Evaluation of a Radar Plot and Display Technique for Anti-collision Assessment of Multiple Targets in True Vector Representation by Application of the Environmental Stress Model

Abstract

It is shown by geometrical interpretation of velocity vectors in a collision scenario that collision lines and cone-shaped collision regions, which are independent of own ship's motion parameters, can be displayed to acquired targets in true vector representation. The geometrical solution of the collision problem results in a radar plot and display technique that enables the mariner to evaluate anti-collision and safe passing distances by judging the tip of own ship's vector in relation to the displayed collision lines and regions. The performance of the technique has been evaluated by the Environmental Stress (ES) model, which is a quantitative method for evaluating the difficulty of ship handling for navigation in restricted and congested waters. The evaluation is based upon a simulator test programme with 3 scenarios of various traffic densities in Tomogashima Suidou. 5 Captains of the NYK Line and 10 students with license participated in three equal-sized groups. It is shown that the two groups of participants judging anti-collision based on the presented technique performed more homogeneous, safe and precise manoeuvres than the group utilising conventional judgement techniques based on standard ARPA and from visual observations. It appears evident that this visualisation of anti-collision information is capable to remove the need for long-term experience in order to judge anti-collision properly.