Method for determining visible elements of fuze against land and sea background

Abstract

The present invention discloses a method for determining visible elements of a fuze to a land and sea background, which has high precision and high efficiency. The method of the present invention comprises the following steps: (10) initial parameter acquisition: dividing land and sea grid elements that meet far field conditions, and acquiring detection field initial parameters and model initial parameters; (20) constructing a land and sea environment fuze detection field extension model: constructing a fuze detection field model according to the fuze detection field initial parameters, and expanding to obtain a land and sea environment fuze detection field extension model, and distinguishing internal elements and boundary elements; (30) land and sea environment detection field boundary element processing: recursively subdividing the land and sea environment boundary elements according to the detection field range determined by the extension model; (40) land and sea environment detection field adaptive processing: adaptively processing the boundary elements after recursive subdivision according to whether the fuze detection area is visible and whether it is blocked by other elements, and obtaining visible elements of the fuze to the land and sea background that contribute to the environmental echo.

Description

Technical Field

[0001] The invention belongs to the technical field of fuze detection, and in particular relates to a method for determining visible elements of a fuze against a ground or sea background. Background Art

[0002] Due to the rapid development of modern low-altitude and ultra-low-altitude radar technology, accurate detection of complex environments such as the ground and sea has become an indispensable link in the implementation of accurate and effective strikes on targets such as shipborne radars and floating radars on the sea surface in low-altitude or even ultra-low-altitude environments. Under the interference of complex ground and sea environments, how to effectively detect and strike targets has become a major issue in low-altitude missions.

[0003] Visible surface elements refer to the surface elements that can be detected within the fuze detection field and contribute to the environmental echo signal under the background of land and sea modeling simulation.

[0004] At present, low-altitude detection experiments generally use real objects instead of targets and conduct detection and rendezvous experiments in a real test field environment. In low-altitude detection simulation experiments, the distance between the projectile and the target is less than the detection distance of the fuze to simulate and obtain visible elements.

[0005] However, when performing experimental tasks at low altitudes, the cost is high, the time period is long, and the environmental requirements are high. When simulating on traditional software platforms, due to the local illumination effect of fuze detection during the detection of the ground and sea surfaces, the randomness of the center point of the surface element at the intersection of the fuze beam and the environmental surface element will cause the calculated contribution of the surface element to deviate too much from the actual value, resulting in reduced accuracy. In addition, excessive processing of surface elements in order to improve accuracy will lead to reduced operating efficiency, and the real-time performance of the simulation cannot be guaranteed, resulting in erroneous simulation results, which greatly reduces the reference value of the visible surface elements provided in the subsequent signal processing process.

[0006] In summary, the problems existing in the prior art are that the accuracy is not high enough and the efficiency is low when determining the visible elements of the fuze against the ground and sea background. Summary of the invention

[0007] The purpose of the present invention is to provide a method for determining visible elements of a fuze against a ground and sea background, which has high accuracy and high efficiency and can reduce the cost of experimental tasks and improve the accuracy and efficiency of traditional experimental simulation methods.

[0008] The technical solution to achieve the purpose of the present invention is:

[0009] A method for determining visible elements of a fuze against a land and sea background comprises the following steps:

[0010] (10) Initial parameter acquisition: Divide the ground and sea grid elements that meet the far-field conditions to obtain the initial parameters of the fuze detection field and the initial parameters of the ground and sea environment models;

[0011] (20) constructing an extended model of the fuze detection field in a land-sea environment: constructing a fuze detection field model according to the initial parameters of the fuze detection field, and then expanding the model to obtain an extended model of the fuze detection field in a land-sea environment, and distinguishing internal facets and boundary facets according to the judgment conditions;

[0012] (30) Processing the boundary facets of the land and sea environment detection field: according to the detection field range determined by the detection field expansion model, subdividing the land and sea environment boundary facets respectively, and recursively subdividing the land and sea environment boundary facets after determining the number of recursive calls;

[0013] (40) Adaptive processing of the land and sea environment detection field: Based on whether the boundary face elements after recursive subdivision are visible to the fuze detection area and whether they are blocked by other face elements, adaptive processing is performed on them to obtain the visible face elements of the fuze to the land and sea background that contribute to the environmental echo.

[0014] Compared with the existing traditional experiments, the present invention has the following significant advantages:

[0015] 1. Improved accuracy of visible facets: The extended model of the fuze detection field for land and sea environment proposed in the present invention improves the detection range of the detection field boundary, thereby ensuring the integrity of the facets at the boundary of the fuze detection field. In addition, the fuze detection method at the boundary is corrected, that is, internal facets and boundary facets are distinguished. The internal facets refer to the environmental facets that are completely within the fuze detection field range, and the boundary facets refer to the environmental facets within the detection field range of the extended model of the fuze detection field except the internal facets. Then, a recursive subdivision algorithm is used for the boundary facets, and the subdivided small facets are detected, judged and calculated, so that the accuracy of the visible facets at the boundary of the fuze detection field for land and sea background is greatly improved;

[0016] 2. Improved efficiency: The internal facet processing method within the land and sea environment detection field proposed in the present invention adopts a simple and efficient center point judgment method, and does not need to recursively subdivide and iterate to increase the amount of calculation like the boundary facets, thereby ensuring the efficiency of the entire algorithm.

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the main flow chart of the method for determining visible elements of the fuze against the ground and sea background of the present invention.

[0019] Figure 2 for Figure 1 Flowchart of the steps for constructing the expansion model of the detection field of the ground-sea environment fuze.

[0020] Figure 3 for Figure 1 Flowchart of the boundary surface element processing steps for the mid-sea environmental detection field.

[0021] Figure 4 Schematic diagram of boundary face subdivision processing.

[0022] Figure 5 for Figure 1 Flow chart of the visible element determination steps for the mid-sea environmental detection field. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, the method for determining visible elements of the fuze against the ground and sea background of the present invention comprises the following steps:

[0024] (10) Initial parameter acquisition: Divide the ground and sea grid elements that meet the far-field conditions to obtain the initial parameters of the fuze detection field and the initial parameters of the ground and sea environment models;

[0025] The (10) initial parameter acquisition step comprises:

[0026] (11) Dividing the ground and sea grid cells to meet the far-field conditions: Under the near-field conditions, the environmental grid cells are divided according to the model surface division criteria in the microwave band, that is, the number of divided cells is not less than the ratio of the model surface area to half the square of the maximum linear size of the model cell, to meet the far-field conditions;

[0027] Fuze detection belongs to the near-field environment. At this time, the distance R between the fuze and the surface element of the land and sea environment model and the maximum linear size D of the surface element of the land and sea environment model are of the same order of magnitude, and no longer meet the far-field conditions. According to the following formula, the criterion for dividing the model surface in the microwave section can make the surface element size of the land and sea grid meet the far-field conditions, and then the small surface elements on the model surface can be treated as point targets. If it is assumed that the surface area of ​​the model is S, and N is the number of surface elements divided by the surface element surface, then the criterion for dividing the model surface in the microwave section is:

[0028]

[0029] In addition, in order to make the obtained model more appropriate to the actual situation, fewer facets can be divided when the surface curvature of the model changes little, and more facets can be divided where the surface curvature of the model changes greatly. The maximum size of the small facet is preferably less than one tenth of the typical value of the distance.

[0030] (12) Obtaining the initial parameters of the fuze detection field: Obtaining the initial parameters of the fuze detection field, including: the fuze action range LaserR, in m, the missile radius missileradius, in m, the fuze beam inclination angle theta1, in degrees, the fuze beam thickness theta2, in degrees, the fuze center offset Fuse_Cntr, in m, the missile axis vector missile_axis_dir, no unit, the fuze yaw angle phi_m, in degrees, the fuze pitch angle theta_m, in degrees, the fuze roll angle gama_m, in degrees;

[0031] (13) Obtaining the initial parameters of the land and sea environment model: Obtaining the initial parameters of the land and sea environment model, including: terrain altitude rnd, in m, sea surface fluctuation level range, unitless, ground height ter_height in m, sea surface height sea_height in m, terrain coefficient A: Ter_A, unitless, terrain coefficient B: Ter_B, unitless, terrain coefficient beta0: Ter_beta0, unitless, and vertex coordinate vectors point1, point2, point3 of the land and sea triangles, normal vector of the triangle, shelter flag indicating whether it is blocked, and sea / ter flag indicating the type of environment surface.

[0032] (20) constructing an extended model of the fuze detection field in a land-sea environment: constructing a fuze detection field model according to the initial parameters of the fuze detection field, and then expanding the model to obtain an extended model of the fuze detection field in a land-sea environment, and distinguishing internal facets and boundary facets according to the judgment conditions;

[0033] like Figure 2 As shown, the step (20) of constructing the ground-sea environment fuze detection field expansion model includes:

[0034] (21) constructing a fuze detection field model: according to the initial parameters of the fuze detection field, determining the inclination angle and thickness of the fuze beam, rotating the inclination beam inward and outward along the angle between the beam and the longitudinal axis of the fuze by half of the thickness of the fuze beam, that is, forming a detection field in a single direction, and rotating the single-direction detection field around the longitudinal axis of the fuze for one circle, thereby obtaining a fuze detection field model corresponding to the initial parameters;

[0035] (22) distinguishing the position of the face element: expanding the fuze detection field extension model to obtain the fuze detection field extension model, and distinguishing the face elements into internal face elements and boundary face elements according to the fuze detection field extension model;

[0036] In the fuze detection algorithm, the angle judgment between the vector between the fuze and the center point and the missile axis vector is extended to a certain range, that is, [theta1-3*theta2, theta1+3*theta2]. At the same time, the effective distance is also extended to 1.2 times of the original effective distance, that is, 1.2*LaserR. In this way, the detection field expansion model covers all environmental surface elements at the boundary of the fuze detection field, ensuring the accuracy of subsequent detection results.

[0037] In the above case, internal face elements and boundary face elements can be distinguished according to different judgment conditions, namely:

[0038] LineDir=Vdir(Get_face_center(temp_face[i].point1,temp_face[i].point2,te mp_face[i].point3),Fuse_Cntr);

[0039] LineDir1=Vdir(temp_face[i].point1,Fuse_Cntr);

[0040] LineDir2=Vdir(temp_face[i].point2,Fuse_Cntr);

[0041] LineDir3=Vdir(temp_face[i].point3,Fuse_Cntr);

[0042] a=AgBV1(LineDir,missile_axis_dir)*180.0 / M_PI;

[0043] a1=AgBV1(LineDir1,missile_axis_dir)*180.0 / M_PI;

[0044] a2=AgBV1(LineDir2,missile_axis_dir)*180.0 / M_PI;

[0045] a3=AgBV1(LineDir3,missile_axis_dir)*180.0 / M_PI;

[0046] In the above expression, LineDir is the line vector between the center point of the i-th face element and the offset of the fuze, and the following LineDir1, LineDir2, and LineDir3 are the line vectors between the 1st, 2nd, and 3rd vertices of the face element and the offset of the fuze, respectively. a is the angle between LineDir and the axis of the missile, a1 is the angle between LineDir1 and the axis of the missile, a2 is the angle between LineDir2 and the axis of the missile, and a3 is the angle between LineDir3 and the axis of the missile.

[0047] a<=thetaa+3*thetab&&a>=thetaa-3*thetab&&absv(LineDir)<1.2*thetac, theta represents the fuze beam inclination, thetab represents the fuze beam thickness, and thetac represents the fuze action distance. When this condition is met, all the facets of the detection field extension model are included. In this case, if the following conditions are met, it indicates that the facet is an internal facet, otherwise the facet is a boundary facet.

[0048] a1<=thetaa+thetab / 2&&a1>=thetaa-thetab / 2&&absv(LineDir1) <thetac&&

[0049] a2<=thetaa+thetab / 2&&a2>=thetaa-thetab / 2&&absv(LineDir2) <thetac&&a3<=thetaa+thetab / 2&&a3> =thetaa-thetab / 2&&absv(LineDir3) <theta

[0050] (30) Processing the boundary facets of the land and sea environment detection field: according to the detection field range determined by the detection field expansion model, subdividing the land and sea environment boundary facets respectively, and recursively subdividing the land and sea environment boundary facets after determining the number of recursive calls;

[0051] like Figure 3 As shown, the step of processing the boundary surface elements of the land and sea environment detection field (30) includes:

[0052] (31) Boundary element subdivision: The boundary elements are divided into ground boundary elements and seaside boundary elements, and the subdivision is performed according to the following process:

[0053] Connect the center points of each side of a triangular face element to divide it into four small triangular face elements. When defining the vertices of the small triangular face elements, after point1 is determined, point2 and point3 should be determined in a unified order (for example, counterclockwise). This ensures that the normal vectors of the generated small triangular face elements are unified to avoid inaccurate subsequent statistical results. For example, Figure 4 As shown;

[0054] (32) Recursive subdivision of boundary elements: Based on the requirements for statistical accuracy and engineering simulation efficiency, the boundary elements are recursively subdivided.

[0055] Different situations may require different accuracy of statistical results and efficiency of engineering simulation. Users can decide the number of recursive subdivisions (creattime) according to actual conditions. That is, after each call to the subdivision function, creattime should be reduced by one. Then, the subdivision function can be called again to realize that a triangle face element is subdivided into small triangle faces multiple times. At this time, a new container (mostnew) should be used. Before each recursion, the data in the container should be cleared, and the subdivided triangle face data should be placed in it. Then, the current mostnew container should be called in the next recursive call, that is, create_triangle(mostnew). Create_triangle is the recursive subdivision function.

[0056] (40) Adaptive processing of the land and sea environment detection field: Based on whether the boundary face elements after recursive subdivision are visible to the fuze detection area and whether they are blocked by other face elements, adaptive processing is performed on them to obtain the visible face elements of the fuze to the land and sea background that contribute to the environmental echo.

[0057] First, the small facets after recursive subdivision are used to judge the fuze detection area. After adding the internal facets, all facets (internal facets and small boundary facets after recursive subdivision) are sorted from near to far, and the center point detection method is applied. That is, only when there is no facet between the vector connecting the fuze detection point and the facet center point, it is judged as a visible facet, and the invalid facets that do not contribute are eliminated.

[0058] like Figure 5 As shown, the (40) land-sea environment detection field adaptive processing step includes:

[0059] (41) Extraction of visible surface elements in the fuze detection area: the boundary surface elements visible to the fuze detection field after recursive subdivision are included in the set of visible surface elements in the fuze detection area;

[0060] Create a new container visible_mix_new, and use the center point detection method to determine whether the small triangular face element after recursive boundary subdivision is within the detection area. If it is within the detection area, put the face element into the container. Finally, for the subsequent visible face element occlusion judgment, the internal large face element also needs to be put into the container.

[0061] (42) Elimination of occluded facets: All facets in the visible facet set of the fuze detection area are sorted from near to far, and occlusion judgment is performed one by one starting from the farthest facet. If the line connecting the fuze and the center point of the facet is occluded by other facets, the facet is determined to be an invisible facet and is eliminated. The facets that remain in the set after the determination process is completed are the visible facets of the fuze relative to the ground and sea background that contribute to the environmental echo.

[0062] All the face elements put into the visible_mix_new container are sorted from near to far, and the judgment starts from the farthest face element. If the line connecting the fuse and the center point of the face element is blocked by other face elements, the face element is judged to be an invalid face element, that is, the shelter flag of the face element is changed to true, and it is put into the visible_mix_see container until all the face elements in the container are traversed. At this point, the face elements in the container are visible face elements that contribute to the environmental echo.

[0063] The scheme of the present invention realizes a method for determining visible facets of the fuze against the ground and sea background. Compared with field tests, the cost of physical experiments, including physical objects, time periods, etc., is reduced; compared with traditional experimental simulation methods, the extended model of the fuze detection field for the ground and sea environment proposed in the present invention improves the detection range of the detection field boundary and ensures the integrity of the facets at the boundary of the fuze detection field. In addition, the scheme of the present invention corrects the fuze detection method at the boundary, that is, it distinguishes between internal facets and boundary facets, and adopts a recursive subdivision algorithm for the boundary facets, so that the accuracy of the visible facets at the boundary of the fuze detection field against the ground and sea background is greatly improved, and the internal facets adopt a simple and efficient center point judgment method to ensure the efficiency of the algorithm.

Claims

1. A method for determining visible elements of a fuze against a land and sea background, characterized in that: The steps include: (10) Initial parameter acquisition: Divide the land and sea grid elements that meet the far-field conditions to obtain the initial parameters of the fuze detection field and the initial parameters of the land and sea environment models; (20) constructing an extended model of the fuze detection field in a land-sea environment: constructing a fuze detection field model according to the initial parameters of the fuze detection field, and then expanding the model to obtain an extended model of the fuze detection field in a land-sea environment, and distinguishing internal face elements and boundary face elements according to the judgment conditions; (21) Constructing a fuze detection field model: according to the initial parameters of the fuze detection field, the inclination angle and thickness of the fuze beam are determined, and the inclination beam is rotated inward and outward along the angle between the beam and the longitudinal axis of the fuze by half of the thickness of the fuze beam, that is, a detection field in a single direction is formed. The single-direction detection field is rotated around the longitudinal axis of the fuze for one circle, and the fuze detection field model corresponding to the initial parameters can be obtained; (22) distinguishing the position of the surface element: expanding the fuze detection field extension model to obtain the fuze detection field extension model, and distinguishing the surface element into an internal surface element and a boundary surface element according to the fuze detection field extension model; (30) Processing of boundary facets of the land and sea environment detection field: according to the detection field range determined by the detection field expansion model, the land and sea environment boundary facets are subdivided respectively, and after determining the number of recursive calls, the land and sea environment boundary facets are recursively subdivided; (40) Adaptive processing of the land and sea environment detection field: Based on whether the boundary face elements after recursive subdivision are visible to the fuze detection area and whether they are blocked by other face elements, adaptive processing is performed on them to obtain the visible face elements of the fuze to the land and sea background that contribute to the environmental echo.

2. The method for determining visible elements of the fuze against the ground and sea background according to claim 1, characterized in that: The (10) initial parameter acquisition step includes: (11) Divide the ground and sea grid elements to meet the far-field conditions: Divide the environment grid elements according to the model surface division criteria in the microwave band under the near-field conditions to meet the far-field conditions; (12) Obtaining the initial parameters of the fuze detection field: Obtaining the initial parameters of the fuze detection field, including: the fuze action range LaserR, in m, missile radius missileradius, in m, fuze beam inclination angle theta1, in degrees, fuze beam thickness theta2, in degrees, fuze center offset Fuse_Cntr, in m, missile axis vector missile_axis_dir, no unit, fuze yaw angle phi_m, in degrees, fuze pitch angle theta_m, in degrees, fuze roll angle gama_m, in degrees; (13) Obtaining the initial parameters of the land and sea environment model: Obtaining the initial parameters of the land and sea environment model, including: terrain altitude rnd, unit m, sea surface fluctuation level range, unitless, ground height ter_height, unit m, sea surface height sea_height, unit m, terrain coefficient A: Ter_A, unitless, terrain coefficient B: Ter_B, unitless, terrain coefficient beta0: Ter_beta0, unitless, and vertex coordinate vectors point1, point2, point3 of the land and sea triangles, normal vector of the triangle, shelter flag indicating whether it is blocked, and sea / ter flag indicating the type of environment surface.

3. The method for determining visible elements of the fuze against the ground and sea background according to claim 1, characterized in that: The step of processing the boundary surface element of the land-sea environment detection field (30) comprises: (31) Boundary element subdivision: Boundary elements are divided into ground boundary elements and seaside boundary elements, and subdivided according to the following process: Connect the center points of each side of a triangular face element to divide it into four small triangular face elements. When defining the vertices of the small triangular face elements, after point1 is determined, point2 and point3 should be determined in a unified order to ensure that the normal vectors of the generated small triangular face elements are unified. (32) Recursive subdivision of boundary elements: Based on the requirements for statistical accuracy and engineering simulation efficiency, the boundary elements are recursively subdivided.

4. The method for determining visible elements of the fuze against the ground and sea background according to claim 1, characterized in that: The step of adaptive processing of the land and sea environment detection field (40) comprises: (41) Extraction of visible surface elements in the fuze detection area: The boundary surface elements visible to the fuze detection field after recursive subdivision are included in the set of visible surface elements in the fuze detection area; (42) Elimination of occluded facets: All facets in the visible facet set of the fuze detection area are sorted from near to far, and occlusion judgment is performed one by one starting from the farthest facet. If the line connecting the fuze and the center point of the facet is occluded by other facets, the facet is determined to be an invisible facet and is eliminated. The facets that remain in the set after the determination process is completed are the visible facets of the fuze relative to the ground and sea background that contribute to the environmental echo.

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