Method for loading electronic chart in dynamic region of ocean vessel based on sailing path

Abstract

The invention relates to a navigation path-based ocean vessel dynamic area electronic chart loading method, which comprises the following steps of: acquiring a starting point and an ending point of a vessel voyage, and generating a navigation path and a chart data range of a whole navigation area; sea areas in the calibration areas on the two sides of the path are defined as the width range of the target loading area; and dynamically adjusting the target loading area according to the current position, sending a request for downloading and loading the sea chart data of the new target loading area to the server, and unloading the sea chart data of the passed area. When the network is interrupted, the background is used for caching the nautical chart data, when the cached nautical chart data is loaded to the boundary use amount, nautical chart cell data are extracted from all related class files according to the geographic position of the target loading area, and follow-up nautical chart data loading is carried out until the network is recovered; and continuously downloading the sea chart data of the server and the sea chart updating compressed data of the navigation area of the non-navigation part. The rendering pressure of the electronic chart software can be effectively reduced, and the operation efficiency and the response speed of the system are improved.

Description

Technical Field

[0001] The invention belongs to the field of marine navigation technology, and in particular relates to a method for loading an electronic nautical chart in a dynamic area of ​​an ocean-going ship based on a navigation path. Background Art

[0002] With the development of modern ocean transportation, electronic charts have become an indispensable navigation tool for ocean-going ships. However, the traditional way of loading electronic charts usually requires pre-downloading and loading the chart data of the entire navigation area, which not only takes up a lot of storage space and bandwidth resources, but may also cause the electronic chart software to load too much data, affecting the performance of the ship system, and thus posing a potential risk to navigation safety. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a navigation method for ocean-going ships based on the dynamic loading of electronic nautical charts on the basis of the navigation path. Through intelligent path analysis and regional data loading, the method can save storage space and data download volume while ensuring navigation safety. At the same time, by real-time judgment of the scope of the navigation area where the ship has navigated and the navigation area where it has not navigated, as a basis for determining whether to trigger an update event, an update compressed package is generated and sent, thereby ensuring the loading of high-resolution charts for the ship when the network is disconnected, and improving the operating efficiency of the ship's electronic nautical chart software.

[0004] To achieve the above object, the present invention discloses a method for dynamically loading an electronic nautical chart for an ocean-going vessel based on a navigation path, which comprises the steps of:

[0005] S1. Obtain the starting point and end point of the ocean-going vessel's voyage, generate the vessel's navigation path and the chart data range of the entire navigation area;

[0006] S2. Analyze the acquired navigation path and define the sea area within the calibrated area on both sides of the path as the width range of the target loading area;

[0007] S3. Define the length range of the target loading area for each section according to the ship's speed and reaction time;

[0008] S4. According to the defined width and length range of the target loading area of ​​each segment, a request is sent to the server electronic chart database to download high-resolution chart data within the width and length range of the target loading area of ​​the current segment, and the background preloads the data of the subsequent calibrated number of segments;

[0009] S5. The vessel updates its current position in real time during navigation, dynamically adjusts the target loading area according to the current position, applies for and loads new chart data, and unloads chart data of the area that has been passed;

[0010] Furthermore, the method also includes a network failure protection step, including:

[0011] P1, according to the range of the nautical chart data of the entire navigation area generated in step S1, dividing the nautical chart data of the navigation area into a plurality of nautical chart cells of the same scale;

[0012] P2. Compare all the divided chart cells, divide the same chart cells into a class, and set an index for each class to record the geographical location of each chart cell in the class;

[0013] P3, record the class representing the chart cell and its index record for each class;

[0014] P4. Compress the class representative chart cells and their index record files of all classes to obtain the compressed chart data of the entire navigation area and send it to the ship for standby;

[0015] P5. According to the scope of the real-time non-navigation area of ​​the ship, determine whether the update of the electronic chart database of the server triggers an update event. If so, generate and send an update compressed package, otherwise, do not send it;

[0016] P6. After receiving the updated compressed package, the ship will parse the file and update the existing chart data in the navigation area according to the category and geographical location, so that the ship can use high-resolution chart data and keep it up to date in real time;

[0017] P7. When the system detects that the network connection is interrupted, the chart data of the cached segment is loaded;

[0018] P8. When the cached chart data has been loaded to the boundary usage, the ship's spare chart data is called, and the chart cell data is extracted from each related class file according to the geographical location of the target loading area, and the chart data of the target loading area of ​​the subsequent voyage of the ship is loaded.

[0019] Furthermore, the scope of the nautical chart data of the entire navigation area in step S1 includes the entire route from the departure point to the destination, potential ports of refuge, alternate routes, coastal areas, narrow waterways, important straits and areas of special concern.

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

[0021] S21. Define the basic width range of the target loading area on both sides of the navigation path:

[0022] S22. Analyze the acquired navigation path, adaptively adjust the basic width range of the target loading area according to the influencing factors, and define the sea areas within the calibrated areas on both sides of the path as the width range of the target loading area.

[0023] Furthermore, in step S21, the basic range of the width of the target loading area on both sides of the navigation path is 2 nautical miles on both sides of the center line of the route.

[0024] Furthermore, the length range D1 loaded in the target loading area of ​​each flight segment in step S3 is:

[0025] D1 = V × T × (1 + A%);

[0026] Among them, D1 is the length range of the target loading area in each section, V is the average speed of the ship, T is the preloading sailing time, and A% is the safety margin for the ship's navigation.

[0027] Further, step P5, judging whether the update of the electronic chart database of the server triggers an update event, if yes, generating and sending an update compressed package, otherwise not sending, includes:

[0028] P51. Real-time determination of the scope of the navigation area where the ship has navigated and the navigation area where the ship has not navigated, as a basis for determining whether to trigger an update event;

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

[0030] P53. If an update event is triggered, an update compressed package is generated and sent to the ship.

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

[0032] When the server's electronic chart database is updated with chart data outside the ship's navigation area, the update event is not triggered;

[0033] When the update of the server's electronic chart database only involves the chart cells of the sailed part of the ship's navigation area, the update event is not triggered;

[0034] When the update of the electronic chart database of the server involves the chart cells of the unnavigated part of the ship's navigation area, an update event is triggered.

[0035] Further, in step P53, if an update event is triggered, an update compressed package is generated and sent to the ship, including:

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

[0037] Compare the updated chart cells with the class representative chart cells of each class that are recorded and retained one by one, and record the comparison results and the geographical location of the chart cells; if the updated chart cell is consistent with a certain retained class representative chart cell, mark the class to add a geographical location; if it is inconsistent with all retained class representative chart cells, create a new class and establish an index to record the geographical location of the chart cells in the class; and also record and retain this new class so that the subsequent updated chart cells can be iteratively judged for consistency;

[0038] All comparison results and the geographic location file of the chart cell are compressed to generate an update compressed package, which is sent to the ship as a chart replacement file for the unnavigated area.

[0039] Furthermore, all the chart cells involved in the update are the chart cells of the changed part of the chart in the area where the ship has not navigated.

[0040] Furthermore, the method further comprises:

[0041] P9, determine whether the network connection is restored. If not, continue to execute P8 to call the ship system backup chart data to load the chart data of the subsequent ship target loading area; if restored, execute S5 to send a request to the server electronic chart database to continue downloading the high-resolution chart data in the current target loading area and the chart data update data of the unnavigated area.

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

[0043] 1. The present invention only loads high-resolution chart data near the navigation path of the current section, greatly reducing the data loading and rendering pressure of electronic chart software, improving system operation efficiency and response speed, and adapting to more terminal devices and low-configuration devices. For some terminal devices with low bandwidth or low computing power, only the charts of the target area are loaded, which can achieve fast loading and display, avoiding the device from being unable to process large-capacity data due to insufficient memory or bandwidth problems, and has better compatibility;

[0044] 2. The present invention utilizes the characteristic of large quantities of repeated data in the nautical chart. According to the generated nautical chart data range of the entire navigation area, the navigation area chart data is first divided into a plurality of class chart cells and address notes, and then compressed and transmitted; subsequently, according to the real-time changing navigation area chart range, only the updated data of the unnavigated navigation area chart is transmitted, and the updated data is only the class representative chart cells and address notes, which can effectively reduce the amount of data transmitted each time, ensure fast and low-cost chart updates, and reduce the bandwidth pressure during each synchronization process;

[0045] 3. The present invention establishes a fault protection mechanism, which stores the classes and addresses of the chart cells, and then dynamically updates various types of chart cells in a targeted manner, so as to realize the storage of high-resolution electronic charts on the ship. When the network is interrupted, only the target loading area is parsed and loaded as needed, which reduces the data processing burden, reduces the data processing and parsing time, and ensures the navigation safety of the ship in various environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a flowchart of a method for ocean-going vessel navigation based on dynamically loading electronic nautical charts on a navigation path. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clear, further description is given below in conjunction with the accompanying drawings and embodiments.

[0048] It should be noted that, in this article, relational terms such as first and second, etc. 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 these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0049] As attached Figure 1 As shown, the present invention provides a method for dynamically loading an electronic nautical chart for an ocean-going vessel based on a navigation path, which comprises the steps of:

[0050] S1. Obtain the starting point and end point of the ocean-going vessel's voyage, generate the vessel's navigation path and the chart data range of the entire navigation area, including:

[0051] S11, obtaining the starting point and the end point of the ocean-going ship's voyage, and generating the ship's navigation path;

[0052] Before an ocean-going vessel sets sail, the starting and ending points of the voyage are input into navigation planning software such as ECDIS (Electronic Chart Display and Information System), and the software can obtain the navigation path of the ship generated based on the input information.

[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). It is widely used in the navigation of modern ships and is the most common navigation planning system. It integrates electronic charts and various navigation functions, including automatic route planning, dangerous area reminders, channel selection, weather information, etc. ECDIS is not only used to display charts, but also can automatically generate navigation paths based on the input starting and ending points to help crew members choose the safest and most efficient routes.

[0054] S12, obtaining the starting point and the end point of the voyage of the ocean-going vessel, and generating the nautical chart data range of the entire navigation area of ​​the vessel;

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

[0056] Full route from departure point to destination: This includes the vessel's direct route from the port of departure to the port of destination and any sea areas it may pass through.

[0057] Potential Port of Refuge: A port to which a vessel may need to change course in an emergency.

[0058] Alternative routes: Due to weather conditions, vessel failure or other reasons, the vessel may need to deviate from the originally planned route, so the chart data on the alternate route also needs to be downloaded.

[0059] Coastal areas: When sailing close to the shore, more detailed chart data may be needed to avoid hazards such as shoals, reefs, etc.

[0060] Narrow waterways and important straits: Charts in these areas require high accuracy as they are often critical parts of navigation, have dense traffic, and may have special navigation regulations.

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

[0062] Internationally regulated nautical charts: According to the regulations of the International Maritime Organization (IMO), certain nautical charts are mandatory, such as those that must be carried in specific sea areas.

[0063] The size of the entire navigation area depends on the scope and complexity of the voyage, and may cover the chart data of several countries or even the entire ocean. According to the starting and ending points of the ocean-going ship's voyage, the scope of the chart data of the entire navigation area can be determined through navigation planning software such as ECDIS.

[0064] S2. Analyze the acquired navigation path and define the sea area within the calibrated area on both sides of the path as the width range of the target loading area;

[0065] The width of the target loading area can be defined based on the type of vessel, 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] A basic width safety range is determined based on the ship's maximum speed and 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. The basic range can be dynamically adjusted as needed.

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

[0069] For ship types: Different types of ships have different operating characteristics, such as cargo ships, tankers, passenger ships, fishing boats, etc. The size, draft, maneuverability and other factors of the ship will affect the range of chart information required for its safe navigation. For large ships or ships with deep draft, the width safety range should be increased to avoid shallow waters and dangerous objects.

[0070] Regarding speed: Faster ships will cover a greater distance in the same amount of time, so more extensive chart information is needed to ensure safety. For faster ships, the width safety range should be increased to ensure there is enough time for course adjustments.

[0071] Regarding route complexity: for tortuous routes, the width safety range should be increased to cover the charts of all possible turning points to assist navigation; for coastal navigation routes, the chart loading range of coastal areas within the coastal navigation distance should be increased to assist navigation; for routes crossing straits and waterways, because straits and waterways may be narrow and traffic-dense, the width safety range of these areas should be increased and ensure that all relevant safety waters are included.

[0072] For navigation risks: For shallow waters, dangerous objects, and bad weather areas, increase the chart loading range of corresponding width; Shallow waters and dangerous objects: It is necessary to increase the chart of corresponding width to avoid dangers such as running aground on reefs; In traffic-intensive areas, increase the chart of corresponding width to ensure that there is enough information for avoidance; Bad weather and sea conditions: Add a wider safety area to deal with possible route deviations.

[0073] Taking all the above factors into consideration, adjust the basic range of the target loading area and determine the final chart loading range of each section.

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

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

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

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

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

[0079] S31, determining the calibration preload navigation time;

[0080] Determine the calibration preload sailing time, which is usually based on the ship's operating procedures and safety requirements. For example, if you choose to preload chart data for a 2-hour sailing: the calibration preload sailing time T = 2 hours.

[0081] S32. Calculate the ship's speed V;

[0082] Determine the average speed V of the vessel in the preload area (which can be the planned speed or the expected speed based on the type of vessel and sea conditions).

[0083] S33, calculate the distance that the preload area should cover each time: D = V × T

[0084] Where: D is the length of the preloading area, V is the average speed of the ship, and T is the preloading sailing time.

[0085] For example, if the average speed of the vessel is 18 knots (1 knot equals 1 nautical mile per hour), the preload sailing time is 2 hours:

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

[0087] S34. Consider the safety margin for ship navigation;

[0088] In order to ensure that there is sufficient safety margin for the ship's navigation, a calibrated percentage can be added to the calculated preload distance as a margin.

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

[0090] D1 = V × T × (1 + A%);

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

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

[0093] D1 = D × 1.10 = 36 nautical miles × 1.10 = 39.6 nautical miles (nautical miles)

[0094] Further, you may also want to consider the data transfer and processing time, and the time required to download the chart data from the server to the local device, as well as the time it takes to process and load the data into the ECDIS system. If these times are long, you may need to further increase the distance of the preload area.

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

[0096] Generally speaking, the target loading area for each loading of a typical vessel may include a distance extending from 24 nautical miles (about 44.5 kilometers) to several hours of sailing from the current position. For example, an area for the next 2-3 hours of sailing can be preloaded. For a ship with a speed of 20 knots, the 2-3 hours of sailing distance is about 40-60 nautical miles. Therefore, a preliminary target loading area length may be 40 to 60 nautical miles.

[0097] The reason why the preloading time is not too long is, on the one hand, to reduce the rendering pressure of the ship's electronic chart software and improve the system's operating efficiency and response speed; on the other hand, it is because the electronic chart data (such as ENC data) on the server is updated irregularly:

[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, navigation mark position, depth, etc. have changed, the chart data needs to be updated. These changes may be caused by natural factors (such as seabed changes, sediment deposition) or man-made projects (such as dredging, reclamation, offshore construction, etc.).

[0100] 2) Replacement or repair of navigation marks: for example, changes in the location, lighting or signals of lighthouses, buoys, and navigation marks.

[0101] 3) Changes in the marine environment: Natural changes in the seabed (such as sediment accumulation and changes in submarine mountains) may affect the accuracy of chart data.

[0102] 4) New survey and investigation data: New data obtained by survey ships, unmanned submersibles, satellites, etc. may lead to revisions to existing chart data. These data include depth measurements, seabed topography, channel changes, etc.

[0103] 5) Changes in international shipping standards: If the International Maritime Organization (IMO)'s requirements for nautical charts or navigation technology change, the relevant electronic nautical chart data may need to be updated to comply with new international standards and regulations.

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

[0105] Regular updates: Most electronic charts (such as ENC data) are updated on a set basis, usually monthly or quarterly. Some areas may be updated more frequently, especially busy shipping areas or where there are frequently changing environments.

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

[0107] Emergency Update: In the event of an emergency (such as loss of a navigation mark, sudden change in water depth or new underwater obstacles), the chart may be updated urgently and provided to users in a timely manner through the chart data service.

[0108] By comprehensively considering the ship's operating procedures and safety requirements and not defining the preloading time to be too long, the nautical chart data of the target area can be downloaded in time, and the real-time water depth, navigation mark position and channel information can be mastered during navigation, so as to more effectively respond to emergencies, reduce deviations, misrouting or re-planning during navigation, save fuel and time, improve navigation efficiency and avoid economic losses.

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

[0110] During the voyage, the preload 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 defined width and length range of the 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 the background preloads the data of the subsequent k length segments;

[0112] According to the target loading area, the chart data is downloaded from the server electronic chart database and stored in the local device. When downloading, the chart data of the current starting section of the voyage can be loaded first, and the chart data of the subsequent sections can be preloaded in the background to ensure that the data is available in real time during the voyage;

[0113] S5. During navigation, the vessel updates its current position in real time through GPS or AIS, and dynamically adjusts the target loading area according to the current position, applies for and loads new chart data, and then unloads the chart data of the area that has been passed.

[0114] Define the trigger conditions for preloading in the vessel ECDIS system: automatically start preloading when the vessel approaches the boundary of the currently loaded chart. Define the distance to trigger preloading to ensure that the new chart data has been downloaded and prepared before reaching the boundary of the current chart data.

[0115] Furthermore, to ensure that the preloading works as expected, the vessel ECDIS system can be monitored during actual navigation to confirm whether the preloaded chart data is downloaded and available at the appropriate time, so as to ensure a smooth transition to the next chart area during navigation without data gaps.

[0116] As a protection step for successfully loading subsequent electronic nautical charts of the navigation area when an ocean-going vessel encounters a network disconnection failure during navigation, the present invention also provides a network disconnection failure protection method for ocean-going vessels to dynamically download and load electronic nautical charts based on a navigation path, comprising:

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

[0118] The purpose of pre-acquiring the generated chart data range of the entire navigation area in step S1 is to ensure that in future navigation, especially in offshore areas without network coverage, the ship's navigation system can access all required high-resolution chart information to ensure the safety and reliability of navigation.

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

[0120] P2. Compare all the divided chart cells and divide the same chart cells into a class. Each class has an index to record 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 scale, there will be a large number of repeated and identical chart cells. For example, multiple chart cells in the same navigation area may contain the same chart information, such as the same water depth data in the deep sea area (the same dark blue or light blue area), the same channel marks, lighthouse locations, etc. This information is repeated in different cells, mainly because different cells may represent different locations of the same sea area, but they contain the same geographical feature data.

[0122] P3, record the class representing the chart cell and its index record for each class;

[0123] P4. Compress the class representative chart cells and their index record files of all classes to obtain the compressed chart data of the entire navigation area and send it to the ship for standby;

[0124] Because each class only takes one class to represent the 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 significant advantages:

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

[0126] Improve transmission speed: Since the compressed data is smaller in size, the time required for transmission is greatly shortened. Compression can speed up the upload and download speed of data. Improve transmission efficiency, especially in low-bandwidth environments to adapt to bandwidth changes: For communication networks with unstable or low bandwidth (such as ocean communications, maritime communications, etc.), compressed data can ensure that the transmission of nautical charts can be completed even in limited bandwidth. Especially in the ocean or remote areas, the bandwidth of the communication network may be unstable or low, and compression can ensure that data is transmitted smoothly at a lower bandwidth.

[0127] Reduce storage space: After the data of the chart cells representing the same class are compressed, the data volume is small, which can reduce the space requirements of the storage device. Especially when the amount of chart data is huge, compression can greatly save storage costs and save several times of storage space.

[0128] Reduce data transmission costs and operating costs: Many transmission networks charge based on data volume, and compressed data can significantly reduce the cost of each transmission. For applications that require frequent transmission of large amounts of nautical chart data (such as marine navigation, navigation instrument updates, etc.), compressed data with small data volumes 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 so, generate and send an update compressed package. Otherwise, do not send it, including:

[0130] P51. Real-time determination of the scope of the navigation area where the ship has navigated and the navigation area where the ship has not navigated, as a basis for determining whether to trigger an update event;

[0131] In the above step S4, according to the defined width and length range of the target loading area, a request is sent to the server electronic chart database, and the high-resolution chart data within the width and length range of the current target loading area is downloaded first. At the same time, when the background preloads the data of the subsequent 1-k length segments, the server will record the current position of the ship according to the applied segment data, and judge the range of the navigation area where the ship has sailed and the navigation area where it has not sailed, as a basis for determining whether to trigger the update event. Among them, k is a positive integer greater than 1, and 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] Furthermore, based on the chart data file applied for by the ship in real time, the chart data range of the unnavigated area on the server is iteratively limited. As the ship continues to sail, the chart data range of the unnavigated area is gradually reduced, thereby reducing the amount of chart data of the area involved in the update and improving data comparison, compression and transmission efficiency.

[0133] P52. Determine whether the update of the electronic chart database of the server triggers an update event, including:

[0134] When the update of the server's electronic chart database is irrelevant to the chart cells of the ship's navigation area, the update event is not triggered;

[0135] When the update of the server's electronic chart database is related to the chart cells of the navigation area where the ship has completed navigation, the update event will not be triggered;

[0136] When the update of the electronic chart database of the server is related to the chart cells of the un-navigated area of ​​the vessel, an update event is triggered and an update compressed package is sent, wherein the compressed package is related to the chart cells of the changed part of the un-navigated area.

[0137] P53. If an update event is triggered, an update compressed package is generated and sent to the ship, including:

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

[0139] If it is consistent with the chart cell represented by a retained class, then the class is marked to add a geographic location; if it is inconsistent with the chart cells represented by all retained classes, a new class is created, and an index is established to record the geographic locations of the chart cells within the class; and this new class is also recorded and retained so that the subsequently updated chart cells can be updated and judged iteratively in sequence.

[0140] All comparison results and the geographic location file of the chart cell are compressed to generate an update compressed package, which is sent to the ship as a chart replacement file for the unnavigated area.

[0141] P6. After receiving the updated compressed package, the ship will parse the file and update the existing navigation area chart data by category and geographical location, so that the ship can use high-resolution chart data and keep it up to date in real time;

[0142] After receiving the updated compressed package, the ship decompresses it, parses the replacement file, and updates the existing navigation area chart data by category and geographic location, including:

[0143] For the received class that is consistent with the retained class representing the chart cell (already on the ship), a geographic location is added to its corresponding index file; for the class that is inconsistent with all the retained class representing the chart cell, the received newly created class and its index file are saved, so that the ship's backup data is high-resolution chart data and its currentness is maintained in real time.

[0144] Furthermore, after receiving the initial compressed package, the ship does not need to decompress it. After receiving the updated compressed package, the two compressed packages are decompressed, the initial file and the replacement file are parsed respectively, and the existing navigation area chart data are updated according to the category and geographical location, and then compressed for standby. Subsequently, this method is used to cycle decompression, update, and recompression for storage, so that the storage resources of the ship system are released to the maximum extent, and the efficiency of the system in processing data is improved.

[0145] P7. When the system detects that the network connection is interrupted, it will use the cached high-resolution chart data and notify the operator to take appropriate navigation measures.

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

[0147] P8. When the cached chart data has been loaded to the boundary usage, the latest spare chart data of the ship system is called, and the chart cell data is extracted from each related class file according to the geographical location of the target loading area, and the chart data of the subsequent target loading area of ​​the ship is loaded;

[0148] When the cached chart data has been loaded to the boundary usage, the boundary usage can be the last target loading area chart. Once the system calls the cached last target loading area chart, the system background calls the latest backup chart data of the ship system, extracts the chart cell data from each related class file according to the geographical location of the target loading area, and loads the chart data of the subsequent target loading area of ​​the ship;

[0149] Furthermore, when executing the compressed storage management of the ship's spare chart data, it needs to be decompressed before calling. Because the use time of the last target loading area chart is generally 2-3 hours (determined by the length of the target loading area chart), and all the used charts stored in the ship system have been deleted at this time, the ship system has enough time, space, and operating resources to handle the parsing and loading of high-resolution spare chart data.

[0150] P9, determine whether the network connection is restored. If not, continue to execute P8 to call the ship system backup chart data to load the chart data of the subsequent ship target loading area; if restored, execute S5 to send a request to the server electronic chart database to continue downloading the high-resolution chart data in the current target loading area and the chart data update data of the unnavigated area.

[0151] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0152] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths, characterized in that: It includes the steps of: S1. Obtain the starting point and end point of the ocean-going vessel's voyage, generate the vessel's navigation path and the chart data range of the entire navigation area; S2. Analyze the acquired navigation path and define the sea area within the calibrated area on both sides of the path as the width range of the target loading area; S3. Define the length range of the target loading area for each section according to the ship's speed and reaction time; S4. According to the defined width and length range of the target loading area of ​​each segment, a request is sent to the server electronic chart database to download high-resolution chart data within the width and length range of the target loading area of ​​the current segment, and the background preloads the data of the subsequent calibrated number of segments; S5. The vessel updates its current position in real time during navigation, 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 been passed.

2. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 1, characterized in that: The method further includes a network failure protection step, including: P1, according to the range of the nautical chart data of the entire navigation area generated in step S1, dividing the nautical chart data of the navigation area into a plurality of nautical chart cells of the same scale; P2. Compare all the divided chart cells, divide the same chart cells into a class, and set an index for each class to record the geographical location of each chart cell in the class; P3, record the class representing the chart cell and its index record for each class; P4. Compress the class representative chart cells and their index record files of all classes to obtain the compressed chart data of the entire navigation area and send it to the ship for standby; P5. According to the scope of the real-time non-navigation area of ​​the ship, determine whether the update of the electronic chart database of the server triggers an update event. If so, generate and send an update compressed package, otherwise, do not send it; P6. After receiving the updated compressed package, the ship will parse the file and update the existing chart data in the navigation area according to the category and geographical location, so that the ship can use high-resolution chart data and keep it up to date in real time; P7. When the system detects that the network connection is interrupted, the chart data of the cached segment is loaded; P8. When the cached chart data has been loaded to the boundary usage, the ship's spare chart data is called, and the chart cell data is extracted from each related class file according to the geographical location of the target loading area, and the chart data of the target loading area of ​​the subsequent voyage of the ship is loaded.

3. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 1, characterized in that: The scope of the nautical chart data of the entire navigation area in step S1 includes the entire route from the departure point to the destination, potential ports of refuge, alternate routes, coastal areas, narrow waterways and important straits.

4. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 1, characterized in that: Step S2: Analyze the acquired navigation path and define the sea area within the marked area on both sides of the path as the width range of the target loading area, including: S21, defining the basic width range of the target loading area on both sides of the navigation path; S22. Analyze the acquired navigation path, adaptively adjust the basic width range of the target loading area according to the influencing factors, and define the sea areas within the calibrated areas on both sides of the path as the width range of the target loading area.

5. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 4, characterized in that: In step S21, the basic range of the width of the target loading area on both sides of the navigation path is 2 nautical miles on both sides of the route centerline.

6. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 1, characterized in that: The length range D1 loaded in the target loading area of ​​each flight segment in step S3 is: D1 = V × T × (1 + A%); Among them, D1 is the length range of the target loading area in each section, V is the average speed of the ship, T is the preloading sailing time, and A% is the safety margin for the ship's navigation.

7. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 2, characterized in that: Step P5: determining whether the update of the electronic chart database of the server triggers an update event, if yes, generating and sending an update compressed package, otherwise not sending, including: P51. Real-time determination of the scope of the navigation area where the ship has navigated and the navigation area where the ship has not navigated, as a basis for determining whether to trigger an update event; P52, determining whether the update of the electronic chart database of the server triggers an update event; P53. If an update event is triggered, an update compressed package is generated and sent to the ship.

8. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 7, characterized in that: Step P52, determining whether the update of the electronic chart database of the server triggers an update event, includes: When the server's electronic chart database is updated with chart data outside the ship's navigation area, the update event is not triggered; When the update of the server's electronic chart database only involves the chart cells of the sailed part of the ship's navigation area, the update event is not triggered; When the update of the server's electronic chart database involves the chart cells of the unnavigated part of the ship's navigation area, an update event is triggered.

9. The method for dynamically loading electronic nautical charts for ocean-going vessels based on navigation paths according to claim 7, characterized in that: Step P53: if an update event is triggered, an update compressed package is generated and sent to the ship, including: Record all chart cells involved in the update; Compare the updated chart cells with the class representative chart cells of each class that are recorded and retained one by one, and record the comparison results and the geographical location of the chart cells; if the updated chart cell is consistent with a certain retained class representative chart cell, mark the class to add a geographical location; if it is inconsistent with all retained class representative chart cells, create a new class and establish an index to record the geographical location of the chart cells in the class; and also record and retain this new class so that the subsequent updated chart cells can be iteratively judged for consistency; All comparison results and the geographic location file of the chart cell are compressed to generate an update compressed package, which is sent to the ship as a chart replacement file for the unnavigated area.

10. The method for loading electronic nautical charts in dynamic areas of ocean-going vessels based on navigation paths according to claim 8, characterized in that: The method further comprises: P9, determine whether the network connection is restored. If not, continue to execute P8 to call the ship system backup chart data to load the chart data of the subsequent ship target loading area; if restored, execute S5 to send a request to the server electronic chart database to continue downloading the high-resolution chart data in the current target loading area and the chart data update data of the unnavigated area.

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