Method for loading electronic sea charts for ocean-going vessels in dynamic areas based on a sailing route

Abstract

The application relates to a kind of ocean ship dynamic area loading electronic chart based on navigation path method, comprising: obtaining the starting point and the terminal point of ship voyage, generating navigation path and the whole navigation area chart data range;The sea area in the calibration area on both sides of the path is defined as the width range of target loading area;According to the current position, dynamically adjust the target loading area, request the server to download, load new target loading area chart data, and unload the chart data of the area that has passed.When the network is interrupted, the background cache chart data is used, when the cache chart data is loaded to the boundary amount, the chart cell data is extracted from each involved class file according to the geographical position of the target loading area, the subsequent chart data loading is carried out, and until the network is restored, the server chart data and the chart update compressed data of the part of the navigation area are continuously downloaded.The application can effectively reduce the rendering pressure of electronic chart software, improve the system operation efficiency and response speed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of marine navigation, and particularly relates to a method for dynamically loading an electronic sea chart for an ocean-going ship based on a sailing path. BACKGROUND

[0002] With the development of modern marine transportation, an electronic sea chart has become an indispensable navigation tool for an ocean-going ship. However, a conventional electronic sea chart loading method usually requires pre-downloading and loading of sea chart data for an entire sailing area, which not only occupies a large amount of storage space and bandwidth resources, but also may cause the electronic sea chart software to load too much data, thereby affecting the performance of the ship system and further causing potential risks to navigation safety. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a navigation method for an ocean-going ship based on dynamic loading of an electronic sea chart based on a sailing path, which, through intelligent path analysis and regional data loading, saves storage space and data download amount while ensuring navigation safety; at the same time, by judging the ranges of a sailed part of a sailing area and a non-sailed part of the sailing area in real time, serving as a basis for determining whether to trigger an update event, generating and sending an update compressed package, and guaranteeing high-resolution sea chart loading of the ship under a network interruption condition, the running efficiency of the electronic sea chart software of the ship is improved.

[0004] To achieve the above object, the present application discloses a method for dynamically loading an electronic sea chart for an ocean-going ship based on a sailing path, which comprises the following steps:

[0005] S1, obtaining a starting point and an ending point of a voyage of an ocean-going ship, generating a sailing path of the ship and a sea chart data range of an entire sailing area;

[0006] S2, analyzing the obtained sailing path, and defining a sea area in a demarcated region on both sides of the path as a width range of a target loading region;

[0007] S3, defining a length range of the target loading region of each sailing section according to a sailing speed of the ship and a reaction time;

[0008] S4, according to the defined width range and length range of the target loading region of each sailing section, sending a request to a server electronic sea chart database, downloading high-resolution sea chart data in the width and length ranges of the target loading region of a current sailing section, and pre-loading data of a subsequent demarcated number of sailing sections in the background;

[0009] S5, updating a current position in real time during sailing of the ship, and dynamically adjusting the target loading region, applying for and loading new sea chart data, and uninstalling sea chart data of a passed region according to the current position;

[0010] Further, the method further comprises a network interruption fault protection step, which comprises:

[0011] P1, the whole sea chart data range of the sailing area generated according to step S1, the sea chart data of the sailing area is divided into a plurality of sea chart cells of the same scale;

[0012] P2, comparing all the divided sea chart cells, the same sea chart cells are divided into a class, and an index record of the geographical position of each sea chart cell in each class is set;

[0013] P3, recording and retaining the class representative sea chart cell of each class and the index record thereof;

[0014] P4, compressing the class representative sea chart cell of all classes and the index record file thereof to obtain sea chart compressed data of the whole sailing area, and sending to the ship standby;

[0015] P5, according to the range of the part of the sailing area not sailed by the real-time ship, judging whether the update of the electronic sea chart database of the server triggers an update event, if yes, generating and sending an update compressed package, otherwise, not sending;

[0016] P6, after the ship receives the update compressed package, parsing the file, and performing coverage update of the existing sea chart data of the sailing area according to the class and the geographical position, so that the ship standby is high-resolution sea chart data, and real-time keeping of the present situation is maintained;

[0017] P7, when the system detects that the network connection is interrupted, the cached sea chart data of the sailing section is loaded;

[0018] P8, when the cached sea chart data is loaded to the boundary limit, the ship standby sea chart data is called, the sea chart cell data is extracted from the related class file according to the geographical position of the target loading area, and the sea chart data loading of the target loading area of the subsequent sailing section of the ship is performed.

[0019] Further, the sea chart data range of the whole sailing area in step S1 includes the whole route from the starting point to the destination, the potential refuge port, the standby route, the coastal area, the narrow waterway, the important strait and the special attention area.

[0020] Further, step S2, analyzing the obtained sailing path, defining the sea area in the demarcated area on both sides of the path as the width range of the target loading area, specifically including:

[0021] S21, defining the basic width range of the target loading area on both sides of the sailing path:

[0022] S22, analyzing the obtained sailing path, adaptively adjusting the basic width range of the target loading area according to the influencing factors, and defining the sea area in the demarcated area on both sides of the path as the width range of the target loading area.

[0023] Further, the width of the target loading area on both sides of the route in step S21 is 2 nautical miles on both sides of the centerline of the route.

[0024] Further, the length of the target loading area in step S3 is D1:

[0025] D1 = V x T x (1 + A%);

[0026] where D1 is the length of the target loading area, V is the average speed of the ship, T is the pre-loading time, and A% is the safety margin of the ship's voyage.

[0027] Further, step P5, determine whether the update of the electronic chart database of the server triggers an update event, if yes, generate and send the update compressed package, otherwise do not send, including:

[0028] P51, determine the range of the part of the voyage area and the part of the voyage area that has not been traveled by the ship in real time, as the basis for determining whether to trigger an update event;

[0029] P52, determine whether the update of the electronic chart database of the server triggers an update event;

[0030] P53, if the update event is triggered, generate the update compressed package and send it to the ship.

[0031] Further, step P52, determine whether the update of the electronic chart database of the server triggers an update event, including:

[0032] When the update of the electronic chart database of the server is the chart data outside the voyage area of the ship, the update event is not triggered;

[0033] When the update of the electronic chart database of the server only involves the chart cells of the part of the voyage area that has been traveled by the ship, the update event is not triggered;

[0034] When the update of the electronic chart database of the server involves the chart cells of the part of the voyage area that has not been traveled by the ship, the update event is triggered.

[0035] Further, step P53, if the update event is triggered, generate the update compressed package and send it to the ship, including:

[0036] Record all the chart cells involved in the update;

[0037] The updated chart cell is compared with each class representative chart cell recorded and reserved one by one, and the comparison result and the geographical position of the chart cell are recorded; if the updated chart cell is consistent with a certain representative chart cell recorded, the class is marked to increase a geographical position; if it is inconsistent with all representative chart cells recorded, a new class is created, and the index of the geographical position of the chart cell in the class is recorded; and the new class is also recorded and reserved, so that the updated chart cell is iterated in sequence for consistency judgment;

[0038] After the comparison results and the geographical position files of the chart cells are compressed to generate an update compression package, the update compression package is sent to the ship as a chart replacement file of the un-navigated sea area.

[0039] Further, all chart cells involved in the update are chart cells of the changed part of the chart of the un-navigated sea area of the ship.

[0040] Further, the method further comprises:

[0041] P9, judging whether the network connection is restored, if not, continuing to execute P8 to call the backup chart data of the ship system to load the chart data of the subsequent target loading area of the ship; if yes, executing S5 to request the server electronic chart database, and continuing to download the high-resolution chart data in the current target loading area and the chart data update data of the un-navigated sea area.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] 1. The present application only loads the high-resolution chart data near the current navigation path, greatly reduces the data loading and rendering pressure of the electronic chart software, improves the system operation efficiency and response speed, and is suitable for more terminal devices and low-configuration devices. For some terminal devices with low bandwidth or low computing power, only the target area chart is loaded, which can realize fast loading and display, avoids the problem that the device cannot process large-capacity data due to insufficient memory or bandwidth problems, and has better compatibility.

[0044] 2. The present application utilizes the characteristics of a large amount of repeated data in the chart, divides the sea area chart data into multiple class chart cells and address notes according to the generated chart data range of the entire sea area, and transmits after compression processing; subsequently, only the un-navigated sea area chart update data is transmitted according to the real-time changed sea area chart range, and the update data is only the class representative chart cell and the address note, which can effectively reduce the data amount of each transmission, ensure fast and low-cost chart update, and reduce the bandwidth pressure in each synchronization process.

[0045] 3、The application establishes a fault protection mechanism, through the class storage and address note of the chart cell, and then dynamically updates various chart cells, so as to reserve high-resolution electronic charts on the ship, when the network is interrupted, only the target loading area is parsed and loaded according to the need, the data processing burden is reduced, the data processing and parsing time is reduced, and the navigation safety of the ship in various environments is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 A flowchart of a kind of navigation method of ocean ship based on the dynamic loading electronic chart of sailing path of the application. DETAILED DESCRIPTION

[0047] To make the purpose, technical scheme and advantages of the application more clear, further description is made below in combination with drawings and examples.

[0048] It should be noted that, in this paper, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0049] As shown in the accompanying Figure 1 The application provides a kind of dynamic area loading electronic chart of ocean ship based on sailing path, which includes the following steps:

[0050] S1, the starting point and the end point of the voyage of ocean ship are acquired, the sailing path of ship and the chart data range of entire navigation area are generated, including:

[0051] S11, the starting point and the end point of the voyage of ocean ship are acquired, and the sailing path of ship is generated;

[0052] Before ocean ship sets sail, the starting point and the end point of voyage are input through ECDIS (Electronic Chart Display and Information System) and other navigation planning software, and the sailing path of ship generated by software according to input information can be acquired.

[0053] ECDIS (Electronic Chart Display and Information System) complies with the regulations of the International Maritime Organization (IMO) and the International Maritime Satellite Organization (ISM), and is widely used in modern ship navigation. It is the most common navigation planning system, which integrates electronic charts and various navigation functions, including automatic route planning, danger area warning, channel selection, weather information, etc. ECDIS not only displays the chart, but also automatically generates a navigation path according to the input starting point and destination, helping the crew to choose the safest and most efficient route.

[0054] S12, obtaining the starting point and destination of the ocean-going ship voyage, generating the chart data range of the entire voyage area of the ship;

[0055] In ocean-going ship navigation, Electronic Navigational Chart (ENC) is an indispensable tool in modern navigation. The chart data of the entire voyage area usually refers to the entire area of the planned voyage of the ship, which includes the following aspects:

[0056] Full route from departure point to destination: This includes the direct route from the departure port to the destination port and any sea area that may be passed through.

[0057] Potential safe haven: In an emergency, the ship may need to change course to a port.

[0058] Backup route: Due to weather conditions, ship breakdown or other reasons, the ship may need to deviate from the planned route, so the chart data on the backup route also needs to be downloaded.

[0059] Coastal areas: When sailing near the coast, more detailed chart data may be needed to avoid shoals, reefs and other dangers.

[0060] Narrow waterways and important straits: The charts of these areas need high precision because they are usually the key parts of the voyage, with dense traffic and may have special navigation rules.

[0061] Areas of special concern: such as oil extraction areas, military exercise areas, fishing areas, etc. These areas may require special chart information.

[0062] International regulations require carrying charts: According to the regulations of the International Maritime Organization (IMO), some charts are mandatory, such as charts that must be carried in certain sea areas.

[0063] The size of the entire voyage area depends on the range and complexity of the voyage, and may cover chart data of several national sea areas or even the entire ocean. According to the starting point and destination of the ocean-going ship voyage, the chart data range of the entire voyage area can be determined through navigation planning software such as ECDIS.

[0064] S2, analyze the obtained navigation path, define the sea area within the calibration area on both sides of the path as the width range of the target loading area;

[0065] The width range of the target loading area can be defined according to the type of ship, speed, route complexity, and possible navigation risks, including:

[0066] S21, define the basic width range of the target loading area on both sides of the navigation path:

[0067] Determine a basic width safety range based on the maximum speed of the ship and the shortest reaction time. The basic safety range of the target area is usually defined as 2 nautical miles on both sides of the center line of the navigation path, and the basic range can be dynamically adjusted as needed.

[0068] S22, analyze the obtained navigation path, and adaptively adjust the basic width range of the target loading area according to the influencing factors, define the sea area within the calibration area on both sides of the path as the width range of the target loading area, including:

[0069] For the type of ship: Different types of ships have different operating characteristics, such as cargo ships, tankers, passenger ships, and fishing boats. The size, draft, and maneuvering performance of the ship will affect the range of chart information required for safe navigation. For large ships or deep-draft ships, the width safety range should be increased to avoid shallow water areas and dangerous objects.

[0070] For speed: Ships with high speed will cover a longer distance in the same time, so they need more extensive chart information to ensure safety. For fast ships, the width safety range should be increased to ensure enough time for route adjustment.

[0071] For route complexity: For a winding route, the width safety range should be increased to cover the charts of all possible turning points to assist navigation; for a route along the coast, the chart loading range of the coastal area along the coast should be increased to assist navigation; for routes crossing straits and channels, because straits and channels may be narrow and traffic-intensive, increase the width safety range of these areas and ensure that all relevant safe water areas are included.

[0072] For navigation risks: For shallow water areas, dangerous objects, and areas with adverse weather, increase the chart loading range of the corresponding width; shallow water areas and dangerous objects: increase the chart of the corresponding width to avoid dangers such as running aground; in traffic-intensive areas, increase the chart of the corresponding width range to ensure enough information for avoidance; adverse weather and sea conditions: increase the wider safety area to deal with possible route deviations.

[0073] Considering all the above factors, adjust the basic range of the target loading area to determine the final chart loading range for each section.

[0074] Further, risk assessment tools such as Fault Tree Analysis (FTA) or Hazard and Operability Studies (HAZOP) can be used to help determine the most appropriate range.

[0075] S23, during navigation, dynamically adjust the chart loading width range according to temporary conditions;

[0076] During navigation, dynamically adjust the chart loading range according to the actual situation (such as weather changes, traffic conditions, etc.).

[0077] Through the above steps, the chart loading area will not be too large to cause resource waste, nor too small to cause navigation risk.

[0078] S3, according to the ship's speed and reaction time, define the length range of the target loading area of each navigation section, including:

[0079] S31, determine the calibration pre-loading navigation time;

[0080] Determine the calibration pre-loading navigation time, which is usually based on the ship's operating procedures and safety requirements. For example, if you choose to pre-load 2 hours of chart data: calibration pre-loading navigation time T = 2 hours.

[0081] S32, calculate the ship's speed V;

[0082] Determine the average speed V of the ship in the pre-loading area (it can be the planned speed, or the expected speed based on the type of ship and sea conditions).

[0083] S33, calculate the distance that each pre-loading area should cover: D = V x T

[0084] Where: D is the length range of the pre-loading area, V is the average speed of the ship, and T is the pre-loading navigation time.

[0085] For example, if the average speed of the ship is 18 knots (knots, 1 knot is equal to 1 nautical mile per hour), and the pre-loading navigation time is 2 hours:

[0086] D = 18 knots x 2 hours = 36 nautical miles

[0087] S34, consider the safety margin of ship navigation;

[0088] To ensure that there is enough safety margin for ship navigation, a certain percentage of the calculated pre-loading distance can be added as a margin.

[0089] That is, the length range D1 of the target loading area loaded each time is:

[0090] D1 = V x T x (1 + A%)

[0091] Where D1 is the length range of the target loading area for each loading, V is the average speed of the ship, T is the pre-loading time, and A% is the safety margin of the ship's navigation.

[0092] For example, if the margin is increased by 10%, the length range of the target loading area for each loading is:

[0093] D1 = D x 1.10 = 36 nautical miles x 1.10 = 39.6 nautical miles

[0094] Further, the data transmission and processing time, as well as the time required to download chart data from the server to the local device, and the data processing and loading into the ECDIS system, can also be considered. If these times are long, the distance of the pre-loading area may need to be further increased.

[0095] Through the above steps, the length range of the target loading area for each loading suitable for the current navigation of the ship can be calculated.

[0096] In general, the target loading area for each loading of a typical ship can include a distance of 24 nautical miles (about 44.5 kilometers) forward from the current position to a few hours of travel. For example, the area for the next 2-3 hours of navigation can be pre-loaded. For a ship with a speed of 20 knots, the distance of 2-3 hours of navigation is about 40-60 nautical miles. Therefore, a preliminary target loading area length can be 40 to 60 nautical miles.

[0097] The reason for not pre-loading for too long is that on the one hand, it is necessary to reduce the rendering pressure of the ship's electronic chart software and improve the system's running efficiency and response speed; on the other hand, it is because of the irregular update of electronic chart data (such as ENC data) on the server:

[0098] The update of electronic chart data on the server is usually determined by the following factors:

[0099] 1) Channel dredging or change: If the channel, port, beacon position, depth, etc. have changed, the chart data needs to be updated. These changes may be due to natural factors (such as changes in the seabed, sediment accumulation) or human engineering (such as dredging, reclamation, offshore construction, etc.).

[0100] 2) Change or repair of beacons: For example, the position or light of a lighthouse, buoy, beacon, etc. has changed.

[0101] 3) Changes in the marine environment: Natural changes in the seafloor (such as sediment accumulation, changes in seamounts) can affect the accuracy of chart data.

[0102] 4) New survey and measurement data: New data obtained by survey vessels, unmanned underwater vehicles, satellites, etc. may lead to corrections to existing chart data. These data include depth measurements, seafloor topography, changes in channels, etc.

[0103] 5) Changes in international shipping standards: Changes in requirements for charts or navigation technology by international maritime organizations (IMO), etc. may require updates to related electronic chart data to comply with new international standards and regulations.

[0104] At the same time, the update frequency of electronic chart data on the server varies by region and data provider. In general, the following are some common update frequencies:

[0105] Regular updates: Most electronic charts (such as ENC data) are updated on a regular basis, usually monthly or quarterly. Some areas may be more frequent, especially in busy shipping areas or areas with frequent changes in the environment.

[0106] Real-time or irregular updates: For more dynamic areas (such as polar regions, areas with significant changes in coastlines, etc.), or chart providers in certain countries / regions, more frequent updates may be provided, even immediate updates after significant changes.

[0107] Emergency updates: In the event of an emergency (such as the loss of a navigation beacon, sudden changes in water depth, or the emergence of new underwater obstacles), charts may be updated in an emergency and provided to users in a timely manner through chart data services.

[0108] By considering the operational procedures and safety requirements of the ship, not defining a pre-loaded time that is too long, and downloading chart data for the target area in a timely manner, real-time water depth, navigation beacon location, and channel information can be obtained during the voyage, thereby more effectively responding to unexpected situations, reducing deviation, misnavigation, or re-planning during the voyage, saving fuel and time, improving navigation efficiency, and avoiding economic losses.

[0109] Further, it also includes temporary dynamic adjustment of the target loading area:

[0110] During the voyage, the pre-loaded area can be temporarily and dynamically adjusted according to the actual position and speed of the ship. If the ship deviates from the original route, new chart data needs to be recalculated and loaded.

[0111] S4, according to the width and length range of the defined target loading area, request the server electronic chart database to download the high-resolution chart data in the width and length range of the current target loading area, and simultaneously pre-load the data of the subsequent k length segments in the background;

[0112] According to the target loading area, download the chart data from the server electronic chart database and store it in the local device. When downloading, the chart data of the current starting segment of the voyage can be preferentially loaded, and the chart data of the subsequent segments can be pre-loaded in the background to ensure that the data is available in real time during the voyage;

[0113] S5, during the voyage of the ship, the current position is updated in real time through GPS or AIS, and the target loading area is dynamically adjusted according to the current position, new chart data is applied and loaded, and the chart data of the area that has passed is unloaded.

[0114] In the ship ECDIS system, the trigger condition for pre-loading is defined: when the ship approaches the boundary of the currently loaded chart, the pre-loading is automatically started. The distance triggering the pre-loading is defined to ensure that the new chart data has been downloaded and ready before reaching the boundary of the current chart data.

[0115] Further, in order to ensure that the pre-loading works as expected, the ship ECDIS system can be monitored during actual navigation to confirm whether the pre-loaded chart data is downloaded and available at the appropriate time, so as to ensure smooth transition to the next chart area during the voyage without data blank.

[0116] As a protection step for a long-distance ship to smoothly load the subsequent electronic chart of the navigation area when encountering a network failure during navigation, the application also provides a network failure protection method for long-distance ships to dynamically download and load electronic charts based on navigation paths, comprising:

[0117] P1, according to the chart data range of the entire navigation area generated in step S1, divide the navigation area chart data into multiple chart cells of the same scale;

[0118] The entire navigation area chart data range generated by step S1 is pre-acquired to ensure that during future navigation, especially in the open sea area without network coverage, the navigation system of the ship can access all the required high-resolution chart information, ensuring the safety and reliability of the voyage.

[0119] According to the chart data range of the entire navigation area generated in step S1, the chart data of the entire navigation area is divided into multiple chart cells of the same scale. The scale of the cell can be determined according to the demand. The small scale cell is between several hundred meters to several kilometers, and the large scale cell is between several kilometers to several tens of kilometers.

[0120] P2, compare all the divided chart cells, divide the same chart cells into a class, and each class has an index record of the geographical location of each chart cell in the class;

[0121] Because the chart data of the entire navigation area is divided into multiple chart cells of the same size, there will be a large number of repeated and identical chart cells. For example, in multiple chart cells of the same navigation area, there may be the same chart information, such as the same water depth data in deep sea areas (the same deep blue or light blue area), the same channel mark, lighthouse position, etc. These information are repeated in different cells, mainly because different cells may represent different parts of the same sea area, but they contain the same geographical feature data.

[0122] P3, record the class representative chart cell and its index record of each class;

[0123] P4, compress all the class representative chart cells and their index record files of all classes to obtain the chart compression data of the entire navigation area, and send it to the ship backup;

[0124] Because each class only takes one class representative chart cell and its index record file for compression, the compressed data is nearly 90% smaller than the original chart data of the entire navigation area. This transmission has the following advantages:

[0125] Save bandwidth and network resources: The compressed data is smaller in size, and the required bandwidth during transmission will be significantly reduced. This is especially beneficial for bandwidth-limited network environments (such as satellite communication, mobile network, etc.), which can effectively avoid transmission bottlenecks and improve transmission efficiency.

[0126] Improve transmission speed: Because the compressed data is smaller in size, the time required for transmission is greatly shortened. Compression can speed up data upload and download speed. Improve transmission efficiency, especially in low-bandwidth environments: For communication networks with unstable or low bandwidth (such as ocean communication, sea communication, etc.), compressed data can ensure that even in the case of limited bandwidth, the transmission of charts can be completed. Especially in the ocean or remote areas, the bandwidth of the communication network may be unstable or low, and compression can ensure smooth data transmission under low bandwidth.

[0127] Reduce storage space: The compressed data size is small according to the same class representative chart cell, which can reduce the space requirement of the storage device. Especially in the case of large amount of chart data, compression can greatly save storage cost and save several times of storage space.

[0128] Reduce data transmission costs and reduce operating costs: Many transmission networks charge according to data volume, and compressed data can significantly reduce the cost of each transmission. For applications that require frequent transmission of large amounts of chart data (such as sea navigation, navigation instrument updates, etc.), small data volume compressed data can effectively reduce data transmission costs.

[0129] P5, determine whether the update of the electronic chart database of the server triggers an update event, if yes, generate and send an update compressed package, otherwise do not send, comprising:

[0130] P51, real-time determine the range of the part of the navigation area that the ship has sailed and the part of the navigation area that the ship has not sailed, as the basis for determining whether to trigger an update event;

[0131] In the above step S4, according to the width and length range of the defined target loading area, a request is sent to the server electronic chart database to preferentially download high-resolution chart data within the width and length range of the current target loading area, and at the same time, the server will record the current position of the ship according to the application of the navigation segment data to determine the range of the part of the navigation area that the ship has sailed and the part of the navigation area that the ship has not sailed, as the basis for determining whether to trigger an update event. Wherein, k is a positive integer greater than 1, at the same time, k is generally 2, k should not be too large, and needs to be determined in combination with the system storage space of the ship.

[0132] Further, according to the real-time application of the chart data file by the ship, the range of the chart data of the part of the navigation area that the ship has not sailed on the server is iteratively limited, and as the ship continues to sail, the range of the chart data of the part of the navigation area that the ship has not sailed gradually decreases, thereby reducing the amount of navigation area chart data involved in the update and improving the efficiency of data comparison, compression and transmission.

[0133] P52, determine whether the update of the electronic chart database of the server triggers an update event, comprising:

[0134] When the update of the electronic chart database of the server is unrelated to the chart cell of the part of the navigation area that the ship has sailed, the update event is not triggered;

[0135] When the update of the electronic chart database of the server relates to the chart cell of the part of the navigation area that the ship has sailed, the update event is not triggered;

[0136] When the update of the electronic chart database of the server relates to the chart cell of the part of the navigation area that the ship has not sailed, the update event is triggered, and an update compressed package is sent. Wherein, the compressed package relates to the chart cell of the part of the chart that has changed in the part of the navigation area that the ship has not sailed.

[0137] P53, if the update event is triggered, generate an update compressed package and send it to the ship, comprising:

[0138] Record the update involved all the chart cells; compare the updated chart cells with each of the recorded class representative chart cells one by one, record the comparison results and the geographical position of the chart cells;

[0139] If consistent with a certain recorded class representative chart cell, mark the class to add a geographical position; if inconsistent with all recorded class representative chart cells, create a new class, index the geographical position of the chart cells in the class, and record the new class for subsequent updated chart cells for iterative update judgment.

[0140] After compressing all comparison results and the geographical position files of the chart cells to generate an update compressed package, send it to the ship as a chart replacement file for untravelled sea areas.

[0141] P6, after the ship receives the update compressed package, parse the file, and perform overlay update of existing sea area chart data by class and geographical position, making the ship's standby high-resolution chart data, and keeping it real-time and up-to-date;

[0142] After the ship receives the update compressed package, decompress it, parse the replacement file, and perform overlay update of existing sea area chart data by class and geographical position, including:

[0143] For the received class representative chart cells consistent with the recorded class representative chart cells (already on the ship), add a geographical position in the corresponding index file; for those inconsistent with all recorded class representative chart cells, save the received newly created class and its index file, so that the ship's standby data is high-resolution chart data, and its real-time and up-to-date is maintained.

[0144] Further, after the ship receives the initial compressed package, it can not be decompressed, and after receiving the update compressed package, decompress the two compressed packages, parse the initial file and the replacement file respectively, perform overlay update of existing sea area chart data by class and geographical position, and then compress and store them, so that the ship's system storage resources are maximized, and the system's data processing efficiency is improved.

[0145] P7, when the system detects that the network connection is interrupted, the cached high-resolution chart data will be used, and the operator will be notified to take appropriate navigation measures.

[0146] In the case of network connection interruption of the ship, relying on the cached chart data, the navigation measures that the operator should take are to ensure that the ship can continue to sail within a safe range, including slowing down, maintaining course, using known channels, and strengthening visual monitoring, etc. to minimize potential risks, and update the data as soon as possible after the network is restored.

[0147] P8, when the cached chart data has been loaded to the boundary amount, the latest backup chart data of the ship system is called, the chart cell data is extracted from the relevant class files according to the geographical position of the target loading area, and the chart data loading of the subsequent target loading area of the ship is performed;

[0148] When the cached chart data has been loaded to the boundary amount, the boundary amount can be the last target loading area chart, the system only calls the cached last target loading area chart, then the background of the system calls the latest backup chart data of the ship system, extracts the chart cell data from the relevant class files according to the geographical position of the target loading area, and performs the chart data loading of the subsequent target loading area of the ship;

[0149] Further, when performing the compression storage management of the backup chart data of the ship, it is necessary to decompress first and then call. Because the use time of the last target loading area chart is generally 2-3 hours (the length of the target loading area chart determines), and at this time all the used charts stored in the ship system have been deleted, the ship system has enough time, space and running resources to process the analysis and loading use of the high-resolution backup chart data.

[0150] P9, it is judged whether the network connection is restored, if not, the backup chart data of the ship system is called in P8 to perform the chart data loading of the subsequent target loading area of the ship; if yes, S5 is executed to request the server electronic chart database, and the high-resolution chart data of the current target loading area and the chart data update data of the untravelled part of the navigation area are continued to be downloaded.

[0151] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

[0152] The above describes the present application and its embodiments, which are not limited, and the shown in the drawings is only one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired thereby, without departing from the principles and spirits of the present application, without creative design, similar structure and embodiments can be designed, which should belong to the protection scope of the present application.

Claims

1. A method for dynamic area loading of electronic charts for ocean-going vessels based on a sailing route, characterized in that, It comprises steps of: S1, obtaining the starting point and the ending point of the voyage of the ocean-going ship, generating the sailing path of the ship and the chart data range of the whole voyage area; S2, analyzing the obtained sailing path, defining the sea area in the calibration area on both sides of the path as the width range of the target loading area; S3, defining the length range of the target loading area of each voyage section according to the sailing speed of the ship and the reaction time; S4, according to the width range and the length range of the target loading area of each voyage section defined, sending a request to the server electronic chart database, downloading the high-resolution chart data in the width and length range of the current voyage section target loading area, and preloading the data of the subsequent calibration number of voyage sections in the background; S5, the ship updates the current position in real time during the sailing process, and dynamically adjusts the target loading area according to the current position, applies for and loads new chart data, and unloads the chart data of the area that has passed. The method further comprises a network failure protection step, comprising: P1, according to the chart data range of the whole voyage area generated in step S1, dividing the voyage area chart data into a plurality of chart cells of the same scale; P2, comparing all the divided chart cells, dividing the same chart cells into a class, and setting an index record for the geographical position of each chart cell in each class; P3, recording and retaining the class representative chart cell and its index record of each class; P4, compressing all the class representative chart cells and their index record files to obtain the chart compression data of the whole voyage area, and sending it to the ship backup; P5, according to the range of the part of the voyage area where the ship has not sailed, judging whether the update of the server electronic chart database triggers an update event, if yes, generating and sending an update compression package, otherwise, not sending; P6, after the ship receives the update compression package, parsing the file, and performing coverage update on the existing voyage area chart data according to the class and geographical position, so that the ship backup is high-resolution chart data, and the real-time keeping is kept; P7, when the system detects that the network connection is interrupted, the cached chart data of the voyage section is loaded; P8, when the cached chart data is loaded to the boundary, the ship backup chart data is called, the chart cell data is extracted from the related class files according to the geographical position of the target loading area, and the chart data loading of the target loading area of the subsequent voyage section of the ship is performed.

2. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 1, wherein, The chart data range of the whole voyage area in step S1 includes the whole route from the starting point to the destination, potential refuge ports, backup routes, coastal areas, narrow waterways and important straits.

3. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 1, wherein, In step S2, the sea area in the calibration area on both sides of the path is defined as the width range of the target loading area by analyzing the obtained sailing path, comprising: S21, defining the basic width range of the target loading area on both sides of the sailing path; S22, analyzing the obtained sailing path, adaptively adjusting the basic width range of the target loading area according to the influencing factors, and defining the sea area in the calibration area on both sides of the path as the width range of the target loading area.

4. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 3, wherein, In step S21, the basic width range of the target loading area on both sides of the sailing path is 2 nautical miles on both sides of the center line of the route.

5. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 1, wherein, The length range D1 loaded by each leg target loading area in step S3 is: D1=V×T×(1+A%); Wherein, D1 is the length range loaded by each leg target loading area, V is the average speed of the ship, T is the pre-loading sailing time, and A% is the safety margin of the ship sailing.

6. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 1, wherein, Step P5, judging whether the update of the electronic chart database of the server triggers an update event, if yes, generating and sending the update compressed package, otherwise, not sending, comprising: P51, judging the range of the part of the sailing area and the part of the non-sailing area of the ship in real time, as the basis for determining whether to trigger the update event; P52, judging whether the update of the electronic chart database of the server triggers an update event; P53, if the update event is triggered, generating the update compressed package and sending it to the ship.

7. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 6, wherein, Step P52, judging whether the update of the electronic chart database of the server triggers an update event, comprising: When the update of the electronic chart database of the server is the chart data outside the sailing area of the ship, the update event is not triggered; When the update of the electronic chart database of the server only involves the chart cells of the part of the sailing area of the ship, the update event is not triggered; When the update of the electronic chart database of the server involves the chart cells of the part of the non-sailing area of the ship, the update event is triggered.

8. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 6, wherein, Step P53, if the update event is triggered, generating the update compressed package and sending it to the ship, comprising: Recording all the chart cells involved in the update; Comparing the updated chart cells one by one with each class representative chart cell recorded and retained, recording the comparison results and the geographical positions of the chart cells; if the updated chart cell is consistent with a certain retained class representative chart cell, marking the class to add a geographical position; if it is not consistent with all the retained class representative chart cells, creating a new class and establishing an index to record the geographical positions of the chart cells in the class; and recording and retaining this new class as well, so as to be iteratively judged for consistency by the subsequent updated chart cells; Compressing all the comparison results and the geographical position files of the chart cells to generate the update compressed package, and sending it to the ship as the chart replacement file of the non-sailing area.

9. The method for dynamically loading electronic charts for ocean-going vessels based on a voyage path according to claim 7, wherein, The method further comprises: P9, judging whether the network connection is restored, if not, continuing to execute P8 to call the backup chart data of the ship system to load the chart data of the subsequent target loading area; if yes, executing S5 to request the electronic chart database of the server, and continuing to download the high-resolution chart data in the current target loading area and the chart data update data of the non-sailing part of the area.

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