Adaptive radar target and AIS target fusion method

Abstract

The invention provides a self-adaptive radar target and AIS target fusion method, which comprises the following steps: step 1, reading radar target data found by different radar devices, merging repeated radar targets and continuous radar targets in the radar target data, and obtaining a to-be-fused radar target; 2, AIS message data are read, and AIS targets to be fused are obtained; 3, sequentially judging whether the to-be-fused radar target and the to-be-fused AIS target meet fusion conditions or not, if yes, performing fusion to obtain a radar AIS fusion target, and if not, performing no fusion; and step 4, obtaining a final radar target, an AIS target and a radar AIS fusion target. According to the adaptive radar target and AIS target fusion method provided by the invention, the target fusion accuracy and fusion efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the maritime field, and in particular to an adaptive radar target and AIS target fusion method. Background Art

[0002] Existing target fusion technology mainly determines whether two targets can be fused based on their speed difference, distance difference, heading difference, time difference, and length difference (in some scenarios). These thresholds are fixed. Existing fusion technology has the following problems:

[0003] 1. Ideally, the longitude and latitude coordinates of the targets detected by different radars are exactly the same as those reported by the ship's AIS, so the fusion accuracy will be relatively high. In reality, there may be a deviation of several hundred meters between the coordinates of the ship located by different radars and the coordinates reported by the ship's AIS. When there are multiple ships within a few hundred meters, it is difficult to accurately fuse the targets.

[0004] 2. The radar may lose the target it is tracking, and the previously lost target will be found as a new target after more than ten seconds. Misjudging the same target as two targets due to equipment problems will cause great risks in practical applications and decision-making assistance.

[0005] 3. Low fusion efficiency and high data delay. Due to the large number of fusion targets, high target update frequency, complex fusion process and huge amount of calculation. When the fusion speed cannot keep up with the data generation speed, data delay will occur, and the delay time will become longer and longer. Summary of the invention

[0006] Aiming at the problems existing in the prior art, an adaptive radar target and AIS target fusion method is provided. By introducing an adaptive distance threshold, a radar connection algorithm, and a grid subdivision parallel calculation and spatial indexing method, the problems of low fusion accuracy and low fusion efficiency of the existing scheme can be solved.

[0007] The technical solution adopted by the present invention is as follows: an adaptive radar target and AIS target fusion method, comprising:

[0008] Step 1: read radar target data discovered by different radar devices, merge repeated radar targets and successive radar targets in the radar target data, and obtain radar targets to be fused;

[0009] Step 2: Read AIS message data to obtain the AIS target to be fused;

[0010] Step 3: determine in turn whether the radar target to be fused and the AIS target to be fused meet the fusion conditions. If they meet the conditions, they are fused to obtain the radar AIS fusion target; otherwise, they are not fused.

[0011] Step 4: Get the final radar target, AIS target and radar AIS fusion target.

[0012] As a preferred solution, the sub-steps of step 1 include:

[0013] Step 1.1, read a radar target data, determine whether the track disappears, if not, go to step 1.2, otherwise, add it to the delayed deletion list and go to step 1.7;

[0014] Step 1.2, determine whether the radar target is a radar target to be fused, if not, proceed to step 1.3, if yes, update the radar target to be fused in the cache, and proceed to step 1.7;

[0015] Step 1.3, determine whether the radar target is bound to the radar target to be fused, if not, proceed to step 1.4, if yes, proceed to step 1.5;

[0016] Step 1.4: Determine whether the radar target to be connected is found. If not, traverse the radar targets to be fused in the cache that are different from the source of the radar target, and determine whether the fusion condition is met, and enter step 1.6; if so, bind the radar target to the target to be connected, cache it, and enter step 1.7;

[0017] Step 1.5, determine whether the unbinding condition is met, if so, cache after unbinding, and go to step 1.8, if not, refresh the binding relationship and cache, and go to step 1.7;

[0018] Step 1.6: If the fusion condition is met, the radar target is cached as the radar target to be fused; otherwise, the radar target is bound to the radar target to be fused in the cache;

[0019] Step 1.7: Repeat the process of steps 1.1 to 1.6 for all radar target data, and output the radar targets to be fused in the cache.

[0020] As a preferred solution, the sub-steps of step 2 include:

[0021] Step 2.1, read an AIS message data and parse it;

[0022] Step 2.2, query whether the AIS target is cached according to the MMSI, if so, update the AIS target to be merged in the cache according to the parsed AIS message; if not, create a new AIS target cache to be merged according to the parsed AIS message;

[0023] Step 2.3: Repeat the process of step 2.1 to step 2.2 for all AIS message data, and output the AIS targets to be fused in the cache.

[0024] As a preferred solution, the specific process of step 3 includes:

[0025] Step 3.1, for the radar target to be fused, establish binding relationships with the targets to be fused that meet the fusion conditions in turn, generate radar AIS fusion targets, and directly output the radar targets to be fused that have not established binding relationships with AIS targets;

[0026] Step 3.2: For the AIS target to be fused, establish binding relationships with the targets to be fused that meet the fusion conditions in turn to generate a radar AIS fusion target. The AIS target to be fused that has not established a binding relationship with the radar target is directly output.

[0027] As a preferred solution, the sub-steps of step 3.1 include:

[0028] Step 3.1.1, obtain any radar target to be fused, and determine whether the track disappears. If so, proceed to step 3.1.6; if not, proceed to step 3.1.2;

[0029] Step 3.1.2, updating the position and state of the radar target to be fused in the cache;

[0030] Step 3.1.3, determine whether the radar target to be fused is bound to an AIS target, if so, proceed to step 3.1.4; if not, proceed to step 3.1.5;

[0031] Step 3.1.4, determine whether the unbinding conditions are met, if so, unbind the relationship and output the radar target, and go to step 3.1.7; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.1.7;

[0032] Step 3.1.5, determine whether there is an AIS target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the radar target and the AIS target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.1.7; if not, output the radar target and enter step 3.1.7;

[0033] Step 3.1.6, delete the radar target to be fused in the cache, and release its binding relationship with the AIS target, select the next radar target to be fused in the cache, and go to step 3.1.1;

[0034] Step 3.1.7: Repeat steps 3.1.1 to 3.1.6 to complete the fusion of all radar targets to be fused and obtain the output radar target and radar AIS fusion target.

[0035] As a preferred solution, the sub-steps of step 3.2 include:

[0036] Step 3.2.1, obtain any AIS target to be fused, and update the position and status of the AIS target in the cache;

[0037] Step 3.2.2: Determine whether the AIS target to be fused is bound to a radar target. If so, proceed to step 3.2.3; if not, proceed to step 3.2.4;

[0038] Step 3.2.3, determine whether the unbinding conditions are met, if so, unbind the relationship and output the AIS target, and go to step 3.2.5; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.2.5;

[0039] Step 3.2.4, determine whether there is a radar target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the AIS target and the radar target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.2.5; if not, output the AIS target and enter step 3.2.5;

[0040] Step 3.2.5: Repeat steps 3.2.1 to 3.2.4 to complete the fusion of all AIS targets to be fused, and obtain the output AIS target and radar AIS fusion target.

[0041] As a preferred solution, the fusion conditions specifically include:

[0042] Determine whether the speed, heading, update time, and length between the two targets are all less than the corresponding preset fusion threshold, and determine whether the distance between the two targets is less than the adaptive distance threshold. If they are all less than, it means that the fusion condition is met, otherwise it means that the fusion condition is not met;

[0043] Among them, the adaptive distance threshold generation method is:

[0044]

[0045] Among them, D max is the upper limit of the distance threshold, Count(i,j) is the number of times target j is the closest target to target i, and α and β are fixed constants set based on experience to control the growth rate of D(i,j).

[0046] As a preferred solution, in step 1.4, the method for determining the subsequent radar target is:

[0047] The speed, heading and duration of signal disappearance of the radar target before the signal was lost are used to estimate the possible location of the radar target that lost the signal. When the newly discovered target happens to appear in the same location, the newly discovered target is identified as the radar target that previously lost the radar signal.

[0048] As a preferred solution, in the fusion process of step 3, the latitude and longitude coordinates of the target are retained to one decimal place, and the decimal points are removed for splicing, thereby converting them into a digital grid ID. The longitude and latitude coordinates with the same digital grid ID are divided into one grid, and multi-threading technology is used to fuse the targets in multiple grids in parallel.

[0049] As a preferred solution, when storing objects in a grid, an R-tree is used to store objects in the same grid, and a spatial index is established for the objects in the same grid.

[0050] Compared with the prior art, the beneficial effect of adopting the above technical solution is that the adaptive radar target and AIS target fusion method proposed in the present invention can effectively improve the target fusion accuracy and fusion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a flow chart of the adaptive radar target and AIS target fusion method proposed by the present invention.

[0052] Figure 2 The figure is a schematic diagram of obtaining radar targets to be fused in one embodiment of the present invention.

[0053] Figure 3 This is a schematic diagram of obtaining an AIS target to be fused in one embodiment of the present invention.

[0054] Figure 4 FIG. 1 is a schematic diagram of radar target fusion to be fused in one embodiment of the present invention.

[0055] Figure 5 FIG. 1 is a schematic diagram of the fusion of AIS targets to be fused in one embodiment of the present invention. DETAILED DESCRIPTION

[0056] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar modules or modules with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limitations on the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0057] In the maritime field, the target fusion of radar and automatic identification system (AIS) is of great necessity and significance, which is mainly reflected in the following aspects:

[0058] 1. Enhanced security

[0059] Collision avoidance: Radar can detect objects within the field of view, including ships without AIS or non-hull obstacles, while AIS provides detailed information about ships equipped with AIS systems, including location, speed, heading, ship type, etc. Fusion of the two data can more accurately determine potential collision threats and improve the accuracy of collision avoidance decisions.

[0060] Improve situational awareness: The fused information can create a more comprehensive picture of maritime traffic, helping shore-based control centers better understand the surrounding environment and enhance navigation safety.

[0061] 2. Improve efficiency

[0062] Optimize waterway management: Combining radar and AIS data, vessel traffic services (VTS) can more effectively monitor and guide vessel flows, reduce congestion, plan more efficient waterways, and reduce waiting time and fuel consumption.

[0063] 3. Data integrity and accuracy

[0064] Complementation and verification: Radar may be affected by weather conditions, while AIS may fail due to signal obstruction or equipment failure. The fusion of the two data can complement each other to ensure data continuity and reliability even in adverse conditions.

[0065] Target Identification and Classification: AIS provides target identity information, which helps radar target identification and classification, especially in high-density traffic areas.

[0066] 4. Promote regulatory compliance and search and rescue operations

[0067] Regulation and Compliance: Fused data can be used to monitor vessels’ compliance with International Maritime Organization (IMO) rules, such as speed limits and no-sail zones.

[0068] Rescue and emergency response: In an emergency, fused information can quickly locate the vessel in distress and provide critical vessel information to rescuers, speeding up the rescue process.

[0069] 5. Environmental protection

[0070] Pollution prevention: Converged technologies can help monitor vessel activities, prevent illegal discharges and oil spills, and protect the marine environment.

[0071] Protecting marine life: Fusion technology has great value in preventing illegal fishing. It improves the coverage and accuracy of monitoring and enhances the capabilities of law enforcement agencies, thereby helping to protect marine resources and maintain the balance of marine ecology.

[0072] However, the existing fusion solutions have the problems of low fusion accuracy and efficiency. The embodiment of the present invention proposes an adaptive radar target and AIS target fusion method, please refer to Figure 1 , specifically including:

[0073] Step 1: read radar target data detected by different radar devices, merge repeated radar targets and successive radar targets in the radar target data, and obtain radar targets to be fused.

[0074] Before target fusion, the radar targets to be fused need to be screened, for example, eliminating targets that have disappeared or been fused, or merging duplicate targets.

[0075] In this embodiment, please refer to Figure 2 , gives a specific method for obtaining the radar target to be fused:

[0076] Step 1.1, read a radar target data, determine whether the track disappears, if not, go to step 1.2, otherwise, add it to the delayed deletion list, and go to step 1.7. In one embodiment, the radar target data can be read from kafka1.

[0077] Step 1.2, determine whether the radar target is a radar target to be fused, if not, proceed to step 1.3, if yes, update the radar target to be fused in the cache, and proceed to step 1.7;

[0078] Step 1.3, determine whether the radar target is bound to the radar target to be fused, if not, proceed to step 1.4, if yes, proceed to step 1.5;

[0079] Step 1.4: Determine whether the radar target to be connected is found. If not, traverse the radar targets to be fused in the cache that are different from the source of the radar target, and determine whether the fusion condition is met, and enter step 1.6; if so, bind the radar target to the target to be connected, cache it, and enter step 1.7;

[0080] Step 1.5, determine whether the unbinding condition is met, if so, cache after unbinding, and go to step 1.8, if not, refresh the binding relationship and cache, and go to step 1.7;

[0081] Step 1.6: If the fusion condition is met, the radar target is cached as the radar target to be fused; otherwise, the radar target is bound to the radar target to be fused in the cache;

[0082] Step 1.7: Repeat the process of steps 1.1 to 1.6 for all radar target data, and output the radar targets to be fused in the cache.

[0083] In the above process, the radar target continuity judgment in step 1.4 is introduced to effectively solve the problem of misjudging a radar tracking target as a new target after it is lost. The main methods include: estimating the possible position of the radar target that lost the signal through the speed, heading and signal disappearance duration of the radar target before the signal was lost. When the newly discovered target happens to appear in the same position, the newly discovered target is identified as the radar target that lost the radar signal before.

[0084] Calculating the distance and direction between two points on the surface of the earth involves spherical trigonometry, and the great circle route calculation method is usually used. However, for short-distance navigation or occasions where the accuracy requirement is not particularly high, in this embodiment, an approximate method is used to simplify the calculation. The speed unit of a ship at sea is usually "knots", 1 knot is equal to 1 nautical mile per hour, and 1 nautical mile is equal to 1852 meters. Therefore, if you want to calculate the longitude and latitude coordinates after t seconds, you first need to convert the speed from knots to meters per second, and then calculate the displacement in the longitude and latitude directions based on the heading. In this embodiment, the specific method for estimating the new position of the radar target is as follows:

[0085] (1)Convert speed units:

[0086]

[0087] Among them, speed m / s is the converted speed (m / s), speed knots is the ship speed (knot).

[0088] (2) Calculate the distance traveled in t seconds

[0089] distance=speed m / s ×t

[0090] (3) Convert heading to radians

[0091] Heading is the direction from true north, usually expressed in degrees. Convert it to radians for mathematical calculations:

[0092]

[0093] Among them, bearing deg For heading, bearing rad In radians.

[0094] (4) Calculate the displacement in the latitude and longitude directions

[0095]

[0096] Among them, earthRadius is the average radius of the earth, approximately 6371000 meters.

[0097]

[0098] where currentLat is the latitude of the current location in radians.

[0099] (5) Convert the displacement into new longitude and latitude coordinates

[0100]

[0101] Among them, newLat is the new latitude and newLon is the new longitude.

[0102] If there is a radar target at the estimated new position of the radar target, it can be regarded as a subsequent radar target, and the current radar can be bound to the subsequent radar target. The radar targets with a binding relationship can be regarded as the same target.

[0103] Step 2: Read AIS message data to obtain the AIS target to be fused.

[0104] In this embodiment, for the AIS target, it is only necessary to determine whether it has been cached. If it has been cached, the information can be directly updated. Figure 3 , the specific process is as follows:

[0105] Step 2.1: Read and parse an AIS message data. In one embodiment, the AIS message data may be read from kafka1.

[0106] Step 2.2: Check whether the AIS target is cached according to the MMSI. If so, update the AIS target to be merged in the cache according to the parsed AIS message; if not, create a new AIS target cache to be merged according to the parsed AIS message.

[0107] Step 2.3: Repeat the process of step 2.1 to step 2.2 for all AIS message data, and output the AIS targets to be fused in the cache.

[0108] Step 3: determine in turn whether the radar target to be fused and the AIS target to be fused meet the fusion conditions. If they meet the conditions, they are fused to obtain the radar AIS fusion target; otherwise, they are not fused.

[0109] In this embodiment, it is necessary to judge the fusion conditions for the acquired radar targets to be fused and the AIS targets to be fused respectively. When judging the fusion conditions, the speed difference, distance difference, heading difference, time difference, length difference, etc. of the two targets are mainly used to judge whether the fusion conditions are met. Traditional schemes all use fixed thresholds for conditional judgment. However, in actual scenarios, there may be a deviation of several hundred meters between the coordinates of the ship located by different radars and the coordinates reported by the ship's AIS. When there are multiple ships within a range of several hundred meters, it is difficult to accurately fuse the targets according to the fixed distance threshold. Due to the accuracy error of the equipment, although the target may be temporarily confused with other targets, as time goes by, the target keeps moving and can always be distinguished from other confused targets. Therefore, in this embodiment, based on the fixed thresholds for speed difference, heading difference, time difference, and length difference, an adaptive distance threshold generation method is proposed to solve the error of target coordinates reported by different devices. Among them, the adaptive distance threshold generation is specifically as follows:

[0110]

[0111] Among them, D max is the upper limit of the distance threshold, Count(i,j) is the number of times target j is the closest target to target i, and α and β are fixed constants set based on experience to control the growth rate of D(i,j). When the speed difference, heading difference, time difference, and length difference between two targets are less than the corresponding preset fusion threshold, the adaptive distance threshold D(i,j) is used to further determine whether the two targets can be fused. As Count(i,j) increases, it continues to increase and infinitely approaches the upper limit of the distance threshold D max It should be noted that the above fusion conditions are also applicable to the judgment in step 1.6 of this embodiment.

[0112] Based on the above fusion conditions, this embodiment provides specific fusion processes of the radar target to be fused and the AIS target to be fused respectively.

[0113] (1) For radar targets to be fused, binding relationships are established with targets to be fused that meet the fusion conditions in turn to generate radar AIS fusion targets. Radar targets to be fused that have not established binding relationships with AIS targets are directly output.

[0114] Please refer to Figure 4 , the specific steps are as follows:

[0115] Step 3.1.1, obtain any radar target to be fused, and determine whether the track disappears. If so, proceed to step 3.1.6; if not, proceed to step 3.1.2;

[0116] Step 3.1.2: The position and status information of the same target identified by the radar is constantly changing over time. When the system receives the latest position status message of the radar target, it updates the position and status of the radar target to be fused in the cache.

[0117] Step 3.1.3, determine whether the radar target to be fused is bound to an AIS target, if so, proceed to step 3.1.4; if not, proceed to step 3.1.5;

[0118] Step 3.1.4, determine whether the unbinding conditions are met, if so, unbind the relationship and output the radar target, and go to step 3.1.7; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.1.7;

[0119] Step 3.1.5, determine whether there is an AIS target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the radar target and the AIS target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.1.7; if not, output the radar target and enter step 3.1.7;

[0120] Step 3.1.6, delete the radar target to be fused in the cache, and release its binding relationship with the AIS target, select the next radar target to be fused in the cache, and go to step 3.1.1;

[0121] Step 3.1.7: Repeat steps 3.1.1 to 3.1.6 to complete the fusion of all radar targets to be fused and obtain the output radar target and radar AIS fusion target.

[0122] (2) For the AIS targets to be fused, the binding relationship is established with the targets to be fused that meet the fusion conditions in turn to generate the radar AIS fusion target. The AIS targets to be fused that have not been bound with the radar targets are directly output. Figure 5 , the specific steps are as follows:

[0123] Step 3.2.1, obtain any AIS target to be fused. The position and status information of the AIS target changes over time. When the system receives the latest position status message of the AIS target, it updates the position and status of the AIS target in the cache;

[0124] Step 3.2.2: Determine whether the AIS target to be fused is bound to a radar target. If so, proceed to step 3.2.3; if not, proceed to step 3.2.4;

[0125] Step 3.2.3, determine whether the unbinding conditions are met, if so, unbind the relationship and output the AIS target, and go to step 3.2.5; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.2.5;

[0126] Step 3.2.4, determine whether there is a radar target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the AIS target and the radar target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.2.5; if not, output the AIS target and enter step 3.2.5;

[0127] Step 3.2.5: Repeat steps 3.2.1 to 3.2.4 to complete the fusion of all AIS targets to be fused, and obtain the output AIS target and radar AIS fusion target.

[0128] In practical applications, since the amount of fusion calculation data is relatively large, it often leads to data delay problems. In this embodiment, grid division and update calculation and spatial index are used to solve the delay problem of the fusion process.

[0129] It should be noted that this embodiment adopts a virtual grid partitioning method, and there is no actual grid object. Specifically, according to the latitude and longitude coordinates of the target, the target is cached in different grids, and only the targets in the same grid are fused and calculated. For example, the coordinate point (127.2234, 38.4532) retains one decimal place, removes the decimal point and concatenates, and the result is 1272384, so this coordinate point is mapped to the grid 1272384 and fused with other coordinates in the grid.

[0130] Since all targets have been mapped to different grids, this embodiment uses multi-threading technology to fuse targets in multiple grids in parallel. Since the time complexity of fusion calculation is O(n2), when the targets are evenly distributed in x grids, the total amount of calculation is only 1 / x of the original. At the same time, multi-threading technology is applied in engineering to fuse targets in x grids in parallel, thereby accelerating the fusion efficiency.

[0131] Since the longitude and latitude coordinates of the fused target belong to two-dimensional space, the spatial index R-tree is used to store the targets in the grid, which can improve the time complexity of the nearest target query from O(n) to O(logmn), where n is the total number of targets stored in the R-tree and m is the maximum capacity of the R-tree node.

[0132] Step 4: Get the final radar target, AIS target and radar AIS fusion target. The fused radar AIS fusion target and the radar target and AIS target that do not meet the fusion conditions can be saved in the database and written to Kafka for consumption by the business system.

[0133] Furthermore, an adaptive radar target and AIS target fusion system is also proposed in this embodiment, including a radar target acquisition module to be fused, an AIS target acquisition module to be fused, a radar target and AIS target fusion module and a target output module, wherein:

[0134] The radar target acquisition module to be fused executes the process of step 1, merges and screens the radar targets discovered by different radar devices, and determines the radar targets to be fused.

[0135] The AIS target acquisition module to be fused executes the process of step 2 to update the cached AIS target and cache the new AIS target to determine the AIS target to be fused.

[0136] The radar target and AIS target fusion module executes the process of step 3 to fuse the radar target to be fused and the AIS target to be fused respectively, and obtains the radar AIS fusion target and the radar target and AIS target that are not fused.

[0137] The target output module is used to output radar AIS fusion targets, fused radar targets and AIS targets.

[0138] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer readable medium, and the computer program includes a program code for executing the method shown in the flowchart.

[0139] It should be noted that the computer-readable medium shown in the embodiment of the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, - but not limited to - an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by an instruction execution system, device or device or used in combination with it. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein a computer-readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0140] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0141] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. The names of these units do not, in some cases, constitute limitations on the units themselves.

[0142] As another aspect, the present application also provides a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of a computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the adaptive radar target and AIS target fusion method described in the above embodiment.

[0143] As another aspect, the present application also provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements the adaptive radar target and AIS target fusion method described in the above embodiment.

[0144] It should be noted that, although several modules or units of the equipment for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0145] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the implementation methods of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation methods of the present application.

[0146] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific situations; the drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0147] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. An adaptive radar target and AIS target fusion method, characterized in that: include: Step 1: read radar target data discovered by different radar devices, merge repeated radar targets and successive radar targets in the radar target data, and obtain radar targets to be fused; Step 2: Read AIS message data to obtain the AIS target to be fused; Step 3: determine in turn whether the radar target to be fused and the AIS target to be fused meet the fusion conditions. If they meet the conditions, they are fused to obtain the radar AIS fusion target; otherwise, they are not fused. Step 4: Get the final radar target, AIS target and radar AIS fusion target.

2. The adaptive radar target and AIS target fusion method according to claim 1, characterized in that: The sub-steps of step 1 include: Step 1.1, read a radar target data, determine whether the track disappears, if not, go to step 1.2, otherwise, add it to the delayed deletion list and go to step 1.7; Step 1.2, determine whether the radar target is a radar target to be fused, if not, proceed to step 1.3, if yes, update the radar target to be fused in the cache, and proceed to step 1.7; Step 1.3, determine whether the radar target is bound to the radar target to be fused, if not, proceed to step 1.4, if yes, proceed to step 1.5; Step 1.4: Determine whether the radar target to be connected is found. If not, traverse the radar targets to be fused in the cache that are different from the source of the radar target, and determine whether the fusion condition is met, and enter step 1.6; if so, bind the radar target to the target to be connected, cache it, and enter step 1.7; Step 1.5, determine whether the unbinding condition is met, if so, cache after unbinding, and go to step 1.8, if not, refresh the binding relationship and cache, and go to step 1.7; Step 1.6: If the fusion condition is met, the radar target is cached as the radar target to be fused; otherwise, the radar target is bound to the radar target to be fused in the cache; Step 1.7: Repeat the process of steps 1.1 to 1.6 for all radar target data, and output the radar targets to be fused in the cache.

3. The adaptive radar target and AIS target fusion method according to claim 1, characterized in that: The sub-steps of step 2 include: Step 2.1, read an AIS message data and parse it; Step 2.2, query whether the AIS target is cached according to the MMSI, if so, update the AIS target to be merged in the cache according to the parsed AIS message; if not, create a new AIS target cache to be merged according to the parsed AIS message; Step 2.3: Repeat the process of step 2.1 to step 2.2 for all AIS message data, and output the AIS targets to be fused in the cache.

4. The adaptive radar target and AIS target fusion method according to claim 1, characterized in that: The specific process of step 3 includes: Step 3.1, for the radar target to be fused, establish binding relationships with the targets to be fused that meet the fusion conditions in turn, generate radar AIS fusion targets, and directly output the radar targets to be fused that have not established binding relationships with AIS targets; Step 3.2: For the AIS target to be fused, establish binding relationships with the targets to be fused that meet the fusion conditions in turn to generate a radar AIS fusion target. The AIS target to be fused that has not established a binding relationship with the radar target is directly output.

5. The adaptive radar target and AIS target fusion method according to claim 4, characterized in that: The sub-steps of step 3.1 include: Step 3.1.1, obtain any radar target to be fused, and determine whether the track disappears. If so, proceed to step 3.1.6; if not, proceed to step 3.1.2; Step 3.1.2, updating the position and state of the radar target to be fused in the cache; Step 3.1.3, determine whether the radar target to be fused is bound to an AIS target, if so, proceed to step 3.1.4; if not, proceed to step 3.1.5; Step 3.1.4, determine whether the unbinding conditions are met, if so, unbind the relationship and output the radar target, and go to step 3.1.7; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.1.7; Step 3.1.5, determine whether there is an AIS target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the radar target and the AIS target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.1.7; if not, output the radar target and enter step 3.1.7; Step 3.1.6, delete the radar target to be fused in the cache, and release its binding relationship with the AIS target, select the next radar target to be fused in the cache, and go to step 3.1.1; Step 3.1.7: Repeat steps 3.1.1 to 3.1.6 to complete the fusion of all radar targets to be fused and obtain the output radar target and radar AIS fusion target.

6. The adaptive radar target and AIS target fusion method according to claim 4, characterized in that: The sub-steps of step 3.2 include: Step 3.2.1, obtain any AIS target to be fused, and update the position and status of the AIS target in the cache; Step 3.2.2: Determine whether the AIS target to be fused is bound to a radar target. If so, proceed to step 3.2.3; if not, proceed to step 3.2.4; Step 3.2.3, determine whether the unbinding conditions are met, if so, unbind the relationship and output the AIS target, and go to step 3.2.5; if not, refresh the binding relationship and output the radar AIS fusion target, and go to step 3.2.5; Step 3.2.4, determine whether there is a radar target to be fused that meets the fusion conditions in the cache. If so, establish a binding relationship between the AIS target and the radar target to be fused that meets the fusion conditions, generate a radar AIS fusion target, and enter step 3.2.5; if not, output the AIS target and enter step 3.2.5; Step 3.2.5: Repeat steps 3.2.1 to 3.2.4 to complete the fusion of all AIS targets to be fused, and obtain the output AIS target and radar AIS fusion target.

7. The adaptive radar target and AIS target fusion method according to claim 1, 5 or 6, characterized in that: The fusion conditions specifically include: Determine whether the speed, heading, update time, and length between the two targets are all less than the corresponding preset fusion threshold, and determine whether the distance between the two targets is less than the adaptive distance threshold. If they are all less than, it means that the fusion condition is met, otherwise it means that the fusion condition is not met; Among them, the adaptive distance threshold generation method is: Among them, D max is the upper limit of the distance threshold, Count(i,j) is the number of times target j is the closest target to target i, and α and β are fixed constants set based on experience to control the growth rate of D(i,j).

8. The adaptive radar target and AIS target fusion method according to claim 1 or 2, characterized in that: The adaptive radar target and AIS target fusion method according to claim 1 is characterized in that the method for determining the subsequent radar target is: The speed, heading and duration of signal disappearance of the radar target before the signal was lost are used to estimate the possible location of the radar target that lost the signal. When the newly discovered target happens to appear in the same location, the newly discovered target is identified as the radar target that previously lost the radar signal.

9. The adaptive radar target and AIS target fusion method according to claim 1, characterized in that: In the fusion process of step 3, the latitude and longitude coordinates of the target are retained to one decimal place, and the decimal points are removed for splicing, so as to be converted into a digital grid ID. The longitude and latitude coordinates with the same digital grid ID are divided into one grid, and multi-threading technology is used to fuse the targets in multiple grids in parallel.

10. The adaptive radar target and AIS target fusion method according to claim 9, characterized in that: When storing the target in the grid, the R-tree is used to store the targets in the same grid and a spatial index is established for the targets in the same grid.

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