Mr Hopkin, Senior Principal Psychologist at the Royal Air Force Institute of Aviation Medicine, discusses the human implications of recent advances in the automation of data processing and display as affecting both the role of the navigator and the safety of navigation. This paper was presented in London on 11 December 1980 at a joint meeting of the Institute and the Nautical Institute.

Thirty years ago, in the April 1950 issue of this Journal (3, 133) J. E. D. Williams published a paper ‘Loxodromic distances on the terrestrial spheroid’, in which inter alia he provided a table of latitude corrections to allow for the varying length of a minute of latitude. In the present paper R. Williams tackles the same problem more directly and proposes a table of ‘latitude parts’.

Following the Amoco Cadiz disaster in 1978 proposals were put forward, and ultimately accepted by IMCO, for a revision of the traffic separation schemes off Ushant and the Casquets, the broad effect of which was to keep large tankers (and those carrying hazardous cargoes) further off the French coast. The modifications came in for some criticism and recent Anglo-French proposals have now secured IMCO agreement. Prior to that a purely United Kingdom working group sought to formulate a comprehensive and continuous routing scheme for the whole English Channel.

Captain Cockcroft who, as an observer for IAIN at IMCO and as RIN representative on the UK working group on Channel Routing, has played a leading part in these discussions, here describes some of the problems and considers issues raised by concepts such as ‘areas to be avoided’, and finally, within the context of traffic separation in straits, proposes alterations to the Collision Regulations which govern the crossing of traffic lanes and the use of inshore traffic zones.

The application of technological developments to the flight-deck for flight management, navigation and displays has been very rapid and there has been a tendency for parts of the operational system to be improved without evaluating fully their interaction on the flight deck and as between ATC and the aircraft. The Civil Avionics section of Operational Systems Division (FS2) at Bedford has been concerned with the development and investigation of techniques for the integration of this modern equipment into the operational environment of the flight deck of the future, with the overall aim of improving airspace utilization. This will have the potential for reducing delays and saving fuel.

The title, the gift of Frank George, derives from The Troublesome Voyage of Captain Edward Fenton, E. G. R. Taylor's masterly edition of narratives relating to one of the less successful of Elizabethan adventures. Fenton's voyage of 1582, to China and Cathay, was a total failure. But the tale endures.

In the title to this paper I have deliberately used the plural, for I do not think it possible that the compass was only invented in one country and knowledge of it transmitted from there to other parts of the world. It is much more likely that the possibilities of its use, not necessarily for purposes of marine navigation, were discovered in several parts of the world, that some who knew of it transmitted it to their neighbours, but that in some areas the original knowledge was lost again. Of course such inventions may have had forms very different from the compass as finally used.

The first definite European account of the compass is contained in the writings of Alexander Neckam (1157–1217), about A.D. 1187. In De Utensilibus he wrote: ‘Qui ergo munitam vult habere navem…habeat etiam acum jaculo suppositam; rotabitur enim et circumvolvetur acus, donec cuspis acus respiciat orientem sicque comprehendunt quo tendere debeant nautae cum cynosura latet in aeris turbatione.’ The translation of this which I accept is as follows: ‘Therefore he who wants to have a well-equipped ship…let him also have a needle placed under a dart; for the needle will rotate until the point of the needle looks towards the East, and thus sailors perceive in which direction they ought to go, when the Little Bear is hidden in disturbed weather’. It has been suggested that in this passage ‘donec cuspis jaculi respeciat’ was probably intended for ‘donee cuspis acus respiciat’.

Although VOR/DME has been the standard airborne navigation aid for over 15 years there are still some features of the system which are far from ideal. In particular, the bearing information from the ground station is noisy and frequently inaccurate. There are a number of sources of error, some avoidable and some not. The quality of maintenance, particularly with respect to alignment and calibration, varies greatly throughout the world – for example there have been a number of reports concerning VOR stations in the Eastern Mediterranean with up to 40° error in the transmitted bearing information.

This paper, which was presented at a meeting of the Bristol Channel Branch of the Institute in Cardiff on 23 April 1980, describes Squadron Leader Cyster's solo flight from Dunsfold to Sydney in a vintage Tiger Moth in 1978.

The establishment of standards for lateral separation between adjacent jet routes depends in large part on an adequate description of aircraft path-keeping ability. While it has been accepted for many years that deviations from route centreline follow a distribution which is more peaked in the core and longer tailed than the gaussian distribution which was initially assumed, the selection of an alternative distribution is still moot. Early studies of oceanic data suggested that a double exponential distribution gave a much better description of the core data. However, this distribution still appeared to underestimate the frequency of occurrence of very large errors, so that a double-double exponential distribution was proposed and is currently used for establishment of MNPS (Minimum Navigational Performance Specification) criteria for the North Atlantic organized track system. A physical rationale for the occurrence of the double-double exponential distribution has recently been derived, with suggestions for consideration of alternative formulations.

In this paper Claud Powell, formerly of the Decca Navigator Company, discusses the antecedents of modern radio position-fixing systems whose position lines are of hyperbolic form. The paper was presented at an Ordinary Meeting held in London on 22 April with Rear-Admiral D. W. Haslam in the Chair.

Until very recently in human history, the fixing of position for navigational and kindred purposes depended principally upon the measurement of angles. An escape from the limitations of this essentially visual process had to await the development, through advances in electrical and later in electronic engineering, of what E. W. Anderson has termed the ‘timing of waves’. This classification covers virtually all the non-visual methods of deriving a line of position, for example the measurement of range by timing the roundtrip of a signal travelling at a known speed to a reflector or transponder and back; the measurement of ‘pseudo-range’ by comparing the times of signal transmission and reception according to local clocks; and the differential measurement of range to two known points some distance apart by timing the interval between the reception of synchronized signals transmitted from those points.

This paper was presented at a meeting of the Institute in London on 21 January 1981 with W. H. McKinlay in the Chair. The views expressed do not necessarily represent CAA policy, but Mr Attwooll discusses the derivation of fuel-uplift requirements from considerations of safety and regularity of the flight, using additional information on the probability of various adverse contingencies such as headwind or ATC delay. Methods of safely reducing fuel reserve requirements are discussed, including improvements in navigation and the on-board decision-making process.

A chart is the data base to which other navigational information is related and yet has to serve ships of widely different draughts. A possible alternative providing more draught-specific information based largely on currently available hardware, would be the creation of ‘banded contour charts’ on microfilm. Produced directly from a computer data bank by a fast flying light-spot microfilm plotter, the master charts would be single frames of 35 mm microfilm mounted in cards 183 by 83 mm. A set of micro-charts would be produced covering the same sea area and differing only in that each has a different, limited band of depth contours of critical importance to ships in a limited draught range: for example, the first going from 0 to 5 metres by 1-metre intervals, the second from 3 to 8, the third from 5 to 10 and so on. All other data, including spot depths outside the contours, would be the same on all charts in the series.

Various methods of standard, or stored, flight planning are in use throughout the world and have some degree of success, but on occasions they are too rigid to accommodate changes to routes or in weather patterns. A standard plan should eliminate the individual differences between manually computed flight plans by two pilots for the same route in identical aircraft. It should be in real time, flexible enough to allow route changes by ground control and capable of taking advantage of fuel-saving tail-wind components. All four requirements are inextricably linked.

This paper, which was presented at an Ordinary Meeting of the Institute in London on 18 March 1981 with Dr J. F. Kemp in the Chair, outlines the scope for using modern programmable hand-held calculators at sea, discusses the functions and facilities required for navigation and describes some of the models now available.

For many years the basic instruments for navigation have been the compass, chart, sextant, log and chronometer; an advanced scientific calculator should now be added to the list. Indeed, this type of calculator should form part of the personal navigation equipment of every navigator—marine or air, military or civil—because the way to get the best out of a machine is to have one of your own; you will seldom get the best out of any machine which is shared.

In a series of three papers Dr Lewison has described the progressive results of a line of research which may have important applications in the consideration of routing schemes. The first paper described a mathematical model which can predict the number of encounters that would occur between ships of different traffic streams in the absence of avoidance manœuvres. In the second paper the number of potential encounters was calculated from estimates of traffic flow, in a particular area of the Dover Strait, then compared with the number of actual collisions to determine the risk of a ship encounter leading to a collision. The third paper updated these results for the Dover Strait and suggested how estimates of collision risk could be made for other UK coastal areas.

‘A labourer works with his hands.

A craftsman works with his hands and his head.

An artist works with his hands, his head and his heart.’

It is the common practice to draw great-circle tracks on gnomonic charts, on which they appear as straight lines, to pick off the latitudes of intermediate points where the track is intersected by the charted meridians, and finally to transfer the pairs of coordinates thus measured to a Mercator chart. The purpose of this note is to present the derivation of some formulae by means of which the coordinates of points along the track may be calculated very easily.

Recent growth in air-traffic movements is causing severe traffic congestion problems in terminal areas and en route. To meet these demands for more effective and safe utilization of airspace, separation standards in an air-traffic-control environment are being studied by the Review of the General Concept of Separation Panel (RGCSP) of the International Civil Aviation Organization.

One of the most effective ways of evaluating separation standards would be a mathematical method using a collision-risk model, for which we require data on the navigation accuracy of current aircraft as one of the parameters. At present, the data on navigation accuracy in the vertical dimension (height-keeping error) do not permit us to derive any definite conclusions on the distribution of navigational errors. In order to survey height-keeping errors we have developed a simple height-finding radar system, the Navigation Accuracy Measurement System (NAMS), based on a curve-fitting method. Thanks to this principle, NAMS has an advantage in its comparatively lower cost and simple structure.

The system consists of an antenna whose radiation pattern is a fan beam, a transceiver, a digitizer and a mini-computer. The antenna rotates about a horizontal axis and scans aircraft flying overhead. The height of an aircraft is estimated by processing the data obtained over several scans, using a mini-computer. This paper first outlines the characteristics of NAMS and then gives results of evaluation tests on its accuracy.

In this paper, by T. Degré and X. Lefèvre of the Organisme de Recherches Informatiques et Opérationnelles appliqués à la Navigation (ORION), the authors outline the principles of a proposed collision avoidance aid based on the concept of a ship's ‘room to manoeuvre’ in the presence of the vessels' or hazards to navigation and a corresponding bridge display.

While navigation in the Suez Canal and the Gulf of Suez has been given much study and has attracted considerable comment in recent years there has been comparatively little said about the Red Sea. In view of the very marked increase in traffic in this area and the attendant upsurge of vessels calling at Red Sea ports, particularly Jeddah, more study of the problems of navigating in this body of water would seem warranted.