Calculation method based on discrete ship target navigational speed and course motion characteristics

Abstract

The invention relates to a calculation method based on discrete ship target navigational speed and course motion characteristics. The calculation method comprises the following steps: S1, acquiring discrete ship target point position information and motion time difference; s2, based on the position information of the discrete ship target point, calculating the big circle distance of the discrete ship target point, and calculating the navigational speed of the discrete ship target point according to the motion time difference and the calculated big circle distance of the discrete ship target point; s3, calculating a spherical distance of a discrete ship target point based on an elliptic model iterative optimization algorithm; s4, constructing a geographic coordinate matrix, and calculating a course angle of a discrete ship target point through a recursion method; and S5, according to the calculated navigational speed, spherical distance and course angle of the discrete ship target point, based on a curve fitting and speed point sampling method, reconstructing the motion track of the discrete ship target point. According to the method, the adaptability to complex motion and sparse redundant data can be improved while the calculation efficiency is ensured, so that a more accurate track analysis result is obtained.

Description

Technical Field

[0001] This invention relates to the field of ship target motion characteristic calculation technology, and in particular to a calculation method based on discrete ship target speed and heading motion characteristics. Background Technology

[0002] Speed ​​and heading are important motion characteristics of surface vessels. Current research often focuses on analyzing these characteristics by collecting and storing AIS data from specific waters. This data is a large data source for studying vessel navigation behavior. However, because AIS transmits dynamic information about vessels every 10 seconds and static information approximately every 6 minutes, the update rate of AIS data sometimes far exceeds the changes in information during vessel navigation. As a result, AIS data contains a large amount of redundant information. The massive amount of AIS data makes data mining and analysis difficult, leading to excessive consumption of hardware storage and computing resources. Furthermore, the accuracy of predicting motion trajectories based on limited sparse discrete vessel target position information is often not high.

[0003] Traditional ship trajectory prediction based on AIS data relies on a spherical model to calculate the distance between two adjacent discrete points, ignoring the elliptical nature of the Earth and introducing systematic errors. Speed ​​calculation is based on linear assumptions, failing to capture nonlinear ship motion, resulting in large speed estimation errors that accumulate with the number of discrete points. Track generation connects adjacent points with straight line segments or great circle arcs, forming a broken track. Track prediction is based on the speed and heading of the last linear segment, using linear extrapolation, which cannot handle nonlinear motion and unexpected situations, making it difficult to reflect the true motion state between two points. This leads to inaccurate speed and track estimations, thus affecting the effectiveness of track analysis and prediction.

[0004] Therefore, there is an urgent need for a calculation method based on the discrete target speed and heading motion characteristics of ships to solve the above problems. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention aims to provide a calculation method based on the speed and heading motion characteristics of discrete ship targets, which can achieve efficient, fast, and accurate calculation of the distance, speed, and heading angle of discrete ship target points.

[0006] To achieve the above-mentioned objectives, this invention provides a calculation method based on the discrete target speed and heading motion characteristics of a ship, comprising the following steps:

[0007] Step S1: Obtain the discrete ship target point position information and motion time difference;

[0008] Step S2: Based on the discrete ship target point position information, calculate the great circle distance of the discrete ship target point, and calculate the speed of the discrete ship target point according to the motion time difference and the calculated great circle distance of the discrete ship target point.

[0009] Step S3: Calculate the spherical distance of the discrete ship target point based on the elliptic model iterative optimization algorithm;

[0010] Step S4: Construct a geographic coordinate matrix and calculate the heading angle of discrete ship target points using a recursive method;

[0011] Step S5: Based on the calculated speed, spherical distance, and heading angle of the discrete ship target point, the motion trajectory of the discrete ship target point is reconstructed using curve fitting and velocity point sampling methods.

[0012] According to the technical solution of the present invention, step S2 specifically includes:

[0013] Step S21: Calculate the great circle distance of the discrete ship target points according to the great circle distance calculation formula;

[0014] Step S22: Calculate the instantaneous speed of the discrete ship target point based on the calculated great circle distance and motion time difference. The instantaneous speed is the ratio of the great circle distance to the motion time difference.

[0015] According to the technical solution of the present invention, in step S21, the calculation of the great circle distance is expressed as follows:

[0016]

[0017] in, The great circle distance between two adjacent discrete ship target points is given. For the Earth's radius, The spherical central angle distance between two adjacent discrete ship target points. The difference in longitude between two adjacent discrete ship target points. and These are the latitude coordinates of two adjacent discrete ship target points. and These are the longitude coordinates of two adjacent discrete ship target points.

[0018] According to the technical solution of the present invention, step S3 specifically includes:

[0019] Obtain the latitude and longitude coordinates and ellipsoid parameters of two adjacent discrete ship target points;

[0020] Using the longitude difference between two adjacent discrete ship target points as the initial longitude difference, the Vincenty algorithm is used to iteratively calculate the longitude difference, and the spherical distance is calculated using the converged parameters.

[0021] According to the technical solution of the present invention, in step S4, the heading angle is calculated using a geographic coordinate matrix, specifically including:

[0022] A geographic coordinate matrix is ​​constructed based on the location information of multiple discrete ship target points, wherein the row number of the geographic coordinate matrix represents the serial number of the discrete ship target point, and the columns of the geographic coordinate matrix are the latitude and longitude coordinates of the discrete ship target points;

[0023] Based on the aforementioned geographic coordinate matrix and recursive formula, calculate the heading angle of the discrete ship target points; where it is assumed that there are n discrete ship target points. The recursive formula is then expressed as:

[0024] in, This represents the heading angle of the (i+1)th discrete ship target point. = This represents the longitude difference between the (i+1)th and the ith discrete ship target points.

[0025] According to the technical solution of the present invention, step S5 specifically includes:

[0026] Step S51: Generate the basic path of the first 5 frames of points based on the great circle distance, instantaneous speed and heading angle of the discrete ship target;

[0027] Step S52: Determine the basic path characteristics of the points in the first 5 frames:

[0028] If the basic path of the current 5 frames of point traces satisfies the condition that the heading angle between two adjacent points is less than a set threshold, it is determined that the basic path of the current 5 frames of point traces is smooth and uniformly changing, and the cubic spline interpolation method is used to fit the ship target trajectory.

[0029] If the basic path of the current 5 frames of points satisfies the condition that the heading angle between two adjacent points is greater than a set threshold, and it is determined that the basic path of the current 5 frames of points fluctuates greatly, then the B-spline interpolation method is used to fit the ship target trajectory.

[0030] According to the technical solution of the present invention, in step S52, when fitting the target trajectory of the ship using the cubic spline interpolation method, a set of n+1 data points is set. In each pair of adjacent data points and Construct a cubic polynomial function between them , represented as

[0031] in, These are the undetermined coefficients of each spline segment; by solving for the undetermined coefficients through the continuity of multiple derivatives and boundary conditions, a unique cubic spline curve is obtained, which serves as the trajectory curve.

[0032] According to the technical solution of the present invention, in step S52, when the B-spline fitting method is used to fit the target trajectory of the ship, the mathematical expression for B-spline fitting is:

[0033]

[0034] in, It is a control point. It is defined in the node vector The k-th order B-spline basis function for fitting the target ship trajectory;

[0035] The ship target trajectory is fitted by adjusting the order of the basis functions and the distribution of the node vectors.

[0036] According to one aspect of the present invention, an electronic device is provided, comprising: one or more processors, one or more memories, and one or more computer programs; wherein the processor is connected to the memory, and the one or more computer programs are stored in the memory; when the electronic device is running, the processor executes the one or more computer programs stored in the memory to cause the electronic device to perform the above-described calculation method based on the discrete ship target speed and heading motion characteristics.

[0037] According to one aspect of the present invention, a computer-readable storage medium is provided, characterized in that it is used to store computer instructions, which, when executed by a processor, implement the above-described calculation method based on the discrete ship target speed and heading motion characteristics.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The calculation method based on the speed and heading motion characteristics of discrete ship targets provided by this invention is based on the calculation of geographical distance using spherical trigonometric formulas combined with an efficient iterative method. Furthermore, the input geographical coordinates are converted into spherical coordinates, and after efficient geometric transformation, the shortest path between two points is obtained. This method not only avoids the iterative errors of traditional algorithms but also improves the stability of the calculation. In addition, to ensure the scalability of this method in large-scale geographic computing tasks, matrix operations are used to accelerate the distance calculation of multiple points. Utilizing a fast decomposition algorithm of spherical geometric matrices effectively reduces the computational complexity, enabling large-scale distance calculation tasks to be completed in a shorter time.

[0040] (2) During the calculation of the ship's target heading, the latitude and longitude information of multiple target points is integrated into a unified geographic coordinate matrix. This matrix contains the latitude and longitude data of all target points, with each row representing the coordinates of a target point and each column corresponding to a different coordinate dimension (such as latitude and longitude). After constructing the geographic coordinate matrix, the heading angle is efficiently solved using matrix decomposition technology. The key to matrix decomposition is to transform the complex multi-point calculation problem into a linear algebra problem, enabling the calculation of the relative positions and heading angles of multiple points at once through matrix multiplication. Matrix multiplication can significantly accelerate this process, not only processing a large amount of coordinate information simultaneously but also improving the parallel processing capability of matrix operations by utilizing hardware conditions.

[0041] (3) The ship target trajectory is fitted by cubic spline interpolation or B-spline fitting. Cubic spline interpolation may face the problem of poor local controllability when dealing with large amounts of data or data with high noise. That is, changing a single data point may affect the shape of the entire curve. In some applications with high requirements for local flexibility, B-spline fitting has obvious advantages. Based on the fluctuation of the ship target point trajectory in the first 5 frames, cubic spline interpolation or B-spline fitting is determined as the main method, and the distribution of ship target points is flexibly adjusted to adapt to different trajectory characteristics. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0043] Figure 1 The schematic diagram illustrates the principle of a calculation method based on discrete ship target speed and heading motion characteristics provided in one embodiment of the present invention.

[0044] Figure 2 The schematic diagram illustrates a specific flowchart of a calculation method based on the discrete target speed and heading motion characteristics of a ship according to an embodiment of the present invention. Detailed Implementation

[0045] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0046] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0047] like Figure 1 and Figure 2 As shown, the present invention provides a calculation method based on the discrete target speed and heading motion characteristics of a ship, comprising the following steps:

[0048] Step S1: Obtain the discrete ship target point position information and motion time difference;

[0049] The obtained discrete ship target location information includes the latitude and longitude coordinates of the discrete ship target location, and the motion time difference is the difference between the timestamps corresponding to the location information of two adjacent discrete ship target points.

[0050] Step S2: Based on the discrete ship target point position information, calculate the great circle distance of the discrete ship target point, and calculate the speed of the discrete ship target point according to the motion time difference and the calculated great circle distance of the discrete ship target point.

[0051] Step S2 specifically includes:

[0052] Step S21: Calculate the great circle distance of the discrete ship target points according to the great circle distance calculation formula;

[0053] The great circle distance is calculated as follows:

[0054]

[0055]

[0056]

[0057] in, The great circle distance between two adjacent discrete ship target points is given. Earth's radius, Let the sphere be the central angle between two adjacent discrete ship target points. The difference in longitude between two adjacent discrete ship target points. and These are the latitude coordinates of two adjacent discrete ship target points. and These are the longitude coordinates of two adjacent discrete ship target points.

[0058] In calculating great circle distance, assuming the Earth is a sphere, the longitudes of the two target geographic coordinate points on Earth are respectively... and Their longitudes are respectively and The spherical distance between two points can be calculated using the above formula.

[0059] Step S22: Calculate the instantaneous speed of the discrete ship target point based on the calculated great circle distance and motion time difference. The instantaneous speed is the ratio of the great circle distance to the motion time difference.

[0060] Step S3: Calculate the spherical distance of the discrete ship target point based on the elliptic model iterative optimization algorithm.

[0061] Step S3 specifically includes:

[0062] Step S31: Obtain the latitude and longitude coordinates and ellipsoid parameters of two discrete ship target points. The ellipsoid parameters include the equatorial radius. Flatness polar radius ;

[0063] Step S32: Normalize the latitude coordinates of the two discrete ship target points, as follows:

[0064] =

[0065] =

[0066] Step S33: Convert the longitudes of the two discrete ship target points from decimal degrees to radians, and calculate the initial longitude difference. ;

[0067] Step S34: Assume the current iteration is the k-th step, and there exists a difference. Utilizing the difference Calculate spherical angles , is represented as:

[0068]

[0069] in, Let be the spherical angle between two discrete ship target points. and These are the latitude values ​​of two discrete ship target points after latitude normalization. The difference in longitude between two discrete ship target points.

[0070] Calculate intermediate quantities related to azimuth:

[0071]

[0072]

[0073] in, This represents the central angle between two discrete ship target points. It is twice the central angle between the two points and is used to correct the effect of ellipsoidal flattening on distance. C is the core correction term, used to quantify the effect of ellipsoidal flattening on distance.

[0074] Updated difference, updated difference Represented as:

[0075]

[0076] Using the longitude difference calculated in the previous step Calculate the new longitude difference The iteration continues until convergence. It stops when the following stopping conditions are met or the maximum number of iterations is reached:

[0077]

[0078] in, Generally, 10 is taken. -12 Left and right (roughly corresponding to a distance error of sub-millimeter level).

[0079] At the same time, set a maximum number of iterations, such as 100; if the iterations are not converged after exceeding this number, it is considered a failure / requires special handling.

[0080] Once the stopping condition is met, it is considered that It is already accurate enough, then use convergence. calculate:

[0081]

[0082]

[0083] Where a and b represent the equatorial radius and the radius of the Earth ellipsoid in the polar direction (polar radius), respectively; u represents the independent variable of the scale correction coefficient, which comprehensively characterizes the influence of "ellipsoidal flattening" and "geodesic alignment" on the path length; A represents the scale correction coefficient. s represents the precise spherical distance between two discrete ship target points. The spherical central angle represents the angle between two discrete ship target points.

[0084] The above calculation method employs the Vincenty algorithm, iteratively calculating the great circle distance to improve the longitude accuracy of the results. The Vincenty algorithm, based on an ellipsoidal model, compensates for the shortcomings of spherical geometry in geodesy by calculating the length of geodesic lines on the ellipsoidal surface. Furthermore, to further optimize computational efficiency, the spherical trigonometry formula has been improved, providing a recursive-based fast angle calculation method that significantly reduces computation time while ensuring accuracy.

[0085] Step S4: Construct a geographic coordinate matrix and calculate the heading angle of discrete ship target points using a recursive method;

[0086] In step S4, the heading angle is calculated using a geographic coordinate matrix, specifically including:

[0087] The latitude and longitude information of multiple discrete ship target points is obtained, and a geographic coordinate matrix is ​​constructed. The row number of the geographic coordinate matrix represents the serial number of the discrete ship target point, and the columns of the geographic coordinate matrix are the latitude and longitude coordinates of the discrete ship target points.

[0088] Based on the geographic coordinate matrix, the heading angle of the discrete ship target point is calculated, wherein the heading angle of the discrete ship target point is calculated recursively.

[0089] The heading angle of the target point is calculated recursively, specifically including:

[0090] Calculate the heading angle of multiple discrete ship target points based on their geographic coordinates and a recursive formula;

[0091] Assume there are multiple discrete ship target points The recursive formula is then expressed as:

[0092]

[0093] in, This represents the heading angle of the (i+1)th discrete ship target point. = This represents the longitude difference between the (i+1)th and the ith discrete ship target points.

[0094] The above method transforms the input latitude and longitude coordinates into angles, simplifying the spherical trigonometry problem into a planar projection calculation, thus yielding the angle values. To improve computational efficiency, the arctangent calculation process is optimized using a fast-converging iterative algorithm, enabling angle calculations in a shorter time. Recursion is also incorporated to accelerate large-scale heading calculations. This method decomposes the angle calculation problem for multiple points into local subproblems, enabling rapid solutions for multiple heading angles. The recursive approach effectively reduces computational complexity, decreasing the complexity from... Down to This significantly improves the efficiency of heading calculation in large-scale tasks.

[0095] Step S4: Based on the calculated speed, spherical distance, and heading angle of the discrete ship target point, the motion trajectory of the discrete ship target point is reconstructed using curve fitting and velocity point sampling methods.

[0096] By using a target speed calculation method based on curve fitting and velocity point sampling, the speed of the ship target is accurately obtained under nonlinear trajectory. The motion trajectory is reconstructed by combining the characteristics of cubic spline interpolation and B-spline fitting with the sequence points of the ship target.

[0097] Step S4 specifically includes:

[0098] Step S41: Generate the basic path of the first 5 frames of points based on the obtained distance and heading angle;

[0099] Step S42: Determine the basic path characteristics of the points in the first 5 frames:

[0100] If the basic path of the current 5 frames of point traces satisfies the condition that the heading angle between two adjacent points is less than a set threshold, it is determined that the basic path of the current 5 frames of point traces is smooth and uniformly changing, and the cubic spline interpolation method is used to fit the ship target trajectory.

[0101] If the basic path of the current 5 frames of points satisfies the condition that the heading angle between two adjacent points is greater than a set threshold, and it is determined that the basic path of the current 5 frames of points fluctuates greatly, then the B-spline interpolation method is used to fit the ship target trajectory.

[0102] Cubic spline interpolation is an interpolation method that approximates the relationship between discrete points using local cubic polynomials, and it is widely used in numerical analysis and trajectory reconstruction. Unlike simple linear interpolation, the continuity of cubic spline curves is reflected not only in the numerical values ​​but also in the continuity of their first and second derivatives at each data point. Therefore, this method has a significant advantage in scenarios with complex trajectory curves and smooth changes in motion. Cubic spline interpolation can not only generate smooth trajectories but also accurately approximate the motion path of ships, especially in areas where the ship's path changes gently, ensuring both the smoothness and accuracy of the trajectory.

[0103] The fitting of the ship target trajectory is performed using cubic spline interpolation, specifically including:

[0104] Assume there is a set of n+1 data points on the target ship's trajectory. In each pair of adjacent data points and Construct a cubic polynomial function between them , represented as

[0105]

[0106] in, These are the undetermined coefficients of each spline segment; by solving for the undetermined coefficients through the continuity of multiple derivatives and boundary conditions, a unique cubic spline curve is obtained, which serves as the trajectory curve.

[0107] B-splines control the shape of a curve by representing it as a linear combination of a set of basis functions. Compared to cubic spline interpolation, the biggest advantage of B-splines is their local controllability; adjusting a single control point only affects a local area of ​​the curve, not the overall shape. This is particularly important for reconstructing ship trajectories, especially in the presence of data noise or outliers, where B-splines can handle such situations more robustly.

[0108] In step S5, when using the B-spline fitting method to fit the ship's target trajectory, the mathematical expression for B-spline fitting is:

[0109]

[0110] in, These are control points on the basic path of the dots in the first 5 frames. It is defined in the node vector The k-th order B-spline basis function for fitting the target ship trajectory;

[0111] The ship target trajectory is fitted by adjusting the order of the basis functions and the distribution of the node vectors.

[0112] The order *k* of the B-spline basis functions determines the polynomial order of each basis function; a higher order results in a smoother curve. The nodal vectors define the influence range of each control point. A core idea of ​​B-spline fitting is that by selecting appropriate nodal vectors and control points, local path changes can be accurately described without sacrificing global smoothness. The locality of B-splines means that fine-tuning a control point only affects a segment of the curve adjacent to that point, not the entire curve. This makes B-splines more stable when handling navigation trajectories with local noise or outliers. By adjusting the order of the basis functions and the distribution of the nodal vectors, more flexible fitting curves can be generated. Especially when the ship's trajectory is complex, B-splines can improve fitting accuracy by increasing the density of control points without significantly increasing computational complexity. Furthermore, B-splines not only ensure curve continuity but also allow control over curve smoothness by adjusting the order, ensuring that the fitted curve accurately reflects the ship's trajectory changes.

[0113] In summary, based on the fluctuations in the ship target point traces in the first five frames, cubic spline interpolation or B-spline fitting is chosen as the primary method. When the basic path of the traces in the first five frames is relatively smooth and the changes are relatively uniform, the cubic spline interpolation method is used to generate a globally smooth and accurate trajectory while ensuring the continuity of the derivative. When the basic path of the traces in the first five frames fluctuates significantly, precise control of the local path is required to maintain accuracy and stability. B-splines provide stronger local control capabilities and can flexibly adjust the distribution of nodes to adapt to different trajectory characteristics of the ship.

[0114] In this invention, firstly, based on the discrete point information of the same ship target, the spherical angle is converted using the great circle distance calculation method. The converted result is then substituted into the spherical geometric model for distance calculation. To improve accuracy, a geodesic algorithm is introduced for auxiliary calculation. By further optimizing the calculation method and performing appropriate spherical interpolation, the results are fine-tuned to obtain a more accurate distance value. Based on the spherical geometric distance, the azimuth angle is calculated using the geographic coordinates (latitude and longitude) of the two points. Finally, a method combining cubic spline interpolation and B-spline fitting is selected to predict the ship target's trajectory, obtaining the fitted speed, heading, and motion characteristics information.

[0115] This invention, based on existing discrete point information of ship targets and drawing on the mathematical principles of the great circle distance formula, designs an efficient distance calculation method. It reads the geographic coordinate data of the ship target, converts the spherical angle using the great circle distance, and substitutes the converted result into a spherical geometric model for distance calculation. To improve accuracy, appropriate spherical interpolation is used to fine-tune the result, resulting in a more precise distance value. Since the Earth is not a perfect sphere, using a spherical model to calculate distances will introduce some error. To reduce this error, a geodesic algorithm is introduced for auxiliary calculation. A geodesic is a shortest path on the Earth's surface, which can more accurately describe the distance between two points in an ellipsoidal model.

[0116] To improve the performance of heading calculation, matrix operations are used to handle heading angle calculations for multiple target points. This method not only improves the system's computational efficiency but also ensures consistent calculation accuracy. When processing hundreds or thousands of target points, the introduction of matrix operations significantly reduces computational complexity. Simultaneously, to efficiently obtain information on the nonlinear motion characteristics of the ship target, a combination of cubic spline interpolation and B-spline fitting is used to reconstruct the ship's trajectory. This effectively improves the utilization efficiency of discrete target position data and generates accurate information on the ship target's speed and heading motion characteristics.

[0117] According to one aspect of the present invention, an electronic device is provided, comprising: one or more processors, one or more memories, and one or more computer programs; wherein the processor is connected to the memory, and the one or more computer programs are stored in the memory; when the electronic device is running, the processor executes the one or more computer programs stored in the memory to cause the electronic device to perform a calculation method based on the discrete ship target speed and heading motion characteristics as described in any of the above technical solutions.

[0118] The processor can be a central processing unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0119] According to one aspect of the present invention, a computer-readable storage medium is provided for storing computer instructions, which, when executed by a processor, implement a calculation method based on the discrete ship target speed and heading motion characteristics as described in any of the above technical solutions.

[0120] Computer-readable storage media can include any medium capable of storing or transmitting information. Examples of computer-readable storage media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, and so on. Code segments can be downloaded via computer networks such as the Internet and intranets.

[0121] Furthermore, it should be noted that the present invention can be provided as a method, apparatus, or computer program product. Therefore, embodiments of the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0122] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0123] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0124] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0125] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A calculation method based on the discrete target speed and heading motion characteristics of a ship, characterized in that, Includes the following steps: Step S1: Obtain the discrete ship target point position information and motion time difference; Step S2: Based on the discrete ship target point position information, calculate the great circle distance of the discrete ship target point, and calculate the speed of the discrete ship target point according to the motion time difference and the calculated great circle distance of the discrete ship target point. Step S3: Calculate the spherical distance of the discrete ship target point based on the elliptic model iterative optimization algorithm; Step S4: Construct a geographic coordinate matrix and calculate the heading angle of discrete ship target points using a recursive method; Step S5: Based on the calculated speed, spherical distance, and heading angle of the discrete ship target point, the motion trajectory of the discrete ship target point is reconstructed using curve fitting and velocity point sampling methods.

2. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 1, characterized in that, Step S2 specifically includes: Step S21: Calculate the great circle distance of the discrete ship target points according to the great circle distance calculation formula; Step S22: Calculate the instantaneous speed of the discrete ship target point based on the calculated great circle distance and motion time difference. The instantaneous speed is the ratio of the great circle distance to the motion time difference.

3. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 2, characterized in that, In step S21, the great circle distance calculation is expressed as: in, The great circle distance between two adjacent discrete ship target points is given. For the Earth's radius, The spherical central angle distance between two adjacent discrete ship target points. The difference in longitude between two adjacent discrete ship target points. and These are the latitude coordinates of two adjacent discrete ship target points. and These are the longitude coordinates of two adjacent discrete ship target points.

4. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 3, characterized in that, Step S3 specifically includes: Obtain the latitude and longitude coordinates and ellipsoid parameters of two adjacent discrete ship target points; Using the longitude difference between two adjacent discrete ship target points as the initial longitude difference, the Vincenty algorithm is used to iteratively calculate the longitude difference, and the spherical distance is calculated using the converged parameters.

5. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 3, characterized in that, In step S4, the heading angle is calculated using a geographic coordinate matrix, specifically including: A geographic coordinate matrix is ​​constructed based on the location information of multiple discrete ship target points, wherein the row number of the geographic coordinate matrix represents the serial number of the discrete ship target point, and the columns of the geographic coordinate matrix are the latitude and longitude coordinates of the discrete ship target points; Based on the aforementioned geographic coordinate matrix and recursive formula, calculate the heading angle of the discrete ship target points; where it is assumed that there are n discrete ship target points. The recursive formula is then expressed as: in, This represents the heading angle of the (i+1)th discrete ship target point. = This represents the longitude difference between the (i+1)th and the ith discrete ship target points.

6. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 4, characterized in that, Step S5 specifically includes: Step S51: Generate the basic path of the first 5 frames of points based on the great circle distance, instantaneous speed and heading angle of the discrete ship target; Step S52: Determine the basic path characteristics of the points in the first 5 frames: If the basic path of the current 5 frames of point traces satisfies the condition that the heading angle between two adjacent points is less than a set threshold, it is determined that the basic path of the current 5 frames of point traces is smooth and uniformly changing, and the cubic spline interpolation method is used to fit the ship target trajectory. If the basic path of the current 5 frames of points satisfies the condition that the heading angle between two adjacent points is greater than a set threshold, and it is determined that the basic path of the current 5 frames of points fluctuates greatly, then the B-spline interpolation method is used to fit the ship target trajectory.

7. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 5, characterized in that, In step S52, when fitting the ship target trajectory using the cubic spline interpolation method, a set of n+1 data points is set. In each pair of adjacent data points and Construct a cubic polynomial function between them , represented as in, These are the undetermined coefficients of each spline segment; by solving for the undetermined coefficients through the continuity of multiple derivatives and boundary conditions, a unique cubic spline curve is obtained, which serves as the trajectory curve.

8. The calculation method based on the discrete ship target speed and heading motion characteristics according to claim 6, characterized in that, In step S52, when using the B-spline fitting method to fit the ship's target trajectory, the mathematical expression for B-spline fitting is: in, It is a control point. It is defined in the node vector The k-th order B-spline basis function for fitting the target ship trajectory; The ship target trajectory is fitted by adjusting the order of the basis functions and the distribution of the node vectors.

9. An electronic device, characterized in that, include: One or more processors, one or more memories, and one or more computer programs; wherein the processor is connected to the memory, and the one or more computer programs are stored in the memory, and when the electronic device is running, the processor executes the one or more computer programs stored in the memory to cause the electronic device to perform the calculation method based on the discrete ship target speed and heading motion characteristics as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, Used to store computer instructions, which, when executed by a processor, implement the calculation method based on the discrete ship target speed and heading motion characteristics as described in any one of claims 1 to 8.

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