Autonomous guidance and navigation based on the COLREGs rules and regulations of collision avoidance

Abstract

”Automatic steering is a most valuable invention if properly used. It can lead to disaster when it is left to look after itself while vigilance is relaxed. It is on men that safety at sea depends and they cannot make a greater mistake than to suppose ...” The statement was made by the Justice Cairns with respect to a collision that had occurred due to the fault in the automatic pilot system when the British cargo ship ”Trentbank” was overtaking the Portu-guese tanker ”Fogo”’ in the Mediterranean in Sep-tember 1964 (Cockcroft and Lameijer (2001)). The verdict not just shows the importance of the AGN systems in ocean navigations but also of the human vigilance of its capabilities and requirements for fur-ther developments. The automatic pilot systems are primary level de-velopments units of the Autonomous Guidance and Navigation (AGN) Systems and their applications have been in the dreams of ship designers in several decades. The development of computer technology, satellite communication systems, and electronic de-vices, including high-tech sensors and actuators, have turned these dreams into a possible reality when designing the next generation ocean AGN sys-tems. The initial step of the AGN system, which made the foundation for applied control engineering, was formulated around 1860 to 1930 with the invention of the first automatic ship steering mechanism by Sperry (1922). Sperry’s work was based on replica-tion of the actions of an experienced helmsman that was formulated as a single input single output sys-tem (SISO). Similarly, the research work done by Minorski (1922) is also regarded as the key contribution to the development of AGN Systems. His initial work was based on the theoretical analysis of automated ship steering system with respect to a second order ship dynamic model. The experiments were carried out by Minorski on New Mexico in cooperation with the US Navy in 1923 and reported in 1930 (Bennett, 1984). Hence both works done by Sperry and by Minor-ski are considered as the replication of non-linear behavior of an experienced helmsman (Roberts et al. (2003)) in ocean navigation. From Sperry’s time to present, much research has been done and consider-able amount of literature has been published on AGN systems with respect to the areas of marine vessel dynamics, navigation path generations, and controller applications, environmental disturbance rejections and collision avoidance conditions. The functionalities of the Multipurpose Guidance, Navigation and Control (GNC) systems are summa-rized by Fossen (1999) on a paper that focuses not only on course-keeping and course-changing maneu-vers (Conventional auto pilot system) but also inte-gration of digital data (Digital charts and weather data), dynamic position and automated docking sys-tems.