Communication accessibility discrete calculation method considering earth curvature and terrain height shielding

Abstract

The invention provides a communication reachability discrete calculation method considering earth curvature and terrain height shielding. The communication reachability discrete calculation method comprises the steps that the vertical distance between the earth center and any two entities is calculated; judging whether the vertical distance is greater than the average radius of the earth, if so, considering that the communication between the entities is reachable under the earth curvature, otherwise, judging whether the vertical distance is greater than the highest point of the earth surface topography, and if so, outputting that the communication between the entities is reachable; otherwise, performing angle uniform discrete division on a triangular plane formed by the entities and the earth center, calculating an angle division ray length distance, and judging whether the angle division ray length distance is greater than the distance from the earth center to the intersection point of the angle division ray and the earth surface earth center; if not, calculating a next discrete division angle until all discrete division angles are calculated one by one and then communication between output entities is available; otherwise, directly outputting that the communication between the entities is reachable. According to the method, simple and rapid calculation of the communication accessibility between any entities in the earth space considering the earth curvature is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of command and control communication combat simulation, and in particular to a discrete calculation method for communication accessibility taking into account earth curvature and terrain height shielding. Background Art

[0002] In the simulation calculation of communication between arbitrary entities in the earth space in the command and control communication combat system, the influence of the earth's curvature is usually ignored or only the earth's curvature is considered while the influence of terrain height shielding is ignored, resulting in low accuracy and authenticity of the calculation of communication accessibility between arbitrary space entities. The current calculation method of communication accessibility between entities in the earth space does not consider the shielding of communication between entities by elevation data under real terrain conditions, and cannot accurately and quickly simulate the simulation calculation of communication accessibility of entities in the earth's continuous space, and its scope of application is limited. Therefore, it is urgent to establish multiple judgment conditions and step-by-step calculation process of communication accessibility considering the shielding of earth curvature and terrain height, realize the discrete quantitative description of continuous space and the hierarchical and rapid discretization calculation of communication accessibility between arbitrary entities in space considering the shielding of earth curvature and terrain height, reduce the number of comprehensive calculations of the communication accessibility calculation algorithm and the overall redundancy of the algorithm, and improve the authenticity, speed and accuracy of communication calculation in the combat simulation system under complex terrain conditions.

[0003] Existing patent literature does not consider the shielding of communication between entities caused by elevation data under real terrain conditions, and cannot truly, accurately and quickly simulate the simulation calculation of entity communication in the continuous space of the earth. Its applicability is limited in complex terrain areas such as hills, mountains and plateaus. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a discrete calculation method and system for communication reachability taking into account the curvature of the earth and the height shielding of the terrain.

[0005] A discrete calculation method for communication reachability considering earth curvature and terrain height shielding provided by the present invention includes:

[0006] Step S1: Calculate the vertical distance between the center of the earth and any two entities in the earth space;

[0007] Step S2: determine whether the vertical distance is greater than the average radius of the earth. If so, the entities are reachable in terms of communication under the curvature of the earth, and step S3 is executed; if not, directly output that the entities are unreachable in terms of communication, and the calculation ends.

[0008] Step S3: Determine whether the vertical distance is greater than the highest point of the earth's surface terrain. If so, the communication between the output entities is reachable; if not, execute step S4;

[0009] Step S4: dividing the triangular plane formed by the entities and the center of the earth into uniform discrete divisions according to angles;

[0010] Step S5: obtaining elevation data of the intersection of the angle division ray and the earth's surface terrain, and calculating the length of the angle division ray;

[0011] Step S6: Determine whether the length of the angle division ray is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle and return to step S5 until all discrete division angles are calculated one by one and the output entities can communicate with each other. If not, directly output the entities can communicate with each other.

[0012] Preferably, the step S1 comprises:

[0013] Step S1.1: Calculate the distances |OA| and |OB| between the entity and the center of the earth respectively, using the following formula:

[0014]

[0015] Among them, O represents the center of the earth, A represents the first entity, and x A ,y A ,z A is the coordinate value of the first entity, B represents the second entity, x B ,y B ,z B are the coordinate values ​​of the second entity;

[0016] Step S1.2: Calculate the distance between entities |AB|, the calculation formula is as follows:

[0017]

[0018] Step S1.3: Calculate the area S of the triangle ΔOAB formed by the centers of any two solid circles and the terrain. The calculation formula is as follows:

[0019]

[0020] Step S1.4: Calculate the vertical distance |OC| from the center of the earth to the entity. The calculation formula is as follows:

[0021]

[0022] Preferably, the highest point on the earth's surface terrain refers to the altitude of Mount Everest, which is 0.8849 km.

[0023] Preferably, the uniform angle discrete division in step S4 includes taking the center of the earth O as the center and the straight line OC as the rotation axis, and uniformly and sequentially discretely dividing the angles ∠COA and ∠COB at a fixed small angle Δθ, wherein A and B are the centers of the first entity and the second entity respectively, and C is the perpendicular point of the perpendicular line from the center of the earth O to the straight line AB.

[0024] Preferably, step S5 includes the intersection point of the rotated ray and the straight line AB being D, the intersection point of the straight line OD and the earth's surface terrain being point E, and the altitude of the earth's surface terrain point E, which is easily obtained according to the global surface high-level data, being H E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

[0025] A communication accessibility discrete computing system considering earth curvature and terrain height shielding provided by the present invention comprises:

[0026] Module M1: Calculate the vertical distance between the center of the earth and any two entities in the earth's space;

[0027] Module M2: Determine whether the vertical distance is greater than the average radius of the earth. If so, the entities are able to communicate with each other under the curvature of the earth, and execute module M3; if not, directly output that the entities are unreachable, and end the calculation.

[0028] Module M3: Determine whether the vertical distance is greater than the highest point of the earth's surface terrain. If so, output that the communication between the entities is reachable; if not, execute module M4;

[0029] Module M4: Divide the triangular plane formed by the entities and the center of the earth into uniform discrete divisions according to angles;

[0030] Module M5: Obtain the elevation data of the intersection of the angle division ray and the earth's surface terrain, and calculate the length distance of the angle division ray;

[0031] Module M6: Determine whether the length of the angle division ray is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle to trigger module M5, until all discrete division angles are calculated one by one and the communication between output entities is reachable; if not, directly output the communication between entities is reachable.

[0032] Preferably, the module M1 comprises:

[0033] Module M1.1: Calculate the distances |OA| and |OB| between the entity and the center of the earth respectively. The calculation formula is as follows:

[0034]

[0035] Among them, O represents the center of the earth, A represents the first entity, and x A ,y A ,z A is the coordinate value of the first entity, B represents the second entity, x B ,y1,z B are the coordinate values ​​of the second entity;

[0036] Module M1.2: Calculate the distance between entities |AB|, the calculation formula is as follows:

[0037]

[0038] Module M1.3: Calculate the area S of the triangle ΔOAB formed by the centers of any two solid circles and the terrain. The calculation formula is as follows:

[0039]

[0040] Module M1.4: Calculate the vertical distance |OC| from the center of the earth to the entity. The calculation formula is as follows:

[0041]

[0042] Preferably, the highest point on the earth's surface terrain refers to the altitude of Mount Everest, which is 0.8849 km.

[0043] Preferably, the uniform angle discrete division in the module M4 includes taking the center of the earth O as the center and the straight line OC as the rotation axis, and uniformly and sequentially discretely dividing the angles ∠COA and ∠COB at a fixed small angle Δθ, wherein A and B are the centers of the first entity and the second entity respectively, and C is the perpendicular point of the perpendicular line from the center of the earth O to the straight line AB.

[0044] Preferably, module M5 includes the intersection point D of the rotated ray and the straight line AB, the intersection point E of the straight line OD and the earth's surface terrain, and the altitude of the earth's surface terrain point E is easily obtained according to the global surface high-level data as H E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The present invention constructs a method for calculating the communication reachability between any entities in the earth's space that is blocked by the earth's curvature, proposes a communication reachability criterion considering the highest altitude of the earth's surface terrain, and realizes a simple and fast calculation of the communication reachability between any entities in the earth's space that takes into account the earth's curvature.

[0047] 2. The present invention is based on the real earth surface terrain elevation data. It divides the continuous plane space between entities into uniform discretized divisions at a fixed small angle, calculates the communication reachability corresponding to the discrete division angles one by one with the vertical line as the center, and iterates the calculations from the most likely place to be shielded by the terrain to reduce the number of algorithm calculations, thereby achieving efficient and rapid calculation of the communication reachability between entities in any space affected by the height shielding of the earth surface terrain along the way.

[0048] 3. The present invention establishes multiple judgment conditions and a step-by-step calculation process for the communication reachability between arbitrary spatial entities, realizes the discrete quantitative description of continuous space and the rapid discretization calculation of the communication reachability between arbitrary spatial entities taking into account the earth's curvature and terrain height shielding, and reduces the number of comprehensive calculations of the communication reachability calculation algorithm and the overall redundancy of the algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0050] Figure 1 A flow chart of a fast discrete calculation method for communication reachability taking into account earth curvature and terrain height shielding in an embodiment of the present invention;

[0051] Figure 2 A schematic diagram of the fast discrete calculation position of communication reachability taking into account the earth's curvature and terrain height shielding in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0053] The present invention constructs a calculation method for communication accessibility between arbitrary entities in earth space that is blocked by earth curvature, considers the judgment of communication accessibility at the highest altitude of the earth's surface terrain, and based on real terrain elevation data, evenly discretizes the continuous plane space between entities in an angle-based manner. A calculation method for communication accessibility between arbitrary space entities that is affected by the height shielding of the earth's surface terrain along the way is proposed, multiple judgment conditions and a step-by-step calculation process for communication accessibility between arbitrary space entities are established, and a discrete quantitative description of continuous space and a fast discretization calculation of communication accessibility between arbitrary space entities that considers the shielding of earth curvature and terrain height are achieved, thereby reducing the number of comprehensive calculations of the communication accessibility calculation algorithm and the overall redundancy of the algorithm.

[0054] Embodiment 1

[0055] According to the present invention, a discrete calculation method for communication reachability considering the earth curvature and terrain height shielding is provided, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0056] Step S1: Calculate the vertical distance between the center of the earth and any two entities in the earth space. A ,y A ,z A ) and entity B(x B ,y B ,z B ) Coordinates in the Earth-centered Earth-fixed coordinate system, the Earth-centered coordinates are O(0,0,0), the average radius of the Earth is R0 = 6371.393km, and the distance from entity A to the Earth's center O |OA|, the distance from entity B to the Earth's center O |OB|, and the distance between entity A and entity B |AB| are obtained. The area S of the triangle ΔOAB is calculated by Heron's formula, and then the perpendicular distance |OC| from the Earth's center to the straight line AB is calculated. The calculation formulas are as follows:

[0057]

[0058] in Then calculate the vertical distance from the center of the earth to the straight line AB

[0059] Step S2: Determine whether the vertical distance is greater than the average radius of the earth. If so, the entity is considered to be reachable under the curvature of the earth, and step S3 is executed; if not, the entity is directly fed back that the communication is unreachable, and the calculation is terminated. The communication accessibility criterion between any entity A and entity B considering the curvature of the earth is: if the vertical distance |OC| from the center of the earth O to the straight line AB is greater than the average radius of the earth R0, that is, |OC|>R0, then entity A and entity B are considered to be reachable under the curvature of the earth, and step S3 is entered; otherwise, the communication between entity A and entity B is directly fed back that the communication is unreachable, and the calculation is terminated.

[0060] Step S3: Determine whether the vertical distance is greater than the highest point of the earth's surface terrain. If so, output that the communication between entities is reachable; if not, execute step S4. It is known that the highest point of the earth's surface terrain is Mount Everest, and the altitude of Mount Everest is 0.8849km. In order to reduce the number of comprehensive calculations of the algorithm, the communication reachability criterion between any entity A and entity B at the highest altitude of the earth's surface terrain is considered as follows: if the vertical distance |OC| from the center of the earth to the straight line AB is greater than the center of the earth to the highest point of the earth's surface terrain, that is, |OC|>(R0+0.8849), then entity A and entity B are considered to be able to communicate at the highest altitude of the earth's surface terrain, and directly feedback that entity A and entity B are able to communicate, and the calculation ends; otherwise, enter step S4.

[0061] Step S4: Perform angle-uniform discrete division on the triangular plane formed by the entities and the center of the earth. Considering the communication accessibility of the terrain height shielding, the ΔOAB triangular plane continuous space is discretized into an angle grid, with the center of the earth O as the center and the straight line OC as the rotation axis, and the angles ∠COA and ∠COB are uniformly discretely divided in turn with a fixed small angle Δθ.

[0062] Step S5: Obtain the elevation data of the intersection point between the angle division ray and the earth's surface terrain, and calculate the length of the angle division ray. The intersection point of the rotated ray and the straight line AB is D, and the intersection point of the straight line OD and the earth's surface terrain is point E. According to the global surface high-level data, it is easy to obtain the altitude of the earth's surface terrain point E as H. E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

[0063] Step S6: Determine whether the angle division ray length distance is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle and return to step S5 until all discrete division angles are calculated one by one and the communication between the output entities is reachable; if not, directly output the communication between the output entities. The criterion for communication accessibility considering the height of terrain shielding is as follows: If the straight line OD distance is not greater than the distance from the earth's surface terrain point E to the center of the earth O |OE|, that is, |OD|≤(R0+H E ), then the direct feedback entity A and entity B are unreachable for communication, and the calculation is terminated; otherwise N=N+1, and the process goes to step S4 until all discrete division angles are calculated one by one, that is, (N×Δθ)>∠COA and (N×Δθ)>∠COB, then the direct feedback entity A and entity B are reachable for communication, and the calculation is terminated.

[0064] In summary, the present invention provides a fast discrete calculation method for communication accessibility taking into account the shielding of the earth's curvature and the height of the terrain, constructs a calculation method for the communication accessibility between any entities in the earth's space subject to shielding by the earth's curvature, gives a communication accessibility criterion considering the highest altitude of the earth's surface terrain, and based on the real earth's surface terrain elevation data, the continuous plane space between entities is uniformly discretized by angle by a fixed small angle, and a calculation method for the communication accessibility between any space entities subject to shielding by the height of the projected earth's surface terrain along the way is proposed, multiple judgment conditions and a step-by-step calculation process for the communication accessibility between any space entities are established, and a discrete quantitative description of the continuous space and a fast discretization calculation of the communication accessibility between any space entities taking into account the shielding of the earth's curvature and the height of the terrain are realized, the number of comprehensive calculations of the communication accessibility calculation algorithm and the overall redundancy of the algorithm are reduced, and the authenticity and speed are high.

[0065] Compared with existing methods, the fast discrete calculation method of communication reachability taking into account the earth's curvature and terrain height shielding provided by the present invention can effectively and quickly determine the communication reachability between any entities in the earth's continuous space, improve the authenticity, speed and accuracy of communication simulation calculations, and is suitable for efficient and fast calculation of communication reachability between entities in complex terrain environments.

[0066] Embodiment 2

[0067] The present invention also provides a discrete calculation system for communication reachability that takes into account earth curvature and terrain height shielding. The discrete calculation system for communication reachability that takes into account earth curvature and terrain height shielding can be implemented by executing the process steps of the discrete calculation method for communication reachability that takes into account earth curvature and terrain height shielding. That is, those skilled in the art can understand the discrete calculation method for communication reachability that takes into account earth curvature and terrain height shielding as a preferred implementation of the discrete calculation system for communication reachability that takes into account earth curvature and terrain height shielding.

[0068] A communication accessibility discrete computing system considering earth curvature and terrain height shielding provided by the present invention comprises:

[0069] Module M1: Calculate the vertical distance between the center of the Earth and any two entities in Earth space. Module M1 includes:

[0070] Module M1.1: Calculate the distances |OA| and |OB| between the entity and the center of the earth respectively. The calculation formula is as follows:

[0071]

[0072] Among them, O represents the center of the earth, A represents the first entity, and x A ,y A ,z Ais the coordinate value of the first entity, B represents the second entity, x B ,y B ,z B are the coordinate values ​​of the second entity.

[0073] Module M1.2: Calculate the distance between entities |AB|, the calculation formula is as follows:

[0074]

[0075] Module M1.3: Calculate the area S of the triangle ΔOAB formed by any two solid circle centers and the terrain. The calculation formula is as follows:

[0076]

[0077]

[0078] Module M1.4: Calculate the vertical distance |OC| from the center of the earth to the entity. The calculation formula is as follows:

[0079]

[0080] Module M2: Determine whether the vertical distance is greater than the average radius of the earth. If so, the communication between entities is reachable under the curvature of the earth, and execute module M3. If not, directly output that the communication between entities is unreachable and end the calculation.

[0081] Module M3: Determine whether the vertical distance is greater than the highest point on the earth's surface. If so, output that the communication between entities is reachable. If not, execute module M4. The highest point on the earth's surface is the altitude of Mount Everest, which is 0.8849 km.

[0082] Module M4: Performing uniform angle discrete division on the triangular plane formed by the entities and the center of the earth. The uniform angle discrete division in module M4 includes taking the center of the earth O as the center and the straight line OC as the rotation axis, and performing uniform angle discrete division on the angles ∠COA and ∠COB in sequence with a fixed small angle Δθ, where A and B are the centers of the first entity and the second entity respectively, and C is the perpendicular point of the perpendicular line from the center of the earth O to the straight line AB.

[0083] Module M5: Obtain the elevation data of the intersection of the angle-divided ray and the earth's surface terrain, and calculate the length of the angle-divided ray. Module M5 includes the intersection of the rotated ray and the straight line AB as D, the intersection of the straight line OD and the earth's surface terrain as point E, and the altitude of the earth's surface terrain point E is easily obtained based on the global surface high-level data as H E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

[0084] Module M6: Determine whether the length of the angle division ray is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle to trigger module M5, until all discrete division angles are calculated one by one and output that the communication between entities is reachable. If not, directly output that the communication between entities is reachable.

[0085] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0086] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A discrete calculation method for communication reachability considering earth curvature and terrain height shielding, characterized in that: include: Step S1: Calculate the vertical distance between the center of the earth and any two entities in the earth's space; Step S2: determine whether the vertical distance is greater than the average radius of the earth. If so, the entities are reachable in terms of communication under the curvature of the earth, and step S3 is executed; if not, directly output that the entities are unreachable in terms of communication, and the calculation ends. Step S3: Determine whether the vertical distance is greater than the highest point of the earth's surface terrain. If so, the output entities are reachable for communication; if not, execute step S4; Step S4: dividing the triangular plane formed by the entities and the center of the earth into uniform discrete divisions according to angles; Step S5: obtaining elevation data of the intersection point between the angle division ray and the earth's surface terrain, and calculating the length distance of the angle division ray; Step S6: Determine whether the length of the angle division ray is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle and return to step S5 until all discrete division angles are calculated one by one and the output entities can communicate with each other. If not, directly output the entities can communicate with each other.

2. The discrete calculation method for communication reachability considering earth curvature and terrain height shielding according to claim 1 is characterized in that: The step S1 comprises: Step S1.1: Calculate the distances |OA| and |OB| between the entity and the center of the earth respectively, using the following formula: Among them, O represents the center of the earth, A represents the first entity, and x A ,y A ,z A is the coordinate value of the first entity, B represents the second entity, x B ,y B ,z B are the coordinate values ​​of the second entity; Step S1.2: Calculate the distance between entities |AB|, the calculation formula is as follows: Step S1.3: Calculate the area S of the triangle ΔOAB formed by the centers of any two solid circles and the terrain. The calculation formula is as follows: Step S1.4: Calculate the vertical distance |OC| from the center of the earth to the entity. The calculation formula is as follows:

3. The discrete calculation method of communication reachability considering earth curvature and terrain height shielding according to claim 1 is characterized in that: The highest point on the earth's surface is the altitude of Mount Everest, which is 0.8849 km.

4. The discrete calculation method for communication reachability considering earth curvature and terrain height shielding according to claim 1 is characterized in that: The uniform angle discrete division in step S4 includes taking the center of the earth O as the center and the straight line OC as the rotation axis, and uniformly and sequentially discretely dividing the angles ∠COA and ∠COB at a fixed small angle Δθ, wherein A and B are the centers of the first entity and the second entity respectively, and C is the perpendicular point of the perpendicular line from the center of the earth O to the straight line AB.

5. The discrete calculation method for communication reachability considering earth curvature and terrain height shielding according to claim 4 is characterized in that: Step S5 includes the intersection point of the rotated ray and the straight line AB being D, the intersection point of the straight line OD and the earth's surface terrain being point E, and the altitude of the earth's surface terrain point E, which is easily obtained according to the global surface high-level data, being H E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

6. A discrete computing system for communication reachability taking into account earth curvature and terrain height shielding, characterized in that: include: Module M1: Calculate the vertical distance between the center of the earth and any two entities in the earth's space; Module M2: Determine whether the vertical distance is greater than the average radius of the earth. If so, the entities are able to communicate with each other under the curvature of the earth, and execute module M3; if not, directly output that the entities are unreachable, and end the calculation. Module M3: Determine whether the vertical distance is greater than the highest point of the earth's surface terrain. If so, output that the communication between the entities is reachable; if not, execute module M4; Module M4: Divide the triangular plane formed by the entities and the center of the earth into uniform discrete divisions according to angles; Module M5: obtain the elevation data of the intersection point between the angle division ray and the earth's surface terrain, and calculate the length distance of the angle division ray; Module M6: Determine whether the length of the angle division ray is greater than the distance from the center of the earth to the intersection of the angle division ray and the center of the earth's surface. If so, calculate the next discrete division angle to trigger module M5, until all discrete division angles are calculated one by one and the communication between output entities is reachable; if not, directly output the communication between entities is reachable.

7. The communication accessibility discrete calculation system considering earth curvature and terrain height shielding according to claim 6, characterized in that: The module M1 comprises: Module M1.1: Calculate the distances |OA| and |OB| between the entity and the center of the earth respectively. The calculation formula is as follows: Among them, O represents the center of the earth, A represents the first entity, and x A ,y A ,z A is the coordinate value of the first entity, B represents the second entity, x B ,y B ,z B are the coordinate values ​​of the second entity; Module M1.2: Calculate the distance between entities |AB|, the calculation formula is as follows: Module M1.3: Calculate the area S of the triangle ΔOAB formed by the centers of any two solid circles and the terrain. The calculation formula is as follows: Module M1.4: Calculate the vertical distance |OC| from the center of the earth to the entity. The calculation formula is as follows:

8. The communication accessibility discrete calculation system considering earth curvature and terrain height shielding according to claim 6, characterized in that: The highest point on the earth's surface is the altitude of Mount Everest, which is 0.8849 km.

9. The communication accessibility discrete calculation system considering earth curvature and terrain height shielding according to claim 6, characterized in that: The uniform angle discrete division in the module M4 includes taking the center of the earth O as the center and the straight line OC as the rotation axis, and uniformly and sequentially discretely dividing the angles ∠COA and ∠COB at a fixed small angle Δθ, wherein A and B are the centers of the first entity and the second entity respectively, and C is the perpendicular point of the perpendicular line from the center of the earth O to the straight line AB.

10. The communication accessibility discrete calculation system considering earth curvature and terrain height shielding according to claim 9, characterized in that: Module M5 includes the intersection point D of the rotated ray and the straight line AB, the intersection point E of the straight line OD and the earth's surface terrain, and the altitude of the earth's surface terrain point E is easily obtained according to the global surface high-level data as H E km, then |OE|=(R0+H E ), we can get angle ∠COD = Δθ × N (where N = 1, 2, ...), and the straight line OD distance can be obtained according to the angle relationship N represents the number of discrete division angles.

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