In order to realize the development vision of USV, the master plan of USV has determined the following objectives:
(1) Determine the capabilities of USV in the near future (5 years), the medium term (5 years to 10 years) and the future (over 10 years), including: mission description and priority, advanced operational concept (CONOPS) of each mission, and determine whether these capabilities are applicable to USV by evaluating alternative capabilities.
(2) Establish the performance level of USV, so that USVs at all levels can meet the capability requirements: ① Recommend several levels of surface boats to build efficient, collectivized and complementary capabilities; (2) In naval projects, define the specific scope of the type and size of USV; ③ Review the modularization and generalization levels within and between USV levels.
(3) Assess the technical requirements and current technical preparations, and put forward corresponding technical input strategies for the development of USV platform and related loads. The USV Master Plan recommends 1 non-standard USV and 3 standard US Navy ships, which can fully meet the capability requirements of the seven mission areas prioritized by the US Navy USV, including:
"Class X" is a nonstandard USV with a length of 3 meters or less. It is built with non-standard modules and can support special forces operations and maritime interception operations. It will provide low-level intelligence, reconnaissance and surveillance capabilities, as well as limited endurance, payload and airworthiness, and support manned operations. It can be deployed by small manned boats, such as 1 1 m rigid inflatable boats or inflatable combat reconnaissance assault boats.
"Harbor class") USV is mainly developed on the basis of the navy's standard 7-meter rigid inflatable boat. It has medium endurance, mainly performs maritime security tasks, has strong intelligence, surveillance and reconnaissance capabilities, and is equipped with lethal and non-lethal weapons. "Harbor Class" USV has the standard interface of 7-meter inflatable boat, which can be deployed by multi-type ships.
"Si Nuo Kohler" USV is a 7-meter-long semi-submersible ship. During the voyage, except for the snorkel, the rest of the hull is underwater. Compared with other surface ships, this mode of operation can provide a more stable platform in class 7 sea conditions. The "Si Nuo Kohler" class USV will support anti-mine warfare towing (search)/mine extinguishing mission, anti-submarine warfare (sea shield), and it can also make full use of its relatively hidden shape to support special operations missions.
Fleet) USV is 1 1 meter planing or semi-planing surface boat, which has moderate speed/endurance when towing minesweeper, but can provide longer endurance when supporting anti-submarine, surface or electronic warfare. When the mission module is removed or replaced, the "fleet class" USV can still support manned driving within 24 hours. In the power of unmanned surface craft, diesel engine is widely used because of its good reliability and high fuel thermal efficiency. Ma Yang Maritime Company is the main supplier of engines for U.S. Navy unmanned surface craft. The company provides a series of diesel engines, each with a maximum output of 720 horsepower. The company's latest diesel engine adopts electronic engine management system to monitor and adjust the engine speed, turbocharging, cooling temperature and throttle, adjust the EFI time and fuel flow, ensure the complete combustion of fuel in the working environment and obtain the maximum fuel thermal efficiency. In addition, the United States is still studying a power source with high energy density. The diesel engine is promoted as a part of the hybrid power system, supplemented by lithium batteries and other possible power sources, to provide an unmanned surface boat with a high reliability and low maintenance engine to ensure that it can run continuously for two weeks without refueling in the marine environment and harsh sea conditions.
Autonomous technology can reduce the demand for personnel and bandwidth of USV, and at the same time expand the tactical application range of over-the-horizon operations. For example, in the fields of maritime security, anti-submarine warfare, anti-mine, etc., USV needs to fight independently for a long time and perform tasks such as long-distance navigation, detection, evaluation, hedging, and information collection. In addition, through independent technology, USV can cooperate with multiple aircraft, which is regarded as an important enabling capability in large-scale anti-submarine warfare and anti-mine warfare. To improve the autonomy of USV, it is necessary to promote the lowest signal processing and decision-making ability, and the level of autonomous control can be measured according to the operator's operating frequency and complexity. USV must collect all kinds of data from sensors, identify threat data independently and respond appropriately. Unpredictable circumstances or data information may cause the aircraft to abandon its mission or change its attack plan. When providing initial capability, USV may require less complex autonomous technology than other types of unmanned systems, because the communication between the controller and the aircraft still needs to be maintained.
The autonomous weapon control technologies of various unmanned systems are being studied through the Joint Ground Robot Program (JGRE) of the Army, Navy, Air Force Laboratory and the Office of the Secretary of Defense. For the near-term capability, the weapon control of most unmanned systems will require personnel to participate in order to determine the correct target. For example, the "kill zone" of USV anti-submarine warfare or the "mine danger zone" of anti-mine warfare will be determined manually. For mine fire extinguishing system, there are some special weapon launching problems, the most important of which is the accuracy of target positioning. Mine fire extinguishing tools must locate the target with the help of low-cost short-range sensors. Before the reliable automatic target recognition (ATR) algorithm is developed, a robust high-frequency command, control and communication system is needed to support the anti-mine warfare task involving personnel.
In a word, the preset program of USV task can't adapt to the dynamic characteristics of all tasks, so USV should be able to adapt to the changes of environment and tasks. At present, the challenge is to provide autonomous adaptability for USV. In the future, more unmanned systems will be needed for autonomous and cooperative operation.
Except for the smallest special mission vehicle, all USVs must have autonomous obstacle avoidance ability. These obstacles include: large coastal areas, ships, low-hanging obstacles (such as bridges and branches encountered in offshore operations), shallow-water obstacles (such as sunken ships, reefs and sandbars) and water obstacles (such as swimmers, buoys and floating objects). ) and the underwater obstacles encountered by the USV towing system.
Most mission areas need the autonomous threat avoidance ability of USV, which will involve ships, planes, active sensor systems (such as radar) and large-scale passive detection systems. What needs to be weighed here is the vulnerability of aircraft to interception or destruction, as well as the complexity and cost of USV self-protection components.
Automatic Target Recognition (ATR) is helpful to avoid obstacles and threats in all mission areas, and it is one of the supporting technologies to complete anti-mine operations, maritime security, anti-submarine warfare and surface operations. ATR is the key to ensure that USV does not need to return to the mother ship or rely on personnel to perform multi-step tasks remotely.
When performing all tasks, USV needs to avoid obstacles and collisions to some extent. Although the boat control algorithm is mature enough, the sensor processing technology in autonomous operation is not perfect enough. In some cases, USV needs to integrate sonar, radar, optical and infrared sensor information, but the image processing algorithms of optical and infrared sensors are still in the primary development stage.
Perception technology is a rapidly developing technical field, which is directly related to USV operations, especially anti-mine warfare, anti-submarine warfare and surface warfare. The demand of USV in this technical field is to further improve the area coverage (ACR), improve the ability of classification and identification and non-traditional tracking technology, and improve the sensors used to detect chemical, biological, nuclear, radioactive and explosive threats. Synthetic aperture sonar (SAS) technology is in a leading position in meeting the requirements of USV anti-mine warfare mission. SAS technology can greatly expand the detection area and improve the resolution of the target, which is of great significance to the development of anti-mine combat module. In addition, broadband underwater acoustic technology also has the ability to improve the detection range of mines.
Sensor processing and related autonomous decision-making technology are the technical fields being developed by USV anti-mine warfare and anti-submarine warfare mission module. For the anti-mine warfare module, the main technical risk is the sonar and optical image automatic processing technology applied in the process of identifying similar mines and determining mines. At present, the research team is developing the second generation of automatic sonar processing equipment, which has realized the automatic processing of sonar signals in a specific environment. However, the optical processing technology used to identify mines and surface objects is only in the initial development stage. For the task module of USV anti-submarine warfare, the biggest technical challenges mainly lie in autonomous processing, target recognition, countermeasure, target motion analysis (TMA) and tactical application.
Automatic deployment and recovery of USV load is an undeveloped technical field, which may take a long time to be fully realized.
The master plan of USV predicts that the capability of USV will be effectively utilized through a large number of different unmanned systems, which requires a centralized control scheme to reduce the dispersion of various special hardware, software, personnel and training and communication systems. At present, the research on joint interoperability standards between the Office of the Secretary of Defense and unmanned systems of various services has not yet begun. However, the Navy and the Office of the Secretary of Defense have started the "JUSC2 ACTD" project, which has taken the first step in the development of centralized control technology for unmanned systems. This early concept demonstration project integrated the centralized control system of unmanned aerial vehicle on Type 0 (Flight 0) of littoral combat ship, and added the joint standard (JAUS &: STANAG 4586), but JUSC2 project only reduced the number of operators. At present, the navy is discussing the transfer of JUSC2 project to a unified centralized console project, which will develop, integrate, configure and maintain a unified standard integrated console for littoral combat ships and other naval surface and submarine platforms, which will completely replace the decentralized control system of individual unmanned aerial vehicles. The key to achieve this ultimate goal is to formulate corresponding standards, including interoperability, communication, hull, mechanical and electrical (hm&E), payload modularization, command and control, communication and computer (C4) architecture.
In order to complete anti-mine warfare, anti-submarine warfare, surface warfare and other tasks, USV must carry and launch corresponding weapons and equipment. The main technical challenge of launching weapons from USV is to aim at the target stably and obtain accurate trajectory in various sea conditions. Bad sea conditions may lead to problems in aiming (such as naval guns, missiles, non-lethal projectiles) and weapon launching (torpedoes, unmanned submarine sensors, etc.) of USV platform. ). For manned USV, maintaining communication will be a technical challenge for USV, especially in the over-the-horizon (OTH) range. In order to meet the operational needs, reliable medium-range acoustic communication and autonomous behavior are also necessary. At present, computer-aided detection and computer-aided classification technology have been demonstrated, and computer-aided identification technology has been considered or will soon become an applicable technology.
It is a controversial issue to equip weapons into unmanned systems, which requires the aircraft itself to meet the requirements of operational laws first. The initial application of weapons and equipment in any unmanned system must be under the active control of the operator. In addition, if the USV is likely to be occupied by the enemy, it is necessary to destroy it. In this case, the ability to remotely destroy weapons and USV will become very important. With the deployment of weapons and equipment and their application in combat, legal concepts, rules and precedents will be determined, which will help to promote the formulation and improvement of rules of engagement for all unmanned system operations.
1, whether the USV military operation can be successfully implemented depends on whether the USV can be successfully deployed and recovered in the combat area. The challenges mainly include:
(1) Deployment and recovery workflow and its safety and operability in various environments;
② Adjust the configuration of deployment and recovery system to adapt to various models of USV.
2. Main platform interfaces and potential conflicts, including:
① Proximity of main propeller;
② Mechanical and fluid interaction between ②USV and deployment and recovery system.
3. Universality and portability of the interface of 3.USV deployment and recovery system;
(1) cannot exclude the inherent characteristics of application on other surface vehicles;
② The configuration of the whole main platform should not be greatly affected;
(3) Reduce the restrictions on the speed and operation concept of the main platform;
(4) Develop a simple system to minimize the manpower demand and the number of people needed for maintenance and combat.
4. The automatic deployment and recovery process of 4.USV can be divided into autonomous homing, position adjustment, attachment and "boarding". The challenges mainly include:
① In order to solve the command problem of low-speed deployment and recovery of USV, an airborne general command and control system was developed.
Improve the operational performance of the aircraft;
(2) Developing the integrated technology of passive sensors and control systems to provide necessary support for the autonomous deployment and recovery of USV;
(3) Develop a solid grab/adsorption mechanism for USV deployment to reduce the impact on USV and shipborne systems.
Solving these technical and engineering problems and automatic operation problems will greatly improve the combat capability of ships equipped with USV. In addition, because the deployment and recovery of USV can only be carried out in low sea conditions, which will affect the whole military operation, the development goals of USV deployment and recovery equipment include achieving safe operation at higher speed and worse sea conditions.