A search method and system for hidden space-time coverage holes based on a civilian ship group

Abstract

The application provides a search method and system for hidden space-time coverage holes based on a civilian ship group, comprising: designing a space-time double-cone hole model for evaluating the coverage capability of the civilian ship group on a target space-time range. First, based on the proposed space-time double-cone hole model, a maximum space-time double-cone hole search problem is established. Then, for the fast search problem of the maximum double-cone hole, a double-cone hole search algorithm based on projection scaling is proposed to quickly locate the position and size of the maximum double-cone hole of the civilian ship group in the target space-time range. Based on the position and size of the maximum double-cone hole obtained by the search, the size and size of the hole region covered by the civilian ship group in the target space-time range can be quickly located to support the scheduling of the civilian ship group.

Description

Technical Field

[0001] This invention relates to the field of holographic exploration fusion technology, and in particular to a method and system for searching spatiotemporal coverage voids based on civilian ship groups. Background Technology

[0002] A large number of civilian vessels, including fishing boats, cargo ships, passenger ships, and cruise ships, are distributed at sea, with fishing boats alone numbering as many as 300,000. These civilian vessels conduct extensive maritime operations year-round, covering a vast area of ​​the ocean, far exceeding the operational range of the Chinese Navy and Coast Guard. This persistent and wide-ranging maritime operation provides a natural resource for integrated maritime surveillance and intelligence activities. Combining maritime surveillance missions with the production operations of civilian vessels, allowing them to complete maritime surveillance tasks incidentally during their production activities, can greatly improve the coverage of maritime missions. In terms of integrated surveillance and intelligence activities, utilizing a group of civilian vessels to continuously monitor target sea areas and collect more comprehensive and richer data can increase the ability to control information in that sea area and further improve the efficiency of information collection in the target sea area.

[0003] Due to the vastness of the ocean and the complexity of civilian vessel movement, civilian vessel groups often experience coverage gaps in target sea areas, which can lead to a lack of information within these gaps. Improving the spatiotemporal coverage quality of target sea areas is a critical issue that urgently needs to be addressed.

[0004] Algorithms for spatiotemporal coverage holes already exist in other fields, including:

[0005] In Wireless Sensor Networks (WSNs), coverage holes occur when a given set of sensors and a target area cannot provide the required level of coverage. Methods for locating coverage holes in WSNs primarily include the sensing boundary method and computational geometry-based methods. The sensing boundary method locates coverage holes by locally examining all points on the boundary of each sensor's sensing area to see if they are adequately covered by their neighbors. Among computational geometry methods, Voronoi diagrams and Delaunay triangulation are the most commonly used computational geometric techniques for coverage hole detection.

[0006] In underwater 3D networks, by dividing the target area into several grids and determining whether each grid point is covered by other grid points or sensor nodes, areas with potential coverage gaps can be identified. In mobile crowdsourced sensing systems, to achieve continuous high-quality information collection, the coverage gap is located by determining whether points of interest are covered. The sensing coverage of the sensing group is constrained by t-timeslot k-coverage, requiring that for any sensing unit, the variance of the number of sensing operations per t time interval is at least k. While ensuring coverage of points of interest, a sensing task optimization allocation algorithm based on viewpoint coverage and spatial entropy is proposed, allowing the trajectory of the task execution to cover a larger spatial range.

[0007] However, the sensing units in sensor networks are typically sensor nodes, whose positions remain constant, so holes often do not change over time. In mobile networks, holes need to be located based on points of interest and grids, lacking the ability to accurately pinpoint the size and location of holes. These methods cannot be directly implemented for identifying spatiotemporal coverage holes in marine areas, firstly because they do not fit the application scenario in marine environments, and secondly because the application prerequisites and constraints are significantly different.

[0008] Therefore, a new search method is needed to determine the spatiotemporal coverage gaps in marine scenarios. Summary of the Invention

[0009] This invention provides a method and system for searching hidden spatiotemporal coverage cavities based on civilian vessel groups, which addresses the deficiency in existing technologies that lack methods for searching hidden spatiotemporal coverage cavities in marine areas. It enables the rapid location of the cavity area and size covered by the civilian vessel group within a target spatiotemporal range by utilizing information on the activities of civilian vessel groups in the marine area and by rationally scheduling the civilian vessel groups.

[0010] In a first aspect, the present invention provides a method for searching hidden spatiotemporal coverage voids based on civilian vessel groups, including:

[0011] Determine the target spatiotemporal range that needs to be covered, obtain the trajectory of the civilian vessel group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range.

[0012] Based on the differences in the rate of change of the perceived target in time and space, the equivalence coefficients of time and space distance are determined, a biconical neighborhood model is established based on the equivalence coefficients, and a spatiotemporal biconical cavity model is established from the biconical neighborhood model.

[0013] Based on the spatiotemporal coverage geometric expression and the spatiotemporal biconical cavity model, a model for the maximum spatiotemporal biconical cavity search problem is established.

[0014] Calculate the coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice in turn;

[0015] Using the isometric scaling and overlay method of cavity projection, and based on the biconical cavity search algorithm of projection scaling, the location and size of the biconical cavity covering the target in the spatiotemporal range are calculated.

[0016] According to the present invention, a method for searching hidden spatiotemporal coverage voids based on civilian vessel groups is provided, which determines the target spatiotemporal range to be covered, obtains the trajectory of the civilian vessel group within the target spatiotemporal range, and establishes a geometric representation of the spatiotemporal coverage range, including:

[0017] Determining the target spatiotemporal range includes the sensing coverage area and the sensing time period, wherein the sensing time period includes the start time and the end time;

[0018] Obtain the effective coverage radius of any individual civilian vessel, and determine the spatiotemporal range covered by any individual civilian vessel within the sensing time period based on the effective coverage radius;

[0019] The spatiotemporal range covered by the civilian vessel group within the perceived time period is determined by the union of the spatiotemporal ranges corresponding to multiple civilian vessels.

[0020] The difference between the spatiotemporal range covered by the civilian vessel group during the perception period and the target spatiotemporal range constitutes a spatiotemporal coverage gap of the group.

[0021] According to the present invention, a method for searching spatiotemporal coverage voids based on civilian vessel groups is provided. This method determines equivalence coefficients for temporal and spatial distances based on the differences in the rate of change of the perceived target in time and space, establishes a biconical neighborhood model based on these equivalence coefficients, and then establishes a spatiotemporal biconical void model from the biconical neighborhood model. The method includes:

[0022] Obtain the spatial and temporal distances between any two different points in spacetime and determine the equivalence coefficients between the spacetime distances.

[0023] The spatiotemporal distance between any two different points in spacetime can be obtained from the equivalent coefficients between the spatial distance, the temporal distance, and the spatiotemporal distance.

[0024] Based on the spatiotemporal distance, the spatiotemporal neighborhood of any spatiotemporal point is determined as the internal space of a cone that is a mirror image of each other in the three-dimensional spatiotemporal coordinate system, and the neighborhood radius of any spatiotemporal point is determined.

[0025] If the spatiotemporal neighborhood of any spatiotemporal point is determined to be within the spatiotemporal coverage cavity of the group, then the spatiotemporal neighborhood of any spatiotemporal point is a double-cone cavity of the group within the target spatiotemporal range, the any spatiotemporal point is the center of the double-cone cavity, and the neighborhood radius is the radius of the double-cone cavity.

[0026] According to the present invention, a method for searching hidden spatiotemporal coverage cavities based on civilian vessel groups is provided. Based on the geometric expression of the spatiotemporal coverage range and the spatiotemporal biconical cavity model, a maximum spatiotemporal biconical cavity search problem model is established, including:

[0027] Based on the group of civilian ships and the spatiotemporal coverage void of the group, the maximum biconical void search problem is determined to be to find the biconical void with the largest bottom radius within the spatiotemporal coverage void of the group.

[0028] According to the present invention, a method for searching spatiotemporal coverage holes based on a group of civilian vessels is provided, which sequentially calculates the coverage projection of individual civilian vessels in each time slice and the coverage hole of the group in each time slice, including:

[0029] The target spatiotemporal range is divided into several time slices, and the coverage area of ​​any civilian vessel is projected onto each time slice to obtain the coverage area projection of the civilian vessel in each time slice.

[0030] Based on the coverage projection of the individual civilian vessels in each time slice, the coverage holes of the group in each time slice are calculated using polygon approximation and polygon overlap methods.

[0031] The present invention provides a method for searching hidden spatiotemporal coverage voids based on civilian vessel groups, utilizing isometric scaling and overlay methods for void projection, including:

[0032] Determine the equivalence coefficients between adjacent time slice intervals and spatiotemporal distances;

[0033] For the projection of the coverage hole in the target spatiotemporal range, the coverage hole is magnified by taking a specified time slice as the center and using the product of the equivalent coefficient between the interval between adjacent time slices and the spatiotemporal distance as the base. The magnification factor is the number of intervals between any time slice and the specified time slice, thus obtaining the coverage hole on any time slice.

[0034] The intersection of the coverage holes in any time slice is determined by the coverage holes in the specified time slice after magnification of symmetrically spaced time slices, and the maximum circle radius that can be contained in the intersection of the coverage holes is obtained.

[0035] The present invention provides a method for searching hidden spatiotemporal coverage cavities based on civilian vessel groups, and a biconical cavity search algorithm based on projection scaling, comprising:

[0036] Obtain the adjacent time slice interval, the equivalent coefficient between the spatiotemporal distances, divide the time slice set, and the set of holes covered by each time slice;

[0037] Within the set of time slices, the time slice parameters of the bottom surface of the double-cone cavity and the time slice length parameters involved in the cross-section of the double-cone cavity are traversed respectively. If it is determined that there is no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter and the base, and there is also no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter plus 1 and the base, then the loop traversal stops.

[0038] If it is determined that the maximum circle radius is less than the current maximum hole radius, then stop the loop traversal;

[0039] The maximum biconical cavity radius and center point location are obtained through iterative searching.

[0040] Secondly, the present invention also provides a system for searching hidden spatiotemporal coverage voids based on civilian vessel groups, comprising:

[0041] The acquisition module is used to determine the target spatiotemporal range that needs to be covered, acquire the trajectory of the civilian ship group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range;

[0042] The first module is used to determine the equivalence coefficients of time and space distance based on the difference in the rate of change of the perceived target in time and space, establish a biconical neighborhood model based on the equivalence coefficients, and establish a spatiotemporal biconical cavity model based on the biconical neighborhood model.

[0043] The second module is used to establish a maximum spatiotemporal biconical cavity search problem model based on the spatiotemporal coverage geometric expression and the spatiotemporal biconical cavity model.

[0044] The first calculation module is used to calculate the coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice in turn.

[0045] The second calculation module is used to calculate the location and size of the biconical cavity covering the target within the spatiotemporal range by utilizing the isometric scaling and overlay method of cavity projection and the biconical cavity search algorithm based on projection scaling.

[0046] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described method for searching hidden spatiotemporal coverage voids based on civilian ship groups.

[0047] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for searching hidden spatiotemporal coverage voids based on civilian ship groups as described above.

[0048] This invention provides a method and system for searching spatiotemporal coverage cavities based on civilian vessel groups. By establishing a spatiotemporal biconical cavity model, it searches for the largest biconical cavity within the target range of the civilian vessel group, assesses the coverage capability of the civilian vessel group over the target spatiotemporal range, and proposes a biconical cavity search algorithm based on projection scaling to quickly locate the position and size of the largest biconical cavity within the target spatiotemporal range of the civilian vessel group. Based on the location and size of the largest biconical cavity obtained from the search, the cavity area and size covered by the civilian vessel group within the target spatiotemporal range can be quickly located to support the scheduling of the civilian vessel group in meeting the spatiotemporal coverage requirements for hidden exploration. It features low implementation difficulty, simple calculation, and high search and positioning accuracy. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0050] Figure 1 This is one of the flowcharts of the method for searching hidden spatiotemporal coverage voids based on civilian ship groups provided by the present invention;

[0051] Figure 2 This is the second flowchart of the method for searching hidden spatiotemporal coverage voids based on civilian ship groups provided by the present invention.

[0052] Figure 3 This is a schematic diagram of the geometric representation model of the spatiotemporal coverage void of the civilian ship group provided by the present invention;

[0053] Figure 4 This is a schematic diagram of the spatiotemporal biconical neighborhood and spatiotemporal biconical cavity model provided by the present invention;

[0054] Figure 5 This is a schematic diagram of the projection calculation of the coverage area of ​​an individual civilian vessel in each time slice, provided by the present invention.

[0055] Figure 6 This is a schematic diagram of the calculation of group coverage holes for each time slice provided by the present invention;

[0056] Figure 7 This is an isometric enlarged schematic diagram of the planar graphic provided by the present invention;

[0057] Figure 8 This is a schematic diagram of the isometric scaling and overlay process of the hole projection provided by the present invention;

[0058] Figure 9 This is a schematic diagram of a spatiotemporal biconical cavity search algorithm provided by the present invention;

[0059] Figure 10 This is a schematic diagram of the structure of the spatiotemporal coverage cavity search system based on civilian ship groups provided by the present invention;

[0060] Figure 11 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0062] Figure 1 This is one of the flowcharts illustrating the spatiotemporal coverage cavity search method based on civilian vessel groups provided in this invention. Figure 1 As shown, it includes:

[0063] Step 100: Determine the target spatiotemporal range to be covered, obtain the trajectory of the civilian ship group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range;

[0064] Step 200: Based on the difference in the rate of change of the perceived target in time and space, determine the equivalence coefficients of time and space distance, establish a biconical neighborhood model based on the equivalence coefficients, and establish a spatiotemporal biconical cavity model based on the biconical neighborhood model;

[0065] Step 300: Based on the spatiotemporal coverage geometric expression and the spatiotemporal biconical cavity model, establish a model for the maximum spatiotemporal biconical cavity search problem;

[0066] Step 400: Calculate the coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice in sequence;

[0067] Step 500: Using the isometric scaling and overlay method of cavity projection, and based on the biconical cavity search algorithm of projection scaling, calculate the location and size of the biconical cavity covering the target in the spatiotemporal range.

[0068] Specifically, such as Figure 2As shown, in this embodiment of the invention, after determining the target spatiotemporal range and obtaining the trajectories of the civilian vessel group within that range, a spatiotemporal biconical cavity model is designed to evaluate the coverage capability of the civilian vessel group over the target spatiotemporal range. First, based on the proposed spatiotemporal biconical cavity model, a maximum spatiotemporal biconical cavity search problem is established. Then, for the fast search problem of the maximum biconical cavity, a biconical cavity search algorithm based on projection scaling is proposed to quickly locate the position and size of the maximum biconical cavity of the civilian vessel group within the target spatiotemporal range.

[0069] Understandably, based on the location and size of the largest biconical cavity obtained from the search, the cavity area and size covered by the civilian vessel group within the target spatiotemporal range can be quickly located to support the scheduling of the civilian vessel group.

[0070] Based on the above embodiments, step 100 includes:

[0071] Determining the target spatiotemporal range includes the sensing coverage area and the sensing time period, wherein the sensing time period includes the start time and the end time;

[0072] Obtain the effective coverage radius of any individual civilian vessel, and determine the spatiotemporal range covered by any individual civilian vessel within the sensing time period based on the effective coverage radius;

[0073] The spatiotemporal range covered by the civilian vessel group within the perceived time period is determined by the union of the spatiotemporal ranges corresponding to multiple civilian vessels.

[0074] The difference between the spatiotemporal range covered by the civilian vessel group during the perception period and the target spatiotemporal range constitutes a spatiotemporal coverage gap of the group.

[0075] Specifically, such as Figure 3 As shown, in this embodiment of the invention, the target spatiotemporal range refers to the temporal and spatial range of the information to be perceived, denoted by the symbol... It indicates. Among them. This indicates the spatial area that needs to be sensed and covered. Indicates the start time as The termination time is The perceived time period. (Using symbols) u When referring to individual civilian vessels, the spatiotemporal range covered by each vessel refers to the spatiotemporal range that each vessel can cover during its movement, denoted by the symbol [symbol missing]. Indicates participants Effective coverage radius, symbol Indicates participants In time period The spatiotemporal range covered by the inner layer.

[0076] A spatiotemporal coverage void refers to a spatiotemporal region within the target's spatiotemporal area that is not covered by the civilian vessel group. (Used as a symbol...) This refers to a group of civilian ships, or a group. Must be within the time period The spatiotemporal extent of the inner coverage is the union of the spatiotemporal coverage extents of all participants in the set, denoted by the symbol This means, that is:

[0077]

[0078] Therefore, the spatiotemporal coverage void of the group U is the difference between the target spatiotemporal space and the group's coverage spatiotemporal space. Using symbols and... Representing a group exist If there is a spacetime covering void, then:

[0079]

[0080] Based on the above embodiments, step 200 includes:

[0081] Obtain the spatial and temporal distances between any two different points in spacetime and determine the equivalence coefficients between the spacetime distances.

[0082] The spatiotemporal distance between any two different points in spacetime can be obtained from the equivalent coefficients between the spatial distance, the temporal distance, and the spatiotemporal distance.

[0083] Based on the spatiotemporal distance, the spatiotemporal neighborhood of any spatiotemporal point is determined as the internal space of a cone that is a mirror image of each other in the three-dimensional spatiotemporal coordinate system, and the neighborhood radius of any spatiotemporal point is determined.

[0084] If the spatiotemporal neighborhood of any spatiotemporal point is determined to be within the spatiotemporal coverage cavity of the group, then the spatiotemporal neighborhood of any spatiotemporal point is a double-cone cavity of the group within the target spatiotemporal range, the any spatiotemporal point is the center of the double-cone cavity, and the neighborhood radius is the radius of the double-cone cavity.

[0085] Specifically, based on the differences in the rates of change of the perceived target in time and space, equivalence coefficients for time and spatial distance are determined. Then, a biconical neighborhood model is established based on these equivalence coefficients. Based on the biconical neighborhood model, a biconical cavity model is established, such as... Figure 4 and Figure 5 As shown.

[0086] The spatiotemporal biconical neighborhood model includes:

[0087] Define two spacetime points , The spacetime distance between them:

[0088]

[0089] in, and Let p and q represent the spatial and temporal distances between points p and q, respectively. The equivalent coefficient between spatiotemporal distances.

[0090]

[0091] Define points based on spatiotemporal distance. of - Neighborhood, :

[0092]

[0093] like Figure 4 As shown in (a), for a spacetime point p, its - The neighborhood is the interior space of a mirror image of a cone in the three-dimensional spacetime coordinate system, and the radius of the neighborhood is denoted as . .

[0094] Spatiotemporal bicone-covered voids include:

[0095] like Figure 4 As shown in (b), for a group of civilian ships Its spatiotemporal coverage void is If the spacetime domain of point p exist Inner time, that is When it is established, it is called Consider a group of civilian ships U within a spacetime range Z, consisting of a double-cone cavity, where p is the center of the double-cone cavity. Let be the radius of the biconical cavity.

[0096] Based on the above embodiments, step 300 includes:

[0097] Based on the group of civilian ships and the spatiotemporal coverage void of the group, the maximum biconical void search problem is determined to be to find the biconical void with the largest bottom radius within the spatiotemporal coverage void of the group.

[0098] Specifically, in this embodiment of the invention, the maximum biconical cavity search problem is: given a group of civilian ships... U and its spacetime coverage void as Therefore, the maximum biconical cavity search problem is: Find the double-cone cavity with the largest base radius. .

[0099] Based on the definitions of biconical neighborhood and spatiotemporal biconical cavity, the radius of the base of the largest biconical cavity that can be contained within the spatiotemporal coverage cavity of a civilian ship group is the upper bound of the distance from a point within the cavity to the group's coverage area. Therefore, searching for the largest biconical cavity within a civilian ship group can quickly determine the location and size of the spatiotemporal range where the civilian ship group has the weakest spatiotemporal coverage of the target area.

[0100] Based on the above embodiments, step 400 includes:

[0101] The target spatiotemporal range is divided into several time slices, and the coverage area of ​​any civilian vessel is projected onto each time slice to obtain the coverage area projection of the civilian vessel in each time slice.

[0102] Based on the coverage projection of the individual civilian vessels in each time slice, the coverage holes of the group in each time slice are calculated using polygon approximation and polygon overlap methods.

[0103] Specifically, in this embodiment of the invention, the spatiotemporal range is divided into several time slices, and the coverage area of ​​an individual civilian vessel is projected onto each time slice. For example... Figure 5 As shown, using symbols Indicates civilian ships u The coverage area in time slices The projection on the surface. Then, based on the coverage projection of each individual civilian vessel in each time slice, the coverage holes in each time slice are calculated using polygon approximation and polygon overlay methods, such as... Figure 6 As shown.

[0104] Based on the above embodiments, the equidistant scaling and overlay method using hole projection includes:

[0105] Determine the equivalence coefficients between adjacent time slice intervals and spatiotemporal distances;

[0106] For the projection of the coverage hole in the target spatiotemporal range, the coverage hole is magnified by taking a specified time slice as the center and using the product of the equivalent coefficient between the interval between adjacent time slices and the spatiotemporal distance as the base. The magnification factor is the number of intervals between any time slice and the specified time slice, thus obtaining the coverage hole on any time slice.

[0107] The intersection of the coverage holes in any time slice is determined by the coverage holes in the specified time slice after magnification of symmetrically spaced time slices, and the maximum circle radius that can be contained in the intersection of the coverage holes is obtained.

[0108] Specifically, this embodiment of the invention introduces the concept of equidistant magnification of a planar figure. For a planar figure X and a circle with radius d, the circle's center moves around the edge of figure X for one revolution. The union of the area swept by the circle during this movement and X is called the d-distance magnification of X, denoted by the symbol... Indicates, such as Figure 7 As shown, the symbol It represents an equidistant magnification of a two-dimensional figure.

[0109] Furthermore, such as Figure 8As shown, by equidistantly enlarging the coverage holes from different time slices to the same time slice according to the time interval, the largest biconical hole centered on that time slice can be determined by calculating the largest inscribed circle within the intersection of the enlarged coverage holes. Furthermore, by comparing the radii of the largest biconical holes centered on different time slices, the location and size of the largest biconical hole can be determined.

[0110] Specifically, for the projection of the spatiotemporal coverage hole within the target spacetime. With time slices Centered on, with As a multiple of the base, distance The further back in time a hole is covered, the greater the magnification factor. The magnification factor increases from the time slice to the time slice. The number of intervals determines this. Therefore, for a time slice... Covering holes The symmetrically enlarged figure is A record of time slices arrive Covering holes on The intersection of the symmetrical magnified centers is ,Right now: At the same time, remember The radius of the largest circle that can be contained within it is It should be noted that the symbols... It represents the equivalent coefficient between spatiotemporal distances, that is, the tan value of the half-apex angle of the search for biconical voids.

[0111] Based on the above embodiments, the biconical hole search algorithm based on projection scaling includes:

[0112] Obtain the adjacent time slice interval, the equivalent coefficient between the spatiotemporal distances, divide the time slice set, and the set of holes covered by each time slice;

[0113] Within the set of time slices, the time slice parameters of the bottom surface of the double-cone cavity and the time slice length parameters involved in the cross-section of the double-cone cavity are traversed respectively. If it is determined that there is no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter and the base, and there is also no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter plus 1 and the base, then the loop traversal stops.

[0114] If it is determined that the maximum circle radius is less than the current maximum hole radius, then stop the loop traversal;

[0115] The maximum biconical cavity radius and center point location are obtained through iterative searching.

[0116] Specifically, in this embodiment of the invention, a biconical cavity search algorithm based on projection scaling is proposed, and the implementation process includes:

[0117]

[0118] Through continuous increase The value and calculation Searching for the base surface using the largest inscribed circle in time slices The largest biconical cavity on the surface is found by comparing the largest biconical cavity on the bottom surface at different time slices, and then the global largest biconical cavity is found.

[0119] The algorithm contains two nested loops. The outer loop iterates through the time slice parameters of the bottom surface of the biconical cavity. The time slice length parameter involved in traversing the biconical cavity section in the inner loop. The parameter in the second row. Used to record the current The fifth line uses an iterative form to calculate the current... ,Right now This is a polygon intersection method. Lines 13-15 search for the radius of the largest biconical cavity during the iteration process. and center point position .

[0120] To reduce the number of loops, lines 6-8 and 10-12 of the algorithm are modified respectively. and Make a judgment. When At that time, there is no bottom surface in the time slice. Above and radius greater than The double-cone cavity. There is also no bottom surface in time slices. Above and radius greater than The double-cone cavity allows it to exit the inner loop. Similarly, when... Smaller than the current largest cavity radius At this time, the inner loop can also be terminated.

[0121] by Figure 9 For example, the search results for the spatiotemporal biconical cavity are shown at t=1, t=2, t=3, t=4, t=5, and t=6.

[0122] The following describes the spatiotemporal coverage cavity search system based on civilian vessel groups provided by the present invention. The spatiotemporal coverage cavity search system based on civilian vessel groups described below can be referred to in correspondence with the spatiotemporal coverage cavity search method based on civilian vessel groups described above.

[0123] Figure 10This is a schematic diagram of the structure of the spatiotemporal coverage cavity search system based on civilian vessel groups provided in an embodiment of the present invention, as shown below. Figure 10 As shown, it includes: an acquisition module 1001, a first establishment module 1002, a second establishment module 1003, a first calculation module 1004, and a second calculation module 1005, wherein:

[0124] The acquisition module 1001 is used to determine the target spatiotemporal range to be covered, acquire the trajectory of the civilian vessel group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range; the first establishment module 1002 is used to determine the equivalence coefficient of time and space distance based on the difference in the rate of change of the perceived target in time and space, establish a biconical neighborhood model based on the equivalence coefficient, and establish a spatiotemporal biconical cavity model based on the biconical neighborhood model; the second establishment module 1003 is used to establish a maximum spatiotemporal biconical cavity search problem model based on the geometric expression of the spatiotemporal coverage range and the spatiotemporal biconical cavity model; the first calculation module 1004 is used to sequentially calculate the coverage range projection of individual civilian vessels in each time slice and the group coverage cavity in each time slice; the second calculation module 1005 is used to calculate the position and size of the group coverage biconical cavity within the target spatiotemporal range using the isometric scaling and overlay method of cavity projection and the biconical cavity search algorithm based on projection scaling.

[0125] Figure 11 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 11 As shown, the electronic device may include: a processor 1110, a communications interface 1120, a memory 1130, and a communications bus 1140, wherein the processor 1110, the communications interface 1120, and the memory 1130 communicate with each other through the communications bus 1140. Processor 1110 can call logic instructions in memory 1130 to execute a method for searching hidden spatiotemporal coverage holes based on civilian vessel groups. This method includes: determining the target spatiotemporal range to be covered, acquiring the trajectory of the civilian vessel group within the target spatiotemporal range, and establishing a geometric expression of the spatiotemporal coverage range; determining equivalence coefficients for time and space distances based on the differences in the rate of change of the perceived target in time and space, establishing a biconical neighborhood model based on the equivalence coefficients, and establishing a spatiotemporal biconical hole model based on the biconical neighborhood model; establishing a maximum spatiotemporal biconical hole search problem model based on the geometric expression of the spatiotemporal coverage range and the spatiotemporal biconical hole model, sequentially calculating the coverage range projection of individual civilian vessels in each time slice and the group coverage hole in each time slice; and using the isometric scaling and overlay method of hole projection, and based on a biconical hole search algorithm using projection scaling, calculating the location and size of the group coverage biconical hole within the target spatiotemporal range.

[0126] Furthermore, the logical instructions in the aforementioned memory 1130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0127] On the other hand, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the above-described methods for searching hidden spatiotemporal coverage holes based on civilian vessel groups. The method includes: determining the target spatiotemporal range to be covered, obtaining the trajectory of the civilian vessel group within the target spatiotemporal range, and establishing a geometric expression of the spatiotemporal coverage range; determining equivalence coefficients of time and space distance based on the difference in the rate of change of the perceived target in time and space, establishing a biconical neighborhood model based on the equivalence coefficients, and establishing a spatiotemporal biconical hole model based on the biconical neighborhood model; establishing a maximum spatiotemporal biconical hole search problem model based on the geometric expression of the spatiotemporal coverage range and the spatiotemporal biconical hole model, sequentially calculating the coverage range projection of individual civilian vessels in each time slice and the group coverage hole in each time slice; and using the isometric scaling and overlay method of hole projection, and based on the biconical hole search algorithm of projection scaling, calculating the position and size of the group coverage biconical hole within the target spatiotemporal range.

[0128] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0129] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for searching hidden spatiotemporal coverage voids based on civilian vessel groups, characterized in that, include: Determine the target spatiotemporal range that needs to be covered, obtain the trajectory of the civilian vessel group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range. Based on the differences in the rate of change of the perceived target in time and space, the equivalence coefficients of time and space distance are determined, a biconical neighborhood model is established based on the equivalence coefficients, and a spatiotemporal biconical cavity model is established from the biconical neighborhood model. Based on the spatiotemporal coverage geometric expression and the spatiotemporal biconical cavity model, a model for the maximum spatiotemporal biconical cavity search problem is established. Calculate the coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice in turn; Using the isometric scaling and overlay method of cavity projection, and based on the biconical cavity search algorithm of projection scaling, the location and size of the biconical cavity covering the target in the spatiotemporal range are calculated; Based on the differences in the rate of change of the perceived target in time and space, equivalence coefficients for time and space distance are determined. A biconical neighborhood model is established based on these equivalence coefficients. A spatiotemporal biconical cavity model is then established from the biconical neighborhood model, including: Obtain the spatial and temporal distances between any two different points in spacetime and determine the equivalence coefficients between the spacetime distances. The spatiotemporal distance between any two different points in spacetime can be obtained from the equivalent coefficients between the spatial distance, the temporal distance, and the spatiotemporal distance. Based on the spatiotemporal distance, the spatiotemporal neighborhood of any spatiotemporal point is determined as the internal space of a cone that is a mirror image of each other in the three-dimensional spatiotemporal coordinate system, and the neighborhood radius of any spatiotemporal point is determined. If the spatiotemporal neighborhood of any spatiotemporal point is determined to be within the spatiotemporal coverage cavity of the group, then the spatiotemporal neighborhood of any spatiotemporal point is a double-cone cavity of the group within the target spatiotemporal range, the any spatiotemporal point is the center of the double-cone cavity, and the neighborhood radius is the radius of the double-cone cavity.

2. The method for searching hidden spatiotemporal coverage voids based on civilian vessel groups according to claim 1, characterized in that, Determine the target spatiotemporal range to be covered, obtain the trajectory of the civilian vessel group within the target spatiotemporal range, and establish a geometric representation of the spatiotemporal coverage range, including: Determining the target spatiotemporal range includes the sensing coverage area and the sensing time period, wherein the sensing time period includes the start time and the end time; Obtain the effective coverage radius of any individual civilian vessel, and determine the spatiotemporal range covered by any individual civilian vessel within the sensing time period based on the effective coverage radius; The spatiotemporal range covered by the civilian vessel group within the perceived time period is determined by the union of the spatiotemporal ranges corresponding to multiple civilian vessels. The difference between the spatiotemporal range covered by the civilian vessel group during the perception period and the target spatiotemporal range constitutes a spatiotemporal coverage gap of the group.

3. The method for searching hidden spatiotemporal coverage voids based on civilian vessel groups according to claim 2, characterized in that, Based on the aforementioned spatiotemporal coverage geometric expression and the aforementioned spatiotemporal biconical cavity model, a model for the maximum spatiotemporal biconical cavity search problem is established, including: Based on the group of civilian ships and the spatiotemporal coverage void of the group, the maximum biconical void search problem is determined to be to find the biconical void with the largest bottom radius within the spatiotemporal coverage void of the group.

4. The method for searching hidden spatiotemporal coverage voids based on civilian vessel groups according to claim 2, characterized in that, The coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice are calculated sequentially, including: The target spatiotemporal range is divided into several time slices, and the coverage area of ​​any civilian vessel is projected onto each time slice to obtain the coverage area projection of the civilian vessel in each time slice. Based on the coverage projection of the individual civilian vessels in each time slice, the coverage holes of the group in each time slice are calculated using polygon approximation and polygon overlap methods.

5. The method for searching hidden spatiotemporal coverage voids based on civilian vessel groups according to claim 1, characterized in that, The isometric scaling and overlay methods using hole projection include: Determine the equivalence coefficients between adjacent time slice intervals and spatiotemporal distances; For the projection of the coverage hole in the target spatiotemporal range, the coverage hole is magnified by taking a specified time slice as the center and using the product of the equivalent coefficient between the interval between adjacent time slices and the spatiotemporal distance as the base. The magnification factor is the number of intervals between any time slice and the specified time slice, thus obtaining the coverage hole on any time slice. The intersection of the coverage holes in any time slice is determined by the coverage holes in the specified time slice after magnification of symmetrically spaced time slices, and the maximum circle radius that can be contained in the intersection of the coverage holes is obtained.

6. The method for searching hidden spatiotemporal coverage voids based on civilian vessel groups according to claim 5, characterized in that, The biconical hole search algorithm based on projection scaling includes: Obtain the adjacent time slice interval, the equivalent coefficient between the spatiotemporal distances, divide the time slice set, and the set of holes covered by each time slice; Within the set of time slices, the time slice parameters of the bottom surface of the double-cone cavity and the time slice length parameters involved in the cross-section of the double-cone cavity are traversed respectively. If it is determined that there is no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter and the base, and there is no double-cone cavity whose bottom surface is on the specified time slice and whose radius is greater than the product of the time slice length parameter plus 1 and the base, then the loop traversal stops. If it is determined that the maximum circle radius is less than the current maximum hole radius, then stop the loop traversal; The maximum biconical cavity radius and center point location are obtained through iterative searching.

7. A system for searching hidden spatiotemporal coverage voids based on civilian vessel convoys, characterized in that, include: The acquisition module is used to determine the target spatiotemporal range that needs to be covered, acquire the trajectory of the civilian ship group within the target spatiotemporal range, and establish a geometric expression of the spatiotemporal coverage range; The first module is used to determine the equivalence coefficients of time and space distance based on the difference in the rate of change of the perceived target in time and space, establish a biconical neighborhood model based on the equivalence coefficients, and establish a spatiotemporal biconical cavity model based on the biconical neighborhood model. The second module is used to establish a maximum spatiotemporal biconical cavity search problem model based on the spatiotemporal coverage geometric expression and the spatiotemporal biconical cavity model. The first calculation module is used to calculate the coverage projection of individual civilian vessels in each time slice and the coverage gaps of the group in each time slice in turn. The second calculation module is used to calculate the location and size of the biconical cavity covering the target within the spatiotemporal range by using the isometric scaling and overlay method of cavity projection and the biconical cavity search algorithm based on projection scaling. The first establishment module is specifically used for: Obtain the spatial and temporal distances between any two different points in spacetime and determine the equivalence coefficients between the spacetime distances. The spatiotemporal distance between any two different points in spacetime can be obtained from the equivalent coefficients between the spatial distance, the temporal distance, and the spatiotemporal distance. Based on the spatiotemporal distance, the spatiotemporal neighborhood of any spatiotemporal point is determined as the internal space of a cone that is a mirror image of each other in the three-dimensional spatiotemporal coordinate system, and the neighborhood radius of any spatiotemporal point is determined. If the spatiotemporal neighborhood of any spatiotemporal point is determined to be within the spatiotemporal coverage cavity of the group, then the spatiotemporal neighborhood of any spatiotemporal point is a double-cone cavity of the group within the target spatiotemporal range, the any spatiotemporal point is the center of the double-cone cavity, and the neighborhood radius is the radius of the double-cone cavity.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method for searching hidden spatiotemporal coverage voids based on civilian ship groups as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for searching hidden spatiotemporal coverage voids based on civilian ship groups as described in any one of claims 1 to 6.

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