Due to the ever-increasing amount of data collected and the requirements for the rapid and reliable exchange of information across many interconnected communication devices, land-based communications networks are experiencing continuous progress and improvement of existing infrastructures. However, maritime communications are still characterized by slow communication speeds and limited communication capacity, despite a similar trend of increasing demand for information exchange. These limitations are particularly evident in digital data exchange, which is still limited to relatively slow and expensive narrowband satellite transmission. Furthermore, with the increasing digitalization of ships and introducing the sustainable concept of autonomous ship operation, large amounts of collected data need to be transmitted in real-time to enable remote voyage monitoring and control, putting additional pressure on the already strained means of maritime communications. In this paper, an adaptive shipboard data compression method based on differential binary encoding is proposed for real-time maritime data transmission. The proposed approach is verified on the actual data collected on board a training ship equipped with the latest data acquisition system. The obtained results show that the proposed data encoding method efficiently reduces the transmitted data size to an average of 3.4% of the original shipboard data, thus significantly reducing the required data transmission rate. Moreover, the proposed method outperforms several other tested competing methods for shipboard data encoding by up to 69.6% in terms of compression efficiency. Therefore, this study suggests that the proposed data compression approach can be a viable and efficient solution for transmitting large amounts of digital shipboard data in sustainable maritime real-time communications.

Traditional methods of marine navigation are undergoing a revolution brought about by the almost universal adoption of the Automatic Identification System (AIS). AIS exchanges a wealth of navigational information among vessels and between ships to shore through Very High Frequency (VHF). With AIS data integrated into the Electronic Chart Display and Information System (ECDIS), the identification and navigational information of surrounding vessels as well as aids to navigation can be reflected on the electronic charts in real time, despite some problems such as the low AIS carriage rate on small vessels where it is not mandatory and the high cost of ECDIS preventing such vessels from installing it. In this paper, we introduce BlueNavi, a lower cost but sustainable maritime information providing platform built with microservices architecture allowing flexible on-demand scalability and cross-platform adaptability. Applications served by BlueNavi can provide users with data either stored in a remote data center through the internet or received locally by devices connected to the station without the need for the internet. From our land test, we show that users with only an internet connection but without any AIS equipment can also obtain live AIS data collected by other stations. Conversely, with access to the internet, BlueNavi can also send data back to the land stations, enabling other ships to identify non-AIS ships as well. Through the live-ship test, we demonstrate that BlueNavi works well offline in cooperation with shipborne AIS equipment. We also look at some possible application scenarios for BlueNavi with other data sources and means of communication other than AIS and VHF that can be expanded to the platform. BlueNavi will enable inexpensive ship identification for small vessels and provide an extension of functionality to ECDIS for large ships.

In order to ensure the safety of maritime navigation, International Maritime Organization (IMO) developed the Global Maritime Distress and Safety System (GMDSS), which includes an important Maritime Safety Information (MSI) Broadcasting System that can broadcast navigational warnings and other crucial information. However, in most sea areas, the broadcast messages are still not pre-classified. Seafarers need to identify the theme of those received messages artificially, with low efficiency and accuracy. To solve this problem, several machine-learning based solutions are presented, implemented, and compared. Thousands of Navigational Telex (NAVTEX) messages, from 2011 to 2017, are used in the training and evaluation progress. The classifiers are compared in terms of accuracy, efficiency, precision and recall rate, and F-Measure respectively; and one of them is chosen as the optimal classifier. The chosen classifier performs well on solving the NAVTEX classification problem, and may further be used in other similar problems.

The Automatic Identification System (AIS) is a kind of navigation equipment that exchanges a wealth of essential information among vessels and between ships to shore through Very High Frequency. Currently, identification and other navigational information can be obtained in real time with AIS data integrated into other shipborne systems, such as the Electronic Chart Display and Information System and radar. However, at present, AIS information is represented in a two-dimensional (2D) way, which is not the same as the three-dimensional (3D) world people perceive visually. In this paper, we introduce RedNavi, a sustainable computer 3D scene building system that visualizes the current sea, specifically the environment and traffic conditions around the ownship, using received AIS data. RedNavi has a wide range of application scenarios. Applying to the maritime education and training field, it can serve as a bridge between the 2D and 3D worlds, helping less experienced trainees build up their capabilities. Applying to actual navigation, it can provide the deck officer with another visual aid to their lookout in addition to existing 2D information systems. In addition, given the microservices architecture RedNavi adopts, the development, deployment, and maintenance processes become relatively lighter, faster, and easier, and therefore more sustainable than traditional monolithic systems.