Virtual AtoN System Design
The purpose of the Virtual AtoN System is to provide a near-instantaneous warning to the mariner of a new danger, such as a wreck, obstruction or floating debris. This warning must be provided in a form that can be received, interpreted and displayed by any class of vessel in the required operational area and carrying appropriate equipment.
Informing the user about the deployment and removal of Virtual AtoNs will be important for them to be fully effective. However, informing the user if the Virtual AtoN has been discontinued before the removal of the wreck or obstacle, whether by intention or because of malfunction, will be crucial to safe navigation. The method of promulgating this information and the time taken to present it to the user should be the subject of a thorough risk analysis.
The ability to provide Virtual AtoNs could be one of the most significant technical developments for the GLA in the medium term. This only becomes possible through the deployment of a network of AIS base stations around the coast and the installation of onboard equipment with the capability of displaying the Virtual AtoN symbols.
A Systems Engineering approach has been used in preparing the outline design and architecture for a GLA Virtual AtoN System. This involves assessing available information; requirements analysis; functional analysis; defining measures of effectiveness; identifying the essential elements and generating a model. A risk analysis will be performed using FMECA techniques.
The requirements will be reviewed and refined in an iterative process, involving formal requirements capture, including a workshop and trials. Since it is recognised that the architecture may change as a result of the detailed requirements analysis and trials, a schematic model has been generated at this stage and used to produce a data flow diagram. In particular, the mode of displaying Virtual AtoNs (symbology, graphical imagery) will be a matter for further investigation. In this way the model will be optimised and a plan will then be created for realising the model.
