The United States is in the process of determining what the future mix of radio-navigation should be for its users. Air, marine and land navigation requirements are being closely re-examined and the ability of future or existing systems to meet these requirements is being investigated. Events such as the destruction of Korean Airline Flight 007 have focused new attention on the Navstar Global Positioning System (GPS), both by the President and Congress. Behind the selection of a future systems mix is a planning process that has been under way for some time. The first Federal Radio-navigation Plan, published in 1980, listed two key decision points in the planning process; a joint preliminary recommendation to be made by the Departments of Defense (DOD) and Transportation (DOT) in 1983 and a national level decision in 1986 (Fig. 1). A national decision will not be made without an opportunity for user comment and international consultations.

At the end of World War II civil aviation inherited an infrastructure in which the state of the art had necessarily been accelerated beyond normal commercial pressures and for which the research and development costs had been funded by military resources and requirements. Within the UK a patchwork quilt of military aerodromes were progressively run-down as military activities decreased and were either adopted by the state, the municipal authorities or private ownership. The possibilities for civil aviation development seemed boundless and to many communities the availability of airline services were deemed sufficiently desirable, because of ancillary benefits, to justify the subsidization of the airport and navigation facilities inherited.

If an operational requirement for an oceanic application of global civil satellite navigational systems is to emerge it is almost certain to appear first in the North Atlantic airspace. Other areas of application, their time-scales or relative time-scales and their possible accuracy requirements are more difficult to anticipate. Perhaps the Central East Pacific routes or the North Pacific routes could be next in line for justification of an operational requirement in the foreseeable future. For this reason the remainder of this paper draws entirely upon the North Atlantic, but the potential application in other areas cannot be overlooked. The views expressed are those of the author and do not necessarily reflect the views of the Civil Aviation Authority.

Recent years have seen a number of proposals for the use of satellites by aviation, either for navigation or for air/ground communications and the question is often asked why commercial aviation, one of the most technologically advanced industries in the world, is so reluctant to utilize satellite techniques. So far, these proposals have not succeeded because they failed to satisfy a genuine operational requirement and were not, by any standard, cost effective. Up to the present time the systems which have evolved over the years have performed the required tasks reasonably adequately and would appear, given the normal process of development, to be able to continue to do so for some years to come.

Since the end of the second world war hyperbolic position-fixing systems have been available for use by merchant vessels. These systems originated in military requirements. Today for the navigation of merchant ships a number of existing systems can be used, such as Decca, Loran C, Omega, Transit and Cikada, the two latter being satellite navigation systems. Transit became operational in 1964 for military use and in 1967 the system was made available for use by merchant shipping.

Everyone needs a knowledge of ‘the time’, even if the accuracy required is only sufficient to keep an appointment, catch a train or watch a particular TV programme. An isolated clock, started at random and ticking at an unknown rate, can only be used to compare intervals of time. Although this is often useful – for example, in cookery or athletics – the full value of a clock can be realized only if its reading provides a model of the status of a continuing process (such as the rotation of the Earth) or if the clock is a member of a group of clocks, all of which show the same time and may be expected to continue to do so. Particular applications may demand that some members of the group must be kept in closer agreement than others, or must all reliably remain within a stated tolerance for a longer period, but specifications of this kind arise only from economic necessity; in principle all clocks should agree at all times – subject, of course to the unavoidable restrictions imposed by the laws of physics and perhaps the complexities of daylight-saving time.

Granas (Global RAdio NAvigation System) is a satellite-based radio navigation system with global coverage, high accuracy and continuous availability for civil users on land, sea and air. Its performance, thus, is superior to existing ground-based radio navigation systems as Omega, Loran, Decca, and so on.

The principle of Granas user-position determination is similar to that of Navstar GPS or Navsat in that a user makes pseudo-range measurements to a number of satellites visible above a 5° elevation angle. These ranging operations are performed using time-of-arrival (TOA) measurements of navigation signals transmitted by satellites. Knowing the discrete positions of four or more satellites and their pseudo-ranges, a user may compute its own clock bias and its position in three dimensions (longitude, latitude and altitude).

Collins Government Avionics Division (CGAD) of Rockwell International became involved with the Navstar Global Positioning System (GPS) in 1974. Since that time, the division has accomplished several key milestones in the development of GPS user equipment including the first transatlantic flight of an aircraft using GPS signals.

The Geostar satellite navigation system is designed to provide a number of user services through inexpensive terminals (transceivers). The services include precise positioning, location radio (the reporting of position back to a fleet headquarters), digital message transmission both send and receive, and connection to non-Geostar digital communications systems through a single node point. A number of additional user services (terrain and shoreline avoidance, warnings of hazards to navigation, ship or aircraft collision avoidance, emergency location and rescue communications, etc.) are provided relatively inexpensively because all messages and positionings in Geostar flow through a single location where powerful computers are available.

This paper, which discusses a preliminary development of a microcomputer-based navigation system for the fishing industry, was presented at the Oceanology International Congress at Brighton in March. Dr Coates is at the University College of North Wales, Mr Dye and Mr Knox with the Sea Fish Industry Authority.

The history of the sea-fishing industry is one in which success has only been achieved at the price of experience, painfully gathered as a consequence of abortive fishing trips or damaged gear. A detailed knowledge of conditions on the sea-bed, in particular preferred fishing areas and sea-floor obstacles such as wrecks or sand-pinnacles, is clearly of paramount importance in maintaining commercial viability. At the present time, for the requirements of the UK Sea-Fishing Fleet, such specialist information is available in the form of the widely used ‘Kingfisher’ chart series. With the advent of cheap, yet powerful microcomputer systems, the possibility now exists to create a data-base version of the Kingfisher Charts, thus offering the advantages of rapid updating of information and convenient wheelhouse presentation of user-selected chart features by means of a video monitor.

This paper examines the evolution of the arctic submarine and the ever-increasing scientific and commercial potential which have accompanied this evolution over the past 340 years. It is a sporadic history of arctic submarine ideas, concepts and actual experiences with vessels at sea. It happens to be a history that is largely American, with important additions as a result of the experiences of the Germans, Soviets and the British, particularly during World War II. Finally, it is a history in which five early visionaries in particular stand out: Bishop John Wilkins of England; Jules Verne of France; Professor Anschutz-Kampfe of Germany; the submarine designer Simon Lake, of the United States — whose influence extended over four decades until well into the twentieth century; and Sir Hubert Wilkins of Australia.

Traffic separation schemes have been established all over the world with the aim of reducing the danger of collision. Field observations have shown that despite the adoption by IMO and the laying down of the schemes on nautical charts a good many vessels do not comply with the steering and sailing rules applicable at traffic separation schemes. This paper attempts to review the apparent difficulties met. Some suggestions for improving of the situation are made.

The separation of traffic into two streams moving in opposite directions has been introduced with the aim of reducing the incidence of collisions. Such a measure results in a decrease of the rate of encounters and an almost total elimination of head-on or fine crossing meetings which are considered dangerous especially in restricted visibility. Investigations have confirmed the effectiveness of the measure in achieving the purpose provided that the steps taken are reasonable from a practical point of view.

Ever since man first ventured to sea, he has needed to know not only where he was in relation to the land but also what dangers lay hidden below the surface, and what courses to steer in order to avoid these unseen dangers so as to arrive safely and speedily at his destination – making due allowances for the effects of tidal streams and currents.

Because his sea-maps were working documents, usually exposed to a hostile environment, fewer such old records have survived than is the case with old land maps. Undoubtedly, whilst many early voyages of exploration emanated from Europe, it should not be forgotten that in the – to European eyes – ‘unexplored’ parts of Asia and the Pacific, similar voyages were being made. However, as trade developed between Europe and the rest of the world, hydrographic surveyors from Europe began to record the information needed along the various trade routes.

Before 1972 the Collision Regulations were drafted so as to enable a court to decide which vessel was to be blamed rather than to assist the mariner to avoid collision. The new Regulations have been drafted primarily to assist mariners to prevent collisions at sea. Even so, actions to avoid collision required by the Rules are described in abstract terms because of the variety of visibility, sea-room available, manoeuvring capability of the vessels and the nature of the encounters. In order to help mariners understand the requirements of action to avoid collision both in quality and quantity, some reference data are recommended by experienced mariners and researchers. This paper is an attempt to introduce a study on quantification of the term substantial action to avoid collision and the distance of last-minute action in turning to avoid collision.