This paper formed the 1990 Anderson Memorial Lecture and was presented to the Bristol Channel Branch on 22 February. In developing his theme, George King concentrated very much on the characters of the navigators concerned with six extraordinary exploits, but without losing sight of the navigation itself. The following version is necessarily much abridged and the editor has reluctantly omitted the detail of fascinating accounts of the expedition commissioned by Thomas Jefferson to explore the American West, the epic open boat voyage by Ernest Shackleton in the Antarctic in 1916, the first solo air crossing of the Atlantic by Charles Lindbergh in 1927, and the spectacularly successful Apollo 11 mission in 1969. The full text of George King's meticulously researched and brilliantly written paper is available to members from the Institute, price £3.

This paper is the third chapter of a series on Air Navigation Systems during the period from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. Some initial comments on the paper are included in the Forum section of this issue of the Journal. Further comments would be welcomed by the author and the editor.

The history of the first 10 years of the Channel Navigation Information Service (CNIS) from its inception in 1972 has been well-documented in Captain Richard Emden's three papers published in the Journal of the Royal Institute of Navigation. While the purpose of this paper is to discuss the period of consolidation following these first 10 years, it is perhaps appropriate to set out briefly the factors leading up to the introduction of CNIS in the Dover Strait, the operating philosophy and some of the major milestones along the way.

In many aviation and nautical contexts, single manning is common. Some aircraft and some vessels are designed for single manning with no choice. Others can have multiple or single manning, usually depending on such factors as operational requirements, mission objectives, intended human roles, task demands, workload, envisaged mission duration, and environmental conditions.

It is over 10 years since this ill-fated Fastnet Race claimed the lives of fifteen yachtsmen and the total loss of five yachts. A total of twenty-four crews abandoned their yachts and in all, 136 people were saved by being winched into helicopters and taken on board merchant and naval ships as well as other yachts. Some eighteen yachts needed the assistance of lifeboats because they had lost their rudders.

Piloting large vessels in increasingly congested waterways is no simple task. As in many ‘decision-making under uncertainty’ scenarios, masters, mates and pilots engaged in piloting are inundated with much information and required to make crucial decisions in real time. Piloting is also an inherently judgmental activity. Pilots and ships' captains invariably develop heuristics for transiting particular waterways. As vessels become larger, cargoes more hazardous, and the waterways more congested, decision aid technology is being considered to improve piloting decision-making. This paper describes one approach to providing improved on-board decision support to masters, mates on watch, and pilots navigating in restricted waters. We discuss (1) the use of cognitive decision aids in piloting, (2) the design of such a decision aid developed for New York harbour, (3) simulator experiments evaluating the expert system, and (4) plans to apply the approach and ‘lessons learned’ to the development of an expert system for tankers transiting the Gulf of Alaska.

The advent of EROPS extended-range flights by twin-engined aircraft demonstrated the need for a computer program to draw charts to assist the flight planner in operational decision-making. An EROPS Planning Aid program (EROPA) was written by the author to run on a desktop computer. This article briefly describes the EROPS rules, and how EROPA is used. Then the subject of chart-drawing using a desktop computer is discussed, and other related applications are considered.

A new threat detection criterion is described which provides a better match to the requirements than the well-known modified tau criterion for a civil air transport collision avoidance system. Experimental evidence is given to show that it also reduces the number of undesirable alerts.

The views expressed in this paper are those of the author and do not necessarily represent CAA policy.

The author would like to give grateful acknowledgement to the various companies from which information has been received. (Note that the original presentation at a RIN ordinary meeting was illustrated by numerous colour slides which cannot be reproduced here, as well as three video films).

Multicollinearity and its effect on parameter estimators such as the Kalman filter is analysed using the navigation application as a special example. All position-fix navigation systems suffer loss of accuracy when their navigation landmarks are nearly collinear. Nearly collinear measurement geometry is termed the geometric dilution of position (GDOP). Its presence causes the errors of the position estimates to be highly inflated. In 1970 Hoerl and Kennard developed ridge regression to combat near collinearity when it arises in the predictor matrix of a linear regression model. Since GDOP is mathematically equivalent to a nearly collinear predictor matrix, Kelly suggested using ridge regression techniques in navigation signal processors to reduce the effects of GDOP. The original programme intended to use ridge regression not only to reduce variance inflation but also to reduce bias inflation. Reducing bias inflation is an extension of Hoerl's ridge concept by Kelly. Preliminary results show that ridge regression will reduce the effects of variance inflation caused by GDOP. However, recent results (Kelly) conclude it will not reduce bias inflation as it arises in the navigation problem, GDOP is not a mismatched estimator/model problem. Even with an estimator matched to the model, GDOP may inflate the MSE of the ordinary Kalman filter while the ridge recursive filter chooses a suitable biased estimator that will reduce the MSE. The main goal is obtaining a smaller MSE for the estimator, rather than minimizing the residual sum of squares. This is a different operation than tuning the Kalman filter's dynamic process noise covariance Q, in order to compensate for unmodelled errors. Although ridge regression has not yielded a satisfactory solution to the general GDOP problem, it has provided insight into exactly what causes multicollinearity in navigation signal processors such as the Kalman filter and under what conditions an estimator's performance can be improved.

This paper presents a concept for selecting a fixed time ocean route via a prefixed grid of points. The ship is to sail with a fixed pitch propeller rotating at a constant rate N. The starting and arrival points A and B are given, as well as the starting and arrival times t0 and t1. The criterion is to obtain a route with a minimal value of N. The method is designed for a discrete navigating system. Thus it can be seen as an application of Bellman's Dynamic Programming Theory1. The ship's speed is estimated with the use of a modern algorithm, based on a well founded and well tested hydrodynamic model.