Marine digital navigation system is practical for broadcasting marine safety information, which is a vital part of a modern Global Maritime Distress and Safety System (GMDSS) and e-Navigation framework. A marine digital navigation system is studied based on Orthogonal Frequency Division Multiplexing (OFDM) modulation technology architecture to test the marine digital navigation system in the Donghai Navigation Safety Administration (DNSA) of China. Marine digital navigation system is a novel shore-based digital broadcasting system that has an outstanding performance over long distances and works on 495505 kHz or medium frequencies. Marine digital navigation system is used to broadcast marine safety information and other service information, whose possible forms include messages, texts, binary files, and images and combined navigation, to ships within the coverage of the communication signals by using a one-way downlink broadcast mode, so that marine digital navigation system can be used to update Electronic Navigation Charts (ENC) conveniently. A single marine digital navigation system base-station covering an A2 sea area through networking technology is tested, and the results show that the marine digital navigation system has the advantages of high broadcast rate, strong system compatibility, and low error rate. In the future, the marine digital navigation system will provide important information services for navigation safety.
In the e-Navigation framework, it is necessary to make an efficient modern marine digital navigation system. At the same time, the GMDSS modernization process, the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) e-Navigation framework, and the Safety of Life at Sea (SOLAS) Convention all put forward a strong demand for high-speed marine digital navigation system. International Maritime Organization (IMO), International Telecommunications Union (ITU), IALA and other international organizations jointly proposed research on the marine digital navigation system.
Marine digital navigation system utilized the 495–505 kHz frequency band into a marine mobile service, in accordance with the final adoption of the current international "Radio Regulations" amendment in the 2012 World Radio-communications Conference. In the same year, ITU-R formally promulgated a new technical proposal ITU-R M.2010 "Characteristics of a digital system, named Navigational Data for broadcasting maritime safety and security related information from shore-to-ship in the 500 kHz band", which made clear that the marine digital navigation system broadcasts at a frequency of 500 kHz on the digital broadcast. Within the system framework of IALA's e-Navigation, the marine digital navigation system service in the 500 kHz band will be an important part of digital communication.
