Research On Some Key Techniques Of Dynamic Information Services In E-Navigation

Navigation is one of the most important economic and social activities. The progress of science and technology is constantly changing the way of sailing.In the information age, navigation increasingly uses automated system. Various automation systems need to integrate effectively to gain a better performance. Multi-party system operating environment requires unified technical and management standards to make sure its efficient functioning. The e-Navigation is not a combination of several information systems, neither a conception nor status of sailing, but an environment of multi systems for increased safety and security in commercial shipping through better organization of data on ships and on shore, and better data exchange and communication between the two. The future of e-Navigation needs all the efforts of international organizations and member States to work out and implement relevant standards, and to promote the technological progress toward the ’cleaner ocean, safer navigation’way.Dynamic information service is an important content of e-Navigation, including dynamic changes of basic geographic information, hydrological and meteorological information, water transportation environment, ship dynamic information. It is an information system based on maritime security information collection, management and services as the main contents.This paper focuses on e-Navigation dynamic information services, especially on several key technical issues. The research presents the Surface of Reference Ellipsoid as the integration of land and water vertical datum to establish a unified terrestrial and marine vertical datum. Non-tide (water level observation) sounding will be performed associated with high-precision GNSS measurement under the unified vertical datum. By combining tide (water level) observation and model projection, terminal personalized services such as underwater topography quick update, real-time depth information service or intelligent shore-based navigation can be easily offered.The paper analyzed the characteristics of e-Navigation spatial information, and proposed a fast indexing method for multi-level grid and free grid, which works well with the both nautical chart subdivision and real-time dynamic service. The research examines the multi-beam bathymetric data selection method in nautical chart quick update process and the navigational environment information collection and service method. The paper develops a dynamic information service system architecture and construction method, followed by its information sharing method in multi-source information fusion technology and e-Navigation environment. At the end, the article gives a future direction about where e-Navigation technology is going.Specific studies:1. This article showed that the depth datum and the inland navigation datum show discontinuous step-like changes among regions and the discussion of non-uniform feature between land vertical datum and sea vertical datum. The research tests the seamless vertical datum, the regional tidal model and non-tide sounding method. Then the article proposed an amphibious integrated vertical datum reference surface based on the Surface of Reference Ellipsoid and the direct underwater elevation measurement using GNSS measurement method. The paper gives a further illustration on sea surface topography measurement method and water level based tidal calculation method.2. Through the research of nautical chart and inland river chart framing principle and the graphical elements’characters, this article proposed a multi-level grid model, which is compatible with both standardized framing program and other chart program features. This model meets the demand for chart (paper chart and electronic chart) producing and application and can be used in e-Navigation spatial information services for information management and rapid searching. What’s more, the research also builds an e-Navigation fundamental spatial database model, which could support the IHO S-100model standard and the fast network demand for information services. Using the flexible NetCDF model in applications, the system is ready to search and release multi-mode and multiple spatial dynamic information services.3. The research studied the AIS data pre-processing method and the rapid distribution method. Based on multi-thread pool and intelligent agent, the research then gave a solution for receiving data, pre-processing and distributing massive data. According to the characters of multi-beam bathymetric data, the bathymetric data radial grid management, the intelligent bathymetric data compression method and the isobaths automatic generation technology are researched in this paper. All of these are parts of the personalized electronic nautical chart service research.4. The article introduced a cloud-based dynamic information service system model and all applications built on this system. It also discusses multi-source information fusion technology and information sharing method in e-Navigation environment.7. The article gives some suggestion to the e-Navigation future and to some specific technique that should be paid significant Attention.