The Effect of Observational Errors on the Avoidance of Collision at Sea

Abstract

At a meeting of the Technical Committee of the Institute held on 9 January 1963 it was suggested that recent theoretical treatments of the collision problem could usefully be extended to include a discussion of the near-miss situation and the effect of observational errors. The basic mathematical relations for near-miss encounters have been set out in this Journal on several occasions, notably by Sadler and Morrell, and in graphical form by Wylie. The recent paper by Parker deals with the effects of both systematic and random errors of radar observations of relative range and bearing.My previous discussion of the collision problem was presented in terms of the idealized situation where two ships are on an actual collision course, in which case the sight line is in the same direction as the relative velocity vector (the relative track). To extend the results to a near-miss situation, one has only to redefine the angle α (see p. 24s of ref. 3) as the angle through which the relative velocity vector rotates when one or both ships manœuvre. I have pointed this out on a previous occasion: ‘The two craft need not be on a collision course; this definition of α applies equally well to a “miss” situation provided that no reference is made to the sight line.

A Line of Sight Counteraction Navigation Algorithm for Ship Encounter Collision Avoidance

“…Efficient use of the COLREGS requires a highly trained and experienced officer in charge of the ship manoeuvres when facing a potential collision situation (Smeaton, 1990 ;Zhao, 1996). In the 1960s, a series of journal papers were published by Calvert and Hollingdale (Calvert, 1960 ;Calvert, 1969 ;Hollingdale, 1964 ;Hollingdale, 1968), which have provided insights into ship collision avoidance problems based on intuitive geometrical case studies. These papers proposed some operational solutions to improve the COLREGS (Calvert, 1960), and emphasised the importance of the radar display and accurate positioning system's to reduce errors caused by human factors (Calvert, 1969).…”