In Heavy Weather Sailing, Adlard Coles defines a survival storm, as distinct from a full gale, as those conditions in which, the wind at Force 10 or above and perhaps gusting at hurricane strength, wind and sea become the masters; there is little the unfortunate mariner can do. It is impossible for anyone in a small boat in the middle of an ocean storm to judge wind-speed or sea-state accurately, if only because the height of eye will be too low to see enough of the sea surface. However, an experienced observer will be able to distinguish between storm-force and gale-force winds and if he knows his craft well enough he will sense when she has become at the mercy of the seas. In precisely these terms I believe Jester to have experienced a survival storm in the vicinity of 48° 30′ N., 12° 30′ W. on 1 August 1986. She was on her way back from Nova Scotia to Plymouth, some 25 days out, 250 miles from her destination. It was her thirteent transatlantic crossing.

The navigation and control of commercial aircraft has developed in an almost random fashion during the past forty years. Now circumstances have produced an opportunity, through the ICAO Special Committee on Future Air Navigation Systems, for the industry to put time aside from more immediate problems to plan ahead for the future. Although our current methods and procedures are immeasurably better than those of forty years ago there is now little scope for further refinement and it is very apparent that by the end of the century present systems will be unable to cope efficiently with the traffic in the world's high-density areas. In addition our current methods do not permit us to operate our aircraft as efficiently as we would wish.

Mobile satellite communications and navigation are, historically and technically, intertwined. This paper offers a historical perspective on this interrelationship to see if the past provides some guidance to the future.

The Global Positioning System (GPS) is a military positioning and navigation system that, like all radio navigation systems, will also be used by the civil community. The system has just completed a transition from the development phase into production. In order to speculate on how the GPS will look in the year 2000 and beyond, a determination must first be made on how the system will look in the 1990s after it has become fully operational and has gained some maturity. As the system is being fielded and after it is operational, certain pressures will be exerted to change the system. These pressures will tend to make it change, and various types of change could occur. These potential changes will be examined primarily from the point of view of the civil use of GPS. The pressures come from at least four sources: the military needs of GPS, money, technological innovation and user requirements. These pressures could also cause changes to occur in the various GPS plans and policies associated with civil use. The pressures and/or new policies and plans could affect the GPS hardware and software. In addition to system or policy changes, new applications of GPS will surface and new ways of installing and integrating GPS on various platforms will emerge.

Significant developments have taken place in navigation and positioning techniques at sea. These include radio, acoustic and inertial methods, and satellite based techniques. The latter consist of the Transit Doppler system, which has now been in operation for over 20 years, and the Global Positioning System which is due to be inaugurated in the early 1990s. These various systems are described in the paper, and their marine engineering, geodetic and geophysical applications discussed. The paper is based on a lecture presented at the Oceanology International Conference held at Brighton in March 1986.

In the past, various authors have published ideas aiming at the functional integration of communication, navigation and surveillance (COM/NAV/SURV) subsystems with the advantage that the same subsystems and components like transmitters, receivers and antennas can be used more efficiently.

Airport visual aids are examined for failure of transfer from chromatic (i.e. normal) to achromatic viewing situations which would suggest a non-redundant use of colour, and for their information value during VFR (visual flight rule) operations as a function of the airport operating classification for which they were designed. From photographs taken under visual meteorological conditions at night, slide sequences representing the visual presentations associated with aircraft movements during taxi-out, take-off, approach and landing operations were prepared and shown to experienced pilots in a time-stressed forced-choice procedure. The results suggest that among displays in current use only the signal light from the control tower is completely colour-dependent. Also, the information value of some taxi-way and approach lighting components might be questioned. An argument is presented for a ‘building-blocks’ review of the airport visual-aids system that could in some cases result in improved relationships between economy of display content and information value.

This paper touches on some of the problems with which the chart compiler has to contend in an area such as the Gulf of Suez. It is assumed that readers are familiar with the system of keeping charts up to date through Notices to Mariners and new editions of charts. Details of the system can be found in The Mariner's Handbook. Space does not allow a full evaluation of all the influences source data for charts may have on the final product, and in particular no treatment is given here of one significant area, the influence of source data on choices of chart limits and scales. The paper will look first at some more general points which find expression in the charting of the Gulf of Suez, and then take as an example chart 2375 of the Strait of Gubal, examining aspects of it in detail in the light of the general points raised.

This paper was presented at an International Conference on ‘Navigation in the Gulf of Suez’ held in Alexandria in October 1986.)

A new application of the Omega navigation system is described in which a ground station is enabled to display multiple vehicle locations. Pulses from the vehicles are triggered by Omega signals and the times of arrival of the pulses at the ground station are processed to provide a ‘radar-like’ display of each vehicle's range and bearing.

This paper was presented at the eleventh Annual Meeting of the International Omega Association held in Quebec in August 1986.

Present and future marine navigation requirements have been analysed recently for different categories of users. This paper relates to those navigation applications which need very high real-time accuracy, high availability and reliability of navigation information. This domain is mainly influenced by marine surveying and navigation community needs such as oil and mineral prospecting, hydrography and future prospecting of maritime economic zones, which are usually of high strategic or economic importance. The majority of identified needs for this limited community of users call for real-time accuracy and repeatability of instantaneous positioning ranging from 2 to 10 m, distances from shore up to 1500 km (water depth 300–1000 m), update rate of position information of a few seconds, and availability and reliability of position information data of 99 per cent or more. To reach such stringent requirements none of the existing means and even new satellites or Earth-based acoustic or radio aids individually can solve the problem. This leads to the necessity of combination or hybridization of several means which together may approach the solution.

Concerning the minimum fuel routeing, the algorithm stated in Section 2 is very effective in the calculation of the (sub)optimum route for most environmental conditions. However, when the weather around the great circle route is extremely severe and the final isochrone bends backwards sharply near the destination, there is a possibility that the route passing through the other side of the great circle causes less fuel consumption than the calculated minimum fuel route. In such a case, to investigate the fuel consumption of that alternative route it is necessary to apply the algorithm for only the other side of the great circle route.