Method and system for dynamically supplementing electronic chart by using shipborne sonar data

Abstract

The invention discloses a method and a system for dynamically supplementing an electronic chart by using shipborne sonar data. The method comprises the following steps: carrying out unified time service on sonar setting and ECDIS; collecting water depth data associated with the timestamp; the water depth data and the position data are aligned through position data interpolation; performing dynamic point-like supplement: performing center positioning according to the ship position, filtering water depth data in a certain range in the center, and displaying the water depth in a point-like supplement layer; automatic blanking: carrying out linear blanking after a set time is exceeded; alarm monitoring is carried out in real time, and when the detected water depth is inconsistent with the chart water depth, an alarm is given in time; and the detected water depth data are shared. According to the invention, shipborne sonar data and an electronic chart are combined, water depth information is obtained in a second level in a navigation process, and water depth change in a navigation channel or a navigation direction is reflected in real time, so that navigation safety and real-time performance of underwater topography reference are improved, and the problems that updating of existing ECDIS chart data is lagged and real-time water depth change cannot be reflected are solved.

Description

Technical Field

[0001] This invention relates to the field of ship navigation technology, and in particular to a method and system for dynamically supplementing electronic nautical charts using shipborne sonar data. Background Technology

[0002] Electronic Chart Display and Information Systems (ECDIS) are widely used in modern ship navigation to display ship position, route, and seabed topography information. The electronic chart (ENC) data used by ECDIS is provided by official hydrographic departments and is typically updated weekly or monthly. In actual navigation, factors such as river siltation, seabed erosion, construction debris, or reef movement can cause discrepancies between the actual water depth and the electronic chart data.

[0003] Currently, electronic nautical charts are updated at most once a week, and sometimes as slowly as several months. Even temporary notices have a time lag (usually measured in days) between discovery, release, and user download and application. They are completely unable to cope with or reflect rapid changes caused by natural factors (typhoons, floods, siltation, ocean currents) or human factors (engineering construction, anchoring and sinking, channel dredging).

[0004] In addition, due to reasons such as maritime signal or economic considerations, some ships have outdated electronic charts and cannot obtain the latest water depth data for their navigable waters.

[0005] Existing shipborne sonar (such as single-beam echo sounders and multi-beam echo sounders) can acquire water depth information in real time, but it is usually only displayed in numerical or alarm form, and does not form a dynamic supplement to electronic charts. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method and system for dynamically supplementing electronic nautical charts using shipborne sonar data. This method and system can combine shipborne sonar data with electronic nautical charts to improve navigation safety and the real-time performance of underwater topographic reference, thereby solving the problem of lagging updates in existing ECDIS nautical chart data and the inability to reflect real-time water depth changes.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for dynamically supplementing electronic nautical charts using shipborne sonar data includes the following steps.

[0009] Step 1: Unify time synchronization and synchronize the ECDIS with the sonar equipment installed on Ship A.

[0010] Step 2: The sonar equipment performs real-time measurement of water depth data at the set frequency f1.

[0011] Step 3: Ship A acquires its own position data in real time at a set frequency f2, interpolates the position data, and aligns it with the water depth data obtained in Step 2, so that each water depth data corresponds to one position data.

[0012] Step 4, Dynamic Point-by-Point Supplementation, specifically includes the following steps:

[0013] Step 4-1, Ship Center Positioning: Obtain the current position A of ship A and use position A as the ship's center point. Step 4-2, Water Depth Data Filtering: The sonar equipment filters and loads water depth data within a distance D from the ship's center point based on a set radius D; subsequently, the loaded water depth data is mapped onto the electronic chart coordinate system in ECDIS to generate a point-based supplementary layer.

[0014] Step 4-3, Layer Generation and Update: Repeat steps 4-1 to 4-3 every set time t seconds to achieve dynamic real-time supplementation of the water depth around ship A. The dotted supplementation layer will be dynamically updated as ship A moves.

[0015] It also includes step 5, automatic hidden removal: for existing data in the dotted supplementary layer, the hidden data is gradually removed based on the timestamp.

[0016] In step 4-2, the dot-matrix supplementary layer is displayed independently of the original electronic chart and can be shown or hidden through layer control.

[0017] In step 5, the method for gradually fading out old data based on timestamps is as follows: the display transparency of old data is reduced in a linear decay manner, and after a preset time T minutes, the old data is completely hidden and unloaded onto the supplementary layer.

[0018] It also includes step 6, alarm monitoring, which specifically includes the following steps:

[0019] Step 6-1, Chart Annotation Depth Matching: Based on the current position of vessel A, obtain the corresponding chart annotation depth value D from the electronic chart. chart Meanwhile, the current location obtains the depth value D from the water depth data collected by the sonar equipment. sonar .

[0020] Step 6-2, Water Depth Alarm: Real-time D chart With D sonar Comparison of values, when D sonar < 0.9 D chart At that time, the water depth alarm was triggered.

[0021] It also includes step 7, data sharing: the ECDIS of vessel A will trigger a water depth alarm and upload the sonar water depth data with location information to the shared database through the communication module, so that the ECDIS of other vessels B can obtain it through the network.

[0022] In step 7, the ECDIS of vessel B performs the following judgment and processing on the acquired sonar depth data:

[0023] A. When vessel B is not equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, the sonar depth data most recent to the current time shall be used.

[0024] B. When vessel B is equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, the received sonar depth data and the sonar depth data detected by vessel B itself belong to the same range. Therefore, the sonar depth data detected by vessel B itself shall be adopted.

[0025] Step 2, the method for real-time measurement of water depth data by sonar equipment, includes the following steps:

[0026] Step 2-1: Acquire sonar signals: Receive sonar analog signals from the sonar equipment, perform analog-to-digital conversion on the sonar analog signals to obtain processable sonar digital signals, and perform standardization processing on the sonar digital signals.

[0027] Step 2-2, Data Buffer: A buffer is created in the processing unit to buffer the standardized sonar digital signal.

[0028] Steps 2-3: Signal preprocessing: The buffered sonar digital signal is smoothed and filtered to remove outliers, resulting in the preprocessed sonar digital signal.

[0029] Steps 2-4: Water Depth Calculation: For each preprocessed sonar digital signal, the water depth d is calculated using the following formula:

[0030] d = v0 × t / 2

[0031] in:

[0032] t=t1-t0

[0033] In the formula, t0 is the time of the sonar pulse transmission; t1 is the time of arrival of the sonar echo.

[0034] v0 is the speed of sound in the waters where ship A is navigating.

[0035] Step 2-5: Generate water depth data: Match each water depth d calculated in step 2-4 with the corresponding sampling timestamp to generate "time-water depth" data.

[0036] Steps 2-3, the signal preprocessing method, include the following steps:

[0037] Step 2-3A: Convert the sonar digital signal with index n The sonar digital signal y[n] is obtained by performing moving average filtering using the following formula:

[0038] In the formula, k represents the window offset, and N represents the window half-width value.

[0039] Step 2-3B: Calculate the average value of the sonar digital signal within the current smoothing window, and record it as... .

[0040] Step 2-3C: Calculate the difference Δ of the sonar digital signal with index n, specifically as follows:

[0041]

[0042] Step 2-3D: Compare Δ with the set signal difference threshold. If Δ is greater than the signal difference threshold, then determine... Filter out any abnormalities.

[0043] Step 3 includes the following steps:

[0044] Step 3-1: Obtain position data: First, sort the water depth data obtained in Step 2 according to its sampling time to form a water depth data sequence; then, ship A obtains its own position data in real time according to the set frequency f2, and sorts it according to the sampling time to form a position data sequence.

[0045] Step 3-2, Location Data Interpolation: Let t be the sampling time corresponding to any water depth data in the water depth data sequence. s Search for whether the location data sequence has t s If location data at any given time is available, it will directly form a set of water depth-location data; otherwise, it will be t. s The location data at any given time is obtained by linear interpolation using the following formula:

[0046]

[0047] in:

[0048] t i ≤t s ≤t i+1

[0049] In the formula, t i and t i+1 Find the corresponding data from the location data sequence and t. sTwo adjacent upstream and downstream moments.

[0050] and After interpolation t s The latitude and longitude coordinates of the location data at any given time.

[0051] and t i Latitude and longitude coordinates of the location data at any given time

[0052] and t i+1 The latitude and longitude coordinates of the location data at any given time.

[0053] Step 3-4, Spatial Data Storage: Repeat step 3-2 until all water depth data and location data in the water depth data sequence are matched one-to-one and spatial water depth data is formed; at this time, each water depth data includes time and three-dimensional location data (X, Y, Z); where X represents longitude; Y represents latitude; and Z represents water depth.

[0054] A system for dynamically supplementing electronic nautical charts using shipborne sonar data, based on a method for dynamically supplementing electronic nautical charts using shipborne sonar data.

[0055] This invention offers the following advantages: It can acquire water depth information in seconds during navigation, instantly reflecting changes in water depth along the channel or navigation direction, such as detecting newly formed shoals or obstacles, thus ensuring navigational safety. Electronic nautical charts originate from large-scale hydrographic surveys and have limited resolution. In small-scale charts in the open ocean, the interval between water depth points can reach several kilometers (mainly marking danger points and main channel information). Even in large-scale charts used in ports and channels, the water depth sampling accuracy is only between a few meters and tens of meters, and the sampling interval of the chart is insufficient to support precise manipulation. This method, however, can achieve meter-level or even higher resolution detection and data acquisition, obtaining near-realistic water depth data to supplement the nautical chart, and enabling higher accuracy in judgment and alarm triggering, thus ensuring safety. Attached Figure Description

[0056] Figure 1 The flowchart shows a method for dynamically supplementing electronic nautical charts using shipborne sonar data according to the present invention.

[0057] Figure 2 A schematic diagram of position data alignment in this invention is shown. Detailed Implementation

[0058] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0059] like Figure 1 As shown, a method for dynamically supplementing electronic nautical charts using shipborne sonar data includes the following steps.

[0060] Step 1: Synchronize the ECDIS time with the sonar equipment installed on ship A via GNSS time synchronization.

[0061] Step 2: The sonar equipment performs real-time measurement of water depth data at a set frequency f1, preferably including the following steps.

[0062] Step 2-1: Acquire sonar signals: Receive sonar analog signals from the sonar equipment, perform analog-to-digital conversion on the sonar analog signals to obtain processable sonar digital signals, and perform standardization processing on the sonar digital signals.

[0063] Step 2-2, Data Buffering: A buffer is created in the processing unit to store the generated high-speed, large-capacity data through a buffering mechanism, balancing the difference between the sonar acquisition rate and the processing unit's processing rate, that is, to buffer the standardized sonar digital signal.

[0064] Steps 2-3: Signal preprocessing: The buffered sonar digital signal is smoothed and filtered to remove outliers, resulting in the preprocessed sonar digital signal.

[0065] The above-mentioned signal preprocessing method preferably includes the following steps.

[0066] Step 2-3A: Convert the sonar digital signal with index n The sonar digital signal y[n] is obtained by performing moving average filtering using the following formula to suppress high-frequency noise and low-frequency drift:

[0067] In the formula, k represents the window offset, and N represents the window half-width value, preferably 10.

[0068] Step 2-3B: Calculate the average value of the sonar digital signal within the current smoothing window, and record it as... .

[0069] Step 2-3C: Calculate the difference Δ of the sonar digital signal with index n, specifically as follows:

[0070]

[0071] Step 2-3D: Compare Δ with the set signal difference threshold. If Δ is greater than the signal difference threshold (preferably 0.5), then determine... Filter out any abnormalities.

[0072] Steps 2-4: Water Depth Calculation: For each preprocessed sonar digital signal, the water depth d is calculated using the following formula:

[0073] d = v0 × t / 2

[0074] in:

[0075] t=t1-t0

[0076] In the formula, t0 is the time of the sonar pulse transmission; t1 is the time of arrival of the sonar echo.

[0077] v0 is the speed of sound in the waters where ship A is navigating.

[0078] Step 2-5: Generate water depth data: Match each water depth d calculated in step 2-4 with the corresponding sampling timestamp to generate "time-water depth" data.

[0079] Step 3: Ship A acquires its own position data in real time at a set frequency f2, interpolates the position data, and aligns it with the water depth data obtained in Step 2, so that each water depth data corresponds to one position data.

[0080] In this embodiment, the location data is preferably GPS location data, but it can also be other location data such as BeiDou.

[0081] Step 3-1: Obtain position data: First, sort the water depth data obtained in Step 2 according to its sampling time to form a water depth data sequence; then, ship A obtains its own position data in real time according to the set frequency f2, and sorts it according to the sampling time to form a position data sequence.

[0082] Step 3-2, Location Data Interpolation: Let t be the sampling time corresponding to any water depth data in the water depth data sequence. s Search for whether the location data sequence has t s If location data at any given time is available, it will directly form a set of water depth-location data; otherwise, it will be t. s The location data at any given time is obtained by linear interpolation using the following formula:

[0083]

[0084] in:

[0085] t i ≤t s ≤t i+1

[0086] In the formula, t i and t i+1 Find the corresponding data from the location data sequence and t. sTwo adjacent upstream and downstream moments.

[0087] and After interpolation t s The latitude and longitude coordinates of the location data at any given time.

[0088] and t i Latitude and longitude coordinates of the location data at any given time

[0089] and t i+1 The latitude and longitude coordinates of the location data at any given time.

[0090] In this embodiment, after the water depth data and location data are aligned, as follows: Figure 2 As shown.

[0091] Step 3-4, Spatial Data Storage: Repeat step 3-2 until all water depth data and location data in the water depth data sequence are matched one-to-one and spatial water depth data is formed; at this time, each water depth data includes time and three-dimensional location data (X, Y, Z); where X represents longitude; Y represents latitude; and Z represents water depth.

[0092] Step 4, Dynamic Point Supplementation, specifically includes the following steps.

[0093] Step 4-1, Ship center positioning: Obtain the current position A of ship A and use position A as the ship's center point.

[0094] Step 4-2, Water Depth Data Screening: The sonar equipment screens water depth data within a distance D from the ship's center point according to the set radius D (preferably 2 kilometers) and loads it; water depth data exceeding the distance D is unloaded to avoid excessive load on the ECDIS.

[0095] Subsequently, the loaded water depth data is mapped onto the electronic chart coordinate system in ECDIS to generate a point supplement layer. This point supplement layer is independent of the original electronic chart display and can be shown or hidden via layer control.

[0096] Step 4-3, Layer Generation and Update: Repeat steps 4-1 to 4-3 every set time t seconds (preferably 10 seconds) to achieve dynamic real-time supplementation of the water depth around ship A. The dotted supplementation layer will be dynamically updated as ship A moves.

[0097] Step 5, Automatic Hidden Data Removal: Existing data in the dotted supplementary layer is gradually hidden based on timestamps. The transparency of the old data decreases linearly, and after a preset time T minutes (e.g., 5 minutes), the old data is completely hidden and unloaded from the supplementary layer.

[0098] Step 6, alarm monitoring, specifically includes the following steps.

[0099] Step 6-1, Chart Annotation Depth Matching: Based on the current position of vessel A, obtain the corresponding chart annotation depth value D from the electronic chart. chart Meanwhile, the current location obtains the depth value D from the water depth data collected by the sonar equipment. sonar .

[0100] Step 6-2, Water Depth Alarm: Real-time D chart With D sonar Comparison of values, when D sonar < 0.9 D chart When the vessel is in motion, a depth alarm is triggered. The depth alarm information includes the vessel's position, measured water depth, depth indicated on the nautical chart, and the trigger time. It may alert the user visually and audibly on the electronic chart interface and can be stored in the log system for auditing.

[0101] Step 7, Data Sharing: The ECDIS of vessel A will trigger a water depth alarm and upload the sonar water depth data with location information to the shared database through the communication module, so that the ECDIS of other vessels B can obtain it through the network.

[0102] The ECDIS of the aforementioned vessel B processes and judges the acquired sonar depth data in the following manner:

[0103] A. When vessel B is not equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, the sonar depth data most recent to the current time shall be used.

[0104] B. When vessel B is equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, if the received sonar depth data and the sonar depth data detected by vessel B itself fall within the same range, then the sonar depth data detected by vessel B itself shall be used. If they do not fall within the same range, it means that vessel B did not detect the depth data, but other vessels did. In this case, the detection data from other vessels should be used as a supplement to the data that vessel B did not detect, and should be used directly.

[0105] A system for dynamically supplementing electronic nautical charts using shipborne sonar data, based on the aforementioned method for dynamically supplementing electronic nautical charts using shipborne sonar data.

[0106] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for dynamically supplementing electronic nautical charts using shipborne sonar data, characterized in that: Includes the following steps: Step 1: Unify time synchronization, and synchronize the ECDIS with the sonar equipment installed on Ship A; Step 2: The sonar equipment performs real-time measurement of water depth data according to the set frequency f1; Step 3: Ship A acquires its own position data in real time at a set frequency f2, interpolates the position data, and aligns it with the water depth data obtained in Step 2, so that each water depth data corresponds to one position data. Step 4, Dynamic Point-by-Point Supplementation, specifically includes the following steps: Step 4-1, Ship center positioning: Obtain the current position A of ship A and use position A as the ship's center point; Step 4-2, Water Depth Data Filtering: The sonar equipment filters out water depth data within a range of D from the ship's center point according to the set radius D and loads it; then, the loaded water depth data is mapped onto the electronic chart coordinate system in ECDIS to generate a point supplementary layer; Step 4-3, Layer Generation and Update: Repeat steps 4-1 to 4-3 every set time t seconds to achieve dynamic real-time supplementation of the water depth around ship A. The dotted supplementation layer will be dynamically updated as ship A moves.

2. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 1, characterized in that: It also includes step 5, automatic hidden removal: for existing data in the dotted supplementary layer, the hidden data is gradually removed based on the timestamp.

3. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 2, characterized in that: In step 4-2, the dot-matrix supplementary layer is displayed independently of the original electronic chart and can be displayed or hidden through layer control. In step 5, the method of gradually fading out the old data based on the timestamp is as follows: the display transparency of the old data is reduced in a linear decay manner, and after a preset time T minutes, the old data is completely hidden and unloaded onto the supplementary layer.

4. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 2, characterized in that: It also includes step 6, alarm monitoring, which specifically includes the following steps: Step 6-1, Chart Annotation Depth Matching: Based on the current position of vessel A, obtain the corresponding chart annotation depth value D from the electronic chart. chart Meanwhile, the current location obtains the depth value D from the water depth data collected by the sonar equipment. sonar ; Step 6-2, Water Depth Alarm: Real-time D chart With D sonar Comparison of values, when D sonar < 0.9 D chart At that time, the water depth alarm was triggered.

5. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 4, characterized in that: It also includes step 7, data sharing: the ECDIS of vessel A will trigger a water depth alarm and upload the sonar water depth data with location information to the shared database through the communication module, so that the ECDIS of other vessels B can obtain it through the network.

6. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 5, characterized in that: In step 7, the ECDIS of vessel B performs the following judgment and processing on the acquired sonar depth data: A. When ship B is not equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, the sonar depth data most recent to the current time shall be used. B. When vessel B is equipped with sonar equipment and receives sonar depth data from multiple ECDIS systems within the same range, the received sonar depth data and the sonar depth data detected by vessel B itself belong to the same range. Therefore, the sonar depth data detected by vessel B itself shall be adopted.

7. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 1, characterized in that: Step 2, the method for real-time measurement of water depth data by sonar equipment, includes the following steps: Step 2-1: Acquire sonar signals: Receive sonar analog signals from the sonar equipment, perform analog-to-digital conversion on the sonar analog signals to obtain processable sonar digital signals, and perform standardization processing on the sonar digital signals; Step 2-2, Data Buffer: A buffer is allocated in the processing unit to buffer the standardized sonar digital signal; Steps 2-3: Signal preprocessing: The buffered sonar digital signal is smoothed and filtered to remove outliers, resulting in the preprocessed sonar digital signal. Steps 2-4: Water Depth Calculation: For each preprocessed sonar digital signal, the water depth d is calculated using the following formula: d = v0 × t / 2 in: t=t1-t0 In the formula, t0 is the sonar emission pulse time; t1 is the arrival time of the sonar echo; v0 is the speed of sound in the waters where ship A is navigating; Step 2-5: Generate water depth data: Match each water depth d calculated in step 2-4 with the corresponding sampling timestamp to generate "time-water depth" data.

8. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 7, characterized in that: Steps 2-3, the signal preprocessing method, include the following steps: Step 2-3A: Convert the sonar digital signal with index n The sonar digital signal y[n] is obtained by performing moving average filtering using the following formula: In the formula, k represents the window offset, and N represents the window half-width value; Step 2-3B: Calculate the average value of the sonar digital signal within the current smoothing window, and record it as... ; Step 2-3C: Calculate the difference Δ of the sonar digital signal with index n, specifically as follows: Step 2-3D: Compare Δ with the set signal difference threshold. If Δ is greater than the signal difference threshold, then determine... Filter out any abnormalities.

9. The method for dynamically supplementing electronic nautical charts using shipborne sonar data according to claim 1, characterized in that: Step 3 includes the following steps: Step 3-1: Acquire position data: First, sort the water depth data obtained in Step 2 according to its sampling time to form a water depth data sequence; then, ship A acquires its own position data in real time according to the set frequency f2, and sorts it according to the sampling time to form a position data sequence. Step 3-2, Location Data Interpolation: Let t be the sampling time corresponding to any water depth data in the water depth data sequence. s Search for whether the location data sequence has t s If location data at any given time is available, it will directly form a set of water depth-location data; otherwise, it will be t. s The location data at any given time is obtained by linear interpolation using the following formula: in: t i ≤t s ≤t i+1 In the formula, t i and t i+1 Find the corresponding data in the location data sequence and t. s Two adjacent upstream and downstream moments; and After interpolation t s Latitude and longitude coordinates of the location data at any given time; and t i Latitude and longitude coordinates of the location data at any given time and t i+1 Latitude and longitude coordinates of the location data at any given time; Step 3-4, Spatial Data Storage: Repeat step 3-2 until all water depth data and location data in the water depth data sequence are matched one-to-one and spatial water depth data is formed; at this time, each water depth data includes time and three-dimensional location data (X, Y, Z); where X represents longitude; Y represents latitude; and Z represents water depth.

10. A system for dynamically supplementing electronic nautical charts using shipborne sonar data, characterized in that: The method for dynamically supplementing electronic nautical charts using shipborne sonar data as described in any one of claims 1-9.

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