The content of this paper is based on my own experience of international cooperation in the field of navigation. For this reason, the presentation is divided into three parts and these are related to the International Association of Lighthouse Authorities (IALA) and to the International Association of Institutes of Navigation (IAIN).

Safety of life at sea and assistance to persons in distress are matters of great importance to seafarers, shipowners and maritime administrations and have been addressed by the International Maritime Organization (IMO) since its foundation.

In a strong wind, groundspeed may vary appreciably during a turn, as, for example, in the case of a landing after a U-turn preceding the localizer intercept. Such conditions are critical for maximum use of the runway, and render human estimation of aircraft motion extremely difficult.

This paper summarizes the tests conducted using a ground-based 4D-guidance program, developed to assist the air traffic controller in maintaining the predicted landing-time sequence with an accuracy better than 10 seconds for each arrival.

This, and the following three papers were presented at the Royal Institute of Navigation meeting ‘Management of Air Traffic Flow in Europe' on 15 November 1989.

One of the growth industries in Europe is the production of articles in newspapers and programmes on radio and television which deal with European air traffic control. They usually have titles like, ‘The Crisis in ATC’, or ‘European Air Traffic Meltdown’. Jane's Airport Review, in October 1989, had an article entitled ‘Wanted: One ATC System for Europe’.

The paper has defined the objectives of flow-management, the techniques it uses, its present organization and the existing problems. It has covered the plans which have been made to radically improve the service and has described the final goal as we can see it from this point, together with the interim development phases.

The situation today can be described as very frustrating for a variety of reasons. Air traffic flow-management (ATFM) has dominated the scene for many years since its conception in 1980. At that time, the principles of ATFM were directed at ensuring that temporary or isolated sector overloads could be handled by ATC and only when broad, prolonged overloads were expected was ATFM activated. Today, we have the reverse situation, where ATFM is active throughout 16 h or more during each day. The system as such was never intended or planned to cope with such a burden and the results are seen in a variety of forms, including departure delays as shown in Fig. 1.

This paper attempts to challenge some of the principles on which en-route airspace is presently allocated, whilst pointing out the practical difficulties of implementing any alternative strategy. The paper does not discuss airport capacity limitations and terminal area problems, although these also contribute to restrictions on traffic flow.

The safety on board medium-sized fishing vessels in relation to working conditions on the bridge is analysed by means of a problem-solving method developed by the Safety Science Group of the Delft University of Technology. The potential of the method is illustrated by a number of case studies on selected aspects of the bridge design, since a complete application of the method is not yet available.

This paper was presented at the 14th annual meeting of the International Omega Association, held at Long Beach, California in October 1989.

The integration of Omega and GPS sensors into a single navigation system offers the advantages of good accuracy under almost all signal conditions, low capital investment, and certifiable worldwide navigation. The accuracy of the existing Omega network can be progressively improved as GPS satellite coverage is fully implemented. This is done by having the GPS system update the Omega navigator. Eventually, the same equipment can provide full GPS navigation accuracy but with Omega as a back-up.

This paper proposes a method of further improving the overall accuracy and reliability of Omega-GPS navigation. The conceptsof Omega-GPS integration, interoperability, modes of operation, and Kalman filter data fusion are presented. Four interoperability modes of operation and their ability to improve navigation reliability are also discussed.

Meeting encounters, in which it is uncertain at what range the give-way ship will manoeuvre, are analysed using a model based on probability theory. Course alteration ranges of both giveway and (if necessary) stand-on ships are closely fitted by a simple mathematical model, which is also used to interpret the efficiency of the Collision Regulations.

In the past, it was perfectly satisfactory for navigators to operate with little regard for the exact meaning of the terms, such as latitude and longitude, or even height, that they used to describe where they were. Latitude was latitude and longitude was longitude and that was the end of the matter. Of course, the positioning methods employed and the objectives of the positioning activity itself were usually so approximate that exact definitions were not important anyway, and no difficulties arose.

The collision between the dredger Bowbelle and the pleasure cruiser Marchioness on the Thames in August 1989 in the vicinity of the centre of London has drawn attention to the need for river mariners to keep a frequent look-out astern as well as ahead. This paper describes calculations of the minimum frequency at which observations astern are required in order to allow sufficient time for a ship about to be overtaken by a faster vessel to be able to take adequate avoidance action should the overtaking craft fail to keep clear.

In this paper the authors obtain analytical expressions for the ground traces of synchronous polar satellites on the polar orthographic projection, confirming that they are circles and pointing out a simple graphic method for the mapping of the subsatellite point.

A well-known navigational method is to determine position through observation of the highest altitude of the Sun at noon. This procedure is based tacitly on the assumption that the observed altitude is a symmetrical function of time about the highest point which appears thus in the meridian. In order to examine the accuracy of this approximation for a fast moving ship, let us consider the situation in more detail. The equations will be formulated using the standard functions in a modern pocket calculator and its application modules.