A method for modeling and simulating the dynamic infrared radiation characteristics of space group targets

Abstract

This invention proposes a method for modeling and simulating the dynamic infrared radiation characteristics of a group of space targets, belonging to the field of simulation technology. The method includes the following steps: S1. Based on the mesh of each sub-target in the space target group, the dynamic temperature distribution sequence of each sub-target is obtained by solving the thermal conductivity differential equation; S2. Based on the position and attitude of each sub-target in the space target group, coordinate transformation is performed using a rotation matrix to rotate each sub-target to a unified CGCS2000 geodetic coordinate system; S3. Dynamic group target mesh construction and surface element temperature assignment are performed to generate the dynamic temperature distribution sequence of the group targets; S4. The occlusion relationship of all surface elements is determined, and the numbers of detectable surface elements are recorded; S5. Combining the detection band, the infrared radiation characteristics of the surface elements are obtained by solving Planck's law, and the infrared radiation characteristics of all visible surface elements are superimposed to obtain the dynamic infrared radiation characteristics of the group targets. This invention solves the problem of excessively high costs associated with modeling and simulation using existing technologies.

Description

Technical Field

[0001] This invention relates to the field of simulation technology, specifically to a method for modeling and simulating the dynamic infrared radiation characteristics of space group targets. Background Technology

[0002] Space targets refer to targets above 100km above the Earth's surface, with spacecraft being a typical example. Deploying decoys or other disruptive objects to lure spacecraft is a relatively effective and technically easy-to-implement penetration method. This can effectively prevent defense systems from accurately detecting, tracking, and identifying spacecraft. Therefore, constructing the dynamic infrared radiation characteristics of space swarm targets is particularly important.

[0003] Currently, relatively complete simulation methods exist for the infrared characteristics of individual space targets. However, solving for the infrared characteristics of a group of space targets requires not only obtaining the temperature field distribution of each sub-target but also considering the mutual occlusion coupling effects between them. Since the positions and attitudes of each sub-target change continuously over time, the method of simulating the infrared radiation characteristics of the target group as a single target is no longer applicable. Because the infrared radiation characteristics of targets have a time-cumulative effect, modeling and simulating at a single point in time requires significant time and manpower; the manpower and time costs required for modeling and simulating at every single moment are immeasurable. Therefore, new solutions must be explored.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a method for modeling and simulating the dynamic infrared radiation characteristics of space group targets, aiming to solve the problem of excessively high cost in modeling and simulating the infrared radiation characteristics of space group targets using existing technologies.

[0006] A method for modeling and simulating the dynamic infrared radiation characteristics of space swarm targets includes the following steps:

[0007] S1. Based on the grid of each sub-target in the space target group, the dynamic temperature distribution sequence of each sub-target is obtained by solving the thermal conductivity differential equation;

[0008] S2. Based on the position and attitude of each sub-target in the space target group, coordinate transformation is performed using a rotation matrix to rotate each sub-target to a unified CGCS2000 geodetic coordinate system.

[0009] S3. Based on the sub-target grids obtained in step S2 under the CGCS2000 geodetic coordinate system, construct a dynamic group target grid, and use the dynamic temperature distribution sequence of each sub-target obtained in step S1 as input to assign surface element temperature values ​​and generate a dynamic temperature distribution sequence of the group target.

[0010] S4. Based on the detection angle, determine the occlusion relationship of all face elements of the target mesh obtained in step S3, and record the number of the detectable face elements.

[0011] S5. Based on the detectable surface element numbers of the group target output in step S4, and combined with the detection band, the infrared radiation characteristics of the surface element are obtained by solving Planck's law. The infrared radiation characteristics of all visible surface elements are superimposed to obtain the dynamic infrared radiation characteristics of the group target, thus completing the modeling and simulation of the dynamic infrared radiation characteristics of the space group target.

[0012] Furthermore, by solving the thermal conductivity differential equation, the expression for solving the temperature distribution of each sub-target based on the thermal conductivity differential equation in the dynamic temperature distribution sequence step of each sub-target satisfies:

[0013]

[0014] Where ρ is density, with units of kg / m³. 3 ;

[0015] c is the specific heat capacity, expressed in J / (kg·K);

[0016] λ is the thermal conductivity, with units of W / (m·K);

[0017] t represents temperature, in Kelvin (K).

[0018] τ represents time, measured in seconds (s).

[0019] q v It is the sum of internal and external heat flows;

[0020] Based on the mesh, the thermal network method is used to integrate and solve the above equation. For a certain node i, the above equation is expressed as:

[0021]

[0022] Where, m i Let be the mass of node i, in kg;

[0023] t i t j Let K represent the temperatures at nodes i and j, in Kelvin (K).

[0024] A ij Let be the projected area of ​​node i along the direction of node j, in meters. 2;

[0025] l ij The effective heat conduction distance is the length of node i in the direction of node j, in meters.

[0026] A i Let be the area of ​​node i, in meters. 2 ;

[0027] ε is the emissivity;

[0028] σ is the Stefan Boltzmann constant, σ = 5.6703 × 10 -8 W / (m 2 ·K 4 );

[0029] dQ1 represents the amount of heat absorbed directly from solar radiation per unit volume per unit time, expressed in W.

[0030] dQ2 is the amount of heat absorbed per unit volume per unit time from solar radiation reflected by the Earth, expressed in W.

[0031] dQ3 is the amount of heat directly radiated from the Earth absorbed per unit volume per unit time, expressed in W.

[0032] Q in The amount of heat generated per unit volume of internal heat source per unit time, expressed in W;

[0033] dQ1=α·E sun ·dA·cos(θ1)

[0034] dQ2=α·E sun-earth ·dA·cos(θ2)

[0035] dQ3=α·E earth ·dA·cos(θ2)

[0036] Where α is the absorption rate;

[0037] E sun The solar direct radiation heat flux per unit area, expressed in W / m². 2 ;

[0038] E sun-earth The heat flow reflected by solar radiation from the Earth, measured in W / m³. 2 ;

[0039] E earth Heat flux from direct radiation of the Earth, measured in W / m³ 2 ;

[0040] θ1 is the angle between the normal of node i and the sun, in degrees;

[0041] θ2 is the angle between the normal of node i and the Earth, in degrees.

[0042] Furthermore, in the step of integrating using the heat network method, for the space target, E sun =1353W / m 2 E sun-earth =0.3×E sun =406W / m 2 E earth =237W / m 2 .

[0043] Furthermore, in the step of rotating each sub-target to a unified CGCS2000 geodetic coordinate system through coordinate transformation using a rotation matrix, the expression for coordinate rotation of each sub-target based on the rotation matrix satisfies:

[0044]

[0045]

[0046]

[0047]

[0048] Where x, y, and z are the position components before rotation, in meters (m);

[0049] X, Y, and Z are the position components after rotation, in meters;

[0050] pitch, yaw, and roll are the pitch angle, yaw angle, and roll angle before rotation, respectively, in degrees.

[0051] Furthermore, based on the detection angle, the occlusion relationship of all facets in the target mesh obtained in step S3 is determined, and the numbers of detectable facets are recorded. The determination of whether a facet can be detected and whether it is occluded by other facets is performed as follows:

[0052] S4.1 Determine whether surface element i can be detected;

[0053] S4.2 When surface element i can be detected, determine whether other surface elements j occlude surface element i;

[0054] S4.3 When surface element j may cause occlusion of surface element i, continue to determine whether the intersection point of the straight line with the reverse observation vector as the straight line direction and passing through the center of surface element i and the plane where surface element j is located is located inside surface element j.

[0055] Furthermore, in the step of determining whether surface element i can be detected, the expression indicating that surface element i can be detected should satisfy:

[0056]

[0057] in, Let i be the unit normal vector of surface element i;

[0058] It is the unit vector in the opposite direction to the direction of the observation line of sight;

[0059] like Then surface element i can be observed;

[0060] like Then surface element i is occluded.

[0061] Furthermore, in the step of determining whether face element i can be detected, for a triangular face element, the normal vector of face element i is represented as:

[0062]

[0063] in, Let be the direction vector pointing from coordinate point 1 to coordinate point 2 of surface element i;

[0064] Let be the direction vector from coordinate point 2 of surface element i to coordinate point 3.

[0065] Furthermore, when surface element i can be detected, in the step of determining whether other surface elements j occlude surface element i, the expression for determining that other surface elements j will not cause the occluding surface element i to radiate in the detection direction satisfies:

[0066]

[0067] in, The direction vector pointing from the center point of surface element i to the center point of surface element j;

[0068] like At that time, element j will not obstruct element i;

[0069] like At that time, element j may cause occlusion of element i.

[0070] Furthermore, in the step of determining whether the intersection point of the line with the reverse observation vector as the direction of the line and passing through the center of surface element i and the plane containing surface element j is located inside surface element j, the mesh is divided into triangular surface elements, and the determination is made based on the reverse observation vector. An expression satisfying the condition that the line passing through the center of surface element i intersects the plane containing surface element j at a point P not located inside surface element j is:

[0071] S(A j1 A j2,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)>S(A j1 A j2 A j3 )

[0072] Among them, A j1 Let j be the first point of surface element j;

[0073] A j2 Let j be the second point of surface element j;

[0074] A j3 Let j be the third point of surface element j;

[0075] S(A j1 A j2 P) is based on A j1 A j2 The area of ​​the triangle formed by points P, P, and P;

[0076] If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)≤S(A j1 A j2 A j3 If the expression is true, it means that point P is inside surface element j, and surface element i is occluded.

[0077] If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)>S(A j1 A j2 A j3 If point P is located outside surface element j, then surface element i is not obscured by surface element j.

[0078] Furthermore, by solving Planck's law to obtain the infrared radiation characteristics of the surface elements, and by superimposing the infrared radiation characteristics of all visible surface elements, the dynamic infrared radiation characteristics of the target group are obtained. In this step, the expression for solving the infrared radiation characteristics of the target group based on Planck's law satisfies:

[0079]

[0080]

[0081] Where Rad represents the radiation intensity in the detection band, in W / sr;

[0082] ε is the emissivity;

[0083] A i Let i be the area of ​​element i, in meters. 2 ;

[0084] θ i Let be the normal vector of surface element i and be the unit vector in the opposite direction of the viewing direction. The included angle, in degrees;

[0085] t i The temperature of element i is expressed in K.

[0086] λ1 represents the initial wavelength band of the probe, in μm;

[0087] λ2 is the termination band of the detection, in μm;

[0088] c1 is the first radiation constant, c1 = 3.7418 × 10 -8 W·m 2 ;

[0089] c2 is the second radiation constant, c2 = 1.4388 × 10 4 μm·K.

[0090] The beneficial technical effects achieved by this invention are:

[0091] Based on the solution of the dynamic temperature characteristics of a single spatial target, and combined with the spatial positional relationships of each sub-target, a dynamic mesh for a group of spatial targets is constructed and its infrared radiation characteristics are solved. First, the temperature sequence of each sub-target is solved. Second, a dynamic group target mesh is constructed and dynamic temperature values ​​are assigned based on the spatial positions of each sub-target. Then, surface source occlusion coupling relationships are determined, and the detectable surface elements are recorded. Finally, the infrared radiation characteristics of the detectable surface elements are solved, and all detectable surface elements are superimposed to obtain the dynamic infrared radiation characteristics of the group of targets. The scheme described in this invention not only obtains the temperature field distribution of each sub-target during modeling and simulation but also considers the mutual occlusion coupling effects between sub-targets. It also avoids modeling and simulating every moment, eliminating invalid surface elements, significantly improving efficiency. This solves the problem of excessively high costs associated with modeling and simulating the infrared radiation characteristics of a group of spatial targets using existing technologies, demonstrating outstanding substantive features and significant progress.

[0092] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0093] Figure 1 This is a flowchart of one specific embodiment of the present invention;

[0094] Figure 2 This is a schematic diagram of the heat flow distribution at node i in one specific embodiment of the present invention. Detailed Implementation

[0095] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Specific details such as particular system structures, models, and technical parameters mentioned in the following description are merely illustrative of the specific embodiments and not intended to limit the scope of protection of the present invention. Furthermore, content that should be known and understood by those skilled in the art will not be repeated here.

[0096] A specific embodiment of a method for modeling and simulating the dynamic infrared radiation characteristics of space group targets involves temperature simulation and dynamic reconstruction of the group target grid based on multiple sub-target grids and flight trajectories, and then, based on the reconstructed group target grid and temperature distribution, solving for dynamic infrared radiation characteristics using Planck's law.

[0097] like Figure 1 As shown, the dynamic infrared radiation characteristics modeling and simulation of space group targets using this specific embodiment includes the following steps:

[0098] S1. Based on the grid of each sub-target in the space target group, the dynamic temperature distribution sequence of each sub-target is obtained by solving the thermal conductivity differential equation;

[0099] The expression for solving the temperature distribution of each sub-target based on the thermal conductivity differential equation satisfies:

[0100]

[0101] Where ρ is density, with units of kg / m³. 3 ;

[0102] c is the specific heat capacity, expressed in J / (kg·K);

[0103] λ is the thermal conductivity, with units of W / (m·K);

[0104] t represents temperature, in Kelvin (K).

[0105] τ represents time, measured in seconds (s).

[0106] q v It is the sum of internal and external heat flows.

[0107] Based on the mesh, the thermal network method is used to integrate and solve equation (1). For a certain node i, the heat flow distribution at node i is as follows: Figure 2 As shown, formula (1) can be expressed as:

[0108]

[0109] Where, m i Let be the mass of node i, in kg;

[0110] t i t j Let K represent the temperatures at nodes i and j, in Kelvin (K).

[0111] A ij Let be the projected area of ​​node i along the direction of node j, in meters. 2 ;

[0112] l ij The effective heat conduction distance is the length of node i in the direction of node j, in meters.

[0113] A i Let be the area of ​​node i, in meters. 2 ;

[0114] ε is the emissivity;

[0115] σ is the Stefan Boltzmann constant, σ = 5.6703 × 10 -8 W / (m 2 ·K 4 );

[0116] dQ1 represents the amount of heat absorbed directly from solar radiation per unit volume per unit time, expressed in W.

[0117] dQ2 is the amount of heat absorbed per unit volume per unit time from solar radiation reflected by the Earth, expressed in W.

[0118] dQ3 is the amount of heat directly radiated from the Earth absorbed per unit volume per unit time, expressed in W.

[0119] Q in The heat generated per unit volume of internal heat source per unit time, expressed in W.

[0120] dQ1=α·E sun ·dA·cos(θ1) (3)

[0121] dQ2=α·E sun-earth ·dA·cos(θ2) (4)

[0122] dQ3=α·E earth ·dA·cos(θ2) (5)

[0123] Where α is the absorption rate;

[0124] E sun The solar direct radiation heat flux per unit area, expressed in W / m². 2 ;

[0125] E sun-earth The heat flow reflected by solar radiation from the Earth, measured in W / m³. 2 ;

[0126] E earth Heat flux from direct radiation of the Earth, measured in W / m³ 2 ;

[0127] θ1 is the angle between the normal of node i and the sun, in degrees;

[0128] θ2 is the angle between the normal of node i and the Earth, in degrees.

[0129] For space targets, generally E sun =1353W / m 2 E sun-earth =0.3×E sun =406W / m 2 E earth =237W / m 2 .

[0130] S2. Based on the position and attitude of each sub-target in the space target group, coordinate transformation is performed using a rotation matrix to rotate each sub-target to a unified CGCS2000 geodetic coordinate system.

[0131] The expression for rotating the coordinates of each sub-target based on the rotation matrix satisfies:

[0132]

[0133]

[0134]

[0135]

[0136] Where x, y, and z are the position components before rotation, in meters (m);

[0137] X, Y, and Z are the position components after rotation, in meters;

[0138] pitch, yaw, and roll are the pitch angle, yaw angle, and roll angle before rotation, respectively, in degrees.

[0139] S3. Based on the sub-target grids obtained in step S2 under the CGCS2000 geodetic coordinate system, construct a dynamic group target grid, and use the dynamic temperature distribution sequence of each sub-target obtained in step S1 as input to assign surface element temperature values ​​and generate a dynamic temperature distribution sequence of the group target.

[0140] S4. Based on the detection angle, determine the occlusion relationship of all face elements of the target mesh obtained in step S3, and record the number of the detectable face elements.

[0141] The following method is used to determine whether a surface element can be detected and whether it is occluded by other surface elements:

[0142] S4.1 First, determine whether surface element i can be detected.

[0143] The expression that allows cell i to be detected should satisfy:

[0144]

[0145] in, Let i be the unit normal vector of surface element i;

[0146] It is the unit vector in the opposite direction to the direction of the observation view.

[0147] like Then surface element i can be observed.

[0148] like Then surface element i is occluded.

[0149] For a triangular facet element, the normal vector of facet element i can be expressed as:

[0150]

[0151] in, Let be the direction vector pointing from coordinate point 1 to coordinate point 2 of surface element i;

[0152] Let be the direction vector from coordinate point 2 of surface element i to coordinate point 3.

[0153] S4.2 Secondly, when surface element i can be detected, determine whether other surface elements j occlude surface element i.

[0154] The expression for determining that other surface element j will not cause occlusion of surface element i in the detection direction satisfies:

[0155]

[0156] in, Let be the direction vector from the center point of surface element i to the center point of surface element j.

[0157] like At that time, element j will not obstruct element i.

[0158] like At this time, face element j may cause occlusion of face element i, and further judgment is required, so step S4.3 is executed.

[0159] S4.3, Determine the vector observed in reverse. Is the intersection point P of the straight line passing through the center of surface element i and the plane containing surface element j located inside surface element j?

[0160] In this specific embodiment, the mesh is divided into triangular facets, and the determination is based on the reverse observation vector. An expression satisfying the condition that the line passing through the center of surface element i intersects the plane containing surface element j at a point P not located inside surface element j is:

[0161] S(A j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)>S(A j1 A j2 A j3 (13)

[0162] Among them, A j1 Let j be the first point of surface element j;

[0163] A j2 Let j be the second point of surface element j;

[0164] A j3 Let j be the third point of surface element j;

[0165] S(A j1 A j2 P) is based on A j1 A j2 The area of ​​the triangle formed by points P, P and P'.

[0166] If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)≤S(A j1 A j2 Aj3 If the expression is true, it means that point P is inside surface element j, and surface element i is occluded.

[0167] If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)>S(A j1 A j2 A j3 If point P is located outside surface element j, then surface element i is not obscured by surface element j.

[0168] S5. Based on the detectable surface element numbers of the target group output in step S4, and combined with the detection band, the infrared radiation characteristics of the surface elements are obtained by solving Planck's law. The infrared radiation characteristics of all visible surface elements are then superimposed to obtain the dynamic infrared radiation characteristics of the target group.

[0169] The expression for solving the infrared radiation characteristics of a group of targets based on Planck's law satisfies:

[0170]

[0171]

[0172] Where Rad represents the radiation intensity in the detection band, in W / sr;

[0173] ε is the emissivity;

[0174] A i Let i be the area of ​​element i, in meters. 2 ;

[0175] θ i Let be the normal vector of surface element i and be the unit vector in the opposite direction of the viewing direction. The included angle, in degrees;

[0176] t i The temperature of element i is expressed in K.

[0177] λ1 represents the initial wavelength band of the probe, in μm;

[0178] λ2 is the termination band of the detection, in μm;

[0179] c1 is the first radiation constant, c1 = 3.7418 × 10 -8 W·m 2 ;

[0180] c2 is the second radiation constant, c2 = 1.4388 × 10 4 μm·K.

[0181] This completes the modeling and simulation of the dynamic infrared radiation characteristics of space group targets.

[0182] The beneficial technical effects achieved by this specific embodiment are:

[0183] Based on the solution of the dynamic temperature characteristics of a single spatial target, and combined with the spatial positional relationships of each sub-target, a dynamic mesh for a group of spatial targets is constructed and its infrared radiation characteristics are solved. First, the temperature sequence of each sub-target is solved. Then, based on the spatial position of each sub-target, a dynamic group target mesh is constructed and dynamic temperature values ​​are assigned. Next, the surface source occlusion coupling relationship is determined, and the detectable surface elements are recorded. Finally, the infrared radiation characteristics of the detectable surface elements are solved. The dynamic infrared radiation characteristics of the group target are obtained by superimposing all detectable surface elements.

[0184] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for modeling and simulating the dynamic infrared radiation characteristics of space group targets, characterized in that, Includes the following steps: S1. Based on the grid of each sub-target in the space target group, the dynamic temperature distribution sequence of each sub-target is obtained by solving the thermal conductivity differential equation; S2. Based on the position and attitude of each sub-target in the space target group, coordinate transformation is performed using a rotation matrix to rotate each sub-target to a unified CGCS2000 geodetic coordinate system. S3. Based on the sub-target grids obtained in step S2 under the CGCS2000 geodetic coordinate system, construct a dynamic group target grid, and use the dynamic temperature distribution sequence of each sub-target obtained in step S1 as input to assign surface element temperature values ​​and generate a dynamic temperature distribution sequence of the group target. S4. Based on the detection angle, determine the occlusion relationship of all face elements of the target mesh obtained in step S3, and record the number of the detectable face elements. S5. Based on the detectable surface element numbers of the group target output in step S4, and combined with the detection band, the infrared radiation characteristics of the surface element are obtained by solving Planck's law. The infrared radiation characteristics of all visible surface elements are superimposed to obtain the dynamic infrared radiation characteristics of the group target, thus completing the modeling and simulation of the dynamic infrared radiation characteristics of the space group target.

2. The method according to claim 1, characterized in that, By solving the thermal conductivity differential equation, the expression for solving the temperature distribution of each sub-target based on the thermal conductivity differential equation in the step of obtaining the dynamic temperature distribution sequence of each sub-target satisfies: Where ρ is density, with units of kg / m³. 3 ; c is the specific heat capacity, expressed in J / (kg·K); λ is the thermal conductivity, with units of W / (m·K); t represents temperature, in Kelvin (K). τ represents time, measured in seconds (s). q v It is the sum of internal and external heat flows; Based on the mesh, the thermal network method is used to integrate and solve the above equation. For a certain node i, the above equation is expressed as: Where, m i Let be the mass of node i, in kg; t i t j Let K represent the temperatures at nodes i and j, in Kelvin (K). A ij Let be the projected area of ​​node i along the direction of node j, in meters. 2 ; l ij The effective heat conduction distance is the length of node i in the direction of node j, in meters. A i Let be the area of ​​node i, in meters. 2 ; ε is the emissivity; σ is the Stefan Boltzmann constant, σ = 5.6703 × 10 -8 W / (m 2 ·K 4 ); dQ1 represents the amount of heat absorbed directly from solar radiation per unit volume per unit time, expressed in W. dQ2 is the amount of heat absorbed per unit volume per unit time from solar radiation reflected by the Earth, expressed in W. dQ3 is the amount of heat directly radiated from the Earth absorbed per unit volume per unit time, expressed in W. Q in The amount of heat generated per unit volume of internal heat source per unit time, expressed in W; dQ1=α·E sun ·dA·cos(θ1) dQ2=α·E sun-earth ·dA·cos(θ2) dQ3=α·E earth ·dA·cos(θ2) Where α is the absorption rate; E sun The solar direct radiation heat flux per unit area, expressed in W / m². 2 ; E sun-earth The heat flow reflected by solar radiation from the Earth, measured in W / m³. 2 ; E earth The direct radiative heat flux of the Earth, measured in W / m³ 2 ; θ1 is the angle between the normal of node i and the sun, in degrees; θ2 is the angle between the normal of node i and the Earth, in degrees.

3. The method according to claim 2, characterized in that, In the step of integral solution using the heat network method, for the space target, E sun =1353W / m 2 E sun-earth =0.3×E sun =406W / m 2 E earth =237W / m 2 .

4. The method according to claim 2 or 3, characterized in that, In the step of rotating each sub-target to a unified CGCS2000 geodetic coordinate system using a rotation matrix, the expression for the coordinate rotation of each sub-target based on the rotation matrix satisfies: Where x, y, and z are the position components before rotation, in meters; X, Y, and Z are the position components after rotation, in meters; pitch, yaw, and roll are the pitch angle, yaw angle, and roll angle before rotation, respectively, in degrees.

5. The method according to claim 4, characterized in that, Based on the detection angle, the occlusion relationship of all facets in the target mesh obtained in step S3 is determined, and the numbers of detectable facets are recorded. In the step of determining whether a facet can be detected and whether it is occluded by other facets, the following method is used: S4.1 Determine whether surface element i can be detected; S4.2 When surface element i can be detected, determine whether other surface elements j occlude surface element i; S4.3 When surface element j may cause occlusion to surface element i, continue to determine whether the intersection point of the straight line with the reverse observation vector as the straight line direction and passing through the center of surface element i and the plane where surface element j is located is located inside surface element j.

6. The method according to claim 5, characterized in that, In the step of determining whether surface element i can be detected, the expression indicating that surface element i can be detected should satisfy: in, Let i be the unit normal vector of surface element i; It is the unit vector in the opposite direction to the direction of the observation line of sight; like Then surface element i can be observed; like Then surface element i is occluded.

7. The method according to claim 6, characterized in that, In the step of determining whether face element i can be detected, for a triangular face element, the normal vector of face element i is represented as: in, Let be the direction vector from coordinate point 1 to coordinate point 2 of surface element i; Let be the direction vector from coordinate point 2 of surface element i to coordinate point 3.

8. The method according to claim 5, characterized in that, When surface element i can be detected, in the step of determining whether other surface elements j occlude surface element i, the expression for determining that other surface elements j will not cause the occluding surface element i to radiate in the detection direction satisfies: in, The direction vector pointing from the center point of surface element i to the center point of surface element j; like At that time, element j will not obstruct element i; like At that time, element j may cause occlusion of element i.

9. The method according to claim 8, characterized in that, In the step of determining whether the intersection of the line with the reverse observation vector as the direction of the line and passing through the center of surface element i with the plane containing surface element j is located inside surface element j, the mesh is divided into triangular surface elements. An expression satisfying the condition that the line passing through the center of surface element i intersects the plane containing surface element j at a point P not located inside surface element j is: S(A j1 ,A j2 ,P)+S(A j2 ,A j3 ,P)+S(A j3 ,A j1 ,P)>S(A j1 ,A j2 ,A j3 ) Among them, A j1 Let j be the first point of surface element j; A j2 Let j be the second point of surface element j; A j3 Let j be the third point of surface element j; S(A j1 A j2 ,P) is based on A j1 A j2 The area of ​​the triangle formed by points P, P, and P; If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)≤S(A j1 A j2 A j3 If the expression is true, it means that point P is inside surface element j, and surface element i is occluded. If S(A) j1 A j2 ,P)+S(A j2 A j3 ,P)+S(A j3 A j1 ,P)>S(A j1 A j2 A j3 If point P is located outside surface element j, then surface element i is not obscured by surface element j.

10. The method according to claim 5, characterized in that, The infrared radiation characteristics of surface elements are obtained by solving Planck's law, and the infrared radiation characteristics of all visible surface elements are superimposed to obtain the dynamic infrared radiation characteristics of the target group. In the step of solving the infrared radiation characteristics of the target group based on Planck's law, the expression for solving the infrared radiation characteristics of the target group satisfies: Where Rad represents the radiation intensity in the detection band, in W / sr; ε is the emissivity; A i Let i be the area of ​​element i, in meters. 2 ; θ i Let be the normal vector of surface element i and be the unit vector in the opposite direction of the viewing direction. The included angle, in degrees; t i The temperature of element i is expressed in K. λ1 represents the initial wavelength band of the probe, in μm; λ2 is the termination band of the detection, in μm; c1 is the first radiation constant, c1 = 3.7418 × 10 -8 W·m 2 ; c2 is the second radiation constant, c2 = 1.4388 × 10 4 μm·K.

Images