This paper first considers the characteristics of the supersonic transport aircraft (S.S.T.) as established by various international authorities and, on the basis of these characteristics, endeavours to deduce the operational requirements for a navigation system. An indication is then given of the extent to which low frequency radio aids (such as Decca and Harco) can meet these requirements in the subsonic, transition and supersonic flight regimes, whilst discussing the relationship of these ground-based systems to self-contained aids. The paper was presented, in a fuller version, at the meeting of the Deutsche Gesselschaft fiir Ortung und Navigation held in Berlin, 22–7 April 1963.

Only ten years ago it would have been premature to imagine that ILS was likely to provide the basic means for completed landing in zero visibility. The system, designed in 1939, had then received only technological improvements, and no feature seemed to lend itself to any notable development. A frequency of 110 Mc/s is much too low to obtain a narrow beam; all the rival systems now being developed experimentally use frequencies 10 to 100 times higher. Nor is the measurement of difference in rate of modulation the most accurate operation possible with electrical magnitudes; pulse-systems or phase-comparison systems are better adapted.

In view of the number of installations in use on the ground and in the air it was, however, practically impossible to envisage any other guidance system to replace ILS; for modifications would have to be ‘compatible’, i.e. not involve a change in airborne receivers.

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.

Whereas almost everyone seems to be agreed that a system of routing ships in the Strait of Dover offers the best solution to reducing the tragic wastage of life and ships that occurs each year in these congested waters, opinions differ on the system of routing that should be adopted.

A Working Group sponsored by the British, French and German Institutes of Navigation has considered the problem and their report has been published in the Journal. They recommended that the navigational aids in the area should be revised and that ships should be advised, by means of Sailing Directions and Notices to Mariners &c., to follow the tracks shown in Fig. 1.

At the end of 1963, to assist ships making use of the extensive facilities in the Gironde estuary, the port of Bordeaux installed surveillance radar covering the mouth of the Gironde. As it is still too early to assess its potentialities, this paper describes the technical arrangements and makes some general comments on the use of radar, suggested by the new installation.

Ships approaching the Gironde estuary from the open sea follow the buoyed channel from the landfall buoy BXA, 18 kilometres west of Pointe de la Coubre. After picking up the pilot they enter the western or outer entrance passage, whose seaward termination lies 8 kilometres from the coast. This provides a dredged channel, 800 metres wide and 3500 metres long, running east–west. The depth of 12 metres at low water springs enables ships to cross the annular river bar separating the deep water on the seaward side from the mud banks at the mouth of the inner channel.

When radar is used at sea as an aid to collision avoidance, the necessary information has to be obtained by maintaining a plot, which, however, can only offer the average course and speed over a passed time. It is not a reliable prediction of future actions, so that to make too long an extrapolation from a plot is hazardous. It might in some circumstances be better if a ship could be called up by radio and asked her intentions, though this requires first a knowledge of her identity and call sign.

This paper outlines a system of communication that would make it possible to call a ship (fitted with the necessary receiving equipment) initially located only by range and bearing, to obtain the identity of the ship and establish courses, speed and intended actions, and if necessary, radio call signs and calling frequencies. The messages passed by a ship would be recorded automatically. It is proposed that the system should have an operating range of 15 miles, though this does not represent a limit to the range possible. There are objections perhaps to trying to get out of a mutilateral situation of danger by bilateral agreements, and at least one school of thought would hold that the danger is likely to be increased by relying on communication. Nevertheless the system described here holds considerable interest and might, as the author suggests, serve other purposes at sea.

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 15 November 1963, sets out to comment on certain aspects of the long-range navigation of civil aircraft. It concentrates on three areas where there seems to be room for improvement: reliability (a failure rate of 1 : 10 is suggested); the integration of navigation information into a single system and display; standardization of navigation facilities so that all aircraft can use the same basic system.

It is concluded that a reliable system is required down to ground level, an indication of reliability should be presented to the pilot, that high reliabilities can be obtained by comparison of ground-based and self-contained aids, that a navigation computer is necessary to reduce the information to a presentable form, and that the use of very low frequencies seems to be the most promising way of developing an aid along these lines.

The inter-relationships between the application of such airborne devices as automatic landing, head-up instrument displays, flare-out computers, and the like, their effect on operating weather minima, and the consequential benefits that may be derived in scheduled regularity, are very involved. The purpose of this note is to set out in simple terms the more important factors so as to provide a framework for further discussion. A cardinal theme of this discussion is the close association between the techniques needed to improve regularity, and those needed to improve safety.

The landing of a transport type aircraft is a task of a routine and repetitive type. It takes place within a fixed envelope of conditions that can be fairly strictly defined, and a high order of precision is needed compared with other phases of normal flight. The repetitive consistency that can be achieved by automatic means makes it natural to consider such a solution. Once such a system has been developed to a satisfactory level, the accuracy and consistency of the landing manœuvre will undoubtedly be much better than can be achieved by a human pilot.

Dr. David Lewis, better known for his own remarkable feats of navigation, which include single-handed transatlantic passages, illuminates the background to various theories on early Polynesian navigation. Reviewing the evidence, which includes the wide dispersion of the Polynesians and their culture as well as methods of navigation and seamanship that were still practised at the period of European contact, Dr. Lewis concludes that they could determine both course and, in effect, latitude with sufficient accuracy to make a landfall within the area of a known island group, and so proceed to any intended destination.

The method of finding the latitude of a ship at sea from an observation of the Sun or other body near the meridian is practised extensively in the Merchant Navy. The history of the method, which dates from the middle of the eighteenth century, is full of interest: and the ex-meridian problem is almost as celebrated in the history of nautical astronomy as the double altitude problem. Considerable attention was devoted to the ex-meridian problem during the last century—a period which was, in truth, the golden age of astronomical navigation. Many ingenious solutions were contrived and a diversity of ex-meridian tables were constructed, all aimed at facilitating the problem of finding latitude at sea.

When designing a bridge for a naval vessel the designer faces a number of requirements which are quite different from those of a merchant vessel. Besnard states that besides a good view, the officer of the watch requires by him the instruments for determining direction and distance or speed, position finding instruments and other electronic aids, and the means of communicating with the helmsman and engine room as well as some check on these communications. He concludes that a cockpit arrangement of the instruments would suit the requirements. Rees, on the other hand, doubts whether the officer of the watch would remain alert for long periods when sitting in an enclosed compartment, and suggests that a cockpit arrangement is only appropriate where there is little space. Further he argues that the duties of the officer of the watch extend beyond those of simply directing the ship.

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.

The Dutch professor Polak has suggested that an increasing number of higher order specific human thinking functions such as memory, supervision, guidance, schooling, &c. will soon be eliminated and replaced by machines. This sounds alarming, but it should be viewed against the general background of the relationship between man and electronics. The entire structure of the working community in general, and on board ship in particular, is already and will be further influenced and changed by the ever increasing introduction of electronics in general and remote control and automation in whatever form in particular.

The navigator at the present time relies greatly on both optical devices and on radio systems utilizing electromagnetic waves ranging in wavelength from millimetres up to hundreds of metres. The laser extends the coherent properties of radio waves into the visible part of the spectrum. It is natural therefore to expect that this increased facility should lead to the possibility of devising systems based on the laser which might help to overcome problems that still exist in navigation.

It is the purpose of this paper to describe the principles and performance of present-day lasers, to survey some of the techniques used in navigation in order to discover those in which the laser might conceivably play a useful part, and to comment on the laser's advantages and disadvantages in comparison with existing methods. Finally, a particular form of laser called the ‘ring laser’ is described and discussed in some detail. The ring laser is of great interest in that it provides a completely novel way of measuring direction relative to inertial space, and is therefore a possible competitor to the gyroscope for inertial navigation. The ring laser can also measure the velocity of a transparent medium moving relative to it, which could be of use in determining vehicle velocity.

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.

Among many records of the first circumnavigation of the globe preserved in Spain is the log-book kept by the pilot who brought the Victoria home—under the command of Sebastian de Elcano. This pilot's name was Francisco Albo. He signed on in the first instance as master's mate of the Trinidad, Magellan's own ship, which did not return. Although a native of the island of Rhodes, he was thoroughly grounded in the Portuguese method of navigation—by observation of the noon Sun. It involved the use of a four-year table of declinations, and an English version of this very table and instructions was presented to Henry VIII about 1540 by Roger Barlow, who was urging an English participation in the new discoveries.

Major Richard C. Henry's paper (Journal, 16, 449) is timely. These comments are restricted to mid-course navigation and are intended to expand and clarify some parts of this excellent paper.

Major Henry divides space navigation into two parts, orbit and trajectory navigation: the first about one body, and the second, about two bodies. For example, Echo Satellite is in orbit about the Earth, while if its path were to include an orbit about the Moon as well as about the Earth, its path would be called trajectory. If we consider the path of a lunar capsule as determined by lunar perturbations of a body in orbit about the Earth, astronomers should be able to compute its trajectory, or path, or ephemeris, or orbit, and supply the information to the space navigator in the form of a Space Almanac. The guild of space navigators would use this shelf item, along with an accurate timepiece, and a marine type sextant, as the basic equipment for accomplishing mid-course navigation.

Very shortly after the second world war merchant seamen found that they had inherited a device which shipbuilders and owners fondly imagined would prove to be an infallible safeguard against navigational hazards: this was radar. After fifteen years had been devoted to examining the disappointing results provided by the new panacea, the International Conference on Safety of Life at Sea, held in London in i960, finally published a radar code. So eagerly had this code been awaited that the Conference recommended its issue without waiting for the new international convention to be implemented.

The observation of a radar display by a human operator leads to the establishment of aircraft tracks. These tracks are subsequently used by the controller. More and more often, it is proposed to replace both PPI display and human observer by an automatic computer, either special or general purpose, to perform tracking.

In the present paper the basic performances of these two modes of operation are examined, taking into account the psychological and physiological features of human vision and hence the mental association of the viewer. The computer is more precise, but more costly and, when saturated, the drop in performance is abrupt. The number of tracks handled by a human operator is small, but the brain is very versatile and works very well in confused situations, with a slower drop in efficiency than the computer.