# Deep-Sea Underwater Cooperative Operation of
## 3 Cooperative Operational Modes
### Unmanned Surface Vehicle-Based Mode  
To realize large-scale and long-distance underwater survey operations and give full play to the advantages of submersible swarm operations, we have also proposed a USV-based manned and unmanned submersible cooperative operational mode, as shown in Figure 6. It comprises of the research vessel R/V, a USV, an HOV, an AUV cluster, and other equipment. The USV is used to monitor the AUV cluster operations in real time instead of the research vessel R/V, transmit the data to the research vessel R/V, and can also accept control commands from the research vessel R/V. The USV can move with the AUV cluster to improve the operating distance and range of the AUV cluster. The research vessel R/V focuses on the underwater operation of the HOV at the far end to monitor the overall situation of the cooperative operation. When the AUV cluster works underwater, the USV is used to track and monitor the underwater operation of the AUV cluster. The USV is equipped with an automatic driving system, unattended control nodes, UACS, GNSS, satellite communication system, etc., as shown in Figure 7. The space-based communication system can establish real-time  
Figure 5: Information flow of a cooperative operation based on the pure research vessel R/V. communication with the research vessel R/V to realize functions, such as data transmission and command delivery. The UACS realizes data transmission with the underwater AUV cluster. GNSS provides unified timing and positioning services. The AUV cluster sends its own status information and detection load information to the USV through UACS, and the USV control system node sends the submersible status, position, and basic information of the USV back to the comprehensive command and monitoring systems of the research vessel R/V through the satellite communication module system. In this way, the surface monitoring personnel can monitor the working  
Figure 6: A scenario of cooperative operation based on USVs. Figure 7: Information flow of a cooperative operation based on USVs. status of the underwater AUV cluster in real time and can issue control instructions to the underwater AUV cluster in real time according to the relevant information returned. The USV is equipped with an autopilot system, which can autonomously plan the ship's course, speed, and other motion state parameters according to the submersible cluster position information, surface sea, wave, and current information, and keep the USV in a low power consumption state. The research vessel R/V can fully guarantee the underwater operation of the HOV and can also consider the monitoring and command of the AUV cluster so that more investigation data can be obtained in a limited time. The introduction of satellite communication system allows surface commanders to monitor the status of AUVs at a distance in real time. In the event of a sudden failure, they can use a response plan prepared in advance to ensure the smooth recovery of the failed AUV. The surface commander can also monitor the detection load data in real time. When receiving the detection information of an underwater target, the research vessel R/V goes directly to the target area to release the HOV or ROV for on-site verification, which is of great significance for underwater salvage and target search. This mode also has certain limitations. The unmanned ship is too small to achieve relatively stable navigation and cannot be equipped with a USBL. The AUV needs to be equipped with an advanced underwater autonomous navigation system. During underwater operations, it can only rely on its own navigation system to calculate real-time position information. At this time, the accuracy and stability of the autonomous navigation system are particularly important, especially in the process of diving. The submersible is in a spiral descent, and the changes in its own attitude and speed make it difficult for the autonomous navigation system to calculate relatively accurate position information.