AIS for Container Overboard Alerts: Development and Evaluation of a Software Defined Radio Transponder

Containers overboard pose a significant threat to ships on sea routes and pose a pollution risk to the ecosystem. This risk can be minimized by transmitting the position of these floating containers to nearby ships on the route. A prototype Software Defined Radio (SDR) transponder with Automatic Identification System (AIS) functionalities has been developed to send the location of salvageable containers to nearby ships or AIS base stations using AIS messages. This prototype transponder has been primarily designed to utilize the Random-Access TDMA (RATDMA) scheme to enter the AIS network. In another approach, the transponder will also have the capability to listen to the AIS Time Division Multiple Access (TDMA) frame to look for available time slots to ensure that it does not interfere with other AIS messages while transmitting. This innovative approach will alert the nearest ship at a predefined interval without disturbing the concurrent communication slots of other vessels in the TDMA frame. This paper not only outlines the use of potential AIS messages for alerting crews, authorities, and freight owners but also describes an innovative prototype architecture and setup for laboratory evaluation. This standalone real-time tracking unit showcases its potential as a reliable solution for enhancing maritime safety and environmental protection. Furthermore, since AIS slot management plays a crucial role and is often unclear to the Layman, this paper provides an insight throughout the investigation.