Fire-fighting detection unmanned ship system for water surface-underwater cooperative operation and fire extinguishing method

Abstract

The invention discloses a water surface-underwater cooperative operation fire-fighting detection unmanned ship system and a fire extinguishing method, and the system comprises an unmanned ship body, an open moon pool located at the gravity center position of the unmanned ship body, an ROV located in the open moon pool, a retractable winch connected with the ROV, and a fire-fighting and fire-extinguishing module and a detection integrated module arranged above the unmanned ship body. A spray pump is arranged at the rear end; according to the unmanned ship system, through the arrangement of the middle moon pool and the portal water cannon, the ROV is protected against direct sea wave impact in the retracting and releasing process, the recoil force of the high-pressure water cannon is balanced, and the stability of the unmanned ship is guaranteed; according to the fire extinguishing method provided by the invention, the ROV and the water monitor cooperatively strike, the ROV locks a fire source and then returns coordinates in real time, the mother ship control system automatically adjusts the water monitor according to the coordinates to carry out precise fire extinguishing, fire-fighting operation is upgraded to fixed-point clearing from previous surface covering, and the fire extinguishing efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of waterborne firefighting and disaster detection technology, specifically to a surface-underwater collaborative firefighting and detection unmanned surface vessel system and firefighting method. Background Technology

[0002] Due to the complex structure and enclosed compartments of ships, and the fact that they often carry dangerous goods such as fuel and chemicals, fires are often accompanied by secondary disasters such as explosions, toxic gas leaks, or capsizing. Currently, waterborne firefighting mainly relies on the following two types of technical equipment: (1) Traditional manned fireboats: equipped with high-flow water cannons, but they are large and have a deep draft. In order to ensure the safety of the crew, they are often unable to get close to the core area when facing complex situations with the risk of explosion or toxic gas, and can only carry out coverage spraying from a distance. (2) Single-function unmanned fireboats: In recent years, unmanned surface vessels (USVs) have solved the problem of personnel safety, but most of them are just moving water cannons to unmanned boats. They can still only see the open flames on the outside of the ship and cannot obtain key information inside the cabin or underwater, such as the location of the hidden fire source, the damage to the bottom of the ship, and the concentration of chemical leaks.

[0003] Currently available "reconnaissance unmanned surface vessels" typically only carry surface electro-optical pods (cameras / radar), or some research projects attempt to combine ROVs with large ships. However, in existing solutions, ROVs usually require manual deployment with the help of a large mother ship crane, making it impossible to achieve automated deployment and retrieval on an unmanned surface vessel platform, and there is a lack of linkage control between the two.

[0004] The patent application with application number "202511502927.X" and titled "Firefighting Unmanned Surface Vessel for Narrow Waters and its Control Method" proposes an unmanned surface vessel system that integrates hull structure optimization, dynamic propulsion, and intelligent firefighting operations, specifically designed for narrow water environments. However, this patent relies on surface-to-line-of-sight sensors, which cannot penetrate the hull to detect hidden fire sources or battery thermal runaway points, resulting in a lack of targeted firefighting efforts. As a single surface platform, it lacks underwater operational capabilities, making it unable to detect underwater hull damage or conduct water quality sampling, thus hindering comprehensive rescue decision-making.

[0005] Although existing technologies have solved some problems, they still have significant shortcomings in dealing with complex ship fires: (1) Low efficiency of "blind attack": It is impossible to find hidden fire sources behind the bulkheads by relying solely on external vision, resulting in a large amount of fire extinguishing agent being wasted in ineffective areas, and it is impossible to assess the risk of reignition after fire extinguishing. (2) Single dimension of information perception: There is a lack of real-time detection means for the integrity of the underwater hull structure (whether it is damaged and flooded) and the water / gas environment, and command and decision-making lack data support. (3) Poor coordination: Fire extinguishing and detection are separated, making it impossible to "detect and strike". (4) Weak ability to operate in wind and waves: Traditional small unmanned boats with external ROVs are extremely difficult to deploy and retrieve in bad sea conditions, which can easily lead to cable entanglement or equipment loss. Summary of the Invention

[0006] Purpose of the invention: This invention proposes a fire-fighting detection unmanned surface vessel system and fire-fighting method that enables automated coordination between surface strikes and underwater / cabin-level detection, thereby solving the problems of low efficiency in blind strikes and difficulties in launching and retrieving in harsh environments in traditional water firefighting.

[0007] Technical Solution: This invention proposes a surface-underwater collaborative firefighting and detection unmanned surface vessel (USV) system, comprising an USV hull, an open moon pool located at the USV's center of gravity, an ROV located inside the open moon pool, a launch and recovery winch connected to the ROV, a fire extinguishing module, and a navigation module; the open moon pool extends through the deck and bottom of the USV hull; the fire extinguishing module includes a gantry fixed above the USV hull and a water cannon; the water cannon is located at the center of the top of the gantry, and pulleys are located below the gantry; the launch and recovery winch... An umbilical cable passes through the pulley and connects to the ROV. The retrieval and deployment trolley is used to retrieve, deploy, and lock the ROV. A detection component is installed at the front end of the ROV, including a thermal imager, an environmental sensor, and a scanning sonar. A navigation module is installed high at the rear end of the ROV, including a GNSS unit, a first camera located below the GNSS unit, and a lidar located below the first camera. A jet pump is also installed at the bottom rear end of the ROV. The ROV is also equipped with a posture sensor and a cooperative control system.

[0008] Preferably, the gantry is fixed to the hull of the unmanned surface vessel (USV) across the open moon pool, and the launch and recovery winch is mounted on the hull of the USV and located at the rear of the open moon pool.

[0009] Preferably, the ROV has several thrusters on both sides, and the detection component at the front end of the ROV is also equipped with a second camera.

[0010] Preferably, the navigation module is further provided with a searchlight, which is positioned above the GNSS unit.

[0011] Preferably, the hull of the unmanned surface vessel adopts a monolithic structure.

[0012] Preferably, the water cannon adopts a multi-degree-of-freedom gimbal structure, and the water cannon is connected to a fire pump inside the unmanned surface vessel via a pipeline.

[0013] A firefighting method for a surface-underwater collaborative firefighting and detection unmanned surface vessel system includes the following steps:

[0014] S1: Receive alarms and approximate target location, drive the unmanned surface vessel and navigate to the target sea area using the GNSS unit;

[0015] S2: Using lidar scanning and first camera identification to obtain relevant parameter information, the collaborative control system generates a preliminary situation assessment result. The parameter information includes the distance between the unmanned surface vessel and the target, the area of ​​the external flame, and the damage status. When the first camera detects open flames and the lidar does not detect structural damage, proceed to S3. When the first camera detects dense smoke and there are no visible open flames on the surface, or when the lidar detects damage, proceed to S4.

[0016] S3: The unmanned surface vessel adjusts its position and calculates the relative distance to the open flame. It then uses the multi-degree-of-freedom gimbal of the water cannon to adjust the pitch and azimuth angles for external spraying to extinguish the fire. It then enters S9.

[0017] S4: The unmanned surface vessel (ROV) enters the fixed-point anchoring / dynamic positioning mode, starts the cable car, and the umbilical cable guides the ROV through the open moon pool to smoothly release it into the water via the pulley.

[0018] S5: The ROV approaches the underwater part of the target to carry out operations or enters the target through the damaged part to carry out operations. The ROV uses a thermal imager to upload video images in real time and lock the center of the fire source. It also uses environmental sensors to acquire environmental data in real time for environmental detection.

[0019] S6: Use scanning sonar to obtain the relative three-dimensional coordinates of the fire source center in the ROV coordinate system, and transmit the relative three-dimensional coordinates of the fire source center, video footage and environmental data back to the surface unmanned surface vessel in real time; the surface unmanned surface vessel converts the relative three-dimensional coordinates of the fire source center into the absolute target point in the water cannon coordinate system through coordinate system matrix transformation and fusion, and then automatically calculates the precise firing parameters required for the water cannon to move through the inverse kinematics formula, including the absolute azimuth and elevation angles;

[0020] S7: After transmitting data, the ROV actively retreats to a safe observation position at a safe radius from the center of the fire source and hovers there. The surface unmanned vessel automatically adjusts the water cannons to accurately extinguish the fire based on the calculated absolute azimuth and pitch angles. The ROV continuously monitors changes in the temperature field.

[0021] S8: When the highest temperature at the center of the fire source transmitted by the thermal imager drops below the reignition safety threshold for 5 consecutive minutes and the environmental sensors do not detect flammable / toxic gases, start the launch and recovery cable car to lift the ROV back into the open moon pool and lock it.

[0022] S9: Mission accomplished, unmanned surface vessel returning to port.

[0023] Preferably, in step S4, the unmanned surface vessel is in a fixed-point anchoring mode when it is in shallow water and a slow-moving area, and in a dynamic positioning mode when it is in deep water or a high-sea-state area.

[0024] Preferably, in step S5, when the target is intact, the ROV operates from its underwater portion outside the target; when the target is damaged, the ROV enters the target through the damaged area. In step S5, a thermal imager is used to locate areas of abnormal temperature accumulation in dense smoke and uploads video footage in real time, locking the center of the pixel cluster with the highest temperature exceeding a set threshold as the fire source center. In step S5, environmental sensors detect the concentration of combustible gas, the pH value of the water, and the concentration of oil. When the concentration of combustible gas reaches the lower explosion limit warning value, an ROV retreat command is triggered, and the water cannon switches to a spray mist mode for dilution and cooling.

[0025] Preferably, in S6, the surface unmanned surface vessel (USV) collaborative control system uses a Kalman filter algorithm to smooth the input noise of the attitude sensor and scanning sonar, and then performs coordinate system matrix transformation and fusion. Combining the GNSS absolute position of the USV, the MRU attitude data obtained by the attitude sensor, the diving depth of the ROV, and the directional angle between the ROV and the USV, the relative three-dimensional coordinates of the fire source center in the ROV coordinate system are converted into the absolute target point in the water cannon coordinate system.

[0026] Beneficial Effects: This invention proposes a surface-underwater collaborative firefighting detection unmanned surface vessel (ROV) system and firefighting method, enabling all-round perception and precise strikes: Through the ROV's "see-through" capabilities (thermal imaging + cabin entry), firefighting operations are upgraded from "surface coverage" to "targeted elimination," greatly improving firefighting efficiency. High Sea State Adaptability: The "centrally positioned moon pool + gantry water cannon" layout protects the ROV from direct wave impact during deployment and retrieval while balancing the recoil of the water cannon, ensuring the stability of the surface ROV. Zero Risk of Personnel Injury: Fully unmanned operation allows firefighting forces to penetrate toxic and explosive core areas inaccessible to personnel. Data-Driven Decision Making: It can provide quantitative data on the internal temperature field, gas concentration, and underwater target conditions of the fire scene, providing a scientific basis for command and control. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the unmanned surface vessel of the present invention;

[0028] Figure 2 This is a cross-sectional view of the open moon pool and hull structure of the unmanned surface vessel of the present invention;

[0029] Figure 3 This is the overall system flowchart of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0031] Example 1

[0032] like Figures 1-2 As shown, this invention proposes a surface-to-underwater collaborative firefighting and detection unmanned surface vessel (USV) system, comprising an USV hull 1, an open moon pool 11, an ROV 10, a launch and recovery winch 4, a firefighting module, and a navigation module. The USV hull 1 adopts a monocoque design, providing excellent resistance to wind and waves. A jet pump 9 is installed at the rear of the USV hull 1, utilizing water jet propulsion technology to provide high-speed navigation and flexible dynamic positioning performance. An open moon pool 11 is located at the center of gravity in the middle of the USV hull 1, vertically penetrating the deck and bottom of the USV hull 1. The open moon pool 11 design utilizes the shielding effect of the hull itself to significantly reduce water surface fluctuations within the moon pool, providing a stable environment for the launch and recovery of the ROV 10. The navigation module is integrated at the top of the mast of the USV hull 1: a GNSS unit 6 provides high-precision satellite positioning data, a lidar 8 is used to detect obstacles on the water surface and construct local maps, a high-definition camera 7 provides panoramic video monitoring of the water surface, and a searchlight 5 is used for auxiliary lighting at night or in low-visibility environments.

[0033] The fire extinguishing module includes a gantry 16 mounted above the open moon pool, which is fixed to the hull 1 of the unmanned surface vessel (ROV). A water cannon 2 is mounted at the top center of the gantry 16, with a pulley 3 below. This layout design ensures that the recoil force of the water cannon acts on the center of the hull, reducing pitch. The water cannon 2 uses a multi-degree-of-freedom gimbal structure, which can adjust the pitch and azimuth angles of the spray according to control commands for remote fire extinguishing. The retrieval winch 4 is fixed to the hull 1 of the ROV and located behind the open moon pool 11. The umbilical cable 18 of the retrieval winch 4 passes upward around the pulley 3 and then vertically downward through the open moon pool to achieve physical and electrical connection with the ROV 10.

[0034] The ROV10 is housed within the open moon pool 11 and is released into the water during operations via a winch 4 and umbilical cable 18. Several thrusters 12 are mounted on both sides of the ROV10 to provide underwater six-degree-of-freedom propulsion. A detection system is located at the front of the ROV10, including one or more of a thermal imager 13, an environmental sensor 14, a second camera 15, and a scanning sonar 17. The thermal imager 13 is used to detect fire sources in dense smoke or dark environments; the environmental sensor 14 is used to collect water quality parameters or gas concentrations; the second camera 15 is used to assist navigation and observation; and the scanning sonar 17 is used to acquire real-time location information.

[0035] Example 2

[0036] like Figure 3 As shown, this invention proposes a firefighting method for a surface-underwater collaborative firefighting and detection unmanned surface vessel system, comprising the following steps:

[0037] S1: The unmanned surface vessel is in a standby, powered-on state when normally moored or on patrol. Upon receiving a fire / accident alarm and the approximate location of the target, the unmanned vessel hull 1 starts up using the power of the jet pump 9 and navigates at high speed to the target sea area using the GNSS unit 6.

[0038] S2: The LiDAR 8 scans the target's external outline and measures the distance. The first camera 7 captures the visible flame characteristics and smoke range, generating a preliminary situation assessment result, including the distance to the target, the area of ​​the external flame, and the damage to the target. The collaborative control system generates a preliminary situation assessment result: When the first camera 7 detects that the open flame is located on an unobstructed surface such as the deck, and the LiDAR does not detect any damage to the ship's structure, proceed to S3; when the first camera 7 detects that the image is mainly dense smoke without any visible open flame, it is determined to be a concealed fire source, or the LiDAR 8 detects damage to the ship's hull, proceed to S4.

[0039] S3: The unmanned surface vessel adjusts its bow to the windward side via the spray pump 9, calculates the relative distance to the open flames, and uses the multi-degree-of-freedom gimbal of the water cannon 2 to adjust the pitch and azimuth angles for direct external spraying to extinguish the fire, then enters S9.

[0040] S4: The unmanned surface vessel (USV) activates fixed-point anchoring mode in shallow water and slow-moving areas; in deep water or high sea state areas, it activates dynamic positioning mode assisted by jet pump 9 to maintain the absolute position of the vessel. Then, the winch 4 is activated, and the umbilical cable 18 is guided by pulley 3 to smoothly release the ROV 10 into the water through the open moon pool 11.

[0041] S5: When the target is intact, the ROV10 operates from its underwater portion outside the target. When the target is damaged, the ROV10 enters the target through the damaged area to operate. The thermal imager 13 locates areas of abnormal temperature accumulation in the dense smoke and uploads video footage in real time. The center of the pixel cluster with the highest temperature exceeding a set threshold is identified as the fire source. Simultaneously, the environmental sensor 14 monitors the concentration of combustible gases (such as methane and carbon monoxide) in the air in real time. If the concentration reaches the lower explosion limit warning value, it indicates an extremely high explosion risk. This data triggers the ROV10 to retreat and instructs the water cannon 2 to switch to a spray mist mode for dilution and cooling. Furthermore, the environmental sensor 14 also simultaneously monitors the pH value and oil concentration of the water to determine if a chemical or fuel leak has occurred, providing data for subsequent pollution control by the maritime authorities.

[0042] S6: Using the scanning sonar 17, the relative three-dimensional coordinates of the fire source center in the ROV coordinate system are obtained. The relative three-dimensional coordinates of the fire source center, video footage, and environmental data are transmitted back to the surface unmanned surface vessel in real time. The collaborative control system of the surface unmanned surface vessel uses the Kalman filter algorithm to smooth the input noise of the attitude sensor and the scanning sonar 17, and performs coordinate system matrix transformation and fusion: combining the GNSS absolute position of the surface unmanned surface vessel, the MRU attitude data of the surface unmanned surface vessel (acquired by the attitude sensor), the current diving depth of ROV10, and the directional angle between ROV10 and the surface unmanned surface vessel, the relative three-dimensional coordinates of the fire source center in the ROV coordinate system are converted into the absolute target point in the water cannon coordinate system. Then, through the inverse kinematics formula, the precise firing parameters required for the action of water cannon 2, including the absolute azimuth and elevation angles, are automatically calculated.

[0043] S7: The unmanned surface vessel automatically adjusts its water cannon 2 for precise firing based on the calculated azimuth and elevation angles. After transmitting data, the ROV10 actively retreats to a safe observation position within a set radius of the fire source center, hovering there and continuously monitoring changes in the target's temperature field.

[0044] S8: When the highest temperature at the center of the fire source transmitted by the thermal imager 13 of ROV10 drops below the reignition safety threshold for 5 consecutive minutes, such as less than 60°C, and the environmental sensor 14 does not detect flammable / toxic gases, the collaborative control system automatically determines that "the fire is completely extinguished and there is no risk of reignition". Then, the winch 4 is started to lift ROV10 and return it into the open moon pool 11 and lock it.

[0045] S9: Mission accomplished, unmanned surface vessel returning to port.

[0046] Example 3

[0047] The unmanned surface vessel (USV) is in a docked, standby, and powered-on state. After receiving a fire alarm and the approximate location of the target, the USV hull 1 starts up using the power of the jet pump 9 and navigates at high speed to the target sea area using the GNSS unit 6.

[0048] The LiDAR 8 scans the external outline of the target and measures the distance. The image from the first camera 7 mainly shows thick smoke and no visible open flames, indicating a hidden fire source. At the same time, the LiDAR 8 detects damage to the hull.

[0049] The unmanned surface vessel (ROV) enters a fixed-point anchoring mode in a shallow and slow-flowing area; then the winch 4 is activated, and the umbilical cable 18 is guided by the pulley 3 to smoothly release the ROV10 into the water through the open moon pool 11.

[0050] The ROV10 enters the target area through the breach to carry out operations; it uses a thermal imager 13 to locate areas of abnormal temperature accumulation in the dense smoke and uploads video footage in real time. The center of the pixel cluster with the highest temperature exceeding a set threshold in the image is identified as the center of the fire source. Simultaneously, an environmental sensor 14 monitors the concentration of combustible gases in the air in real time, and also monitors the pH value and oil concentration in the water to determine if a chemical or fuel leak has occurred.

[0051] The scanning sonar 17 is used to obtain the relative three-dimensional coordinates of the fire source center in the ROV coordinate system. The relative three-dimensional coordinates of the fire source center, video footage, and environmental data are transmitted back to the surface unmanned surface vessel in real time. The cooperative control system of the surface unmanned surface vessel uses the Kalman filter algorithm to smooth the input noise of the attitude sensor and the scanning sonar 17, and performs coordinate system matrix transformation and fusion: combining the GNSS absolute position of the surface unmanned surface vessel, the MRU attitude data of the surface unmanned surface vessel, the current diving depth of ROV10, and the directional angle between ROV10 and the surface unmanned surface vessel, the relative three-dimensional coordinates of the fire source center in the ROV coordinate system are converted into the absolute target point in the water cannon coordinate system. Then, through the inverse kinematics formula, the precise firing parameters required for the water cannon 2 to move are automatically calculated, including the absolute azimuth and elevation angles.

[0052] The unmanned surface vessel (ROV-10) automatically adjusts its water cannon 2 for precise firing based on the calculated azimuth and elevation angles. After transmitting the data, the ROV-10 actively retreats to a safe observation position with a set radius of 5 meters from the center of the fire source, hovering there and continuously monitoring changes in the target's temperature field.

[0053] When the highest temperature at the center of the fire source transmitted by the thermal imager 13 of the ROV10 drops below the reignition safety threshold of 50°C for 5 consecutive minutes, and the environmental sensor 14 does not detect any combustible / toxic gases, the collaborative control system automatically determines that "the fire is completely extinguished and there is no risk of reignition". Then, the winch 4 is activated to lift the ROV10 back into the open lunar pool 11 and lock it in place. The mission is completed and the unmanned surface vessel returns to port.

Claims

1. A surface-underwater collaborative firefighting and detection unmanned surface vessel system, characterized in that, The system includes an unmanned surface vessel (USV) hull (1), an open moon pool (11) located at the center of gravity of the USV hull (1), an ROV (10) located inside the open moon pool (11), a launch and recovery winch (4) connected to the ROV (10), a fire extinguishing module, and a navigation module. The open moon pool (11) extends through the deck and bottom of the USV hull (1). The fire extinguishing module includes a gantry (16) fixed above the USV hull (1) and a water cannon (2). The water cannon (2) is located at the center of the top of the gantry (16), and a pulley (3) is located below the gantry (16). The umbilical cable (18) of the launch and recovery winch (4) passes through the pulley (3) and connects with the ROV (10). The ROV (10) is connected, and the take-up and drop cable car (4) is used to take up, drop and lock the ROV (10). The front end of the ROV (10) is provided with a detection component, which includes a thermal imager (13), an environmental sensor (14) and a scanning sonar (17). The rear end of the unmanned surface vessel (1) is provided with a navigation module, which includes a GNSS unit (6), a first camera (7) located below the GNSS unit (6) and a lidar (8) located below the first camera (7). The rear end of the unmanned surface vessel (1) is also provided with a spray pump (9), and the unmanned surface vessel (1) is also provided with a pose sensor and a cooperative control system.

2. The surface-underwater collaborative firefighting and detection unmanned surface vessel system according to claim 1, characterized in that, The gantry (16) spans the open moon pool (11) and is fixed to the hull (1) of the unmanned vessel. The take-up and release winch (4) is mounted on the hull (1) of the unmanned vessel and is located behind the open moon pool (11).

3. The surface-underwater collaborative firefighting and detection unmanned surface vessel system according to claim 1, characterized in that, The ROV (10) is provided with several thrusters (12) on both sides, and the detection component at the front end of the ROV (10) is also provided with a second camera (15).

4. The surface-underwater collaborative firefighting and detection unmanned surface vessel system according to claim 1, characterized in that, The navigation module is also equipped with a searchlight (5), which is positioned above the GNSS unit (6).

5. The surface-underwater collaborative firefighting and detection unmanned surface vessel system according to claim 1, characterized in that, The hull (1) of the unmanned surface vessel adopts a monolithic structure.

6. The surface-underwater collaborative firefighting and detection unmanned surface vessel system according to claim 1, characterized in that, The water cannon (2) adopts a multi-degree-of-freedom gimbal structure, and the water cannon (2) is connected to the fire pump inside the hull (1) of the unmanned vessel through a pipeline.

7. A fire extinguishing method for a surface-underwater collaborative fire detection unmanned surface vessel system according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Receive alarm and approximate target location, drive the unmanned surface vessel and use GNSS unit (6) to navigate to the target sea area; S2: Using the laser radar (8) to scan and the first camera (7) to identify relevant parameter information, the collaborative control system generates a preliminary situation assessment result. The parameter information includes the distance of the unmanned surface vessel from the target, the area of ​​the external flame, and the damage status. When the first camera (7) identifies open flame and the laser radar (8) does not detect structural damage, proceed to S3. When the first camera (7) identifies dense smoke and there is no visible open flame on the surface, or when the laser radar (8) detects damage, proceed to S4. S3: The unmanned surface vessel adjusts its position and calculates the relative distance to the open flame. It then uses the water cannon (2) multi-degree-of-freedom gimbal to adjust the pitch and azimuth angles for external spraying fire extinguishing. It then enters S9. S4: The unmanned surface vessel (ROV) is put into fixed-point anchoring / dynamic positioning mode, and the cable car (4) is started. The umbilical cable (18) is guided by the pulley (3) to smoothly release the ROV (10) into the water through the open moon pool (11). S5: The ROV (10) approaches the underwater part of the target to carry out operations or enters the target through the damaged part to carry out operations. The ROV (10) uses a thermal imager (13) to upload video images in real time and lock the center of the fire source. It also uses an environmental sensor (14) to acquire environmental data in real time for environmental detection. S6: Use scanning sonar (17) to obtain the relative three-dimensional coordinates of the fire source center in the ROV coordinate system, and transmit the relative three-dimensional coordinates of the fire source center, video images and environmental data back to the surface unmanned vessel in real time; the surface unmanned vessel converts the relative three-dimensional coordinates of the fire source center into the absolute target point in the water cannon coordinate system through coordinate system matrix transformation and fusion, and then automatically calculates the precise firing parameters required for the water cannon (2) to move through the inverse kinematics formula, including the absolute azimuth angle and elevation angle; S7: After transmitting the data, the ROV (10) actively retreats to a safe observation position at a safe radius from the center of the fire source and hovers. The surface unmanned boat automatically adjusts the water cannon (2) according to the calculated absolute azimuth and pitch angle to carry out precise fire extinguishing. The ROV (10) continuously monitors the changes in the temperature field. S8: When the highest temperature at the center of the fire source transmitted by the thermal imager (13) drops below the reignition safety threshold for 5 consecutive minutes and the environmental sensor (14) does not detect combustible / toxic gas, start the take-up and release cable car (4), lift the ROV (10) back into the open moon pool (11) and lock it. S9: Mission accomplished, unmanned surface vessel returning to port.

8. The fire extinguishing method of the surface-underwater collaborative fire detection unmanned surface vessel system according to claim 7, characterized in that, In S4, the fixed-point anchoring mode is activated when the surface unmanned vessel is in shallow water and a slow-moving area, and the dynamic positioning mode is activated when the surface unmanned vessel is in deep water or a high sea state area.

9. The fire extinguishing method of the surface-underwater collaborative fire detection unmanned surface vessel system according to claim 7, characterized in that, In S5, when the target is not damaged, the ROV (10) operates in the underwater part outside the target. When the target is damaged, the ROV (10) enters the target through the damaged part to operate. In S5, the thermal imager (13) is used to find the temperature abnormal accumulation area in the thick smoke and upload video images in real time. The center of the pixel cluster with the highest temperature in the image and exceeding the set threshold is locked as the fire source center. In S5, the environmental sensor (14) detects the concentration of combustible gas, the pH value of water and the concentration of oil. When the concentration of combustible gas reaches the lower explosion limit warning value, the ROV (10) is triggered to retreat. At the same time, the water cannon (2) switches to the flowering water mist mode to dilute and cool down.

10. The fire extinguishing method of the surface-underwater collaborative fire detection unmanned surface vessel system according to claim 7, characterized in that, The S6 surface unmanned surface vessel cooperative control system uses the Kalman filter algorithm to smooth the input noise of the pose sensor and scanning sonar (17), and then performs coordinate system matrix transformation and fusion. Combining the GNSS absolute position of the surface unmanned surface vessel and the MRU attitude data obtained by the pose sensor, the diving depth of the ROV (10) and the directional angle between the ROV (10) and the surface unmanned surface vessel, the relative three-dimensional coordinates of the fire source center in the ROV coordinate system are converted into the absolute target point in the water cannon coordinate system.

Images