Over the past few years several papers have been written based on the results of surveys of marine traffic in different parts of the world. The general knowledge of the overall picture of the behaviour of ships at sea has increased considerably but there are still many aspects which need to be explored. One of the main fields of interest of the Marine Traffic Research Unit at the City of London Polytechnic is the use that mariners make of available sea room. For any particular area the navigational difficulties are going to vary considerably in situations where ships enter the area at different points, travelling indifferent directions, from situations in which the ships tend to keep to a number of defined routes through the area. If ships do tend to adopt a routing structure through an area, the next question of interest is how wide the various routes are, given no physical limitations for their width. The behaviour patterns may vary for different types of ship, and speed is another variable which may affect the situation. Answers to all these questions would be needed if one wanted to analyse the efficiency and safety aspects of marine traffic in an area.

Each navigational aid has its advantages and disadvantages and for that reason the optimum aid will be a combination of several aids. The best way of combining the aids seems to be by means of an automatic dead reckoning computer which continuously computes position from true air-speed and wind-speed and other data which can be fed into the existing navigational aids by means of a data transformer. Data from the integrated system can be transmitted by data link to air traffic control to correct the flight programme, &c. This paper, which was presented at Dusseldorf at the German Navigation Society's meeting (5–7 June 1962), surveys the field of integrated navigation systems and describes a number of possibilities. Formulae are derived for the accuracy of Vortac and D.R. and Vortac and doppler. It is published with the kind permission of the German Navigation Society.

If we look critically at the navigational aids which are available today we find that all have advantages and disadvantages, and that no one aid can be claimed to be suitable for all purposes. This situation will still exist for many years. Therefore it seems very advantageous to combine the available navigational aids to form an integrated navigation system in such a way that the possibilities may be fully utilized.

One aspect of marine navigation which has particular application to the protection of the environment is the establishment of traffic separation schemes and other routing measures in coastal waters. Extensive pollution may be caused by marine casualties. The use of routing to reduce the risk of strandings and of collisions between ships or with offshore structures will be considered in this paper.

At the present day European ATC is exercised by a multiplicity of more-or-less autonomous control centres. ‘Flow Regulation’ is used roughly to match traffic demand to the capacity of the en-route ATC and of the destination airport. The ATC authority at the point of departure for a remote destination cannot however give any guarantee that the pilot will be able to follow his chosen trajectory. The filed flight plan and the departure clearance have been described as a ‘licence to get into the sky and see what happens’.

This paper puts forward a case for more precise navigation at sea. It commences by briefly outlining existing and forthcoming navigation aids. The integration of marine navigation systems, and in particular the use of Kalman filtering is then discussed. After outlining the developments in the aerospace industries, the authors suggest why marine developments have not been so rapid as those in the air. The idea of automatic collision avoidance is also raised and a method for tracking radar targets discussed. Finally, the authors survey marine applications of Kalman filtering techniques, including some references to their own work, and assess the need for further research and development.

In May 1948 the Radio Technical Commission for Aeronautics, a cooperative association of United States government and industrial air telecommunication agencies, issued a report outlining a comprehensive scheme for the development of air traffic control facilities in U.S.A. for the next fifteen years. This report was prepared by a committee set up by the R.T.C.A., Special Committee 31, and it is generally known as the SC31 Report. It was the result of a study undertaken at the request of the Technical Division of the Air Coordinating Committee, an inter-departmental committee established by the Secretaries of State, War, Navy and Commerce, and directed by the President to examine aviation problems of mutual concern and to develop and recommend integrated policies and actions to be taken for their solution.

To the layman navigation may sometimes appear as an old lady whose fads have acquired the sanctity of tradition. In every tradition, however, there is something venerable; and we would be very wrong to laugh at the traditions of the sea, for they are a legacy we have inherited from all our seafaring ancestors since the days of Noah.

The core of this inheritance is the notion of freedom. For centuries the freedom of the seas was absolute and unconditional; all men were free to use the sea, for no man can plant his flag on its restless immensities; and all were free to choose their routes and navigate as they pleased, for encounters at sea were so infrequent that it would be only a most uncommon stroke of ill-luck that produced a collision between two vessels in the vast emptiness of the oceans.

The recent history and background of the Channel Navigation Information Service (CNIS) have been well documented in this journal by my illustrious forebears, Captain Richard Emden and Commander James Neill. Whilst this paper describes some of the changes in the service since those papers were published, it may be appropriate to review the key events in the introduction of what was once a unique initiative, and remind the reader of the operational doctrine and philosophy of the system.

Most readers of this Journal will know a good deal about the long-established practice of setting adrift in the sea sealed bottles or other watertight vessels containing messages or questionnaire papers. There are numerous records stretching over a very long term of years of this having been done with the aim of conveying information—often in a jovial sort of way, but sometimes when it was feared that a ship seemed likely to be lost. In the latter case to which very few authentic records relate, mariners fearing the worst adopted the practice for obvious enough reasons. In the former case, records of the practice are legion and, a century or so ago, it was a common thing for floating bottles with papers inside to be flung overboard from outbound emigrant ships. The habit was still fairly common in much more recent times, and the writer once had quite a goodly number of missives recovered from stranded beer and wine bottles which, after the conclusion of a farewell party, had been thrown out from ships bound for America from the Elbe and other departure points. Generally speaking, such corked bottles were used empty (apart from the enclosed message), and so would perform journeys decided in large part by the winds. Where a serious intent lay behind the launching of a bottle designed to convey true news of distress, no very strong hopes could ever have been reposed in the glass messenger, since there could never have been any idea as to when it might go ashore and be found. It is probable that many bottles carrying messages of the sort have, over the years, been broken on rocky coasts or have stranded on unvisited shores perhaps to suffer burial in shifting sands.

The almost complete constellation of GPS satellites now provides excellent positional information for aircraft, with typical worst-case errors of the order of 100 metres. The low frequency waves used for Omega navigation have wavelengths of the order of 30 kilometres and thus, even in an aircraft moving at varying speeds up to around 500 km per hour, it is now a simple matter to measure VLF phase with a significance at the 1 degree level. This paper describes the use of GPS to provide accurate positional information to VLF receivers located on aircraft of the Royal New Zealand Airforce (RNZAF) en-route to Antarctica. The marked phase irregularities on signals from La Reunion and Argentina, observed north of the icecap in earlier studies using aircraft fitted with inertial navigation systems, have been confirmed and described with much greater precision. Smaller phase anomalies have also been observed on signals from Omega Australia and Omega Hawaii, whilst flying directly over the Antarctic icecap. The latter signal was previously regarded as unperturbed and used in earlier studies as a phase reference. Small-scale periodic variations of phase and amplitude have also been recorded on signals propagating from Omega Australia. These variations are considered to be caused by the reflection of the VLF waves at discontinuities in the height (e.g. mountains) or the lower boundary conductivity of the Earth-ionosphere waveguide. Reflections of smaller amplitude have also been observed flying over the open ocean before reaching Antarctica.

The Institute’s NAV 88 Conference, with the above title, was held in London from 22 to 24 March. It included nearly 40 papers concerned broadly with the way ahead for radionavigation in Europe. The Jull proceedings of the Conference are available on application to the Director, price £30 (plus £3 p & p) for Members (£60 plus p & p for non-Members). A summary of the Conference is presented below, and this is followed by one of the Conference papers which describes a rationalization of radionavigation in the USA.

The three basic problems of navigation are determination of position, definition of direction, and steering the direction required. In polar regions, all these problems are affected either by the high latitude, or by the polar climate, or by both. In this paper the various problems which arise are reviewed, possible solutions are discussed, and it is indicated where further research and experiment might be desirable.

The word ‘statistics’ implies populations. The practical navigator uses the methods of statistics to reduce errors. However, he is concerned not with a number of craft but with one particular craft. He may therefore use statistical terms in a somewhat inexact fashion. For example, the navigator generally assumes that the distribution of errors is Guassian because he has no way of telling what it really is. In navigating a craft, the blunder rate tends to add large skirts to the Guassian distribution. In equipments, these skirts may be suppressed by limits in manufacturing tolerances.

Few aspects of geography are more satisfying than to follow the progress of geographical discovery across the oceans from the documents that remain to us, and the careful work of many scholars allows us to find some of the excitement of the early voyages without much effort to ourselves. But geographical exploration was only the first phase, and during the past 300 years much effort has been spent in finding out something about the oceans themselves: as early as 1698 Halley sailed as far as S. 52° on a purely scientific voyage, returning with useful information about magnetic variation and the trade winds. The promoters of the scientific voyage of H.M.S. Challenger argued that the vast oceans lie scientifically unexplored, and we say much the same today; but much has been done and in its way it provides a story as interesting as that of geographical discovery.

This paper, which will be presented for discussion at the Eastbourne tripartite conference, 12–14 May, examines the efforts made in recent years to improve marine radar in three respects, namely greater expressiveness of the display, simplification of measurement and computation, and increased reliability. Particular developments in each of these directions are discussed, their effectiveness and shortcomings mentioned and the conclusion reached that there is still a long way to go.

The following discussion took place at an Ordinary Meeting of the Institute held at the Royal Geographical Society in London on 19 February 1960, with the President, Wing Commander E. W. Anderson, O.B.E., D.F.C, A.F.C, in the Chair. Dr. J. G. Porter is at the Royal Greenwich Observatory, Herstmonceux, Mr. D. J. Cashmore and Mr. T. McClymont are both with English Electric Aviation Limited.

This paper describes the basic principles of a method developed to guide aircraft accurately down to the runway in a time-of-arrival constrained environment. The method is designed to be used in a ‘zone of convergence’ context or in any similar advanced air traffic control system characterized by the integration of control phases over an extended area on the one hand and true ‘computer assistance’ to the air traffic controller on the other; that is, assistance provided at the decision-making level through the automatic generation of guidance advisories.

The method includes two closely-coupled basic components; namely, a ‘predictor’, which computes a trajectory once initial conditions and plans are known, and a ‘profile manager’, which adapts the plans to meet the time constraints and generates the guidance directives on the basis of present position, actual surveillance information, aircraft operation and route constraints.