Modelling and Simulation of Errors in ARPA Data due to Measurement Point of Target Echo withApplication to a Visualization-based Collision Avoidance Support System

摘要

Ship-ship collisions have the potential to causeserious maritime accidents with human casualtiesand environmental damages. Collision avoidanceis a major operative task for the ship officer onwatch (OOW). Large volumes of marine trafficdata are available from shipboard navigationsensor sources such as the Automatic RadarPlotting Aid (ARPA) systems. The accuracy oftarget data information and how collision risk isdisplayed to the OOW are of importance fornavigational safety at sea.The measurement point of the target echo thatforms the basis for calculating ARPA target data isgenerally not at the target’s center, nor at a fixedposition on the echo, and may therefore beregarded to cause errors in standard ARPA plottingresults. The nature and significance of these errorsdepends on the definition of measurement point.This has been investigated theoretically byapplying a simplified description of target and itsradar echo.A visualization-based collision avoidance supportsystem (VCASS) is proposed as an improvementto standard ARPA displays. It focuses on visuallypresenting the collision risk of multiple targets andselection of feasible evasive maneuvers byjudging the tip of own ship’s velocity vector inrelation to cone-shaped collision danger regions intrue motion. The effect of errors in ARPA data dueto different measurement point on target echo isdiscussed with respect to settings of minimumsafety margins in VCASS.