Introduction and intelligence of maritime patrol ship

Ii. Introduction of maritime patrol ships

China is A major maritime and shipping country, a Category A member of the IMO, and plays an important role in the peaceful development and utilization of Marine resources and the implementation of international conventions. However, due to historical reasons, China's water traffic safety supervision and management capacity has not adapted to the needs of economic development, and the status of China's maritime power and shipping power is extremely inconsistent. In 2001, the Outline of China's Maritime Development proposed that by 2005, China's maritime industry would bring international shipping routes and maritime facilities within 1,000 nautical miles into the scope of supervision, and that the emergency arrival time within 50 nautical miles of important trunk routes and near important ports should be no more than three hours. The requirement of realizing this goal exists in many aspects, one of the important reasons is the modern maritime patrol ship with long distance sailing ability.

Maritime patrol ships play a key role in maritime patrol law enforcement and many other aspects, and their tasks mainly include:

1, the implementation of maritime patrol, supervision, warning, escort, traffic facilitation

2. Law enforcement and forensics: handling and investigating all necessary means of transport for maritime accidents and maintaining water order

3, emergency search and rescue: undertake water search and rescue organizations and maritime emergency duty work, coordination and guidance of the relevant work.

The photoelectric tracking and forensics system that should be equipped on maritime patrol ships can well realize maritime forensics, and effectively carry out activities such as traffic accident investigation and treatment, search and water pollution detection at sea. Evidence at sea is not as rigid as evidence on land, and can change or even disappear with time and changes in ocean currents and wind direction. Timely and accurate maritime evidence is of Paramount importance. Therefore, the system can be used in maritime patrol ships.

The maritime patrol ship also has a special cabin - the multi-function Hall. This room is similar to a conference room, except that the kiosk has a large display screen and an operating desk where computers and various electronic devices are installed. This hall is not only used for convening emergency meetings, but also through the Ethernet network system, the field headquarters can use special frequency points or even high frequency wireless calls to communicate with fisheries administration and customs ships. It is also possible to access the national maritime network and even the International Maritime Organization through the maritime satellite system on board.

Maritime patrol ships can guarantee the security of our territorial waters and help our country achieve the ambitious goal of maritime transparency. And its more intelligent is the development trend of maritime patrol ships, but also the direction we should work hard.

Second, the intelligence of maritime patrol ships

Based on the characteristics of maritime patrol ship and the existing technical basis, it is necessary and feasible to realize the limited intelligence of maritime patrol ship. The task and function of maritime patrol ship has its particularity, which is different from other kinds of ship. Its main types of tasks include patrol escort, regulatory law enforcement, search and rescue command, pollution prevention and control operations, and safeguarding national security and interests. [5] According to the regulatory objectives set out in the National Water Traffic Safety and Rescue System Layout Regulations, patrol vessels must be able to reach any waters within 200 nmile offshore within 12h, and key waters within 50nmile offshore within 90 minutes. This task requires the ship's speed to put forward obvious requirements, but considering the fuel saving, the ship's daily cruise is low-speed sailing, only when needed to rapidly improve the speed, so the ship is required to have a low fuel consumption rate at medium and low speed and high speed. At the same time, considering that most of the major maritime disasters occur in bad sea conditions, ships are required to have excellent maneuverability and seaworthiness, large endurance and structural strength, and advanced communication command and rescue equipment. Table 1 summarizes the correlation between the main tasks of maritime performance and the main performance of ships, in which the survivability of ships mainly refers to the stability and anti-sinking of ships [6].

In view of the above regulations and requirements for maritime patrol ships, this paper will discuss the possible measures and ideas for maritime patrol ships in the aspects of communication and identification, safety and automatic navigation and power.

1. Communication and identification

Communication between ships is mainly through satellite communication and ground communication. As for communication between maritime patrol fleets, mobile AD hoc network technology can be considered. AD hoc network is a multi-hop temporary autonomous system composed of a group of mobile nodes with a wireless receiver. It is mainly used in environments without network infrastructure support or where the existing network cannot meet the requirements such as mobility. The AD hoc network generally adopts the on-demand routing policy. On-demand routing considers that in the dynamic changing AD hoc environment, it is not necessary to maintain routes to other nodes. On-demand route discovery is performed only when the nodes that do not go to the AD hoc network travel, and the topology and routing table are established on demand. Through the above deployment, real-time data exchange between the formation can be realized.

Regarding the identification of ships, in the late last century, the United States, Japan and Western European countries developed the intelligent transportation system (ITS), which has now matured, pointing out the direction for the development of this field. Vessel traffic service system (VTS) was first established in Europe, initially used in inland waters, and has been widely used in coastal countries.

For maritime patrol ships, its main law enforcement objects include both large ships that are forced to install AIS systems, and small ships in relevant waters. Based on the relevant situation, this paper mainly puts forward two identification methods based on VTS+AIS mode (Ship traffic management system automatic identification system) and GPS+GIS+GPRS/CDMA system.

The VTS is an electronic system that displays the position, speed, and direction of a ship on the display through the front-end radar and the back-end integrated information processing system to realize traffic flow organization and navigation assistance. The advantages of this combination

It can maximize the complementary role of radar and radar, and basically achieve full coverage for large (and other ships that require mandatory installation of terminal equipment). However, the cost of shipborne equipment is relatively high, so the cost of installation is too large, and small ships such as sand and gravel carriers are non-ships, there is no mandatory installation terminal requirements, therefore, this program is not easy to promote the implementation of small ships.

GPS+GIS+GPRS/CDMA system positioning accuracy is relatively high, the resolution can reach 15 meters, the speed measurement accuracy can reach 0.1 meters second; It can more accurately grasp the surrounding information, mark the ship's position information on the chart through the map, realize the monitoring and management of the ship, and provide navigational assistance services for the safe navigation of ships in areas with high coverage of mobile and unicom networks such as coastal and inland rivers. It is more conducive to real-time communication. Within the coverage of mobile and Unicom networks, the network transmission speed is faster and the transmission accuracy is higher, which also achieves the goal of network communication. Economical and practical, cost-effective, which is also the biggest advantage compared with other ship monitoring methods. Some small construction ships, forcing them to install expensive equipment, will bring great economic pressure on these ships. The based scheme can make full use of the public communication service network, the network communication cost is low, the cost of shipboard terminal is lower, and it will not increase the economic burden of the ship like the equipment, which is more conducive to promotion.

Because the data format of GPS information and AIS information can be converted by technical means, the data information of the boat can be integrated in the system.

2. Safe and autonomous navigation

The navigation of intelligent ship puts forward high requirements for the safety of communication and the reliability of equipment. For communication, generally speaking, a complete security model should be composed of the following five parts: security management, intrusion detection, security protection, security recovery, security response. The evaluation of the degree of network security should follow the "wooden barrel principle", that is, the lowest degree of network security as the basis for judgment. Therefore, a secure and leak-free system should strengthen network security from all aspects, and a multi-layer security protection network should be built. In the realization of positioning function and data transmission, the GPS positioning system with stable signal and low cost is selected, as well as GPRS network system, highlighting the idea of saving funds; In the application of small boat monitoring system to management, through the study of the new system, we find a way to integrate the small boat AIS target into the target, which caters to the trend of system integration. In the aspect of network architecture, the VTS security network is carefully analyzed and studied, and a four-layer security architecture is proposed, which embodies the concept of network security.

The automatic navigation of intelligent ship needs a series of hardware and software support, the existing one-person bridge and unmanned engine room technology is not stable, usually can not play a due role in the practice process. In the algorithm design of intelligent ship, variable theory domain fuzzy control should be adopted to realize the precise control of ship heading by controlling the rudder Angle output in real time. At present, expert system, fuzzy control, neural network and other control algorithms as the core of the fourth generation autopilot system. At present, the common ship course control system is mainly composed of host computer, course controller, rudder servo system, etc. The host computer is the sending end of data parameters, which mainly realizes the setting of course control value and the input of the current ship disturbance. The course controller realizes the output of rudder Angle by intelligent algorithm based on the relevant data. Finally, the rudder servo system realizes the steering gear control and the current rudder Angle feedback, so as to realize the ship course intelligent control.

The collision avoidance function of intelligent ship is also an important issue to be considered in the course of ship navigation. Different ship types have different turning radii and different turning angular speeds at different speeds. In order to realize the ARPA function of ship collision avoidance, the mathematical model of each ship type is different. If it is a transport ship, different (load), its characteristics are not the same. In other words, the ship collision avoidance ARPA software also has the ability of "continuous learning" to adapt to the needs of maritime patrol ships. Compared with the traditional "ARPA function", the new navigation radar has an interface relationship with the "ship energy efficiency management system" to realize the input and real-time correction of its own ship characteristics data.

Compared with the traditional "observation", the new navigation radar has to interface with the "ship meteorological instrument" and other meteorological equipment to obtain automatic input and real-time correction of weather, wave and other meteorological characteristics data. According to the size of the target needs to change the range, or need to adjust the gain, the new navigation radar itself can achieve automatic adjustment. In addition, with the help of the shore-based support center, automatic adjustment can also be achieved remotely.

Modern navigation radar displays can be integrated with the Electronic Chart Display and Information System (ECDIS) and the Automatic Ship Identification System (AIS). This radar screen is the real-time scene of smart ships. Compared with the traditional "fusion observation", the new navigation radar can have an interface relationship with the external communication system or intelligence system, and can transmit the "real-time scene" to the shore-based support center in order to achieve shore-based interaction, better safeguard China's interests, and realize the scheduled functions of maritime patrol ships.

3. Ship power

Maritime patrol boats have clear requirements for speed, requiring them to reach the accident area within a specified time, and require them to be able to achieve a long cruise. This requires the performance, especially speed and reliability, of the power plant of maritime patrol boats. The current ship power system types can be divided into: diesel engine power system and gas turbine power system, the former advantages are: safe and reliable, economical start fast power range large part of the load operation performance good efficiency considerable technology is relatively mature, and more than half of the ships on the market is the use of this system; The latter has excellent characteristics such as light weight, large power, small size and environmental protection, but it also has the disadvantages of high fuel consumption and high fuel requirements. At present, the development trend of domestic ship power system: conventional intelligent diesel engine power system with large output power of dual fuel single cylinder, electric power system (AC frequency conversion technology, easy to arrange, energy saving, low noise, easy to achieve automatic control), and hybrid power system (high reliability, often used in military ships and large ocean merchant ships).

PID controller is often used in the process of speed regulation of Marine steam turbine, mainly because PID algorithm has the characteristics of simple structure and easy implementation, which is conducive to the realization of intelligent control of power system. However, the conventional PID algorithm requires manual trial-and-error, which is not conducive to the realization of ship intelligence. The fuzzy PID controller based on fuzzy neural network is adopted for intelligent transformation.