1) to enhance the ship identification ability. For data such as ship position, ship heading and ship speed to the ground, radar obtains the average value of historical tracks, while AIS obtains instantaneous data, so the accuracy of AIS is higher than that of radar. Radar can only obtain the dynamic information of ships. In areas with high ship density, tag exchange or tracking loss often occurs when two ships cross or meet. The information transmitted by A IS includes not only the dynamic information of the ship, but also the static information, and there is almost no data loss.
2) Improve the dynamic tracking ability and expand the tracking range. AIS data can be received by other AIS stations and relay stations, and ship information can be received and tracked within the maximum receiving range of VHF wireless communication frequency.
High precision. The accuracy of ship position data provided by GPS/DGPS is less than 5 m, which greatly improves the tracking resolution and accuracy and shortens the stability time of tracking vector. When the delay of radar data processing is about 20 antenna scanning cycles, it is about 1. 5 min, and using IS information tracking, the dynamic data of the target can be directly obtained for identification, with no stable time and high tracking reliability. The transmitted data is not affected by weather and sea conditions, and the reliability of tracking can be significantly improved by using international dedicated channels and SOTMA technology information exchange.
3) Integrate and supplement VTS functions. The information provided by ARPA (automatic radar p lotting aid) is very limited, so it is impossible to identify other ships and their operation intentions. Especially in narrow waterways, channel bends, behind islands, waters with high density of ships, and when encountering bad weather and sea conditions, the automatic tracking function will cause false tracking or even fail to detect the target. Moreover, with the increase of observation distance, the measurement accuracy and resolution of the target are very high. Because A IS uses VHF band as wireless communication link, its ability to resist the interference of waves, rain and snow is better than that of ordinary radar, and its ability to capture and track targets is more effective. The communication link of AIS can maintain a good connection and make up for the weakness of radar in bad weather conditions. Radar waves can only travel in a straight line. When a ship is blocked by other ships or tall objects, it forms a blind spot of radar, and AIS can also make up for the shortage of radar.
4) VTS based on AIS has a good cost performance. Because A IS has good remote control performance, one control station can remotely control multiple base stations, and a small number of control stations and a large number of base stations can cover a wide area, while the investment of AIS base stations is much lower than that of radar stations. In ports with low traffic density, ships equipped with AIS can form "unmanned VTS" without shore platform; In busy ports, AIS will reduce the workload of VTS operators and improve their work efficiency in tasks such as traffic management and information service.
Application of AIS in Real-time Release of Hydrometeorological Information
The format of hydrometeorological information can be registered with the International Association of Lighthouse Authors of Navigation Aids in advance in order to realize international application. Hydrometeorological information generally includes average wind speed, wind direction, water level, water temperature, air temperature, velocity and direction of different concentrations, tidal information, etc.
Application of Ship Position Report Based on AIS
AIS makes the position report more accurate and fast. Broadcast AIS can automatically and continuously send ship navigation information or insert ship and voyage information according to query requirements, and then send it to the reporting station through wireless communication network and then to the calculation center. According to the requirements of the system, the computing center will establish a database of all ships according to the specified time, period and required information, and analyze and process the static data of ships, electronic charts and meteorological data according to the requirements of users, so as to provide ship information and search and rescue decisions for search and rescue departments. The ship AIS and electronic map display technology are integrated into "BLM-Shipping System" to receive ship AIS data and provide intuitive ship positioning, real-time dynamic query and historical trajectory tracking services. Therefore, it has broad application prospects in maritime management, has the ability to supervise the ship traffic management, has the ability to manage the transport fleet, has the ability to guide ships in and out of the port, has the ability to search and rescue ships in distress, and has great navigation warning and meteorological information capabilities for ships sailing at sea.
Application of Navigation Mark Telemetry and Remote Control System Based on AIS
AIS navigation mark telemetry and remote control system consists of automatic navigation mark equipment and AIS transponder. Compared with the existing navigation mark telemetry and remote control system, it has the following advantages: it does not need to apply for telemetry and remote control channels, and directly uses AIS international dedicated channels CH87B and CH88B to transmit data; The construction of special communication network can be omitted, and only navigation AIDS and AIS transponders need to be configured; AIS's open system interconnection mode enables it to access the Internet conveniently, and enables the competent department of navigation AIDS to monitor and manage navigation AIDS facilities through the Internet. Navigation information can also be applied in a way similar to "ship-to-ship". IS can also be used as a virtual navigation sign. Virtual navigation mark can be the virtualization of specific navigation mark facilities or the virtual navigation mark system. AIS navigation mark telemetry and remote control system has the advantages of less equipment, low investment cost, short construction period, powerful function, convenience and quickness.
With the continuous improvement and development of AIS technology, the application of AIS in maritime management will continue to expand. At present, there are three AIS data centers in Beihai, Donghai and Nanhai respectively. As a new science and technology, AIS has promoted the informationization and intelligent construction of maritime management, and the combination of AIS and other information technologies has actively promoted the construction of "digital maritime affairs".