Modeling method of chaff cloud physical dynamic model

Abstract

The invention belongs to the chaff cloud technical field, and relates to a chaff cloud physical dynamic model modeling method comprising the following steps: obtaining a chaff cloud comprising a plurality of chaffs moving randomly; the position of the chaff obeys normal distribution with the explosion point as the original point, the spatial orientation of the chaff obeys bimodal normal distribution, the helical angular velocity of the chaff obeys normal distribution, and the wind-related velocity of the chaff obeys normal distribution, an initial parameter model of the chaff cloud is established, and the initial parameter model of each chaff is obtained; carrying out stress analysis on the chaff in the space, and establishing a helical motion model of the chaff; according to the initial parameter model and the spiral motion model of the chaff, the attitude angle and the position of each chaff are updated at a preset time step length, a motion diffusion model of the chaff cloud is obtained, and construction of the chaff cloud physical dynamic model is achieved. The method can fit the actual situation, reduces the modeling error, and improves the modeling precision.

Description

Technical Field

[0001] This application relates to the technical field of chaff cloud, and particularly to a modeling method for the physical dynamic model of chaff cloud. Background Art

[0002] As the core means of the passive interference system, the chaff cloud forms an electromagnetic barrier through the reflection of dense metal wires, showing irreplaceable actual combat value in electronic countermeasures. Historical battle examples show that it can effectively paralyze the enemy's radar detection and command links by generating high-density false signals. For example, it can cover penetration operations, mislead the defense system to attack false targets, etc., and has become a typical tactical tool in modern warfare to "exchange low losses for a high battle loss ratio". Facing the current complex geopolitical security situation, deepening the research on chaff cloud technology is crucial for enhancing both offensive and defensive capabilities: on the offensive end, it can break through the regional air defense network, and on the defensive end, it can weaken the threat of precision guidance. Its multi-scenario adaptability and low-cost characteristics have significant practical significance for breaking military encirclement and building strategic deterrence.

[0003] Among them, the accurate evaluation and optimization of chaff cloud performance highly depend on the reliability of its dynamic modeling. Currently, there are two main directions for the physical modeling of chaff cloud. The first is to analyze the dynamic characteristics of a single chaff: in a high-speed scattering environment (such as fighter jets and missile carriers), the chaff needs to withstand complex aerodynamic loads and transient flow field interference, and its motion trajectory needs to be described in real time through a high-precision aerodynamic model. The second is the modeling of the collective motion law: the large-scale diffusion of chaff cloud involves the random distribution, mutual interference, and cluster motion coupling effect of tens of thousands of metal wires, and a multi-scale model that balances computational efficiency and physical authenticity needs to be constructed. These challenges not only limit the accuracy of interference efficiency prediction but also become an academic frontier in the field of aerodynamics.

[0004] In the prior art, the modeling methods for the physical dynamic model of chaff cloud mainly include: generating chaff cloud with geometric shapes (ellipsoids, cuboids) and modeling with simple vector transmission theory, etc.

[0005] However, the models established by the above methods do not conform to the actual situation, have large errors, and insufficient accuracy. Summary of the Invention

[0006] Based on this, it is necessary to provide a modeling method for the physical dynamic model of chaff cloud in view of the above technical problems, which can conform to the actual situation, reduce modeling errors, and improve modeling accuracy.

[0007] A modeling method for the physical dynamic model of chaff cloud includes: Obtaining a chaff cloud, where the chaff cloud includes multiple randomly moving chaffs; The position of the chaff follows a normal distribution with the explosion point as the origin, the spatial orientation of the chaff follows a bimodal normal distribution, the helical angular velocity of the chaff follows a normal distribution, and the wind entrainment velocity of the chaff follows a normal distribution. An initial parameter model of the chaff cloud is established to obtain the initial parameter model of each chaff. Analyze the forces acting on the chaff in space and establish a helical motion model of the chaff. According to the initial parameter model and the helical motion model of the chaff, update the attitude angle and position of each chaff at a preset time step to obtain a motion diffusion model of the chaff cloud, thus realizing the construction of the physical dynamic model of the chaff cloud.

[0008] In one embodiment, analyzing the forces acting on the chaff in space and establishing a helical motion model of the chaff includes: Analyze the forces acting on the chaff in space. According to the low Reynolds number flow theory, obtain the component of the aerodynamic force acting on the chaff parallel to the axial direction of the chaff and the component of the aerodynamic force acting on the chaff perpendicular to the axial direction of the chaff. Analyze the forces acting on the chaff in space to obtain the vertical component of the motion velocity of the chaff and the horizontal component of the motion velocity of the chaff. Establish a helical motion model of the chaff based on the component of the aerodynamic force acting on the chaff parallel to the axial direction of the chaff, the component of the aerodynamic force acting on the chaff perpendicular to the axial direction of the chaff, the vertical component of the motion velocity of the chaff, the horizontal component of the motion velocity of the chaff, the air buoyancy, and the gravity.

[0009] In one embodiment, the position of the chaff follows a normal distribution with the explosion point as the origin, including:

[0010] where are the position components of the three coordinate axes in the geographical coordinate system, , is the standard deviation.

[0011] In one embodiment, the spatial orientation of the chaff follows a bimodal normal distribution, including:

[0012] where

[0013] where is the attitude tilt angle, is the attitude azimuth angle, is the angle standard deviation, is the distribution coefficient, is the specific inclination angle.

[0014] In one embodiment, the helical angular velocity of the chaff follows a normal distribution, including:

[0015] Wherein, is the angular velocity, is the standard deviation of the angular velocity.

[0016] In one embodiment, the wind entrainment velocity of the chaff follows a normal distribution, including:

[0017] Wherein, is the wind entrainment velocity, is the standard deviation of the wind entrainment velocity, is the mathematical expectation.

[0018] In one embodiment, the force analysis of the chaff in space is carried out. According to the low Reynolds number flow theory, the component of the aerodynamic force on the chaff parallel to the axial direction of the chaff and the component of the aerodynamic force perpendicular to the axial direction of the chaff are obtained, including:

[0019] Wherein, is the component of the aerodynamic force parallel to the axial direction of the chaff, is the component of the aerodynamic force perpendicular to the axial direction of the chaff, is the component of the oncoming flow velocity in the direction parallel to the axial direction of the chaff, is the component of the oncoming flow velocity in the direction perpendicular to the axial direction of the chaff, is the viscosity coefficient of the air fluid, is the length of the cylindrical chaff, is the radius of the cylindrical chaff.

[0020] In one embodiment, the force analysis of the chaff in space is carried out to obtain the component of the movement velocity of the chaff in the vertical direction and the component of the movement velocity in the horizontal direction, including:

[0021] Wherein,

[0022] Wherein, is the component of the movement velocity in the horizontal direction, is the component of the movement velocity in the vertical direction, is the acceleration due to gravity, is the difference in density between the chaff and the air, is the density of the chaff, is the density of the air, is the radius of the cylindrical chaff, is the attitude tilt angle, is the viscosity coefficient of the air fluid.

[0023] The above modeling method of a chaff cloud physical dynamic model is for the multi-physical field coupling modeling of the chaff cloud airburst transient. It conducts a correlation analysis on the dynamic characterization accuracy of its kinematic characteristics and the electromagnetic scattering mechanism. Through high-precision physical modeling and research on the electromagnetic scattering mechanism, it solves the electromagnetic compatibility problem in the current chaff cloud interference effectiveness evaluation and electronic countermeasure system optimization, and has the following technical effects, providing theoretical support and technical reserves for the future research and development of intelligent electronic countermeasure equipment and the construction of complex battlefield electromagnetic environments.

[0024] 1. This application has parameter scalability. It not only completely defines the explosion parameters, distribution parameters, and motion parameters, but also adds the gravitational acceleration term, which includes the three-dimensional position standard deviation and the bimodal distribution ratio parameter. All physical parameters can be directly modified, and it supports the rapid adaptation of different projectile types of parameters.

[0025] 2. This application considers the position distribution, spatial orientation distribution, helical angular velocity distribution, and wind entrainment velocity distribution of the chaff. It adopts a composite motion model, and simultaneously considers the translational motion caused by the wind field, the helical trajectory generated by the rigid body rotation, and the sedimentation effect caused by gravity; for the diffusion model of the chaff cloud, it uses the explicit Euler method for numerical solution of the motion to update the attitude angle and position of the chaff, and adds the influence of the helical motion component and gravitational acceleration on the z direction.

[0026] 3. This application enhances the visualization of the result display. It uses a black background and professional color maps, dynamically displays the simulation time, and conducts the final state multi-dimensional distribution analysis (position, velocity, angular velocity), presenting an overall professional-level three-dimensional visualization effect.

[0027] 4. This application can simulate different wind field conditions. Generally, according to various phenomena generated when the wind blows on objects on the ground or water surface, the wind force is divided into 13 levels, with the minimum being level 0 and the maximum being level 12. This application can select 0 - 12 wind levels for modeling according to the simulation needs, which is more in line with the actual chaff cloud motion trajectory.

[0028] 5. This application can conform to the actual situation, reduce the modeling error, and improve the modeling accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic flow chart of a modeling method of a chaff cloud physical dynamic model in an embodiment; Figure 2 is a schematic diagram of the forces acting on a single chaff in an embodiment; Figure 3 is a schematic diagram of the attitude angle of a single chaff in an embodiment; Figure 4 is an effect diagram of the chaff cloud motion after 1 s in a specific embodiment; Figure 5 The effect diagram after 5s of chaff cloud movement in a specific embodiment; Figure 6 The effect diagram after 10s of chaff cloud movement in a specific embodiment; Figure 7 The effect diagram after 15s of chaff cloud movement in a specific embodiment; Figure 8 The distribution diagram of the final state position of the chaff cloud in a specific embodiment; Figure 9 The distribution diagram of the final state wind entrainment velocity of the chaff cloud in a specific embodiment; Figure 10 The distribution diagram of the final state spiral angular velocity of the chaff cloud in a specific embodiment; Figure 11 The graph of the total RCS of the chaff cloud changing with time in a specific embodiment; Figure 12 The graph of the signal-to-interference ratio of the chaff cloud changing with time in a specific embodiment. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0031] In addition, in the present application, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "multiple groups" is at least two groups, such as two groups, three groups, etc., unless otherwise specifically defined.

[0032] In the present application, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, a physical connection or a wireless communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0033] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0034] The present application provides a modeling method for a chaff cloud physical dynamic model. As shown in the Figure 1 flow schematic diagram, in one embodiment, it includes: Step 101: Obtain a chaff cloud, where the chaff cloud includes multiple randomly moving chaffs.

[0035] In this step, the movement of a single chaff in the chaff cloud is random. However, for the chaff cloud as a whole, due to the existence of the group effect, the chaffs in the chaff cloud all follow a certain statistical distribution.

[0036] Step 102: The positions of the chaffs follow a normal distribution with the explosion point as the origin, the spatial orientations of the chaffs follow a bimodal normal distribution, the helical angular velocities of the chaffs follow a normal distribution, and the wind entrainment velocities of the chaffs follow a normal distribution. Establish an initial parameter model of the chaff cloud to obtain the initial parameter model of each chaff.

[0037] Specifically: Assume that all chaffs are in the initial stage of maturity. The positions of the chaffs follow a normal distribution with the explosion point as the origin:

[0038] In the formula, are the position components of the three coordinate axes in the geographical coordinate system, , is the standard deviation; When studying the chaff echo characteristics, it is necessary to analyze the variation law of the characteristic quantities extracted from different dimensions with respect to the sensitive parameters; when analyzing the influence degree of other factors except the chaff attitude on the characteristic quantities, it is necessary to determine the attitude distribution of the chaffs in the air. The chaff echo characteristics are affected by the statistical distribution of the spatial orientation. In the actual dense atmospheric environment, assume that the spatial orientation vector of the chaff is , and the spatial orientation of the chaffs follows a bimodal normal distribution:

[0039] Among them,

[0040] In the formula, is the spatial orientation expression of the chaff; is the attitude tilt angle, within the range of with inclination angles and as the centers, following a standard deviation ofD The normal distribution of is the attitude azimuth angle, which follows a uniform distribution on is the angle standard deviation, is the distribution coefficient, is the specific inclination angle; The spiral angular velocity of chaff follows a normal distribution:

[0041] wherein, is the angular velocity, is the angular velocity standard deviation; In a dense atmospheric environment, the wind-induced velocity of chaff (i.e., the velocity induced by the wind) follows a normal distribution:

[0042] wherein, is the wind-induced velocity, is the wind-induced velocity standard deviation, is the mathematical expectation; Based on the fact that the position of chaff follows a normal distribution with the explosion point as the origin, the spatial orientation of chaff follows a bimodal normal distribution, the spiral angular velocity of chaff follows a normal distribution, and the wind-induced velocity of chaff follows a normal distribution, an initial parameter model of the chaff cloud is established; according to the initial parameter model of the chaff cloud, an initial parameter model of each chaff is obtained.

[0043] In this step, how to establish the initial parameter model of the chaff cloud and how to obtain the initial parameter model of each chaff belong to the prior art and will not be elaborated here.

[0044] Step 103: Analyze the forces acting on the chaff in space and establish a spiral motion model of the chaff.

[0045] Specifically: Analyze the forces acting on the chaff in space, and according to the low Reynolds number flow theory, obtain the component of the aerodynamic force on the chaff parallel to the chaff axis and the component of the aerodynamic force on the chaff perpendicular to the chaff axis; Analyze the forces acting on the chaff in space, and obtain the vertical component of the chaff's motion velocity and the horizontal component of the chaff's motion velocity; Based on the component of the aerodynamic force on the chaff parallel to the chaff axis, the component of the aerodynamic force on the chaff perpendicular to the chaff axis, the vertical component of the motion velocity, the horizontal component of the motion velocity, the air buoyancy, and the gravity, establish a spiral motion model of the chaff.

[0046] More specifically: In the atmospheric environment, the air flow around the chaff is a low Reynolds number flow. By analyzing the forces acting on the chaff in space and according to the low Reynolds number flow theory, the component of the aerodynamic force on the chaff parallel to the chaff axis and the component of the aerodynamic force perpendicular to the chaff axis are obtained:

[0047] In the formula, is the component of the aerodynamic force parallel to the chaff axis, is the component of the aerodynamic force perpendicular to the chaff axis, is the component of the oncoming flow velocity parallel to the chaff axis, is the component of the oncoming flow velocity perpendicular to the chaff axis, is the viscosity coefficient of the air fluid, is the length of the cylindrical chaff, is the radius of the cylindrical chaff; By analyzing the forces acting on the chaff in space and based on the relationship between the chaff motion velocity components and the oncoming flow velocity components, and according to the force balance of the chaff, the component of the chaff motion velocity in the vertical direction and the component of the chaff motion velocity in the horizontal direction are obtained:

[0048] Among them,

[0049] In the formula, is the component of the chaff motion velocity in the horizontal direction in the air under windless conditions (i.e., the horizontal motion velocity component of the chaff in the air under windless conditions), is the component of the chaff motion velocity in the vertical direction in the air under windless conditions (i.e., the vertical motion velocity component of the chaff in the air under windless conditions), is the acceleration due to gravity, is the difference in density between the chaff and the air, is the density of the chaff, is the density of the air, is the radius of the cylindrical chaff; is the attitude tilt angle, which is the angle between the chaff axis and the vertical direction. In the spiral mode, the attitude tilt angle remains constant; is the viscosity coefficient of the air fluid; It can be seen from the above formula that when the chaff is horizontally oriented, i.e., θ = π / 2, the horizontal velocity component u of the chaff is 0, and at this time, the descent velocity of the chaff is the slowest, with a magnitude of ; when the chaff is vertically oriented, i.e., θ = 0 or 0 = π, the horizontal velocity component u of the chaff is 0, and at this time, the descent velocity of the chaff is the fastest, with a magnitude of ; When the chaff is in a double-inclined orientation, i.e., θ = π / 4 or θ = 3π / 4, the horizontal velocity of the chaff reaches its maximum, with a magnitude of . When the length l of the chaff is fixed, the rate of chaff cloud diffusion is closely related to the thickness of the chaff .

[0050] Based on the component of the aerodynamic force of the chaff parallel to the chaff axis, the component of the aerodynamic force perpendicular to the chaff axis, the vertical component of the motion velocity, the horizontal component of the motion velocity, the air buoyancy (F_float), and the gravity (G), as Figure 2 shown, a helical motion model of the chaff is established.

[0051] In this step, the electromagnetic scattering characteristics of the chaff cloud are closely related to its motion and diffusion characteristics. The electromagnetic echo signal of the chaff cloud is a strongly time-varying signal. Therefore, to study the accurate interpretation of the scattering characteristics of the chaff interference signal quickly, it is necessary to fully understand the motion and diffusion characteristics of the chaff cloud in the air. Analyzing the motion and diffusion characteristics of the chaff cloud is the premise and foundation for studying the electromagnetic scattering characteristics of the chaff cloud. According to the electromagnetic scattering model of the chaff cloud, the electromagnetic scattering echo of the chaff cloud is related to the motion velocity of the chaff and the distance between the chaff and the radar. Therefore, the electromagnetic scattering model of the chaff cloud is dynamically corrected using real-time chaff velocity and position information, thereby improving the accuracy of extracting electromagnetic scattering information of the chaff cloud.

[0052] Step 104: According to the initial parameter model and helical motion model of the chaff, update the attitude angle and position of each chaff at a preset time step to obtain the motion and diffusion model of the chaff cloud, and realize the construction of the physical dynamic model of the chaff cloud.

[0053] Specifically: According to the helical motion model, add a helical motion component to the initial parameter model of the chaff, and update the attitude angle and position of each chaff at a preset time step to obtain the current attitude angle and position of each chaff, then obtain the motion and diffusion model of each chaff, and further obtain the motion and diffusion model of the chaff cloud, realizing the construction of the physical dynamic model of the chaff cloud.

[0054] More specifically: Taking the center of the chaff as the origin, establish the x, y, and z axes in the due south, due east, and vertical directions respectively. Then the attitude of the chaff in the geographical coordinate system is as Figure 3 shown. Among them, the angle θ between the chaff and the vertical z-axis is called the attitude inclination angle, and the angle φ between the projection of the chaff in the xoy plane and the x-axis is called the attitude azimuth angle, and φ = φ0 + wt; where φ0 represents the initial attitude azimuth angle of the chaff, and w is the helical angular velocity of the chaff rotating around the z-axis. In addition, adding the wind entrainment velocity , the velocity components of the chaff at each moment on the x-axis and y-axis are obtained:

[0055] In the formula, is the velocity component of the chaff in the x-axis direction at each moment, is the velocity component of the chaff in the y-axis direction at each moment, is the velocity component of the wind entrainment velocity in the x-axis direction, is the velocity component of the wind entrainment velocity in the y-axis direction, is the attitude azimuth angle.

[0056] In this step, the velocity components are the velocity components of each chaff, and based on this, the subsequent motion states (including attitude angle and position) of the chaff are analyzed to construct a motion diffusion model; since the motion process and motion position of each chaff are randomly recorded, rather than only focusing on the overall motion, dynamic correction can be performed accordingly to improve the modeling accuracy.

[0057] The above modeling method for a physical dynamic model of chaff cloud aims at the multi-physical field coupling modeling of the transient air burst of chaff cloud, conducts a correlation analysis on the dynamic characterization accuracy of its kinematic characteristics and the electromagnetic scattering mechanism, and through high-precision physical modeling and research on the electromagnetic scattering mechanism, solves the electromagnetic compatibility problem in the current evaluation of chaff cloud interference effectiveness and the optimization of electronic countermeasure systems, and has the following technical effects, providing theoretical support and technical reserves for the research and development of future intelligent electronic countermeasure equipment and the construction of complex battlefield electromagnetic environments.

[0058] 1. This application has parameter scalability. It not only completely defines the explosion parameters, distribution parameters, and motion parameters, but also adds a gravitational acceleration term, which includes the three-dimensional position standard deviation and the bimodal distribution ratio parameter. All physical parameters can be directly modified, and it supports the rapid adaptation of different ammunition types of parameters.

[0059] 2. This application considers the position distribution, spatial orientation distribution, helical angular velocity distribution, and wind entrainment velocity distribution of the chaff, adopts a composite motion model, and simultaneously considers the translational motion caused by the wind field, the helical trajectory generated by the rigid body rotation, and the sedimentation effect caused by gravity; for the diffusion model of the chaff cloud, the explicit Euler method is used for numerical solution of the motion to update the attitude angle and position of the chaff, and the helical motion component and the influence of gravitational acceleration on the z direction are added.

[0060] 3. This application enhances the visualization of the result display, uses a black background and professional color maps, dynamically displays the simulation time, and conducts an end-state multi-dimensional distribution analysis (position, velocity, angular velocity), presenting an overall professional-level three-dimensional visualization effect.

[0061] 4. This application can simulate different wind field conditions. Generally, according to various phenomena generated when the wind blows on objects on the ground or water surface, the wind force is divided into 13 levels, with the minimum being level 0 and the maximum being level 12. This application can select 0 - 12 wind levels for modeling according to simulation needs, which is more in line with the actual movement trajectory of chaff clouds.

[0062] 5. This application can conform to the actual situation, reduce the modeling error, and improve the modeling accuracy.

[0063] This application uses the Gaussian Mixture Model (GMM) to achieve the generation of the bimodal distribution of the attitude inclination angle, optimizes the parameter estimation through the EM algorithm, ensures that the mathematical representations of the two peaks conform to the true warhead explosion parameters, and realizes the generation of the bimodal mixture distribution; establishes the covariance matrix of the wind speed vector, realizes the correlated multi-dimensional normal distribution through Cholesky decomposition, and conducts three-dimensional wind field coupling modeling; combines the low Reynolds number fluid-rigid body coupling dynamics, an improved algorithm based on the Physical Optics (PO) approximation, introduces the attitude angle dynamic correction factor, and conducts the solution of the dynamic electromagnetic scattering characteristics. Among them, the multi-modal statistical modeling technology, the low Reynolds number fluid-rigid body coupling dynamics, the improved algorithm of the Physical Optics (PO) approximation, the explicit Euler method used for the translational equation, the three-dimensional quaternion Runge-Kutta method used for the rotational equation, and the use of the k-d tree spatial partitioning to accelerate the neighbor search are all existing technologies. Further, using the above models and principles, numerical simulation is adopted to program and process the data for analysis to obtain the physical dynamic model of chaff clouds.

[0064] It should be understood that although Figure 1 the steps in the flowchart of Figure 1 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0065] at least a part of the steps in

[0066] 1) Generate the initial parameter model of the chaff cloud. Set the chaff length to 10 cm, the number of chaff to 10,000, and the chaff bomb to explode at a height of 100 m. The explosion center of the chaff bomb is the coordinate point (0 m, 0 m, 100 m). According to statistical theory, the initial position distribution of 10,000 chaff needs to satisfy the normal distribution, where the position standard deviations in the x, y, and z directions are all 10 m; the attitude angle distribution needs to satisfy the bimodal attitude angle distribution, where the bimodal angle means in the x and y directions are π / 4 and -π / 4 respectively, the bimodal angle standard deviations are both π / 12, and the proportion of the first peak is 0.6; the wind entrainment velocity distribution needs to satisfy the normal distribution, where the wind speed means in the x, y, and z directions are 5 m / s, 5 m / s, and 0 respectively, and the wind speed standard deviations are 0.5 m / s, 0.5 m / s, and 0.2 m / s respectively; the angular velocity mean is 4π rad / s and the standard deviation is π.

[0067] 2) After generating the initial parameter model according to step 1, generate the motion diffusion model of the chaff cloud. Set the time step to 0.05 s, update the attitude angle and position every 0.05 s, add a helical motion component to the model, set the helical radius to 0.5 m, and then add the influence of gravity in the z direction.

[0068] 3) Combine step 1 and step 2, write code, and use MATLAB software to realize model visualization and result visualization. First, set the coordinate system. The range of the x-axis is [-100, 200], the range of the y-axis is [-100, 200], and the range of the z-axis is [0, 150]. Use the parula color map for the background and perform color mapping; secondly, perform a dynamic update loop, update the scatter data, display the time in real-time, control the frame rate, and record the dynamic process. The schematic diagram of the chaff cloud moving with time is as Figures 4 to 7 shown, respectively showing the shapes and positions after the chaff moves for 1 s, 5 s, 10 s, and 15 s.

[0069] 4) Perform auxiliary visualization to realize the final state distribution analysis. First, draw the position distribution diagram. The final position distribution is as Figure 8 shown. The center of the chaff cloud position is approximately at (80 m, 80 m, 80 m). The final state distribution of the wind-induced entrainment velocity is as Figure 9 shown, mainly distributed between 6.5 m / s and 7.5 m / s; the final state distribution of the angular velocity is as Figure 10 shown, mainly distributed between 13 - 14 rad / s.

[0070] 5) Finally, calculate the RCS and signal-to-interference ratio for the overall model. Set the X-band radar with a wavelength of 3 cm and the incident wave direction along the x-axis direction. First, calculate the RCS value of each chaff, and then obtain the overall RCS value through vector addition. The result of the total RCS value changing with time is as Figure 11 shown. A peak value of 7.1 * 10 appears at 1.3 s5 m 2 , a secondary peak value of 7.08 * 10 appears at 13.8 s 5 m 2 . After that, as time goes by, the RCS value gradually stabilizes. It can be judged from this that the overall RCS value of the chaff cloud changes the most at 1.3 s and 13.8 s. Then, calculate the average position and distance of the chaff cloud, and calculate the signal-to-interference ratio. The result of the signal-to-interference ratio changing with time is as Figure 12 shown. As time increases, the signal-to-interference ratio increases from -98.43 dB to -92.42 dB. From this, it can be concluded that as the chaff cloud diffuses and gets farther away from the radar, the interference shielding performance will decline.

[0071] In summary, the present invention first realizes the characterization of airburst transient parameters through multivariate statistical distribution modeling, and establishes an initial state model of the chaff cloud including the bimodal distribution of attitude inclination angle, the Gaussian distribution of angular velocity, and the three-dimensional wind field perturbation effect. Then, based on the low Reynolds number hydrodynamics framework, a rigid body spiral motion dynamics model is constructed to reveal the diffusion and evolution law under the action of aerodynamic-mechanical coupling. Finally, a quantitative analysis method for electromagnetic scattering effects that integrates kinematic simulation and dynamic RCS calculation is developed, and the interference effectiveness attenuation mechanism is revealed through the time-varying characteristics of the signal-to-interference ratio (SIR). This method solves the problem of insufficient modeling accuracy by accurately characterizing the kinematic characteristics and electromagnetic scattering mechanism of the chaff cloud airburst transient, and provides a reliable theoretical basis for subsequent research. This method also studies the rigid body spiral motion law and the evolution of its dynamic RCS characteristics during the diffusion process of the chaff cloud, and through multi-dimensional visualization verification and battlefield environment simulation, it can be applied to the field of modern electronic countermeasures, providing a quantitative basis for radar anti-jamming effectiveness evaluation and the optimization design of electronic warfare systems. At the same time, it provides theoretical support and key technical support for the research and development of future intelligent electronic countermeasure equipment, tactical optimization, and the construction of complex battlefield electromagnetic environments, promotes the development of electronic warfare technology towards autonomy and intelligence, and is closer to the complex electromagnetic environment of actual combat, providing a high-fidelity scenario for tactical training and equipment testing.

[0072] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0073] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered that the scope described in this specification.

[0074] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A modeling method for a chaff cloud physical dynamic model, characterized in that: include: Acquire a chaff cloud, the chaff cloud comprising a plurality of randomly moving chaffs; The position of the foil strips obeys the normal distribution with the explosion point as the origin, the spatial orientation of the foil strips obeys the bimodal normal distribution, the spiral angular velocity of the foil strips obeys the normal distribution, and the wind-involved velocity of the foil strips obeys the normal distribution. The initial parameter model of the foil strip cloud is established, and the initial parameter model of each foil strip is obtained; Conduct force analysis on foil strips in space and establish a spiral motion model of foil strips; According to the initial parameter model and spiral motion model of the foil strip, the attitude angle and position of each foil strip are updated with a preset time step to obtain the motion diffusion model of the foil strip cloud, thereby realizing the construction of the physical dynamic model of the foil strip cloud.

2. A modeling method for a chaff cloud physical dynamic model according to claim 1, characterized in that: The force analysis of the foil strip in space is carried out and the spiral motion model of the foil strip is established, including: The force analysis of the foil strip in space is carried out. According to the low Reynolds number flow theory, the aerodynamic force component parallel to the axial direction of the foil strip and the aerodynamic force component perpendicular to the axial direction of the foil strip are obtained. The force analysis of the foil strip in space is performed to obtain the component of the foil strip's moving speed in the vertical direction and the component of its moving speed in the horizontal direction; A spiral motion model of the foil strip is established based on the aerodynamic force component parallel to the axial direction of the foil strip, the aerodynamic force component perpendicular to the axial direction of the foil strip, the component of the motion velocity in the vertical direction, the component of the motion velocity in the horizontal direction, air buoyancy and gravity.

3. A modeling method for a chaff cloud physical dynamic model according to claim 2, characterized in that: The location of the foil strips follows a normal distribution with the explosion point as the origin, including: In the formula, are the position components of the three coordinate axes in the geographic coordinate system, , is the standard deviation.

4. The modeling method of a chaff cloud physical dynamic model according to claim 3, characterized in that: The spatial orientation of the foil strips follows a bimodal normal distribution, including: in, In the formula, is the attitude tilt angle, is the attitude azimuth, is the standard deviation of the angle, is the distribution coefficient, is a specific inclination angle.

5. A modeling method for a chaff cloud physical dynamic model according to claim 4, characterized in that: The spiral angular velocity of the foil strip follows a normal distribution, including: In the formula, is the angular velocity, is the standard deviation of angular velocity.

6. A modeling method for a chaff cloud physical dynamic model according to claim 5, characterized in that: The wind-induced velocity of the foil follows a normal distribution, including: In the formula, The wind involves speed, is the standard deviation of wind velocity, is the mathematical expectation.

7. A modeling method for a chaff cloud physical dynamic model according to any one of claims 2 to 6, characterized in that: The force analysis of the foil strip in space is carried out. According to the low Reynolds number flow theory, the aerodynamic force parallel to the axial direction of the foil strip and the aerodynamic force perpendicular to the axial direction of the foil strip are obtained, including: In the formula, is the component of aerodynamic force parallel to the chaff axis, is the component of aerodynamic force perpendicular to the chaff axis, is the component of the incoming flow velocity parallel to the foil strip axis, is the component of the incoming flow velocity perpendicular to the foil strip axis, is the viscosity coefficient of air fluid, is the length of the cylindrical foil strip, is the radius of the cylindrical foil strip.

8. A modeling method for a chaff cloud physical dynamic model according to any one of claims 2 to 6, characterized in that: The force analysis of the foil strip in space is performed to obtain the component of the foil strip's movement velocity in the vertical direction and the component of the movement velocity in the horizontal direction, including: in, In the formula, is the component of the velocity in the horizontal direction, is the component of the velocity in the vertical direction, is the acceleration due to gravity, is the difference between the density of the foil strip and the density of air, is the density of the foil strip, is the density of air, is the radius of the cylindrical foil strip, is the attitude tilt angle, is the viscosity coefficient of air fluid.

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