A system and method for predicting the underwater sinking position of a lost target object

Abstract

The present invention discloses a system and method for predicting the underwater bottom position of a lost object, belonging to the field of shipbuilding and marine engineering technology. The system is used to predict the underwater position of a lost object. The system includes a user terminal and a system computing platform, and the user terminal and the system computing platform communicate with each other via an ocean communication satellite. The method includes outputting the parameters of the lost object to a module for calculating the underwater landing point distribution of the lost object, outputting the wave and current information of the lost sea area to the module for calculating the underwater landing point distribution of the lost object, predicting the bottom landing point distribution of the lost object, establishing an underwater 6-degree-of-freedom motion equation for the lost object, and predicting the underwater landing point distribution of the lost object based on the underwater 6-degree-of-freedom motion equation in combination with a Monte Carlo simulation method. The present invention can sequentially conduct searches based on the probability of the lost object's landing point distribution, thereby rationally allocating search resources, increasing the success rate of deep-sea searches, and reducing the cost of deep-sea operations.

Description

Technical Field

[0001] The invention discloses a system and method for predicting the underwater bottom position of a wrecked object, belonging to the technical field of ship and ocean engineering. Background Art

[0002] Underwater searches for lost objects are like finding a needle in a haystack, exceedingly difficult. Deep ocean currents are complex and unpredictable, making accurate predictions difficult. Furthermore, the sudden nature of marine accidents leads to significant randomness in the initial location and motion of the object. Furthermore, the periodic influence of unsteady wake vortices on the structure's drifting posture is stochastic. Combined with these factors, the underwater landing point of a lost object is subject to significant uncertainty, and the search area often extends over tens or even hundreds of kilometers. Accurately predicting the underwater landing zone of a lost object would make underwater searches more targeted, significantly improving the success rate and efficiency of the search. After a lost object is lost, it is essential to calculate and analyze its underwater location, combining information from the current field in the area of ​​the accident, thereby reducing the cost of underwater search operations. Currently, underwater detection and searches for lost objects often rely on past search experience to determine the target's final bottoming range, allowing for large-scale searches. This excessive reliance on past experience leads to significant uncertainty, resulting in a low success rate for deep-sea search and detection, and high costs for deep-sea operations. Summary of the Invention

[0003] The purpose of the present invention is to provide a system and method for predicting the underwater bottom position of a lost object, so as to solve the problem of difficulty in searching for lost objects in the prior art.

[0004] A system for predicting the underwater sinking position of a lost object includes a user terminal and a system computing platform. The user terminal and the system computing platform communicate with each other via an ocean communication satellite. The user terminal includes a user input module and a user output module. The system computing platform includes a lost object information monitoring and prediction module, an ocean information monitoring and prediction module, a lost object underwater landing point dispersion calculation module, and a result analysis module.

[0005] The user inputs the crash time and crash location of the crashed object through the user input module, and outputs them to the crashed object information monitoring and forecasting module;

[0006] The accident target information monitoring and prediction module obtains accident target parameters, including the type, shape parameters, initial motion speed, and initial motion posture of the accident target, matches the accident target parameters with the accident time and location input by the user-side input module, and outputs the accident target parameters, accident time, and location to the underwater landing point dispersion calculation module.

[0007] The ocean information monitoring and forecasting module monitors and forecasts the wave and current information of the sea area where the target object was lost, and provides real ocean environment parameters. The user input module, the lost target information monitoring and forecasting module, and the ocean information monitoring and forecasting module together constitute a virtual underwater scene, and output the wave and current information of the lost sea area to the underwater landing point dispersion calculation module of the lost target;

[0008] The underwater landing point distribution calculation module of the lost target predicts the bottom landing point distribution of the lost target based on the parameters of the lost target provided by the virtual underwater scene. The result analysis module provides the search personnel with a search strategy based on the calculation results of the underwater landing point distribution calculation module of the lost target, and gives the best search strategy among the search strategies based on the expert evaluation, and outputs it to the user end. The user end output module presents the expert evaluation results and the best search strategy to the search personnel.

[0009] A method for predicting the underwater bottom position of a lost object, using the aforementioned system for predicting the underwater bottom position of a lost object, comprises:

[0010] S1. Randomize the parameters of the crashed object and expand the parameters of the crashed object to The parameters of the crash target object in the three-dimensional random crash position coordinates are selected when calling the crash target object parameters. The data of three-dimensional random accident location coordinates are processed. ;

[0011] S2. Outputting the parameters of the crashed object to a calculation module for the underwater landing point distribution of the crashed object;

[0012] S3, outputting the wave and current information of the accident sea area to the underwater landing point distribution calculation module of the accident target;

[0013] S4. Predict the distribution of the points where the crashed object will sink to the bottom, including establishing the underwater 6-DOF motion equation of the crashed object, and predicting the distribution of the underwater points where the crashed object will sink to the bottom based on the underwater 6-DOF motion equation combined with the Monte Carlo simulation method.

[0014] Outputting the parameters of the wrecked object to the wrecked object water drop point distribution calculation module includes:

[0015] ;

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] Where, 、 、 It is The crashed object passed through The actual crash location coordinates for each time step, 、 、 It is The crashed object is in The three-dimensional motion displacement within a time step, 、 、 It is The crashed object passed The three-dimensional real-time speed of time steps, 、 、 It is The crashed object is in The three-dimensional velocity change within a time step.

[0025] S3 includes S3.1, calculation of wave height, wave phase and roll angle of the wrecked object:

[0026] ;

[0027] ;

[0028] ;

[0029] Where, is the wave height, is the wave phase, is the amplitude, is the wave number, For the wave direction, is the wave frequency, 、 、 is the three-dimensional wavefront position, It's time, is the roll angle of the crashed object.

[0030] S3 includes S3.2, calculation of three-dimensional wave propagation velocity and three-dimensional wave propagation acceleration:

[0031] ;

[0032] ;

[0033] Where, 、 、 is the three-dimensional wave propagation speed, 、 、 is the three-dimensional wave propagation acceleration, is the acceleration due to gravity, is a natural constant.

[0034] S3 includes S3.3, calculation of the coupled velocity of three-dimensional wave velocity and ocean current velocity:

[0035] ;

[0036] ;

[0037] Where, 、 、 is the coupling velocity of three-dimensional wave velocity and ocean current velocity, 、 、 is the three-dimensional ocean current velocity, is the transformation matrix, 、 are the pitch angle and yaw angle of the crashed object respectively.

[0038] S3 includes S3.4, calculating the relative velocity of the crashed object relative to the wave current:

[0039] ; ;

[0040] ; ;

[0041] ; ;

[0042] Where, 、 、 is the relative velocity of the crashed object relative to the wave current, 、 、 is the three-dimensional real-time velocity of the crashed object, yes The angular velocity of rotation in the direction yes The angular velocity of rotation in the direction It is along Position variables for directions, is the length of the crashed object.

[0043] Establishing the underwater 6-DOF motion equations of the wrecked object includes establishing the translational motion equations of the wrecked object in three directions:

[0044] ;

[0045] ;

[0046] ;

[0047] Where, is the mass of the accident object, is the density of water, is the volume of the crashed object, is the acceleration due to gravity, 、 、 is the drag force on the crashed object in three directions, 、 、 For the crashed object 、 、 Three translational additional masses in three directions, 、 、 is the angular velocity within one time step 、 、 The change value of The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, is the vortex induced force, 、 is the lateral lifting force on the crashed object in two directions, yes The angular velocity of rotation in the direction.

[0048] Establishing the underwater 6-DOF motion equation of the wrecked object includes establishing the rotation equations of the wrecked object in three directions:

[0049] ;

[0050] ;

[0051] ;

[0052] ;

[0053] ;

[0054] ;

[0055] Where, 、 、 For the crashed object 、 、 Three rotating additional masses in three directions, 、 、 The crash targets are 、 、 The moment of inertia of the direction, is the kinematic viscosity coefficient of water, is the diameter of the crashed object, 、 、 For the crashed object 、 、 The drag coefficients in three directions, 、 is the drag torque on the crashed object in two directions, 、 It is the vertical lifting moment exerted on the crashed object in two directions.

[0056] The crash target 、 The lateral lifting forces in two directions and the crashed object 、 The drag torque in two directions and the crash target 、 The vertical lifting moments in the two directions are:

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] ;

[0062] ;

[0063] Where, To calculate the circulation.

[0064] Compared with the existing technology, the present invention provides reasonable search strategies and professional suggestions for underwater detection and search of lost objects. It can carry out searches in sequence according to the probability of the landing points of the lost objects, thereby rationally allocating search resources, increasing the success rate of deep-sea searches, and reducing the cost of deep-sea operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 Schematic diagram of the overall structure of the prediction system of the present invention;

[0066] Figure 2 This is a workflow diagram of the prediction system of the present invention;

[0067] Figure 3 Flow chart of the technology for predicting the underwater landing point of the lost target;

[0068] Figure 4 Comparison between the XZ-axis prediction model results of the present invention and the water tank test results for working condition 1;

[0069] Figure 5 Comparison between the XZ axis prediction model results of the present invention and the water tank test results for working condition 2;

[0070] Figure 6 This is the overall landing point location diagram for working conditions three and four;

[0071] Figure 7 This is the local landing point location diagram for working conditions three and four;

[0072] Figure 8 The XZ axis trajectory diagram of the five-dimensional rectangular crash target falling in still water;

[0073] Figure 9 The YZ axis trajectory diagram of the five-dimensional rectangular crash target falling in still water;

[0074] Figure 10 The XZ-axis falling posture and trajectory of the cuboid crashed object in still water considering the influence of eccentric moment for working condition 6;

[0075] Figure 11 The YZ-axis falling posture and trajectory of the cuboid crashed object in still water considering the influence of eccentric moment for working condition 6;

[0076] Figure 12 The XZ-axis falling posture and falling trajectory of the rectangular crashed object in uniform flow considering the influence of eccentric moment for working condition seven;

[0077] Figure 13 The YZ-axis falling posture and falling trajectory of the rectangular crashed object in uniform flow considering the influence of eccentric moment for working condition seven;

[0078] Figure 14 The preliminary search strategy is given based on the probability diagram of the landing point of the cuboid accident target object calculated by the present invention. DETAILED DESCRIPTION

[0079] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0080] A system for predicting the underwater sinking position of a lost object includes a user terminal and a system computing platform. The user terminal and the system computing platform communicate with each other via an ocean communication satellite. The user terminal includes a user input module and a user output module. The system computing platform includes a lost object information monitoring and prediction module, an ocean information monitoring and prediction module, a lost object underwater landing point dispersion calculation module, and a result analysis module.

[0081] The user inputs the crash time and crash location of the crashed object through the user input module, and outputs them to the crashed object information monitoring and forecasting module;

[0082] The accident target information monitoring and prediction module obtains accident target parameters, including the type, shape parameters, initial motion speed, and initial motion posture of the accident target, matches the accident target parameters with the accident time and location input by the user-side input module, and outputs the accident target parameters, accident time, and location to the underwater landing point dispersion calculation module.

[0083] The ocean information monitoring and forecasting module monitors and forecasts the wave and current information of the sea area where the target object was lost, and provides real ocean environment parameters. The user input module, the lost target information monitoring and forecasting module, and the ocean information monitoring and forecasting module together constitute a virtual underwater scene, and output the wave and current information of the lost sea area to the underwater landing point dispersion calculation module of the lost target;

[0084] The underwater landing point distribution calculation module of the lost target predicts the bottom landing point distribution of the lost target based on the parameters of the lost target provided by the virtual underwater scene. The result analysis module provides the search personnel with a search strategy based on the calculation results of the underwater landing point distribution calculation module of the lost target, and gives the best search strategy among the search strategies based on the expert evaluation, and outputs it to the user end. The user end output module presents the expert evaluation results and the best search strategy to the search personnel.

[0085] A method for predicting the underwater bottom position of a lost object, using the aforementioned system for predicting the underwater bottom position of a lost object, comprises:

[0086] S1. Randomize the parameters of the crashed object and expand the parameters of the crashed object to The parameters of the crash target object in the three-dimensional random crash position coordinates are selected when calling the crash target object parameters. The data of three-dimensional random accident location coordinates are processed. ;

[0087] S2. Outputting the parameters of the crashed object to a calculation module for the underwater landing point distribution of the crashed object;

[0088] S3, outputting the wave and current information of the accident sea area to the underwater landing point distribution calculation module of the accident target;

[0089] S4. Predict the distribution of the points where the crashed object will sink to the bottom, including establishing the underwater 6-DOF motion equation of the crashed object, and predicting the distribution of the underwater points where the crashed object will sink to the bottom based on the underwater 6-DOF motion equation combined with the Monte Carlo simulation method.

[0090] Outputting the parameters of the wrecked object to the wrecked object water drop point distribution calculation module includes:

[0091] ;

[0092] ;

[0093] ;

[0094] ;

[0095] ;

[0096] ;

[0097] ;

[0098] ;

[0099] ;

[0100] Where, 、 、 It is The crashed object passed through The actual crash location coordinates for each time step, 、 、 It is The crashed object is in The three-dimensional motion displacement within a time step, 、 、 It is The crashed object passed The three-dimensional real-time speed of time steps, 、 、 It is The crashed object is in The three-dimensional velocity change within a time step.

[0101] S3 includes S3.1, calculation of wave height, wave phase and roll angle of the wrecked object:

[0102] ;

[0103] ;

[0104] ;

[0105] Where, is the wave height, is the wave phase, is the amplitude, is the wave number, For the wave direction, is the wave frequency, 、 、 is the three-dimensional wavefront position, It's time, is the roll angle of the crashed object.

[0106] S3 includes S3.2, calculation of three-dimensional wave propagation velocity and three-dimensional wave propagation acceleration:

[0107] ;

[0108] ;

[0109] Where, 、 、 is the three-dimensional wave propagation speed, 、 、 is the three-dimensional wave propagation acceleration, is the acceleration due to gravity, is a natural constant.

[0110] S3 includes S3.3, calculation of the coupled velocity of three-dimensional wave velocity and ocean current velocity:

[0111] ;

[0112] ;

[0113] Where, 、 、 is the coupling velocity of three-dimensional wave velocity and ocean current velocity, 、 、 is the three-dimensional ocean current velocity, is the transformation matrix, 、 are the pitch angle and yaw angle of the crashed object respectively.

[0114] S3 includes S3.4, calculating the relative velocity of the crashed object relative to the wave current:

[0115] ; ;

[0116] ; ;

[0117] ; ;

[0118] Where, 、 、 is the relative velocity of the crashed object relative to the wave current, 、 、 is the three-dimensional real-time velocity of the crashed object, yes The angular velocity of rotation in the direction yes The angular velocity of rotation in the direction It is along Position variables for directions, is the length of the crashed object.

[0119] Establishing the underwater 6-DOF motion equations of the wrecked object includes establishing the translational motion equations of the wrecked object in three directions:

[0120] ;

[0121] ;

[0122] ;

[0123] Where, is the mass of the accident object, is the density of water, is the volume of the crashed object, is the acceleration due to gravity, 、 、 is the drag force on the crashed object in three directions, 、 、 For the crashed object 、 、 Three translational additional masses in three directions, 、 、 is the angular velocity within one time step 、 、 The change value of The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, is the vortex induced force, 、 is the lateral lifting force on the crashed object in two directions, yes The angular velocity of rotation in the direction.

[0124] Establishing the underwater 6-DOF motion equation of the wrecked object includes establishing the rotation equations of the wrecked object in three directions:

[0125] ;

[0126] ;

[0127] ;

[0128] ;

[0129] ;

[0130] ;

[0131] Where, 、 、 For the crashed object 、 、 Three rotating additional masses in three directions, 、 、 The crash targets are 、 、 The moment of inertia of the direction, is the kinematic viscosity coefficient of water, is the diameter of the crashed object, 、 、 For the crashed object 、 、 The drag coefficients in three directions, 、 is the drag torque on the crashed object in two directions, 、 It is the vertical lifting moment exerted on the crashed object in two directions.

[0132] The crash target 、 The lateral lifting force in two directions and the crashed object 、 The drag torque in two directions and the crash target 、 The vertical lifting moments in the two directions are:

[0133] ;

[0134] ;

[0135] ;

[0136] ;

[0137] ;

[0138] ;

[0139] Where, To calculate the circulation.

[0140] The overall structure diagram of the prediction system of the present invention is shown in Figure 1, which includes a user-side input module [1], a crash target information monitoring module [2], an ocean information monitoring module [3], a crash target underwater drop point distribution calculation module [4], a result analysis module [5] and a user-side output module [6]. The user-side and the system computing platform are connected via an ocean communication satellite. The workflow diagram of the prediction system of the present invention is shown in Figure 1. Figure 2 As shown, the user-side input module [1], the accident target information monitoring module [2], and the ocean information monitoring module [3] together form a virtual underwater scene, which is input into the accident target underwater landing point distribution calculation module [4], and then sequentially input into the result analysis module [5] and the user-side output module [6]. The system of the present invention is based on a mobile terminal, including a tablet computer, a computer, and a mobile electronic device. The system realizes the user-side functions through the above devices and completes the interaction between the system and the user through the Internet connection.

[0141] The technical flow chart of the prediction technology for the underwater landing point of the crashed target is as follows: Figure 3 As shown, after the start, three branches are processed separately. The first branch performs initial situation randomization, and then obtains the initial landing point, initial posture and initial speed, and performs accuracy verification. If it fails the accuracy verification, it returns to the initial situation randomization. If it passes the accuracy verification, random variables are introduced; the second branch performs complex ocean current randomization, and then obtains the current type, current velocity and current direction, and performs accuracy verification. If it fails the accuracy verification, it returns to the complex ocean current randomization. If it passes the accuracy verification, random variables are introduced; the third branch performs nonlinear hydrodynamic randomization, and then the wake vortex induced force, drag coefficient and wake action point are verified for accuracy. If it fails the accuracy verification, it returns to the nonlinear hydrodynamic randomization. If it passes the accuracy verification, random variables are introduced; the three random variables are introduced into the underwater 6-degree-of-freedom motion equation of the crashed target, and the landing point distribution prediction is performed in combination with the Monte Carlo method.

[0142] The present invention collects seven working conditions, as shown in Table 1.

[0143] Table 1 Working conditions

[0144] .

[0145] Figure 4 This is a comparison diagram of the predicted results of the present invention and the water tank test results in the XZ axis plane for working condition 1. It can be seen from the figure that the predicted results of the present invention are in good agreement with the test results, and the motion trajectory is basically straight. When the cylinder moves to a depth of about 2.5m, the movement direction of the cylinder will change. The predicted results of the present invention can accurately capture the change in movement direction, proving the accuracy of the present invention. Figure 5This is a comparison diagram of the predicted results of the present invention and the water tank test results in the XZ axis plane for working condition 2. It can be seen from the figure that the predicted results of the present invention are in good agreement with the test results, and the motion trajectory is basically straight. When the cylinder moves to a depth of about 2.9m, the direction of motion of the cylinder changes. The predicted results of the present invention can accurately capture the change in motion direction, proving the accuracy of the present invention. Figure 6 The overall impact point scatter plots calculated by the present invention for Conditions 3 and 4 show that the underwater impact point distribution varies for different structures. Condition 3, where the object is a cylinder, has a larger distribution range, with a trend of spreading outward from the center in all four directions. Condition 4, where the object is a cuboid, has a more concentrated distribution range, with a similar trend to Condition 3. Differences in object type, mass, and other parameters significantly influence the probability of impact point distribution. Figure 7 The locally enlarged landing point scatter diagrams calculated by the present invention for working conditions three and four are mainly intended to more clearly analyze the landing point scatter rules.

[0146] Figure 8 The falling posture and trajectory diagram of the XZ axis plane calculated by the present invention for working condition five can be clearly seen from the figure that when there is no eccentric moment influence, the falling trajectory of the cuboid in still water is basically vertical, and the falling posture remains basically horizontal without obvious posture changes. Figure 9 The falling posture and trajectory diagram of the YZ axis plane calculated by the present invention for working condition five can be clearly seen from the figure that when there is no eccentric moment influence, the falling trajectory of the cuboid in still water is basically vertical, and the falling posture remains basically horizontal without obvious posture changes. Figure 10 The falling posture and trajectory diagram of the XZ axis plane calculated by the present invention for working condition six can be clearly seen from the figure that when the influence of the eccentric moment is considered, the falling trajectory of the rectangular parallelepiped in still water no longer remains vertical, and its falling posture will show a large deflection. Figure 11 The falling posture and trajectory diagram of the YZ axis plane calculated by the present invention for working condition six can be clearly seen from the figure that when the influence of the eccentric moment is considered, the falling trajectory of the rectangular parallelepiped in still water no longer remains vertical, and its falling posture will show a large deflection.

[0147] Figure 12 The falling posture and trajectory diagram of the XZ axis plane calculated by the present invention for working condition seven can be clearly seen from the figure that when the influence of the eccentric moment is considered, the falling trajectory of the cuboid in the uniform flow is more obvious, and its falling posture will show a larger deflection. Figure 13 The falling posture and trajectory diagram of the YZ axis plane calculated by the present invention for working condition seven can be clearly seen from the figure that when the influence of the eccentric moment is considered, the falling trajectory of the cuboid in the uniform flow is more obvious, and its falling posture will show a larger deflection. Figure 14 The present invention provides a search strategy based on the landing point distribution results. The red-bordered area is the area with a high landing point probability, and the yellow-bordered area is the area with a low landing point probability. In actual search, it is necessary to carry out a full-coverage search in the red-bordered area, a semi-coverage search in the yellow-bordered area, and a quick search in the remaining areas.

[0148] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting the underwater bottom position of a lost object, using a system for predicting the underwater bottom position of a lost object, characterized in that: The system includes a user terminal and a system computing platform. The user terminal and the system computing platform communicate with each other via an ocean communication satellite. The user terminal includes a user input module and a user output module. The system computing platform includes a lost target information monitoring and forecasting module, an ocean information monitoring and forecasting module, a lost target underwater landing point dispersion calculation module, and a result analysis module. The user inputs the crash time and crash location of the crashed object through the user input module, and outputs them to the crashed object information monitoring and forecasting module; The accident target information monitoring and prediction module obtains accident target parameters, including the type, shape parameters, initial motion speed, and initial motion posture of the accident target, matches the accident target parameters with the accident time and location input by the user-side input module, and inputs the accident target parameters, accident time, and location into the underwater landing point dispersion calculation module of the accident target; The ocean information monitoring and forecasting module monitors and forecasts the wave and current information of the sea area where the target object was lost, and provides real ocean environment parameters. The user input module, the lost target information monitoring and forecasting module, and the ocean information monitoring and forecasting module together constitute a virtual underwater scene, and input the wave and current information of the lost sea area into the underwater landing point dispersion calculation module of the lost target; The underwater landing point distribution calculation module of the lost object predicts the bottom landing point distribution of the lost object based on the parameters of the lost object provided by the virtual underwater scene. The result analysis module provides a search strategy to the search personnel based on the calculation results of the underwater landing point distribution calculation module of the lost object. The optimal search strategy among the search strategies is given based on the expert evaluation and input into the user-side output module. The user-side output module presents the expert evaluation results and the optimal search strategy to the search personnel. Methods include: S1. Randomize the parameters of the crashed object and expand the parameters of the crashed object to The parameters of the crash target object in the three-dimensional random crash position coordinates are selected when calling the crash target object parameters. The data of three-dimensional random accident location coordinates are processed. ; S2. Inputting the parameters of the accident target into the underwater landing point distribution calculation module of the accident target; S3, inputting the wave and current information of the accident sea area into the underwater landing point distribution calculation module of the accident target; S4. Predicting the distribution of the sinking point of the crashed object, including establishing the underwater 6-degree-of-freedom motion equation of the crashed object and predicting the distribution of the underwater landing point of the crashed object based on the underwater 6-degree-of-freedom motion equation in combination with the Monte Carlo simulation method; Inputting the parameters of the wrecked object into the wrecked object water drop point distribution calculation module includes: ； ； ； ； ； ； ； ； ； Where, 、 、 It is The crashed object passed through The actual crash location coordinates for each time step, 、 、 It is The crashed object is in The three-dimensional motion displacement within a time step, 、 、 It is The crashed object passed The three-dimensional real-time speed of time steps, 、 、 It is The crashed object is in Three-dimensional velocity changes within a time step; S3 includes S3.1, calculation of wave height, wave phase and roll angle of the wrecked object: ； ； ； Where, is the wave height, is the wave phase, is the amplitude, is the wave number, For the wave direction, is the wave frequency, 、 、 is the three-dimensional wavefront position, It's time, is the roll angle of the crashed object; S3 includes S3.2, calculation of three-dimensional wave propagation velocity and three-dimensional wave propagation acceleration: ； ； Where, 、 、 is the three-dimensional wave propagation speed, 、 、 is the three-dimensional wave propagation acceleration, is the acceleration due to gravity, is a natural constant; S3 includes S3.3, calculation of the coupled velocity of three-dimensional wave velocity and ocean current velocity: ； ； Where, 、 、 is the coupling velocity of three-dimensional wave velocity and ocean current velocity, 、 、 is the three-dimensional ocean current velocity, is the transformation matrix, 、 are the pitch angle and yaw angle of the crashed target respectively; S3 includes S3.4, calculating the relative velocity of the crashed object relative to the wave current: ； ； ； ； ； ； Where, 、 、 is the relative velocity of the crashed object relative to the wave current, 、 、 is the three-dimensional real-time velocity of the crashed object, yes The angular velocity of rotation in the direction yes The angular velocity of rotation in the direction It is along Position variables for directions, is the length of the crashed object; Establishing the underwater 6-DOF motion equations of the wrecked object includes establishing the translational motion equations of the wrecked object in three directions: ； ； ； Where, is the mass of the accident object, is the density of water, is the volume of the crashed object, is the acceleration due to gravity, 、 、 is the drag force on the crashed object in three directions, 、 、 For the crashed object 、 、 Three translational additional masses in three directions, 、 、 is the angular velocity within one time step 、 、 The change value of The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, The target of the accident The eccentric coordinates of the direction, is the vortex induced force, 、 is the lateral lifting force on the crashed object in two directions, yes Angular velocity of rotation in direction; Establishing the underwater 6-DOF motion equation of the wrecked object includes establishing the rotation equations of the wrecked object in three directions: ； ； ； ； ； ； Where, 、 、 For the crashed object 、 、 Three rotating additional masses in three directions, 、 、 The crash targets are 、 、 The moment of inertia of the direction, is the kinematic viscosity coefficient of water, is the diameter of the crashed object, 、 、 For the crashed object 、 、 The drag coefficients in three directions, 、 is the drag torque on the crashed object in two directions, 、 is the vertical lifting moment in two directions on the crashed object; The crash target 、 The lateral lifting force in two directions and the crashed object 、 The drag torque in two directions and the crash target 、 The vertical lifting moments in the two directions are: ； ； ； ； ； ； Where, To calculate the circulation.

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