With the ever increasing information rates characteristic of modern electronic systems it is not surprising that display technology is one of the most vigorous fields of current research. A wide variety of phenomena is being exploited in order to produce displays suitable for a diversity of applications. This paper, which was presented at a meeting of the Institute in London on 17 December 1975, with Captain B. J. Calverb in the Chair, reviews recent developments in both emissive and passive displays, emphasizing the advantages of alternative types for particular applications.

Man's knowledge of the world in which he lives is steadily increasing and, compounded with a rapidly increasing capacity for communication, this leads to a need for new means of displaying the available information. The development of computers further increases this requirement since they make large quantities of information quickly accessible. It is to be expected that in many situations, where formerly the printed page or spoken word would at best have been the only practical possibilities, the advantages offered by modern electronic displays will increasingly be appreciated. In both civil and military applications it is clear for example that much information transmitted at present by letter could be better sent telegraphically, once suitably convenient displays are available; the need for ‘hard copy’ can be met where required. Considerable savings in time and convenience, not to mention paper, could clearly be made.

Time is so much a part of everyday experience that no thought is normally given to the meaning of the word. The scientific measurement of a quantity such as time, however, requires the definition of a gauge as a standard of measurement that is reasonably invariant to human experience and the creation of a measurement language capable of independent empirical reproduction so that one laboratory can share experience with another using only a written language to do so.

Time as a means of scientific measurement for navigation requires a further extension of this experience to independent reproduction on a moving craft.

The institute of navigation has been formed to promote the interests of science and of practical navigation, by uniting together in a scientific body those who are concerned with or are interested in the science and art of navigation. For navigation is both a science and an art, whose development must be based upon the knowledge and experience of many different types of persons. The formation of the Institute was stimulated by the formation in 1945 in the United States of an Institute with the same aims; it is likely that similar Institutes will be formed in other countries also. Arrangements are in hand whereby the members of either the British or the American Institute will have the privileges of both, and it is planned to form an international committee to co-ordinate the work of the various separate Institutes. In navigation, as in other branches of science, there is much to be gained by international co-ordination and co-operation.

With the comparative absence of navigation aids in the earlier days of flying, up to about ten years ago, the navigator was constantly engaged in associating observations, calculations and chart work in what was essentially a high-class guessing game. The low speeds (just over 100 knots on flying boats and just under 200 knots on landplanes) provided enough time for this rather intriguing exercise to be carried out in a fairly relaxed atmosphere, conducive to an individualistic approach that could be justified by results. The navigator's performance was largely (at that stage of aviation) judged on the neatness of his plotting, the accuracy of E.T.A.'s and the absence of late course corrections before arriving at destination or a check point. If there is anything in the view that navigation is an art, this particular yardstick certainly induced considerable artifice in the navigator.

To optimize the man-machine relationship different approaches are possible, the adaptation of man to the machine or of the machine to man. The first relates to training and selection, the second is generally called ‘human engineering’, now of great interest both in the naval and merchant marine context. Changing factors like the density of traffic in harbours, the harbour environment, the speed of ships and problems of manning and automation have all contributed to that interest. A ship designer is increasingly confronted with design problems where the man/machine relationship involves the operator as a controller. The desired increase in performance is achieved only if human possibilities are put to their best use.

Milford Haven has expanded as a port extremely rapidly over the last few years, largely as the result of a government decision to make it the major deep-water oil port in the country. Between 1959 and 1974 the amount of cargo handled rose from 200,000 to nearly sixty million tons. In this paper, which was presented at an Ordinary Meeting of the Institute held on 19 November 1975 in the City of London Polytechnic with the President in the Chair, the Harbourmaster describes this development, the problems it brought and how they were solved, and some of the lessons learned.

Contours of constant probability density have been calculated for Loran systems in different service areas, and from these some ‘Loran navigational charts’, which indicate to the navigator the best two pairs of stations to select, are drawn up. The constant probability density contours are shown in Figs 1–6 (a) and the Loran navigational charts are given in Figs 1–6 (b). The areas covered are: Fig. 1. Japan and the adjacent seas; Fig. 2. NW. Pacific; Fig. 3. Hawaii; Fig. 4. N. Pacific; Fig. 5. NW. Atlantic; Fig. 6. N. Atlantic.

IN the course of a systematic search for tables or graphs using the principles appealed to in the Experimental Astronomical Navigation Tables (see p. 333), I examined a copy of the above tables, whose full title follows:

‘Margetts's Horary Tables for shewing by Inspection the Apparent Diurnal Motion of the Sun, Moon and Stars, the Latitude of a Ship and the Azimuth, Time or Altitude corresponding with any Celestial Object.

‘London. Printed for and sold by the Author. “Published as the Act directs 1st July 1790.”’

These tables (or diagrams) do not appear to be well known and they seem to possess sufficient interest to warrant notice. The author's own description is so precise that I can do no better than to repeat it verbatim with a few added notes of explanation. The accompanying photograph, reproduced from the copy in the collection of navigational books and tables in the Admiralty Library by kind permission of the Admiralty Archivist, shows a typical opening of the tables.

I have been unable, in the course of an admittedly hurried and incomplete search, to find any biographical information about Margetts. Perhaps some reader of the Journal can supply the deficiency.

The accelerated growth of aircraft operations is causing severe congestion problems at major airports throughout the world and adding heavy burdens on Air Traffic Control which result in traffic delays. Area navigation is regarded as a solution to this problem and a means of more efficient and safe utilization of airspace, both en route and in the terminal area. It is important to evaluate the navigation accuracy of RNAV systems in the Japanese airspace before introducing the concept of Area Navigation technique.

The United Kingdom's interest in the Joint Tactical Information Distribution System (JTIDS) and its Relative Navigation (relnav) capability began in 1979 with studies into an Electronic Counter-measures (ECM) Resistant Communications System (ERCS). The Singer Kearfott Division (SKD) Time Division Multiple Access (TDMA) JTIDS system, which includes a relnav and position reporting capability, was selected to fulfill this requirement. Early in 1985, approval was also granted to the Royal Navy to procure an ERCS.

Technical studies on JTIDS for airborne applications are being directed by RAE Farnborough and by ARE Portsdown for maritime use. Systems Designers Scientific (SD Scientific) is providing technical support in a number of areas including relnav.

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 15 January, gives a very brief overview of JTIDS and describes the principles of relnav before outlining the structured approach to JTIDS relnav evaluation which has been adopted.

The Loran C radio position-fixing system has been described in technical detail at international conferences and elsewhere. This paper tries to convey the general ‘feel’ of the system and its characteristics and to indicate, with as few irrelevancies as possible, what sort of process makes the two readout counters go round and give the navigator his position fix. The equipment to which the paper refers is the AN/SPN-31 marine Loran C receiver, which was designed and produced by Decca to a U.S. Bureau of Ships specification. Individual makes of Loran C set differ in various ways, but SPN-31 will serve for illustrative purposes.

My first reaction on being invited by the Editor to contribute a ‘twenty-first birthday’ article on the above subject for the Journal was that there is little new to say. However, it is now 13 years since I prepared the presidential address on ‘The Place of Astronomy in Navigation’ (this Journal, 9, 1, 1956) and, apart from any other developments, space navigation has since become established as an operational science as well as a theoretical discipline. There have, in fact, been many developments and much progress in these 21 years; and, although these appear in the Journal and elsewhere mainly as gradual changes, a comparison over the whole interval reveals drastic changes, particularly in outlook and appreciation.

Mr. Blake has given us an outline of what is needed in the context of Navigation of Long-Range Subsonic Transports in the 1970's. I now intend to pursue the theme by saying what I think v.l.f. navigation techniques can contribute to the solution of the navigation problem. In particular, I want to talk very briefly about the contributions that we feel v.l.f. might make towards the particular problem of limiting the numbers of aircraft which creep beyond Mr. Blake's navigation tolerance ‘fringe’ in addition to, possibly, by adding navigational information, increasing the effective M.T.B.F. of the total navigation system.

Clearly, addition of equipment cannot reduce M.T.B.F. in the narrow sense of the term—more equipment must have more faults—but if one interprets ‘fault’ as the incidence of a navigation error beyond the specified limit rather than narrowly as an electronic malfunction, I do think that v.l.f. navigation has its contribution to make to effective M.T.B.F.

Before a helicopter takes off from an airport on the Norwegian coast to fly to an offshore installation it is cleared in the usual way and is followed by the air traffic control; even after having left controlled airspace the helicopter gets flight-following and alerting services as long as contact can be kept by vhf radio.

When the helicopter approaches its destination it has to enter the platform area by flying over a certain reference point (e.g. an outer platform, Fig. 1), which is to be passed at an altitude of 500 feet and which uses a special frequency for its non-directional beacon (NDB) transmissions; it can thus be easily recognized. Before the reference point is reached, radio contact between the helicopter pilot and the platform area will have been established so that necessary information can be transferred. The pilot then asks all platforms to turn off their NDB's and his destination platform to turn on its own (all NDB's unless otherwise mentioned use the same frequency).

Terminal area A.T.C. must provide each aircraft with access to a network of different facilities. If these each treat their customers on a “first-come first-served” basis, congestion arises which could be avoided by more comprehensive planning. In a large busy terminal area it is at present necessary to decentralize the control process to avoid overloading the human controllers and it is then hard to avoid using “firstcome first-served”. This undesirable trend can be reversed if we hand over part of the decision-making process to an electronic computer.

This paper will be presented for discussion at the Eastbourne tripartite conference, 12–14 May.

In all sciences, the experimenter is constantly seeking to improve both the accuracy of his observations and the speed with which they can be obtained. He wishes, further, to use the minimum of basic equipment, and to obtain the maximum simplicity in collecting his results. Unfortunately, these factors frequently act in opposite senses: an expensive apparatus, for example, may be required to collect accurate data quickly. In certain fields, it is even worth while deliberately to sacrifice accuracy in order to gain advantage both in speed and simplicity. Thus, in astronomical navigation, it may be possible to simplify sight reduction, to cut down on the bulk of tables carried in the air, and to reduce the time taken for observation and reduction of a sight. The penalty will be a loss in accuracy, but, provided this is not reduced beyond a certain level, it may well be worth while. A review of the requirements for air navigation, and an examination of the problems of position finding by the stars against these requirements may lead to some conclusions as to whether an advantage is to be obtained by simplifying the methods.

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.

Commander Paton's paper, here slightly condensed, was presented at the Fourth International Symposium on Vessel Traffic Services held in Bremen from 28 to 30 April 1981. The author is Hydrographic Adviser to the Department of Trade, but the views expressed here should not be taken to represent those of the Department. Commander Paton has also for some years been Chairman of IMCO's Working Group on routing matters.

Apart from some wartime measures, modern ship routing really dates from the early sixties, when the Institutes of Navigation in Britain, France and Germany set up a joint Working Group on traffic separation. The principal result of their labours was the Dover Strait traffic separation scheme, jointly submitted to IMCO by the British, French and German Governments and implemented in 1967. This was followed by various proposals for the North Sea, Baltic and elsewhere, considerable impetus being given by the Torrey Canyon disaster off the Scilly Isles in 1967.