bluuebunny/crossref_metadata_2025 huggingface dataset:
I—The Development of the Specification
Authors: Brooker P.
Published: November 2009

Every day several hundred subsonic aircraft travel between the European and North American continents. Because of noise limitations at major airports, aircraft turn-around times and the time difference between the continents, the direction of the main traffic flow changes through the day. In the afternoon (GMT) the flow is predominantly westbound, while in the early hours of the morning the flow is predominantly eastbound. Oceanic air traffic control for the North Atlantic region has evolved into what is now known as the Organized Track System; traffic is divided into streams, each stream flying at a specified set of flight levels on one of several adjacent tracks. Figure 1 shows an example of the subsonic track system during the westbound peak. To secure operating economy the layout of the track system on any day is matched to the pattern of the upper winds.
The Impact of Low Cost Micro-processors on Airborne Navigation Systems
Authors: Hearne P. A. , Hamlin D. J.
Published: November 2009

The following paper was presented at an Ordinary Meeting of the Institute held in London on 21 March 1979 with Mr S. S. D. Jones in the Chair.

This paper is not so much a forecast of future navigation systems as a personal view of the philosophy of the increased use of micro-processors. Digital computers were first introduced into airborne systems in the late 1950s to meet the demands of new sensors such as inertial navigators and star trackers for which analog computation methods proved inadequate and inaccurate, but their cost restricted their application to specialized high accuracy systems.
Risk: Taken or Controlled?
Authors: Tanner P. H.
Published: November 2009

The practice of safety can be treated as the operation of a system with which it is intended to control the level of some parameter ‘risk’. The following is an attempt at a description of the behaviour of a population of individuals engaged in a risky occupation in terms of such a system. In the first section the casualty figures for commercial airline operations are analysed to show that there is a prima facie case for a belief that in this case risk level is regulated by those immediately engaged in the industry. The second section contains a description of a proposed ‘input/output’ model of an individual regulating his own risk, and preliminary results are given for a simulated population of aircraft operators having these characteristics. Lastly, the credibility of the model in terms of known human behaviour is examined, some tentative conclusions are drawn and an indication is given of its proposed use and development.
Navigation and Society
Authors: Ritchie G. S.
Published: November 2009

Taking the dictionary meaning of society to be the civilized body of mankind – what are the relationships between society and the art or science of navigation? To define navigation itself I have used Wing Commander Anderson's definition of 1961 – ‘Navigation is the business of conducting a craft as it moves about its ways’.
Automation and Air Traffic Control
Authors: Goodwin John
Published: November 2009

It is of course a truism to note the profound effect that transportation has had on modern society, which is quite simply unimaginable without communications by land, sea and air. The role played by navigational science and its application has of course been somewhat different in each medium. Navigation by air, though, has a special distinguishing feature in that the aviator frequently shares responsibility for the safe and efficient conduct of his flight with another agency, the air traffic control system.

For the foreseeable future, air traffic control will have a major part to play in the navigation and safety of travel by air and so, by implication, future developments in air traffic control will have an influence on society at large.

Turning now from the general to the particular, the author would like to give an example, which may be symptomatic and serve to illustrate the magnitude of the problems that the air transport industry, including air traffic control, may face in the future.
Strategies for Marine Traffic
Authors: Goodwin Elisabeth , Richardson R. B.
Published: November 2009

Although its achievement may prove long and difficult, it is surely time to think out the lines along which future traffic systems must inevitably be developed, for we are still largely without any real rationale as to what it is we are to achieve when traffic measures are introduced, whether with IMCO agreement or nationally. We have some of the right answers but have we yet asked the right questions?

Before we can evolve any realistic strategy there must be some consensus across several disciplines; disaster seems to show itself the only effective antidote to fixed ideas. Society is not likely to tolerate this approach indefinitely and a more acceptable mode of progress must begin now, before irrational forces take charge.

The dominant factor has hitherto been safety of navigation, though navigation concerns only the ship and not her cargo, with its contractual obligations and penalties. Yet the risk to society derives almost wholly from the nature of the cargo.

The laws concerning carriage of goods and contracts of affreightment – the province of the ship-operator and his litigation processes – can often be in direct conflict with the statutory requirements of governments relating to navigation and collision, whose theme is safety of life per se and is not concerned with efficiency. It would be reasonable to accept the proposition that the demands of society towards these problems should be solved by traffic-oriented rather than ship-oriented schemes.
Some Aspects of Commercial Sail
Authors: Mudie Colin
Published: November 2009

There can be little doubt that the concept of using wind power for ships has a great deal to commend it and equally little doubt that the extensive use of the natural power available from wind, sea and sun in order to conserve fossil fuel resources must be urgently considered. If we leave aside sea and sun, although both are potential sources of some proportion of propulsion, and concentrate on wind power the immediate and largest problem is one of the time available. We may all believe in the principle but the problem is one of arriving at an industry with the appropriate technical ability in any short time. We know that it is possible, as witness the hovercraft industry, and this was achieved by grafting the new technology to the stem of the existing aircraft industry. It might equally have been attached to shipbuilding or boatbuilding or even the car industry. I think in fact that the right decision was made and that hovercraft have benefited from their attachment to the industry with the greatest life in it.
ATC and the Airborne Traffic-Situation Display
Authors: Ford R. L.
Published: November 2009

In this paper, which was presented at an Ordinary Meeting of the Institute in London on 23 May 1979 with S. Ratcliffe in the Chair, Dr R. L. Ford outlines proposals for an airborne traffic-situation display. By providing pilots with a visual synopsis of ATC strategy in the terminal area and a collision warning facility, the display would enable them to play a more constructive role in maintaining safety and efficiency in aircraft operations.
Navigational Measurements
Authors: Anderson E. W.
Published: November 2009

In this paper we shall seek to discover what information we need in order to navigate and how this information is obtained. To do this we first define what we are talking about and then, by a logical process, determine the components involved and the ways they can be measured. Efforts to discover whether another science has been approached in this basic way have failed. All that can be said with certainty is that the path is fraught with difficulties.

The word navigation has nautical origins but the scope of the discipline is far wider today. Nevertheless, a modern definition must stem naturally from marine operations. There would seem to be four factors:

(a) A ship at sea is not navigating when she is docked. There has to be motion.

(b) Rocking to and fro is not enough. The motion has to be from one place to another.

(c) Drifting helplessly before the wind is not being navigated. The motion has to be under control.

(d) The word ‘control’ has a negative and restricting connotation whereas travel has positive aims. Hence the control has to be exercised to a purpose. Steering aimlessly, however complete the control, is not navigating.

A definition of navigation should therefore include four features, motion, place, control and purpose. A possible wording might be:

‘Navigation is purposeful control of motion from place to place’.
Projective Geometry and Collisions
Authors: Goodwin Elisabeth M.
Published: November 2009

A few years ago a series of papers by Frank Coffman Bell was published in this Journal suggesting how collision avoidance manoeuvres could be analysed using projective geometry. However it is probably true that most non-mathematicians have little experience of any type of geometry other than the Euclidean metric geometry which is taught in schools. Euclid's approach was to elaborate a science of the measurement of physical space and for this purpose he deduced a number of geometrical theorems starting from the intuitional ideas of point, line, distance and length. To Euclid and his followers the notion of distance was completely obvious and basic and underlay everything in geometrical science, hence the terminology that is given to this work ‘metric geometry’. Another concept of geometry was however put forward by a group of geometers of whom Pappus is one of the best known. His work shows that he was interested in theorems concerned not with distance but with such things as concurrence of lines and collinearity of points. This type of theorem may be thought of as the projective type. If for example it is assumed that any two lines in a plane meet in a point, then two parallel lines must also meet in a point which may be termed a point at infinity. In projective geometry no distinction is then made between ordinary points and points at infinity.
US Research into Shiphandling Simulators for Mariner Training and Licensing
Authors: Hammell Thomas J. , Gardenier John S.
Published: November 2009

Shiphandling training simulators have come into use since 1967. Several such simulators, with differing technical characteristics and training goals, are now in use around the world. They are commonly used to familiarize already competent masters with new vessels, restricted water areas, or some form of standard bridge procedures. Acceptance of these simulators by highly experienced master trainees has been predominantly favourable. Ship radar simulators have been in use for a somewhat longer time. They are typically used for training entry level officers as well as experienced masters.

The aviation and nuclear reactor industries, with a greater experience of simulator technology and its training value, use simulators for both training and licensing. The military (e.g. Navy) and other government agencies (e.g. National Aeronautics and Space Administration) have extensively used simulators for training and qualification. It has been suggested (Schumacker, Madsen and Nicastro, 1972; IMCO Standards of Training and Watchkeeping Convention of 1978, Resolution 17) that simulators could be used for proficiency demonstration on the part of mariners. The US Port and Tanker Safety Act of 1978 requires standards for licence qualifications by use of simulators.

The United States Coast Guard and Maritime Administration have funded research into the role, technology, and effectiveness of ship-handling simulators. Depending partly on conclusions from this research, the Coast Guard will consider partial credit toward licences for successful completion of approved simulator training. The Maritime Administration may assist maritime training academies to design and procure simulator-based training systems.
The Industrial Archaeology of Lighthouses
Authors: Komesaroff M. B.
Published: November 2009

Most lists of the seven wonders of the world include the Colossus of Rhodes. This bronze figure of Apollo, which the sculptor Chares took several years to construct, stood near a harbour on the island of Rhodes in the Eastern Mediterranean. It is reported that ships in full sail could pass between its legs whilst navigation lights were kept burning in its eyes. Whilst such descriptions are coloured by romance and myth, there is little doubt that early lighthouses were substantially tall towers supporting an open wood or coal fire. Such lights existed in Britain until as late as 1819, when Flathom light in the Bristol Channel was replaced by more modern equipment.

In time the open-flame coal brazier gave way to tallow candles. In 1696 Winstanley introduced a chandelier with tallow candles into the lantern of his famous Eddystone Tower. In 1759 Smeeton's Tower, which now stands on the Hoe at Plymouth, incorporated two superimposed iron rings that contained twenty-four candles.

By and large it was the improvements in optical systems that governed the development and introduction of oil and then, at a later date, electric illuminants.

The first attempt to intensify a lighthouse beam was in 1727 by the French at Cordouan. Mariners had complained that they could not see the light at more than 2 miles. In an attempt to improve on this, a cone of wood was covered with tin plate and suspended above the open fire.
The Province of the Institute
Authors: Richey M. W.
Published: November 2009

The following Address, by the retiring Director of the Institute, was presented at the thirty-fifth Annual General Meeting held in London on 27 October 1982 at the Royal Geographical Society with the President, Captain B. J. Calvert, in the Chair. The President said that Mr Richey's pending departure (although he would continue to edit the Journal) was an event of considerable importance in the Institute's history and he felt it appropriate to have invited him on this occasion to present an Address in place of the Presidential Address normally delivered at the Annual General Meeting. Calling the Meeting to order, the President drew attention to a gavel, around which the names of past Presidents and Directors were to be inscribed, made from wood, for the anvil, from HMS Victory and, for the striker, from the yacht Jester. After the Address Wing Commander Anderson gave a reply reminding the Institute of Mr Richey's achievements during his long period in office. The audience then broke all traditions by giving the Director a standing ovation. His successor as Director, Rear Admiral R. M. Burgoyne, was then introduced to the Meeting.
Integrated Navigation Actual and Potential: Human Aspects of Integrated Navigation in the Air
Authors: Hopkin V. David
Published: November 2009

Automated aids, computer assistance and other forms of advancing technology are gradually changing the human involvement in many tasks, so that the primary roles of man are to monitor, verify, manage resources and respond to emergencies, rather than to participate actively and continuously in the control loop. Many of the terms traditionally employed to designate or describe jobs are retained throughout this process although they are no longer apposite, and they can give a misleading impression of the nature of the residual human roles and of the skills required to fulfil them. In many respects an aircraft pilot may no longer actually fly his aircraft for much of the time, but monitor equipment that flies it automatically. A nominal supervisor may remain in many environments where revised human roles and facilities mean that effective supervision is impracticable. An assistant may not in fact be able to offer true assistance because he has no facilities to share any of the tasks, do parts of them, or assume temporary responsibility for them. The future navigator may not need to be able to navigate in the traditional sense.
Aircraft Separation Assurance: Systems Design
Authors: Brooker Peter
Published: November 2009

One of the major concerns in the operation of an air traffic system is the maintenance of adequate separation between aircraft. The assurance of an ‘acceptably low’ risk of collision is a crucial element in the system design. A number of factors need to be assessed in this process. What is the navigational performance of the aircraft in the system ? What are the possibilities for radar surveillance ? Are procedural arrangements together with position reporting a suitable mechanism? What difference would be made by collision avoidance or warning systems? Given that any combination of these or other factors has an implication on the minimum separation between aircraft, the level of safety ‘assured’ has to be balanced against the costs of the various alternatives which may present themselves.

In planning for change the implications of new operating practices or devices have to be assessed carefully. For most changes the process is one of evolution rather than revolution, although collision avoidance devices may have more of the latter's characteristics. Even for ‘revolutionary’ changes it may be possible to model the new system. Thus the existing situation is studied and its characteristics observed, then there are hypotheses of the ways in which the change alters the mechanisms in the system and finally the likely effects on system performance through mathematical and computer (often fast-time simulation) modelling.
The Impact of Filtering on Sea and Air Operations
Authors: Pearson M. G.
Published: November 2009

Estimation methods and filtering techniques are nowadays an integral part of any computer-based navigation system. The purpose of these techniques is to provide an estimate of required variables which is sufficiently accurate for real-time command and control purposes. Repeatability, which is important for so many applications, is deemed to be a by-product of the estimation process. For this requirement it is not strictly necessary for the process to be accurate, it is sufficient if it is only consistent; these are closely linked but one does not imply the other. The modern approach is to minimize the variance of the noisy observations or the sum of the squares of the residuals, and the methods available for doing this are increasingly refined. The impression given in the literature (and it is extensive) is that data processing can somehow compensate for the shortcomings of the basic sensors with respect to the operation being considered. Within certain limits this is true, but the real reason for the sudden surge of Kalman filtering for real-time on-line applications was the relative simplicity of the computational process. In a way, Kalman filtering has done for estimation theory what the Fast Fourier Transform has done for spectral analysis.

The concept is simple enough to state. It consists of combining two independent estimates of a variable to form a weighted mean. One of these estimates is a forecast and the other is the current measurement.
Recent Surveys
Authors: de F. Browne R.
Published: November 2009

Figure 1 shows the present state of surveys over the UK continental shelf. Out of an area of some 173 000 square miles contained within the British Fishery limits, 36 per cent has been surveyed by echo sounder, but not necessarily to a scale suitable for modern standards, and only surveys to full modern standards are sufficient to ensure safe navigation within r m of the seabed; a modern standard survey must be carried out using a modern echo-sounder and include a thorough sonar sweep. All hips of the Survey Flotilla are now fitted with a Kelvin Hughes MS48 echo sounder and an OAL side-scan sonar.

New technology, such as the towed side-scan system, has enabled the surveyor to examine the whole of the sea bed between a regular pattern of sounding lines, spaced to ensure that the sonar beam from one line searches at least 50 m beyond the adjacent lines either side. This ensures that all wrecks, rocks and other obstructions on the sea bed which could be a danger to navigation are located, and subsequently closely examined for the least depth over them. Side-scan sonar is best operated at a speed of 5 or 6 knots, which means that the time taken to carry out a survey to full modern standards is far longer than twenty years ago, but during the last five years almost 8 per cent of the UK continental shelf has been fully surveyed to modern standards.

Our Survey Flotilla comprises eleven vessels, four Ocean Survey Ships – Heda, Hecate, Herald and Hydra; four Coastal Survey Vessels – Bulldog, Beagle, Fox and Fawn; and three Inshore Survey Craft – Egeria, Enterprise and Echo.
Changes in Admiralty Chart Specification
Authors: Magee G. A.
Published: November 2009

Users of Admiralty charts will be familiar with the fact that the specifications which are followed in respect of content and design evolve continually; some of the changes are in response to suggestions put forward by users. It is intended, for example, to add the morse identification of racon signals on charts, following a suggestion by Trinity House. The Hydrographer is always anxious to encourage comments from sea and the Chart Users' Advisory Panel is dedicated to that end. Some changes result from new developments in the navigational field: the representation of vhf radio lighthouses, for example, is now being considered so that they may be charted by symbol when they emerge from their present on-test status to become fully operational. Other changes stem from office considerations, such as new cartographic techniques or the requirements of effective maintenance of the published charts. The more important of these changes are announced through Admiralty Notices to Mariners as corrections to the Symbols and Abbreviations booklet, 5011, a document indispensable to chart users since charts do not themselves carry a key to the symbols used; over 40000 copies of 5011 have gone into circulation in the past two years alone. Other innovations, less significant or self-evident, are not normally announced by Notices to Mariners in this way but implemented through office instructions to the cartographic staff of the Department. Recent examples have been the decisions to include notes giving the relationship of charted latitudes and longitudes to WGS-based positions, so that SatNav observations can be reliably plotted on charts; and, on a minor level, to add the label ‘o’ (zero) to the drying line at intervals in the same way that other depth contours on metric charts are labelled with their values, a step deemed to be useful in case copies of charts have to be printed without the superimposed colour tints.
The Use and Misuse of Charts
Authors: Morris R. O.
Published: November 2009

We recognize that in the general line of trade (or, as we have had underlined again recently, of war) there will be places where ships have to go but where, with the best will in the world, we have not been able to provide adequate charting or even to recommend anyone else's chart as fit for use. The master and his owners, or the naval commanding officer and his operational authorities, have got to weigh the advantages of calling at that port, or using that route, against the danger to the ship and decide whether the gain justifies the risk.

In 1973 we were astonished to hear that a foreign coaster on passage from a Bristol Channel port to Penzance had attempted to go between Godrevy Point, the north-eastern head of St Ives Bay, and Godrevy Island, some 2½ cables offshore, at low water. Fortunately for her, she was spotted by the local coastguard before she was irrevocably committed to the passage – and dissuaded. The largest scale chart of the area, Chart 1168, is on a scale of 1: 25000, and shows the passage as some ¾ inch across from high waterline, or less than half an inch between drying rock shelves. Admittedly it did show a narrow gap where the contour lines suggested that more than 5 m of water could be carried through the centre of the passage. The sailing directions state that the channel outside the island, between it and the outer shoals, should not be used without local knowledge. The inner passage is briefly mentioned but no instructions for passing through it are given.
Admiralty Sailing Directions
Authors: Pryor J. S. N.
Published: November 2009

In 1970 a review of the Sailing Directions was undertaken to find out if they met the needs of the twentieth-century mariner. This review was based mainly on the response to a questionnaire promulgated by Notices to Mariners, to which some 900 replies were received. The general assessment was that considerable improvement was required in the port and pilotage information; a loose-leaf type of book, for ease in correction, was also suggested.

The outcome of the review was the adoption of a new style, involving a stricter geographic sequence in dealing with the coastal features, more headings to divide up the text and proper names highlighted by the use of bold type at the principal mention. At the same time the international A4 size was adopted to provide a shorter line of print in two columns, and a better page size for graphics. Much pure description of the chart has been removed, but there is still rather too much repetition of detail which can already be seen from the chart.
The Work of the International Hydrographic Organisation
Authors: Ritchie G. S.
Published: November 2009

Real Admiral Ritchie, who retired on 1 September 1982 after ten years as President of the Directing Committee of the International Hydrographic Bureau in Monaco, here looks at the work of the International Hydrographic Organisation, more particularly in those areas which are of direct interest to the navigator.

In 1919 an International Hydrographic Conference was called in London at which representatives from the hydrographic services of twenty-four nations attended. After discussing at length cooperation in the fields of charting, Notices to Mariners, and the international exchange of hydrographic data, it was resolved to set up a permanent Bureau. The Conclusion to the Conference reads as follows:

The International Hydrographic Bureau whose formation is here suggested fulfils, in our opinion, an imperative need. Assuring a close and permanent association between the National Hydrographic Services, it allows of the cooperation of the efforts of all maritime Powers to furnish navigators with more perfect and up-to-date nautical documents. Without limiting in any way the liberty and initiative which should be retained by the Offices of the countries concerned, the new organisation will avoid unnecessary effort and wasteful expenditure; it will create amongst the surveyors of the different countries a fruitful rivalry and personal relations which are frequently of great value. We are convinced that its rôle will constantly increase in the future, and that its establishment will tend greatly to advance the Science of Hydrography.

The italics in the above statement are mine. These words still reflect the most important aim of the International Hydrographic Organisation over sixty years later.
Rotations in Navigation
Authors: Anderson E. W.
Published: November 2009

Wing Commander Anderson, the author of The Principles of Navigation in which he emphasized the essential unity of philosophy which underlies all forms of navigation, has further developed this concept in two papers in this Journal published in 1980, ‘Navigational Measurements’ and ‘The Magic of Animal Navigation’ (Vol. 33, pp. 33 and 444). In the present paper he examines further in non-mathematical terms some of the difficulties met with in the analysis of rotations in navigation, including the effects of the Earth's rotation on its axis.
Over Reliance on Nautical Charts
Authors: Haslam D.
Published: November 2009

As a result of the loss of the French passenger liner Antilles after grounding on an uncharted rock in the Grenadine Islands in the West Indies, on 8 January 1971, the owners of the ship filed a petition for limitation of or exoneration from liability in the United States District Court for the Southern District of New York. A number of claimants against the owners, chiefly passengers in the ship at the time of loss, entered the limitation proceedings and moved the New York Court to transfer the case to the District of Puerto Rico. After the case had been so transferred, several claimants filed direct action suits against the owners and their insurers; these suits were stayed pending the outcome of the limitation proceedings.
Matthew Flinders and Ship Magnetism
Authors: Cotter Charles H.
Published: November 2009

It appears that the earliest recorded reference to the effect of the magnetism of a ship or her fittings on the magnetic compass was made by the Portuguese explorer João de Castro in his Roteiro de Lisboa a Goa of 1538. João noticed that the compass he used to observe for variation was affected by iron objects on board placed near to the compass.
Spherical Hyperbolae and Ellipses
Authors: Freiesleben H. C.
Published: November 2009

Dr. Freiesleben, an Honorary Member of this Institute, discusses the geometry of ellipses and hyperbolae on the sphere. These are the curves which correspond to position lines based on the constant sum or difference of distances from two fixed points. Originally applied to astronomical position lines they now have a wider application to electronic fixing systems of global coverage like Omega.
Navigation Lights
Authors: George B. D.
Published: November 2009

It is natural that present attitudes towards safety at sea and collision avoidance should reflect a justifiable preoccupation with electronics in meeting the exigencies of marine traffic congestion and collision hazards. Despite the frequency with which marine casualties occur during darkness and in conditions of poor visibility there is a tendency to minimize the positive, if modest, contribution of efficient and distinctive ships' navigation lights towards safety at sea in these circumstances.
A Tabular Method for Star-Sight Reduction
Authors: Nastro V. , Russo A.
Published: November 2009

In a recent paper in this Journal the Director of the Royal Institute of Navigation describes some methods of navigating small vessels; he rightly includes classical astronomical navigation and describes some speedy and well-known methods of solution. In spite of the availability of such tables and mechanical devices the solution is not within everybody's reach because nautical ephemerides are always necessary; convenient tables are the Sight Redaction Tables for Air Navigation (A.P. 3270) from which the elements for tracing out the lines of position through the intercept method can easily be extracted. The simpler tables here proposed present the following advantages:

(i) the ephemeris is not required

(ii) the observed sextant altitude need not be corrected for refraction and dip.
Nevil Maskelyne, the Nautical Almanac, and G.M.T.
Authors: Howse Derek
Published: November 2009

Early in 1967, a few months before the restored Meridian Building of the Old Royal Observatory was opened to the public by Sir Richard Woolley, the Astronomer Royal, I received a visitor in my office then in the Meridian Building — later, I was to move to the west summer house of Flamsteed House. My visitor was Colonel Humphrey Quill, Royal Marines, Master of the Worshipful Company of Clockmakers that same year and author of the hookJohn Harrison, the Man who Found Longitude, which has become a standard work. He brought with him some manuscripts written by the subject of this lecture — Nevil Maskelyne, fifth Astronomer Royal, who lived in Flamsteed House for 46 years from 1765, making most of his important astronomical observations in the very building in which Col. Quill and I were sitting.
Developments of Time Systems Since 1884
Authors: Pilkington J. D. H.
Published: November 2009

During the century since 1884 there have been fundamental changes in the principles on which timekeeping is based; nevertheless, almost all countries now base their civil timekeeping on a time scale which is the standard time of the Greenwich meridian and which remains within 1 second of the time envisaged at the Washington Conference. The system of time zones, in which universally valid hourly markers were given longitude-dependent labels, spread rapidly under the influence of the railway systems, with legislation usually following established practice. Daylight saving time, first introduced in many countries in 1916, is a form of mass self-deception which provides extended summer evenings in the temperate zones but causes inconvenience to the travel industry and confuses its customers.
Random Air Traffic Generation for Computer Models
Authors: Goodwin J. L. , Ford R. L.
Published: November 2009

Methods of generating random air traffic are described for two- and three-dimensional computer models used in a study of the problem of managing off-route traffic. Edge effects which influence the estimation of conflicts taking place near the boundaries of such models are explained and quantified.

The applications of computer models in air traffic management studies are many and varied. References 1 and 2 describe some of these for which the appropriate model required the generation of randomly distributed aircraft following straight-line flight paths at constant speeds. Such behaviour can be a plausible representation of that of off-route air traffic for many purposes and the main objective of this paper is to describe methods for generating random traffic of this nature, that is traffic outside airways, terminal control areas and aerodrome control zones.
Weather Routing of Ships for the Northern Oceans
Authors: Motte R.
Published: November 2009

Time and space scales are compared for selected speeds of ships in the North Atlantic and North Pacific oceans. Viability of westbound passages on some northern great circle routes is discussed.

There would be no problem in precisely weather routing a vessel across an ocean if it were possible to forecast with total accuracy the actual sea state existing for the duration of a voyage. All mariners are well aware that such an ideal circumstance is not as yet possible. Depending upon the general synoptic situation existing for the period, it is fair to make the assumption that the actual accuracy of a weather forecast deteriorates as time progresses.
Speed Control: A Useful Tool of VTS
Authors: Koburger C. W.
Published: November 2009

This paper discusses some of the implications of speed control in the vessel traffic picture, emphasizing how speed relates to other safety factors so that control can be utilized with understanding and sensitivity. Speed control can seldom if ever be examined in isolation. The structuring of vessel traffic schemes implies a need for some form of speed control as an integral part of almost all those schemes. One technique reinforces the other. Speed limits become extremely critical at the lower end of the speed scale, the higher the traffic density, the more critical the limits. Again, the requirement for enforcement becomes clear. No over-emphasis of these operational limitations should be allowed to cloud the indisputable fact that — for the individual ship as well as for traffic management — speed control can be a most useful tool. At least three papers have been published in recent years pointing out that speed reduction by ships for safety purposes, either by individual ships themselves or through general imposition by a shore-based vessel traffic system (VTS), needs in all cases to be used with great care, reluctance even. Their warnings can easily be turned into a negative approach to such control. A number of points would therefore seem to demand looking at again.
An Inquiry into North Sea Navigation
Authors: Ligthart V. H. M.
Published: November 2009

Some results are here described of research carried out in the Netherlands with regard to marine traffic problems on the Dutch part of the continental shelf with emphasis on the preliminary results of the ‘Nautical Questionnaire North Sea’.

The North Sea is a busy and interesting area, often presenting a challenge to the professional and amateur mariner, and to government bodies who have to see that people operating there do so in a responsible and safe manner. Figs 1 and 2 give an impression of the various types of activities on the Dutch continental shelf and of the collision and grounding positions of vessels in the North Sea over the period 1973–7. To reconcile the claims of all operations has become increasingly difficult as offshore activities have multiplied.
The Calculation of Marine Collision Risks
Authors: Lamb W. G. P.
Published: November 2009

It has been recognized for some time that calculations of potential encounter rates based on the speed and lateral distributions of ships using sea routes provide only a partial estimation of the actual collision risk, as all encounters are usually given equal rating, and no attempt is made to include factors such as the degree of domain penetration or the relative speed of the ships. One possible solution to the problem consists in attempting to weight the calculated potential encounter rates according to the most relevant factors, and thus replace the calculated rates by weighted values to provide a relative estimate of collision risk. Goodwin, Lamb and Kemp reported a first attempt at such a procedure in their calculation of weighted encounter rates based on the observed traffic distributions and flow rates in the Sunk Lightship area in the neighbourhood of Harwich. A two-part index was used in the work; the first part employed a weighting factor based on the ratio of the time required for the completion of a manoeuvre involving a specified angle of course change, to the time available as measured from the ‘decision-distance’ at which the manoeuvre was deemed to commence. The second part used a factor based on the time required to pass and draw clear after completion of the manoeuvre.
Automation in Air Traffic Management
Authors: Ratcliffe S.
Published: November 2009

By Air Traffic Management or ATM is meant the totality of the processes used, in the air and on the ground, to ensure safe and expeditious movement of all air traffic using controlled airspace. Computers are used on a large scale to support human planners in the management processes. Flight management computers in the aircraft, together with radar and flight-plan data processors on the ground, are conspicuous examples. Decision processes remain tasks for human controllers, although off-line computer models of traffic flow provide a background for the longer-term management decisions.
The Delco Performance Management System
Authors: Moore P. , Page D. M.
Published: November 2009

Since the early nineteen-seventies, when the price of fuel went up so dramatically, airlines have been seeking methods of saving fuel. Climb, cruise and descent speeds were refined to give the most economical operation. Advisory systems came on the market, but these did little more than give crews information which could be obtained from operations manuals. Then equipment such as performance management systems (PMS) and flight management systems (FMS) was produced. The potential of these systems can be measured by the number of airlines who have purchased the equipment, and also by the fact that most of the new generation of aircraft are being built with PMS as part of the standard aeroplane.
I – V. W. Attwooll
Authors: Attwooll V. M.
Published: November 2009

The three papers which follow were presented at a meeting sponsored jointly by the Institute with the Royal Aeronautical Society, held in London on 20 February 1985 with the President, Mr J. E. D. Williams, in the Chair. Mr Attwooll is with the Chief Scientist's Division of the Civil Aviation Authority, Captain Lister is a member of the Flight Operations Inspectorate of the same Authority and Captain Grieve is the Chief Pilot of Britannia Airways.
Vessel Traffic Management Systems: Some Considerations
Authors: Wepster A.
Published: November 2009

When planning the replacement of an existing shore-based radar advice chain, which may have admirably served the port area under consideration for the past fifteen or twenty years, a number of basic elements have to be reviewed. The review and the ensuing process of analysis should be steps towards the adoption of a basic philosophy for the eventual development of a replacement system; this is necessary to judge requirements in relation to the many possible solutions, ranging from a simple shore-based radar advice service to sophisticated vessel traffic management systems. Elements for consideration include:

(i) The area to be served, present and future.

(ii) The traffic pattern, present and future.

(iii) The technology available or under development.

(iv) The other operational and administrative services available to shipping.

(v) The quality of manning and manning scales.

(vi) The economics of the shipping industry.

(vii) The cost of the new system.

(viii) The distribution of this cost over shipping and the community in general.

(ix) Legal aspects.

Besides these factual considerations and their analysis we should develop a philosophy regarding the aims of the system, which could be an improvement in port operation efficiency, in traffic safety, or in vessel turn-around time. The realization of these aims will probably result in economic benefits both for the port and for shipping and these will have to be weighed when investigating the distribution of system cost over shipping and the community in general.
Strapped-Down Systems and Gyroscope Technology
Authors: Smith S. G.
Published: November 2009

Inertial navigation systems have for many years been mechanised as a cluster of gyros and accelerometers mounted in a servo-controlled gimbal system which isolates the cluster from the motion of the carrying vehicle. Until the spectacular advance in computer technology over the last decade no other mechanization was really feasible, but serious consideration is now being given to strapped-down systems. This paper compares the two mechanizations, outlines some of the advantages of strapped-down systems, and considers some of the contenders for rate-sensing in such systems.
Computing and Sensor Requirements for Strapped-Down Inertial Navigation
Authors: Harris D. G.
Published: November 2009

The current situation with aircraft inertial systems is that virtually all are based on gimballed platforms so that this technology is very well understood, including the cost of maintenance. Strapped-down IN promises the already well demonstrated advantages of gimballed equipment but at a much lower cost of ownership; but although the technical feasibility of strapped-down systems has been demonstrated, the realization of the economic advantages is still in process.
Recent Developments in Gyroscope Technology
Authors: Nisbet D. B. , Scott J. N. G.
Published: November 2009

Recent advances in the speed and capability of miniature computers have made possible a strapped-down mechanization for airborne inertial navigation systems. The implementation of this mechanization is critically dependent on the availability of suitable accelerometers and gyroscopes able to measure, and yet withstand, the effects of vehicle motion. The laser gyroscope is now considered a major contender for angular measurement in that it offers the possibility of a cheap, reliable instrument with the wide dynamic range required for strapped-down implementation.
Lord Kelvin and His Compass
Authors: May W. E.
Published: November 2009

It is now more than thirty years since Commander W. E. May, R.N. (formerly of the Admiralty Compass Observatory), drafted this hitherto unpublished paper, recording his opinions based on a study of documents made available to him in 1947 by Messrs Kelvin, Bottomley and Baird. The documents referred to in the paper are:

The Thomson v. Moore case as presented to the House of Lords in the Thomson v. Moore case (Patent Design and Trade Mark Cases, Vol. VII, No. 36.)

The case of Thomson v. Hughes (Patent Design and Trade Mark Cases, Vol. VII, Nos. 9 and 22.)

Report of Proof of case of Kelvin v. Whyte Thomson &. Co.

Bound volume of patent specifications referred to in the last named.

It is a curious habit of editors and publishers to invite well-known persons to write articles on subjects outside their normal orbit. Thus in 1874 Sir William Thomson was invited to write for Good Words an article on the mariner's compass. He took up the task and soon realized that he did not know enough of the subject to complete the article. He then began to study the compass and the final part of the article was published in 1879. Such is one of Lord Kelvin's explanations of how he came to interest himself. In 1885, in an affidavit for the Moore case, he said that he took up the study of the compass in 1871, whilst elsewhere he said that it was the necessity of writing for the Royal Society an obituary notice on Archibald Smith, who died in 1872, which first turned his attention to compasses.
The Special Theory of Relativity
Authors: Bondi Hermann
Published: November 2009

It does indeed give me great pleasure to have been honoured by the request to give this lecture. And it is with a little trepidation that I have chosen my subject, the very title of which could frighten off many people, and I am very glad to see that your Institute consists of people made of sterner stuff. On the other hand, I did feel that the subject in question met the nature of this lecture. It was generally cultural and it relates to navigation. And so let me start on this subject which has a reputation for being difficult. And let me assure you that Einstein's work on relativity is not at all difficult. It is very simple. But it rests on the extremely difficult, abstract theories that we owe to Galileo and to Newton.
The Admiralty Compass Observatory
Authors: Fanning A. E.
Published: November 2009

The paper by Captain Cotter on Edward Johnson and the early history of ship's magnetism published in the September Journal sets the scene for the birth, in 1842, of the Compass Department of the Admiralty. Commander Fanning, a former Deputy Director of the Admiralty Compass Observatory, as it later became, here relates its subsequent history. The paper was presented to an Ordinary Meeting of the Institute held in London on 19 December 1979 with Dr J. F. Kemp in the Chair.

This paper traces the fortunes and development of a small department, one of the oldest Admiralty technical departments, from its early struggles with the magnetic compass, through many vicissitudes, economies, defence cuts, wars, intrigues, take-overs and even human frailties. We shall see how technical advances have led to ever more demanding requirements and I hope to show how, by meeting each new challenge, there has emerged the lively, forward-looking organization that today is still responsible for ‘everything that matters’ in navigation equipment, as it was at its inception in 1842.
A Statistical Study of Factors Affecting Navigation Decision-making
Authors: Holmes J. D.
Published: November 2009

This study consists of an investigation of the point at which ships' masters make decisions to avoid collisions, with regard to the time and distance separation from the other ship. The objective of the study is to find out what factors influence them to make their decisions to manoeuvre at this point rather than at any other; this involves the examination of various factors which could be relevant to the decision-making process, such as the speeds of the two ships, the relative bearing of the other ship, and the length of sea experience of the navigator.

Several computer simulation models for marine traffic systems have been built but various subjective assumptions have had to be made about the criteria on which a decision to make a collision avoidance manoeuvre is based. This study represents the first systematic investigation of the statistical relationships among the factors affecting these criteria.