Large ship sensing and displaying system and method based on Beidou No.3 high-precision positioning

Abstract

The invention discloses a large-scale ship sensing and display system method for Beidou No.3 high-precision positioning, and the system method is based on a single Beidou No.3 high-precision positioning RTK technology and a virtual reality technology, and comprises the steps: laying three-point positioning reference points on a large-scale ship, obtaining real-time geodetic coordinates through Beidou No.3 RTK equipment, and carrying out the real-time positioning of the large-scale ship through the real-time geodetic coordinates. In combination with a conversion algorithm of a ship local coordinate system and a world coordinate system, attitude parameters such as heading, rolling and pitching of the ship are accurately calculated; and meanwhile, a Unity3D engine is adopted to construct a ship 3D model and a scene display interface, AR / VR visual presentation of the ship attitude is realized, and NMEA0183 protocol output data is packaged. The attitude measurement precision is high, the display is visual and vivid, the core technology is autonomous and controllable, the cost is only 30%-50% of that of traditional high-precision equipment, the method can be widely applied to scenes such as severe sea condition navigation, narrow channel passing, berthing and unberthing operation and loading and unloading operation of large ships, and the ship navigation safety and the operation efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of ship navigation and attitude monitoring technology, specifically to a method for a large ship perception and display system based on BeiDou-3 high-precision positioning. Background Technology

[0002] In the shipping industry, large ships of 50,000 tons or more (such as 100,000-ton bulk carriers) can reach a total length of 250 meters, a beam of about 43 meters, and a cargo hold area exceeding 160 meters in length. Their massive hull structure places stringent requirements on the accuracy and coverage of attitude perception. Although ship attitude perception technology has undergone several generations of development, significant shortcomings still exist.

[0003] Early magnetic compasses had an accuracy of only ±3°, while electric compasses, although improved to ±0.5°, required regular replacement of the gyroscope ball, resulting in high maintenance costs. Micromechanical gyroscopes (MEMS), while low in cost and long in life (exceeding 100,000 hours), have limited accuracy and are only suitable for small carriers such as drones, failing to meet the needs of large ships.

[0004] The mainstream application of satellite (GNSS) / inertial compass relies on dual antenna measurements with a short baseline of 1-4 meters. The orientation accuracy is 0.05° when the baseline is as long as 4 meters. However, the short baseline cannot cover the cargo hold area of ​​large ships, which is hundreds of meters wide. The sensed data is only a reference for the ship's attitude and does not reflect the actual motion state. Fiber optic combined gyroscope (FOG) uses a customized 4-meter baseline. The heading accuracy is ≤0.05° and the attitude angle accuracy is ≤0.03°, but it costs about 200,000 yuan and some core technologies are imported. Ring laser gyroscope (RLG) has an attitude angle accuracy of ≤0.01°, but the price exceeds one million yuan and most of them are foreign products, which limits their popularization in civilian use.

[0005] Meanwhile, current equipment displays only simple instrument panels, outputting only NMEA0183 serial port data, failing to provide intuitive, scenario-based information. Drivers must synthesize data from multiple instruments to make judgments, which can easily lead to delayed decisions in complex scenarios. Furthermore, high-precision equipment often relies on GPS or foreign technology, posing a risk of positioning interruption in special scenarios and compromising navigation safety. These problems severely restrict the safe and efficient operation of large vessels in adverse sea conditions and narrow waterways. Therefore, it is necessary to design a large vessel perception and display system based on BeiDou-3 high-precision positioning. Summary of the Invention

[0006] The purpose of this invention is to provide a method for a large ship sensing and display system based on BeiDou-3 high-precision positioning, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for a large ship sensing and display system based on BeiDou-3 high-precision positioning, comprising the following steps:

[0008] A. Deploy Beidou-3 RTK positioning reference points: Set reference origin point C on the center line of the keel projection of the bridge of the large ship, set point B on the port side edge of the cargo hold, and set point A on the starboard side edge of the cargo hold. Record the fixed relative coordinates of points A, B, and C in the ship's local coordinate system (LCS): A′(X_A′,Y_A′,Z_A′), B′(X_B′,Y_B′,Z_B′), and C′(X_C′,Y_C′,Z_C′).

[0009] B. Obtaining Real-Time Geodetic Coordinates: Using a single BeiDou-3 high-precision positioning RTK device, the real-time coordinates of points A, B, and C in the World Coordinate System (WCS) are collected: A(X_A,Y_A,Z_A), B(X_B,Y_B,Z_B), and C(X_C,Y_C,Z_C). The BeiDou-3 RTK device operates at frequencies including BDS B1I, B2I, B3I, B1C, B2a, and B2b, supporting multi-frequency on-chip RTK positioning calculation and 60dB narrowband anti-interference. The RTK positioning accuracy is 0.8cm+1 in the plane. pp m, elevation 1.5cm+1 pp m, data output frequency is 20Hz;

[0010] C. Transmitting positioning data: The real-time geodetic coordinates of points A, B, and C are transmitted to the data access / storage unit through the microwave network data transmission unit to realize real-time data reception and backup;

[0011] D. Calculate ship attitude parameters: Based on the fixed relative coordinates from step A and the real-time geodetic coordinates from step B, construct the real-time vectors v1 = AB and v2 = AC in the world coordinate system and the fixed vectors v1′ = A′B′ and v2′ = A′C′ in the local coordinate system. Calculate the vector v3 perpendicular to v1 and v2 through the three-dimensional vector cross product, and obtain the unit vectors of the X and Z axes in the local coordinate system after normalization. μ x μ z, derive the Y-axis unit vector μ based on the left-hand cross product rule. y ; with μx, μ y A 3×3 orthogonal rotation matrix R is constructed using column vectors μz. Euler angles are solved in reverse order of ZYX rotation to obtain the ship's heading angle, roll angle, and pitch angle.

[0012] E. Ship Attitude Display and Data Output: Transmit the ship attitude parameters calculated in step D to Unit y 3D view unit, utilizing Unit y The 3D engine loads the ship's 3D model and port electronic charts to simulate real-time weather and sea conditions, displaying the navigation status using bow-stern vectors, ground speed vectors, and lateral speed vectors; it also encapsulates the NMEA0183 protocol to output attitude data to the bridge navigation equipment or roll reduction device via serial port.

[0013] F. Risk Warning and Decision Support: Based on the attitude parameters set in step D, overturning risk alarm thresholds and cargo tilting alarm thresholds are set. When the attitude parameters exceed the thresholds, an early warning is triggered. Combined with the visualization interface in step E, auxiliary decision support is provided for large ships entering and exiting locks, two-way navigation in narrow channels, and berthing and unberthing operations.

[0014] Preferably, the BeiDou-3 RTK device in step B supports interference detection. When satellite signal interference is detected, it automatically switches to anti-interference mode to ensure the continuity of positioning data. The microwave network data transmission unit in step C adopts an encrypted transmission protocol with a transmission rate of ≥10Mbps and a transmission delay of ≤50ms.

[0015] Preferably, the formula for calculating the three-dimensional vector cross product in step D is: if vector a = (a1, a2, a3) and vector b = (b1, b2, b3),

[0016] Then a × b = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1); the vector normalization process uses the vector magnitude formula: for vector a, its magnitude |a| = √(a1b3 - a2b2 - a3b3); 2 +a2 2 +a3 2 ), unit vector μ=a / |a|.

[0017] Preferably, the expression for the rotation matrix R in step D is: R = [μ_xxμ_yxμ_zx][μ_xyμ_yyμ_zy][μ_xzμ_yzμ_zz] where μ_xx, μ_xy, and μ_xz are the components of the X-axis unit vector μx in the world coordinate system, μ_yx, μ_yy, and μ_yz are the components of the Y-axis unit vector μy in the world coordinate system, and μ_zx, μ_zy, and μ_zz are the components of the Z-axis unit vector μz in the world coordinate system; the inverse Euler angle solution uses the arctangent function.

[0018] Preferably, in step E, the bow-stern vector is displayed as follows: the bow-stern line extends 1 / 5 of the ship's length along the bow and stern directions, and the longitudinal velocity vector is displayed at 1 / 5 of the bow length, with a vector length equal to the ship's 6-minute travel distance; the ground speed vector is displayed as follows: at 1 / 5 of the ship's length extending from the point where the port or starboard bow intersects with the outer side, the ground speed vector is displayed along the ground direction, with a vector length equal to the ship's 6-minute travel distance; the lateral velocity vector is displayed as follows: at 1 / 5 of the ship's width extending from the point where the port or starboard bow intersects with the outer side, the lateral velocity vector is displayed, with a vector length equal to the ship's 6-minute travel distance.

[0019] Preferably, the Unit in step Ey The 3D view unit supports multi-view switching, including the ship's front view, side view, top view, and first-person driving view; the electronic nautical chart supports offline loading, and the chart update frequency is synchronized with the latest port data. The weather and sea state scenario simulation parameters include wind speed, wave height, and visibility, and the data comes from the ship's meteorological sensors or remote meteorological services.

[0020] Preferably, the capsizing risk alarm threshold in step F is dynamically adjusted according to the ship type and load status. Specifically, for large bulk carriers, the roll angle alarm threshold is ≤15° when unloaded and ≤10° when fully loaded. The cargo loading / unloading tilt alarm threshold is set to a pitch angle ≤5°. When this threshold is exceeded, an audible and visual alarm is triggered, and the alarm is displayed in Unit [unit name missing]. y The 3D interface displays the tilt direction and adjustment suggestions.

[0021] Preferably, a BeiDou-3 high-precision positioning system for large ships' sensing and display includes a single BeiDou-3 RTK positioning unit, a microwave transmission DTU unit, an attitude algorithm computing unit, a data access and storage unit, and a unit... y The 3D view unit and data output unit are connected to a single BeiDou-3 RTK positioning unit, which is connected to a microwave transmission DTU unit. The microwave transmission DTU unit is connected to a data access and storage unit, which is connected to an attitude algorithm computing unit. The attitude algorithm computing unit is connected to Unit... y 3D view unit, data output unit.

[0022] Beneficial effects:

[0023] (1) The attitude measurement accuracy of this invention is high, the display is intuitive and realistic, the core technology is independently controllable, and the cost is only 30%-50% of that of traditional high-precision equipment. It can be widely used in scenarios such as large ships sailing in bad sea conditions, passing through narrow channels, berthing and unberthing operations, and loading and unloading operations, thereby improving the safety of ship navigation and operational efficiency.

[0024] (2) This invention breaks through the limitations of traditional equipment with a short baseline of 1-4 meters. It adopts a three-point positioning design with an ultra-long baseline of more than 100 meters covering the cargo hold area of ​​large ships. Combined with single Beidou-3 RTK technology, it realizes the actual measurement of the overall attitude of the ship. The bow accuracy is ≤0.01° and the attitude angle accuracy is ≤0.015°. Its performance is close to that of a million-level ring laser gyroscope and better than that of a 200,000-level fiber optic combined gyroscope. It can accurately support the control of anti-roll device under severe sea conditions and reduce the risk of ship capsizing.

[0025] (3) This invention is based on Unit yThe 3D engine constructs an AR / VR scene-based interface, loading 3D ship models and port electronic charts to simulate real-time weather and sea conditions. It intuitively displays the navigation status using bow-stern vectors and ground speed vectors, and supports multi-view switching. The operator does not need to integrate multiple instrument data to quickly grasp the relationship between the ship's attitude and the surrounding environment, reducing the risk of collision by more than 60% when navigating in both directions in narrow channels.

[0026] (4) This invention can dynamically adjust the risk of capsizing and the alarm threshold for loading and unloading tilt, providing early warning for berthing, unloading and loading operations; it supports access to meteorological sensors and radar data to achieve multi-data fusion analysis; the high-precision attitude data output can also support the autonomous driving of unmanned ships, meeting the diversified operation and intelligent upgrading needs of large ships.

[0027] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more apparent and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0028] Figure 1 This is a block diagram illustrating the principle of the present invention;

[0029] Figure 2 A top view of the three-point distribution of a single BeiDou-3 high-precision positioning system;

[0030] Figure 3 This is a flowchart of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0033] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0035] Please see Figures 1-3 This invention discloses a method for a large ship sensing and display system based on BeiDou-3 high-precision positioning, comprising the following steps:

[0036] A. Deploy Beidou-3 RTK positioning reference points: Set reference origin point C on the center line of the keel projection of the bridge of the large ship, set point B on the port side edge of the cargo hold, and set point A on the starboard side edge of the cargo hold. Record the fixed relative coordinates of points A, B, and C in the ship's local coordinate system (LCS): A′(X_A′,Y_A′,Z_A′), B′(X_B′,Y_B′,Z_B′), and C′(X_C′,Y_C′,Z_C′).

[0037] B. Obtaining Real-Time Geodetic Coordinates: Using a single BeiDou-3 high-precision positioning RTK device, the real-time coordinates of points A, B, and C in the World Coordinate System (WCS) are collected: A(X_A,Y_A,Z_A), B(X_B,Y_B,Z_B), and C(X_C,Y_C,Z_C). The BeiDou-3 RTK device operates at frequencies including BDS B1I, B2I, B3I, B1C, B2a, and B2b, supporting multi-frequency on-chip RTK positioning calculation and 60dB narrowband anti-interference. The RTK positioning accuracy is 0.8cm+1 in the plane. pp m, elevation 1.5cm+1 pp m, data output frequency is 20Hz;

[0038] C. Transmitting positioning data: The real-time geodetic coordinates of points A, B, and C are transmitted to the data access / storage unit through the microwave network data transmission unit to realize real-time data reception and backup;

[0039] D. Calculate ship attitude parameters: Based on the fixed relative coordinates in step A and the real-time geodetic coordinates in step B, construct the real-time vectors v1 = AB and v2 = AC in the world coordinate system and the fixed vectors v1′ = A′B′ and v2′ = A′C′ in the local coordinate system. Calculate the vector v3 perpendicular to v1 and v2 through the three-dimensional vector cross product. Normalize the vectors to obtain the unit vectors μx and μz of the X and Z axes in the local coordinate system. Derive the unit vector μy of the Y axis according to the left-hand cross product rule. Construct a 3×3 orthogonal rotation matrix R with μx, μy, and μz as column vectors. Solve the Euler angles in the ZYX rotation order to obtain the ship's heading angle, roll angle, and pitch angle.

[0040] E. Ship Attitude Display and Data Output: The ship attitude parameters calculated in step D are transmitted to the Unity3D view unit. The Unity3D engine is used to load the ship 3D model and port electronic chart to simulate real-time weather and sea conditions. The navigation status is displayed using bow-stern vectors, ground speed vectors, and lateral speed vectors. At the same time, the NMEA0183 protocol is encapsulated, and the attitude data is output to the bridge steering equipment or roll reduction device via serial port.

[0041] F. Risk Warning and Decision Support: Based on the attitude parameters set in step D, overturning risk alarm thresholds and cargo tilting alarm thresholds are set. When the attitude parameters exceed the thresholds, an early warning is triggered. Combined with the visualization interface in step E, auxiliary decision support is provided for large ships entering and exiting locks, two-way navigation in narrow channels, and berthing and unberthing operations.

[0042] In this invention, the BeiDou-3 RTK device in step B supports interference detection. When satellite signal interference is detected, it automatically switches to anti-interference mode to ensure the continuity of positioning data. The microwave network data transmission unit in step C adopts an encrypted transmission protocol with a transmission rate of ≥10Mbps and a transmission delay of ≤50ms.

[0043] In this invention, the formula for calculating the three-dimensional vector cross product in step D is: if vector a = (a1, a2, a3) and vector b = (b1, b2, b3),

[0044] Then a × b = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1); the vector normalization process uses the vector magnitude formula: for vector a, its magnitude |a| = √(a1b3 - a2b2 - a3b3); 2 +a2 2 +a3 2 ), unit vector μ=a / |a|.

[0045] In this invention, the expression for the rotation matrix R in step D is: R = [μ_xxμ_yxμ_zx][μ_x] y μ_ yy μ_zy ][μ_xzμ_ y zμ_zz]where μ_xx and μ_x y μ_xz represents the components of the X-axis unit vector μx in the world coordinate system. y x、μ_ yy μ_ y z is the unit vector along the Y-axis, μ y The components in the world coordinate system, μ_zx, μ_z y μ_zz is the unit vector along the Z-axis. μ The z-component in the world coordinate system; the inverse Euler angle solution uses the arctangent function, combined with quadrant judgment correction, to avoid angle calculation errors.

[0046] In this invention, the bow-stern vector in step E is displayed as follows: the bow-stern line extends 1 / 5 of the ship's length along the bow and stern directions, and the longitudinal velocity vector is displayed at 1 / 5 of the bow length, with a vector length equal to the ship's 6-minute travel distance; the ground speed vector is displayed as follows: at 1 / 5 of the ship's length extending from the point where the ship's port or starboard bow intersects with the outer side, the ground speed vector is displayed along the ground direction, with a vector length equal to the ship's 6-minute travel distance; the lateral velocity vector is displayed as follows: at 1 / 5 of the ship's width extending from the point where the ship's center port or starboard bow intersects with the outer side, the lateral velocity vector is displayed, with a vector length equal to the ship's 6-minute travel distance.

[0047] In this invention, the Unit mentioned in step E y The 3D view unit supports multi-view switching, including the ship's front view, side view, top view, and first-person driving view; the electronic nautical chart supports offline loading, and the chart update frequency is synchronized with the latest port data. The weather and sea state scenario simulation parameters include wind speed, wave height, and visibility, and the data comes from the ship's meteorological sensors or remote meteorological services.

[0048] In this invention, the capsizing risk alarm threshold in step F is dynamically adjusted according to the ship type and load status. Specifically, for large bulk carriers, the roll angle alarm threshold is ≤15° when unloaded and ≤10° when fully loaded. The cargo loading / unloading tilt alarm threshold is set to a pitch angle ≤5°. Exceeding this threshold triggers an audible and visual alarm, and this is displayed in Unit [unit name missing]. y The 3D interface displays the tilt direction and adjustment suggestions.

[0049] Furthermore, this invention also discloses a large ship sensing and display system based on BeiDou-3 high-precision positioning, comprising a single BeiDou-3 RTK positioning unit 1, a microwave transmission DTU unit 2, an attitude algorithm computing unit 3, a data access and storage unit 4, and a Unit y3D view unit 5, data output unit 6, the single Beidou-3 RTK positioning unit 1 is connected to microwave transmission DTU unit 2, the microwave transmission DTU unit 2 is connected to data access and storage unit 4, the data access and storage unit 4 is connected to attitude algorithm computing power unit 3, the attitude algorithm computing power unit 3 is connected to Unit y 3D view unit 5, data output unit 6. A single BeiDou-3 RTK positioning unit consists of three single BeiDou-3 RTK devices, installed at points A, B, and C respectively. These devices are responsible for collecting real-time geodetic coordinates, supporting interference detection and anti-interference switching to ensure positioning continuity. The microwave transmission DTU unit uses microwave network transmission equipment, operating at a frequency of 2.4GHz or 5.8GHz, with a transmission rate ≥10Mb. p With a latency of ≤50ms, RTK data is transmitted to the data access / storage unit via an encrypted protocol, supporting simultaneous access from multiple devices. The data access / storage unit uses an industrial-grade server, supporting real-time data reception and local backup. The attitude algorithm computing unit uses an embedded processor to run attitude calculation algorithms and output heading, roll, and pitch parameters, with computing power meeting the 20Hz data processing requirements. y The 3D view unit consists of an industrial-grade display and a unit y 3D software components, monitor resolution ≥1920×1080, refresh rate ≥60Hz, Unit y The 3D software loads the ship's 3D model and electronic nautical chart to achieve scene-based display and interactive operation; the data output unit includes a serial port output module and an early warning module; the serial port output module encapsulates the NMEA0183 protocol and outputs attitude data to the bridge navigation equipment and anti-roll device through RS485 / RS232 interface; the early warning module sets the capsizing risk and loading / unloading tilt thresholds, and when the parameters exceed the thresholds, it triggers an audible and visual alarm and pops up an early warning prompt on the display interface.

[0050] Example:

[0051] Application of this system in two-way navigation in narrow waterways

[0052] A narrow waterway, only 100 meters wide, needs to allow two 100,000-ton bulk carriers to pass in both directions. This system is applied to provide navigation assistance.

[0053] Before a ship enters the waterway, the RTK equipment locks onto ≥10 BeiDou-3 satellites, collects the coordinates of points A, B, and C in real time, and calculates the heading angle, roll angle, pitch angle, and ground speed.

[0054] Unit y The 3D interface loads the electronic nautical chart of the channel, showing the relative position of the ship's 3D model and the oncoming ships. The bow and stern vectors point to the centerline of the channel, the ground speed vector shows the 6-minute sailing distance, and the lateral speed vector is 0.3kn.

[0055] The pilot observed through the interface that the oncoming vessel was 5 nautical miles ahead of the pilot's ship, with a lateral distance of 30 meters. Based on the pilot's lateral speed, the pilot determined that the course needed to be adjusted to the left by 2° to avoid a collision. The system output adjustment suggestions based on attitude parameters. After the pilot executed the suggestions, the lateral speed was reduced to 0.1 knots, and the pilot safely passed through the channel.

[0056] After applying this system, the two-way navigation time in narrow waterways was reduced to 80% of the original time, the risk of collision was reduced by 70%, and no navigation accidents occurred.

[0057] In summary, the present invention offers high attitude measurement accuracy, intuitive and realistic display, and its core technology is independently controllable. The cost is only 30%-50% of that of traditional high-precision equipment. It can be widely applied to scenarios such as large ships navigating in harsh sea conditions, passing through narrow channels, berthing and unberthing operations, and loading and unloading operations, thereby improving ship navigation safety and operational efficiency.

[0058] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for a large ship sensing and display system based on BeiDou-3 high-precision positioning, characterized in that: Includes the following steps: A. Deploy Beidou-3 RTK positioning reference points: Set reference origin point C on the center line of the keel projection of the bridge of the large ship, set point B on the port side edge of the cargo hold, and set point A on the starboard side edge of the cargo hold. Record the fixed relative coordinates of points A, B, and C in the ship's local coordinate system as A′(X_A′,Y_A′,Z_A′), B′(X_B′,Y_B′,Z_B′), and C′(X_C′,Y_C′,Z_C′). B. Obtaining Real-Time Geodetic Coordinates: Using a single BeiDou-3 high-precision positioning RTK device, the real-time coordinates of points A, B, and C in the world coordinate system are collected respectively: A(X_A,Y_A,Z_A), B(X_B,Y_B,Z_B), and C(X_C,Y_C,Z_C). The BeiDou-3 RTK device operates at frequencies including BDS B1I, B2I, B3I, B1C, B2a, and B2b, supports multi-frequency on-chip RTK positioning calculation and 60dB narrowband anti-interference, and has an RTK positioning accuracy of 0.8cm+1ppm for horizontal and 1.5cm+1ppm for vertical. The data output frequency is 20Hz. C. Transmitting positioning data: The real-time geodetic coordinates of points A, B, and C are transmitted to the data access / storage unit through the microwave network data transmission unit to achieve real-time data reception and backup; D. Calculate ship attitude parameters: Based on the fixed relative coordinates in step A and the real-time geodetic coordinates in step B, construct the real-time vectors v1 = AB and v2 = AC in the world coordinate system and the fixed vectors v1′ = A′B′ and v2′ = A′C′ in the local coordinate system. Calculate the vector v3 perpendicular to v1 and v2 through the three-dimensional vector cross product. Normalize the vectors to obtain the unit vectors μx and μz of the X and Z axes in the local coordinate system. Derive the unit vector μy of the Y axis according to the left-hand cross product rule. Construct a 3×3 orthogonal rotation matrix R with μx, μy, and μz as column vectors. Solve the Euler angles in the ZYX rotation order to obtain the ship's heading angle, roll angle, and pitch angle. E. Ship Attitude Display and Data Output: The ship attitude parameters calculated in step D are transmitted to the Unity3D view unit. The Unity3D engine is used to load the ship 3D model and port electronic chart to simulate real-time weather and sea conditions. The navigation status is displayed using bow-stern vectors, ground speed vectors, and lateral speed vectors. At the same time, the NMEA0183 protocol is encapsulated, and the attitude data is output to the bridge steering equipment or roll reduction device via serial port. F. Risk Warning and Decision Support: Based on the attitude parameters set in step D, overturning risk alarm thresholds and cargo tilting alarm thresholds are set. When the attitude parameters exceed the thresholds, an early warning is triggered. Combined with the visualization interface in step E, auxiliary decision support is provided for large ships entering and exiting locks, two-way navigation in narrow channels, and berthing and unberthing operations.

2. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The BeiDou-3 RTK device mentioned in step B supports interference detection. When satellite signal interference is detected, it automatically switches to anti-interference mode to ensure the continuity of positioning data. The microwave network data transmission unit mentioned in step C adopts an encrypted transmission protocol with a transmission rate of ≥10Mbps and a transmission delay of ≤50ms.

3. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The formula for calculating the three-dimensional vector cross product in step D is as follows: If vector a = (a1, a2, a3) and vector b = (b1, b2, b3), Then a × b = (a2b3 - a3b2, a3b1 - a1b3, a1b2 - a2b1); the vector normalization process uses the vector magnitude formula: for vector a, its magnitude |a| = √(a1b3 - a2b2 - a3b3); 2 +a2 2 +a3 2 ), unit vector μ=a / |a|.

4. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The expression for the rotation matrix R in step D is: R = [μ_xxμ_yxμ_zx][μ_xyμ_yyμ_zy][μ_xzμ_yzμ_zz] where, μ_xx, μ_xy, and μ_xz are the components of the X-axis unit vector μx in the world coordinate system, μ_yx, μ_yy, and μ_yz are the components of the Y-axis unit vector μy in the world coordinate system, and μ_zx, μ_zy, and μ_zz are the components of the Z-axis unit vector μz in the world coordinate system; the inverse Euler angle solution uses the arctangent function.

5. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The bow-stern vector in step E is displayed as follows: the bow-stern line extends 1 / 5 of the ship's length along the bow and stern directions, and the longitudinal velocity vector is displayed at 1 / 5 of the bow length, with a vector length equal to the ship's 6-minute travel distance; the ground speed vector is displayed as follows: at 1 / 5 of the ship's length extending from the point where the port or starboard bow intersects with the outer side, the ground speed vector is displayed along the ground direction, with a vector length equal to the ship's 6-minute travel distance; the lateral velocity vector is displayed as follows: at 1 / 5 of the ship's width extending from the point where the port or starboard bow intersects with the outer side, the lateral velocity vector is displayed, with a vector length equal to the ship's 6-minute travel distance.

6. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The Unity3D view unit in step E supports multi-view switching, including the ship's front view, side view, top view, and first-person driving view; the electronic nautical chart supports offline loading, and the chart update frequency is synchronized with the latest port data. The weather and sea state scenario simulation parameters include wind speed, wave height, and visibility, and the data comes from ship meteorological sensors or remote meteorological services.

7. The method for a large ship sensing and display system based on BeiDou-3 high-precision positioning according to claim 1, characterized in that: The capsizing risk alarm threshold in step F is dynamically adjusted according to the ship type and load status. For large bulk carriers, the roll angle alarm threshold is ≤15° when empty and ≤10° when fully loaded. The tilt alarm threshold for loading and unloading cargo is set to ≤5°. When the threshold is exceeded, an audible and visual alarm is triggered, and the tilt direction and adjustment suggestions are displayed on the Unity3D interface.

8. A large ship sensing and display system based on BeiDou-3 high-precision positioning, characterized in that: It includes a single Beidou-3 RTK positioning unit (1), a microwave transmission DTU unit (2), an attitude algorithm computing power unit (3), a data access and storage unit (4), a Unity3D view unit (5), and a data output unit (6). The single Beidou-3 RTK positioning unit (1) is connected to the microwave transmission DTU unit (2), the microwave transmission DTU unit (2) is connected to the data access and storage unit (4), the data access and storage unit (4) is connected to the attitude algorithm computing power unit (3), and the attitude algorithm computing power unit (3) is connected to the Unity3D view unit (5) and the data output unit (6) respectively.

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