops, and the optimal set of feasible paths is screened and represented as:

[0026]

[0027] According to a technical solution of the present invention, in step S333, it specifically includes:

[0028] Select several preferred principle attribute parameters and construct the path multi-attribute decision matrix, denoted as

[0029]

[0030] where A is the constructed path multi-attribute decision matrix, D, E, O, R, and J respectively represent different preferred principle attribute parameters, and the types of the preferred principle attribute parameters include benefit attributes and cost attributes; n represents the total number of paths in the optimal set of feasible paths.

[0031] According to a technical solution of the present invention, in step S334, weight setting is performed on the path multi-attribute decision matrix, specifically including:

[0032] The information entropy method is used to determine the weights of the path multi-attribute decision matrix and perform normalization, denoted as:

[0033]

[0034] where a ij is the element in the i-th row and j-th column of the path multi-attribute decision matrix, max j a ij is the maximum value of the j-th column, min j a ij is the minimum value of the j-th column, raij is the attribute value of the preferred principle attribute parameter of normalization, and its value range is [0, 1];

[0035] The weight of the j-th selection principle attribute parameter in the path multi-attribute decision matrix is defined as:

[0036]

[0037] where 0 ≤ w j ≤ 1, E j is the information entropy of the j-th selection principle attribute parameter, and its calculation formula is:

[0038]

[0039] where x is a constant, p ij is the evaluation value of the j-th selection principle attribute parameter.

[0040] In the step S334, the preference function is defined by the Gaussian evaluation function method, specifically including:

[0041] For any two paths p i1 and p i12 in the optimal feasible path set P', p i1 = {v0e 1 v1e 2 …e i1 v i1} and p k = {v0e 1 v1e 2 …e i2 v i2}, where v0 = v s , v i1 = v i2 = v D , define the preference function f j (p i1 , p i2 ), which is used to describe the preference degree of path p i1 relative to path p i2 with respect to the j-th preferred principle attribute parameter, ra i1j and ra i2j are the corresponding attribute values in the normalized path multi-attribute decision matrix, d = ra i1j - ra i2j , then:

[0042]

[0043] Among them, G(d) is an evaluation function used to convert the difference between attributes into the actual preference magnitude. Using the Gaussian evaluation function, we have:

[0044]

[0045] Among them, the value range of d is (0, 1], and the value range of the evaluation function G(d) is [0, 1], and σ = 0.5;

[0046] In the step S334, a preference index matrix is constructed according to the preference function and the weight of the preferred principle attribute parameters, which specifically includes:

[0047] Path p i1 Relative to path p i2 The preference index for the jth preferred principle attribute parameter is S(p i1 , p i2 ) = ∑ j w j f j (p i1 , p i2 ), and the preference index matrix S is obtained as:

[0048]

[0049] According to a technical solution of the present invention, in the step S335, it specifically includes:

[0050] Define the path net superiority to represent the absolute preference degree of the paths in the optimal feasible path set P'. For any path p i1 , i1 = 1,..., n, its superiority is Path p i1 The inferiority is Then the path net superiority φ(p i1 ) is: i1 ) = φ

[0051] φ(p i1 ) = φ + (p i1 ) - φ - (p i1 )

[0052] Arrange the optimal feasible path set P' from the best to the worst according to the path net superiority, and obtain the optimal path, which is expressed as:

[0053] max φ(p) p ∈ P'

[0054] Among them, φ(p) represents the path net superiority for evaluating each path in the optimal feasible path set.

[0055] According to a technical solution of the present invention, in the step S4, the link delay analysis and calculation specifically include:

[0056] Step S41, calculation of the inter-satellite link length:

[0057] The transmission distance d of the inter-satellite link between satellite nodes B1 and B2 B1B2 The calculation formula is

[0058]

[0059] where H and Re are the orbital altitude of the satellite and the radius of the earth respectively, and D B1B2 is the included angle between satellite nodes B1 and B2 with respect to the center of the earth;

[0060] cosD B1B2 = [cos 2 (Δ / 20 - cos 2 I·sin 2 (Δ / 2)]cos(r B1 -r B2 ) + cosI·sinΔsin(r B1 -r B2 ) - sin 2 I·sin 2 (Δ / 2)·cos(r B1 +r B2 +2wt')

[0061] where Δ is the included angle between two satellite orbital planes, I is the orbital inclination, r A 、r B are the initial phases of satellite nodes B1 and B2 respectively, w is the angular velocity of the satellite, and t’ is the time compared with the initial moment.

[0062] Step S42, calculation of the path transmission delay:

[0063] The calculation formula for the inter-satellite link transmission delay t between satellite nodes B1 and B2 is:

[0064]

[0065] where d AB is the transmission path length between satellite nodes B1 and B2, c is the propagation rate of electromagnetic waves, generally calculated using the speed of light, which is 3×10 8 m / s; the path transmission delay T is the arithmetic sum of the inter-satellite link transmission delays corresponding to all inter-satellite links in the path.

[0066] According to a technical solution of the present invention, in the step S5, the link transmission rate analysis and calculation specifically include:

[0067] The link transmission rate analysis and calculation are achieved by calculating the information rate;

[0068] For the SCPC single-channel single-carrier mode, the calculation formula for its information rate is:

[0069] R b = R B ×log2M×C r

[0070] In the formula, R b is the information rate, with the unit of bps; R B is the symbol rate, with the unit of Baud; M is the number of levels representing the symbol, log2M is the modulation order; C r is the channel coding efficiency;

[0071] The symbol rate R B The calculation formula is:

[0072]

[0073] Among them, B W is the occupied bandwidth, with the unit of Hz; α is the roll-off factor;

[0074] For the TDM / TDMA communication system, the calculation formula for its information rate is:

[0075] R b = R B ×log2M×C r ×K slot

[0076]

[0077] Among them, K slot represents the proportion of carrier time slots occupied by the receiving end, p' represents the total number of designed carrier time slots, and q represents the number of satellite receiving time slots.

[0078] According to a solution of the present invention, a remote sensing satellite relay transmission requirement calculation system is provided for implementing the above method, including:

[0079] A remote sensing satellite earth observation task acquisition module for obtaining remote sensing satellite earth observation task parameters;

[0080] A relay transmission basic task parameter design module for setting relay transmission basic task parameters;

[0081] A relay transmission requirement calculation module for calculating relay transmission requirements, including relay transmission link optimization, link delay analysis, and link transmission speed calculation;

[0082] A display module for displaying the calculation results of the relay transmission requirement calculation module.

[0083] Compared with the prior art, the present invention has the following beneficial effects:

[0084] In the present invention, through algorithms such as information entropy and Gaussian evaluation function, the relay transmission tasks of remote sensing satellites for earth observation are optimized and calculated to generate the relay transmission requirements for each satellite observation task, providing a scientific and reasonable calculation method for the relay transmission requirements of remote sensing satellites. By decoupling and calculating the earth observation tasks of remote sensing satellites, the inherent constraints of the transmission communication links of remote sensing satellites and relay satellites, and applying digital drive technology, the analysis and calculation of the relay transmission requirements for a large number of complex earth observation tasks of remote sensing satellites are realized, providing scientific and reasonable inputs for subsequent relay satellite mission planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0086] Figure 1 Schematically showing a flowchart of a method for calculating the relay transmission requirements of a remote sensing satellite according to an embodiment of the present invention;

[0087] Figure 2 Schematically showing a structural diagram of a device for calculating the relay transmission requirements of a remote sensing satellite according to an embodiment of the present invention;

[0088] Figure 3 Schematically showing a working flowchart of the relay transmission link optimization according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0089] The description of the embodiments of this specification should be combined with the corresponding drawings, and the drawings should be regarded as an integral part of the complete specification. In the drawings, the shapes or thicknesses of the embodiments may be enlarged and simplified or conveniently marked. Furthermore, the parts of each structure in the drawings will be described separately. It should be noted that the elements not shown or not described in words in the drawings are in the forms known to those of ordinary skill in the art.

[0090] In the description of the embodiments herein, any reference to directions and orientations is for the convenience of description only and should not be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments involves combinations of features, which may exist independently or in combination. The present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0091] As Figure 1 shown, a method for calculating the relay transmission requirements of a remote sensing satellite according to the present invention includes the following steps:

[0092] Step S1, obtaining the parameters of the remote sensing satellite's earth observation mission;

[0093] The parameters of the remote sensing satellite's earth observation mission include scene parameters, remote sensing satellite parameters, ground target parameters, and observation mission parameters;

[0094] The scene parameters include the scene start time and the scene end time;

[0095] The remote sensing satellite parameters include satellite ID, satellite type, and orbital parameters;

[0096] The ground target parameters include target ID, target type, target location, and target observation requirements;

[0097] The observation mission parameters include mission ID, mission start time, mission end time, mission transmission type, and mission data volume size.

[0098] Step S2, setting the basic task parameters of relay transmission according to the parameters of the remote sensing satellite's earth observation mission;

[0099] In step S2, the setting of the basic task parameters of relay transmission includes setting the capabilities of the relay data transmission terminal of the remote sensing satellite and the basic information parameters of the relay satellite;

[0100] The capabilities of the relay data transmission terminal of the remote sensing satellite include the data transmission rate range, data transmission delay, data transmission terminal type, and adjacent task merging duration of the remote sensing satellite;

[0101] The basic information parameters of the relay satellite include satellite ID, satellite orbital parameters, number of satellite antennas, deployment location, antenna pointing ability, beam range, data reception and processing delay, and data reception rate.

[0102] Step S3, optimizing the relay transmission link according to the set basic task parameters of relay transmission;

[0103] In step S3, the optimization of the relay transmission link specifically includes:

[0104] Step S31: Conduct inter-satellite node visibility analysis, calculate the visible arc segments of inter-satellite nodes, and based on the calculated visible arc segments of inter-satellite nodes, perform prediction reading, time slot selection, and link establishment information statistics to generate an inter-satellite visibility matrix;

[0105] Step S32: According to the inter-satellite link time slot table, inter-satellite link working mode, and mission scenario configuration generated in Step S32, use the minimum-delay link establishment method to complete the inter-satellite link time slot planning and generate an inter-satellite link time slot table;

[0106] The inter-satellite link time slot planning specifically includes:

[0107] Step S321: Define ISLA→B as the inter-satellite link between satellite node A and satellite node B, and D(ISLA→B) as the transmission cost from satellite node A to satellite node B, which is evaluated using the link weight LW of the static network topology. The calculation formula is:

[0108]

[0109] where C is the speed of light, is the information propagation delay on the inter-satellite link; p represents the permanence of the inter-satellite link, and its value range is [0, 1]. The smaller the p value, the weaker the permanence of the inter-satellite link; pos represents the relative position between satellite nodes, and its value range is [0, 1];

[0110] Step S322: Define the multi-hop path P S between the source satellite node v D and the destination satellite node v S→D as:

[0111] P S→D ={ISL 0→1 , ISL 1→2 , …, ISL i→(i+1) , …, ISL n-1)→n |S = 0, D = n}

[0112] Then the total transmission delay on the multi-hop path P S→D is expressed as:

[0113]

[0114] Step S323: According to the path set P S of the source satellite node v D and the destination satellite node v S→D , calculate the shortest-delay path, which is expressed as:

[0115]

[0116] Step S33: Complete the inter-satellite link routing plan according to the inter-satellite link routing algorithm, routing principles, or the configured routing table, perform link optimization, and generate an inter-satellite link routing table.

[0117] In step S3, the inter-satellite link routing algorithm specifically includes:

[0118] Step S331: Define the network topology model of the satellite network. The network topology model is in the form of a directed graph G(V, E) of the inter-satellite link network, which is a periodic repetition sequence of several topological snapshots of satellite positions within a period T. Here, V represents the set of satellite nodes, and E represents the set of all ISLs in the network.

[0119] The network topology model is regarded as a periodic repetition sequence of N topological snapshots of satellite positions within a period T. This network topology can be considered fixed within each time interval Δt: [t0 = 0, t1], [t1, t2], …, [t N-1 , t N = T], T = kΔt, k = 0, …, N - 1. Each snapshot at these points is modeled as a constant graph, and link state changes occur only at discrete times t0, t1, …, t N .

[0120] Step S332: According to the network topology model, perform optimization by restricting the number of hops, and screen to obtain an optimal feasible path set.

[0121] Define (v S , v D ) to represent the source-destination satellite node pair in the satellite network. A sequence of alternating points and edges from the source satellite node v S to the destination satellite node v D is called a path, denoted as p = {v0e 1 v1e 2 …e m v m}, where v0 = v S , v m = v D , and e m is the m-th inter-satellite link in path p, and v m is the m-th satellite node passed by path p; use e ∈ p to indicate that e is an inter-satellite link in path p, and use v ∈ p to indicate that v is a satellite node in path p; P represents the set of feasible paths from the source satellite node v S to the destination satellite node v D , P = {p1, p2, …, p k}, and k represents the total number of paths in the feasible path set.

[0122] Optimization is carried out by restricting the number of hops, and the optimal feasible path set is selected and represented as:

[0123]

[0124] Among them, P' represents the optimal feasible path set from the source satellite node v S to the destination satellite node v D and n represents the total number of paths in the optimal feasible path set.

[0125] Step S333: Select the preferred principle attribute parameters and formulate a multi-attribute decision matrix for the path;

[0126] In step S333, it specifically includes:

[0127] In this embodiment, the five preferred principle attribute parameters are link transmission rate, bit error rate, path hop count, propagation path length, and link delay. The calculation formulas for link transmission rate, bit error rate, propagation path length, and link delay are

[0128]

[0129] Pe (p) = max e∈p {p (e)}

[0130] Among them, V(e) is the total link transmission rate of path p, which is the arithmetic mean of the transmission rates of all inter-satellite links of path p, and Ne is the total number of inter-satellite links of path p; Delay(p) is the end-to-end delay of path p, ∑ e∈p Delay(e) is the propagation delay of path p, ∑ v∈p Delay(v) is the queuing delay; A (p) is the total length of the path from the source satellite node to the destination satellite node on path p, a (e) is the length of a single inter-satellite link in path p; Pe (p) is the total bit error rate of the path from the source satellite node to the destination satellite node on path p, and p (e) is the bit error rate of a single inter-satellite link in path p;

[0131] The path hop count is the number of times the data is forwarded on path p;

[0132] Then, according to the preferred principle attribute parameters, construct the multi-attribute decision matrix for the path, which is represented as

[0133]

[0134] Among them, A is the constructed path multi-attribute decision matrix. D, E, O, R, and J respectively represent link transmission rate, bit error rate, path hop count, propagation path length, and link delay. The path transmission rate is a benefit attribute, and the rest are cost attributes; n represents the total number of paths in the optimal feasible path set.

[0135] Step S334: Set the weights of each of the preferred principle attribute parameters in the path multi-attribute decision matrix by the information entropy method, define a preference function by the Gaussian evaluation function method, and construct a preference index matrix according to the preference function and the weights of the preferred principle attribute parameters.

[0136] In step S334, setting the weights of the path multi-attribute decision matrix specifically includes:

[0137] Use the information entropy method to determine the weights of the constructed path multi-attribute decision matrix, and eliminate the influence of the differences in attribute meanings and dimensions and the incommensurability between attributes on the decision result through attribute normalization, which is expressed as:

[0138]

[0139] where a ij is the element in the i-th row and j-th column of the path multi-attribute decision matrix, max j a ij is the maximum value of the j-th column, min j a ij is the minimum value of the j-th column, ra ij is the normalized attribute value, and its value range is [0, 1];

[0140] The weight of the j-th preferred principle attribute parameter in the path multi-attribute decision matrix is defined as:

[0141]

[0142] where 0 ≤ w j ≤ 1, E j is the information entropy of the preferred principle attribute parameter j, and its calculation formula is:

[0143]

[0144] where x is a constant, p ij is the evaluation value of the j-th preferred principle attribute parameter.

[0145] In the step S334, defining the preference function by the Gaussian evaluation function method specifically includes:

[0146] Assume pi1 ={v0e 1 v1e 2 …e i1 v i1} and p i2 ={v0e 1 v1e 2 …e i2 v i2} are two paths of the optimal feasible path set P', where v0 = v s , v i1 = v i2 = v D , that is, p i1 and p i2 have the same source satellite node and destination satellite node; for each preferred principle attribute parameter, the preference function is defined as converting the difference between the evaluations obtained from two alternative path schemes into a preference degree from 0 to 1. The larger the value of the preference function, the greater the preference difference; when the value of the preference function is zero, there is no preference difference between the two alternative path schemes. The larger the value of the preference function, the greater the preference difference. When the value is zero, there is no preference difference between the two alternative path schemes. That is to say, the advantages and disadvantages between the two paths are determined by the magnitude of the gap between the attribute values of each path scheme.

[0147] The preference function f j (p i1 , p i2 ) is used to describe the preference degree of the alternative path scheme p i1 relative to p i2 with respect to the jth preferred principle attribute parameter. ra i1j and ra i2j are the corresponding attribute values in the normalized path multi-attribute decision matrix. d = ra i1j - ra i2j , then:

[0148]

[0149] where G(d) is an evaluation function used to convert the difference between attributes into the actual preference magnitude. Using the Gaussian evaluation function, we have:

[0150]

[0151] where the value range of d is (0, 1], and the value range of the evaluation function G(d) is [0, 1], and σ = 0.5.

[0152] In the step S334, a preference index matrix is constructed according to the preference function and the weights of the preferred principle attribute parameters, specifically including:

[0153] Alternative path p i1 With respect to path p i2 The preference index for the j-th preferred principle attribute parameter is S(p i1 , p i2 ) = ∑ j w j f j (p i1 , p i2 ), and the preference index matrix S is obtained as follows:

[0154]

[0155] Step S335: Evaluate the path net advantage of each path in the optimal feasible path set according to the preference index matrix, and obtain the optimal path.

[0156] In the step S335, it specifically includes:

[0157] Define the path net advantage degree to represent the absolute preference degree of the paths in the optimal feasible path set P'. For any path p i1 , i1 = 1,..., n, its advantage is The disadvantage of path p i1 is Then the net advantage degree φ(p i1 ) of path p i1 is:

[0158] φ(p i1 ) = φ + (p i1 ) - φ - (p i1 )

[0159] Arrange the optimal feasible path set P' from the best to the worst according to the path net advantage degree, and obtain the optimal path, denoted as:

[0160] max φ(p) p ∈ P'

[0161] where φ(p) is used to evaluate the quality of each path, and its value determines the priority of the path.

[0162] When φ(p i ) = φ(p k ), path p i is irrelevant to path p k . When φ(p i ) > φ(p k ), path p i is superior to path p k . Select. When φ(p i ) < φ(pk )), path p i is inferior to path p k selection.

[0163] Step S4: According to the preferred relay transmission link, perform link delay analysis and calculation;

[0164] Step S41: Inter-satellite link length calculation:

[0165] The transmission distance d of the inter-satellite link between satellite nodes B1 and B2 B1B2 The calculation formula is

[0166]

[0167] where H and Re are the orbital altitude of the satellite and the radius of the earth respectively, and D B1B2 is the included angle between satellite nodes B1 and B2 with respect to the center of the earth;

[0168] cosD B1B2 =[cos 2 (Δ / 20 - cos 2 I·sin 2 (Δ / 2)]cos(r B1 - r B2 ) + cosI·sinΔ·sin(r B1 - r B2 ) - sin 2 I·sin 2 (Δ / 2)·cos(r B1 + r B2 + 2wt')

[0169] where Δ is the included angle between the two satellite orbital planes, I is the orbital inclination, r A , r B are the initial phases of satellite nodes B1 and B2 respectively, w is the angular velocity of the satellite, and t' is the time compared to the initial moment.

[0170] Step S42: Path transmission delay calculation:

[0171] The calculation formula for the inter-satellite link transmission delay t between satellite nodes B1 and B2 is:

[0172]

[0173] where d AB is the transmission path length between satellite nodes B1 and B2, c is the propagation speed of electromagnetic waves, generally calculated using the speed of light, which is 3×10 8 m / s; the path transmission delay T is the arithmetic sum of the inter-satellite link transmission delays corresponding to all inter-satellite links in the path.

[0174] Step S5: Calculate the link transmission rate according to the preferred relay transmission link.

[0175] In the step S5, the analysis and calculation of the link transmission rate specifically include:

[0176] The analysis and calculation of the link transmission rate are achieved by calculating the information rate; the information rate represents the transmission speed of information and measures the maximum amount of information that a communication system can transmit per unit time. The demand for future space information is increasing, and the amount of information to be transmitted is also increasing. For a certain link channel rate, the larger the amount of information, the longer the transmission time required, and the larger the total transmission time of a single complete information record. Therefore, the information rate has a direct impact on the effectiveness of channel transmission. Satellite communication links can generally be divided into different communication systems such as FDMA (Frequency Division Multiple Access) and TDM / TDMA (Time Division Multiplexing / Time Division Multiple Access) from the communication system. The information rate calculation methods for different systems are slightly different.

[0177] For the SCPC (Single Channel Per Carrier) method, the communication parties exclusively use this communication link, and the calculation formula for its information rate is:

[0178] R b = R B × log2M × C r

[0179] In the formula, R b is the information rate, with the unit of bps; R B is the symbol rate, with the unit of Baud; M is the number of levels representing symbols, log2M is the modulation order; C r is the channel coding efficiency;

[0180] When the symbol rate R B is not given and only the astrological bandwidth is given, the symbol rate R B can also be calculated through the following formula:

[0181]

[0182] Among them, B W is the astrological bandwidth, with the unit of Hz; α is the roll-off factor;

[0183] For the TDM / TDMA communication system, multiple receivers share a physical carrier, and each receiving end occupies a certain number of time slots divided by the carrier. Therefore, the satellite communication system of this system also needs to consider the time slot allocation, and the calculation formula for its information rate is:

[0184] R b = R B × log2M × C r × Kslot

[0185]

[0186] Among them, K slot represents the proportion of carrier time slots occupied by the receiving end, p represents the total number of designed carrier time slots, and q represents the number of satellite receiving time slots.

[0187] Step S6: Display the results of the relay transmission link optimization, the link delay analysis and calculation, and the link transmission rate calculation. The forms of display include two-dimensional maps and data charts. The evaluation and display can be realized through two-dimensional maps and data charts.

[0188] As Figure 2 shown, the present invention also provides a calculation system for the relay transmission requirements of a remote sensing satellite, including:

[0189] A remote sensing satellite earth observation mission acquisition module for obtaining the parameters of the remote sensing satellite earth observation mission. The remote sensing satellite earth observation mission acquisition module obtains the relevant mission parameters of the remote sensing satellite earth observation data, including the basic parameters and mission-related parameters of the remote sensing satellite earth observation, and can realize functions such as data import and data preprocessing to support flexible data acquisition and preprocessing of the data source file.

[0190] A relay transmission basic mission parameter design module for setting the relay transmission basic mission parameters, including the basic parameters and mission parameters related to the data transmission from the remote sensing satellite to the relay satellite. The relay transmission basic mission parameter design module supports the user to set the capability parameters of the remote sensing satellite relay data transmission terminal and the basic information of the relay satellite.

[0191] A relay transmission requirement calculation module for calculating the relay transmission requirements, including relay transmission link optimization, link delay analysis, and link transmission speed calculation;

[0192] A display module for displaying the calculation results of the relay transmission requirement calculation module.

[0193] It should be noted that in this article, the terms "including", "comprising", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or terminal device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article, or terminal device. Without further limitations, the element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article, or terminal device including the said element.

[0194] Finally, it should be noted that the above description is the preferred embodiment of the present invention. It should be pointed out that although the preferred embodiments of the present invention have been described, for those skilled in the art of this technology, once the basic creative concept of the present invention is known, several improvements and refinements can be made without departing from the principle described in the present invention. These improvements and refinements should also be regarded as the protection scope of the present invention. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A method for calculating the relay transmission requirements of a remote sensing satellite, characterized in that, It includes the following steps: Step S1: Obtain the parameters of the remote sensing satellite's earth observation mission; Step S2: Set the basic parameters of the relay transmission according to the parameters of the remote sensing satellite's earth observation mission; Step S3: Optimize the relay transmission link according to the set basic parameters of the relay transmission; Step S4: Analyze and calculate the link delay according to the optimized relay transmission link; Step S5: Calculate the link transmission rate according to the optimized relay transmission link; Step S6: Display the results of the relay transmission link optimization, the link delay analysis calculation, and the link transmission rate calculation. The display forms include two-dimensional maps and data charts.

2. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 1, wherein In step S3, the relay transmission link optimization specifically includes: Step S31: Analyze the visibility of the inter-satellite nodes, calculate the visible arcs of the inter-satellite nodes, and perform prediction reading, time slice selection, and link establishment information statistics according to the calculated visible arcs of the inter-satellite nodes to generate an inter-satellite visibility matrix; Step S32: Complete the time slot planning of the inter-satellite link by using the minimum delay link establishment method according to the inter-satellite link working mode and task scenario configuration to generate an inter-satellite link time slot table; Step S33: Complete the routing planning of the inter-satellite link according to the inter-satellite link time slot table, the inter-satellite link routing planning algorithm, the routing planning principle, or the configured routing table generated in step S32, perform link optimization, and generate an inter-satellite link routing table.

3. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 2, wherein In step S3, the inter-satellite link routing planning algorithm specifically includes: Step S331: Define the network topology model of the satellite network. The network topology model is in the form of a directed graph G(V, E) of the inter-satellite link network, which is a periodic repetition sequence of several topological snapshots of the satellite positions within a period. Here, V represents the set of satellite nodes, and E represents the set of ISLs of the entire network; Step S332: Optimize by restricting the number of hops according to the network topology model, and filter to obtain the optimal feasible path set; Step S333: Select the attribute parameters of the optimization principle, and formulate a multi-attribute decision matrix for the paths; Step S334: Set the weights of the attribute parameters of the optimization principle in the multi-attribute decision matrix for the paths by using the information entropy method, and define the preference function by using the Gaussian evaluation function method. Construct a preference index matrix according to the preference function and the weights of the attribute parameters of the optimization principle; Step S335: Evaluate the path net advantage of each path in the optimal feasible path set according to the preference index matrix, and obtain the optimal path.

4. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 3, wherein In step S332, it specifically includes: Define (v S , v D ) to represent the source-destination satellite node pair in the satellite network. A sequence of alternating points and edges from the source satellite node v S to the destination satellite node v D is called a path, and the path is represented as p = {v0e 1 v1e 2 …e m v m}, where v0 = v S , v m = v D , and e m is the m-th inter-satellite link in the path p, and v m is the m-th satellite node passed by the path p; use e ∈ p to indicate that e is an inter-satellite link in the path p, and use v ∈ p to indicate that v is a satellite node in the path p; P represents the set of feasible paths from the source satellite node v S to the destination satellite node v D , P = {p1, p2, …, p k}, and k represents the total number of paths in the set of feasible paths; Optimize by restricting the number of hops to filter out the optimal feasible path set, which is expressed as:

5. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 4, wherein In step S333, it specifically includes: Select several attribute parameters of the optimization principle and construct the multi-attribute decision matrix for the paths, which is expressed as where A is the constructed multi-attribute decision matrix for the paths, D, E, O, R, and J respectively represent different attribute parameters of the optimization principle. The types of the attribute parameters of the optimization principle include benefit attributes and cost attributes; n represents the total number of paths in the optimal feasible path set.

6. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 5, wherein In step S334, weight setting is performed on the path multi-attribute decision matrix, specifically including: The information entropy method is used to determine the weights of the path multi-attribute decision matrix and perform normalization, expressed as: where a ij is the element in the i-th row and j-th column of the path multi-attribute decision matrix, max j a ij is the maximum value of the j-th column, min j a ij is the minimum value of the j-th column, ra ij is the attribute value of the normalized preferred principle attribute parameter, and its value range is [0, 1]; The weight of the j-th selection principle attribute parameter in the path multi-attribute decision matrix is defined as: where 0 ≤ w j ≤ 1, E j is the information entropy of the j-th selected principle attribute parameter, and its calculation formula is: where x is a constant, p ij is the evaluation value of the j-th selected principle attribute parameter. In step S334, a preference function is defined through the Gaussian evaluation function method, specifically including: For any two paths p i1 and p i2 in the optimal feasible path set P', p i1 ={v0e 1 v1e 2 …e i1 v i1} and p i2 ={v0e 1 v1e 2 …e i2 v i2}, where v0 = v s , v i1 = v i2 = v D . Define the preference function f j (p i1 , p i2 ) to describe the preference degree of path p i1 relative to path p i2 with respect to the j-th preferred principle attribute parameter. ra i1j and ra i2j are the corresponding attribute values in the normalized path multi-attribute decision matrix. d = ra i1j - ra i2j . Then: Among them, G(d) is the evaluation function, which is used to convert the differences between attributes into the actual preference magnitude. Using the Gaussian evaluation function, we have: Among them, the value range of d is (0, 1], and the value range of the evaluation function G(d) is [0, 1], and σ = 0.5; In step S334, a preference index matrix is constructed according to the preference function and the weights of the preferred principle attribute parameters, specifically including: Path p i1 With respect to path p i2 The preference index for the j-th preferred principle attribute parameter is S(p i1 , p i2 ) = ∑ j w j f j (p i1 , p i2 ), and the preference index matrix S is obtained as follows:

7. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 6, characterized in that In step S335, it specifically includes: Define the path net superiority to represent the absolute preference degree of the paths in the optimal feasible path set P'. For any path p in the optimal feasible path set P' i1 , i1 = 1, …, n, its superiority is The path p i1 's inferiority is Then the path p i1 's net superiority φ(p i1 ) is: φ(p i1 ) = φ + (p i1 ) - φ - (p i1 ) According to the path net superiority degree, the optimal feasible path set P' is arranged from the best to the worst, and the optimal path is obtained, expressed as: maxφ(p)p∈P′ Among them, φ(p) represents the net superiority degree for evaluating each path in the optimal feasible path set.

8. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 1, wherein In step S4, the link delay analysis and calculation specifically include: Step S41: Calculation of the inter-satellite link length: The inter-satellite link transmission distance d between satellite nodes B1 and B2 B1B2 The calculation formula is where H and Re are the orbital altitude of the satellite and the radius of the Earth respectively, and D B1B2 is the included angle between the satellite nodes B1 and B2 with respect to the center of the Earth; cosD B1B2 = [cos 2 (Δ / 2) - cos 2 I·sin 2 (Δ / 2)]cos(r B1 - r B2 ) + cosI·sinΔ·sin(r B1 - r B2 ) - sin 2 I·sin 2 (Δ / 2)·cos(r B1 + r B2 + 2wt') where Δ is the angle between the two satellite orbital planes, I is the orbital inclination, r A and r B are the initial phases of satellite nodes B1 and B2 respectively, w is the angular velocity of the satellite, and t’ is the time compared to the initial moment; Step S42: Calculation of the path transmission delay: The formula for the inter-satellite link transmission delay t between satellite nodes B1 and B2 is: Among them, d AB is the transmission path length between satellite nodes B1 and B2, c is the propagation speed of electromagnetic waves, generally calculated using the speed of light, which is 3×10 8 m / s; the path transmission delay T is the arithmetic sum of the inter-satellite link transmission delays corresponding to all inter-satellite links in the path.

9. The method for calculating the relay transmission requirements of a remote sensing satellite according to claim 1, characterized in that In step S5, the link transmission rate analysis and calculation specifically include: The link transmission rate analysis and calculation are realized by calculating the information rate; For the SCPC single-channel single-carrier mode, the formula for its information rate is: R b = R B × log2 M × C r Wherein, R b is the information rate, with the unit of bps; R B is the symbol rate, with the unit of Baud; M is the number of levels representing symbols, and log2M is the modulation order; C r is the channel coding efficiency; Meet rate R B The calculation formula is as follows: Among them, B W is the astrological bandwidth, in Hz; α is the roll-off coefficient; For the TDM / TDMA communication system, the formula for its information rate is: R b = R B × log2 M × C r × K slot Among them, K slot represents the proportion of carrier time slots occupied by the receiving end, p' represents the total number of designed carrier time slots, and q represents the number of satellite receiving time slots.

10. A remote sensing satellite relay transmission requirement calculation system, characterized in that, For implementing the method according to any one of claims 1 to 9, it includes: A remote sensing satellite earth observation task acquisition module, which is used to obtain remote sensing satellite earth observation task parameters; A relay transmission basic task parameter design module, which is used to perform relay transmission basic task parameter setting; A relay transmission requirement calculation module, which is used to perform relay transmission requirement calculation, including relay transmission link optimization, link delay analysis, and link transmission speed calculation; A display module, which is used to display the calculation results of the relay transmission requirement calculation module.

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