bluuebunny/crossref_metadata_2025_split huggingface dataset:
‘The Effective Use of Airspace’
Authors: Richardson F. C. , Fraser D. O. , Dickie E. J. 
Published: January 2010

The following contributions are selected from contributions to the discussion on Wing Commander E. J. Dickie's paper ‘The Effective Use of Airspace’. The paper was presented at an Institute meeting held in the Royal Geographical Society's house on 21 March, and is printed in the last number of the Journal.I remember on many occasions in my Service experience undertaking cross-country flights with a large number of other aircraft flying along exactly the same route at almost precisely the same time. These were usually navigation training flights and, therefore, to some extent the errors which arose might not be held to be representative of what one would expect to happen to seasoned airline operators. Nevertheless, it was a commonplace to find on such occasions, very shortly after taking off, that all aircraft became so scattered as often to disappear from each other's view completely. And yet, at each turning point and again at the destination they all arrived at the same time. I am sure that there is something to learn from this particular aspect of flight along identical or parallel tracks. I do not think a simple fore-and-aft radar indicator would provide the safety in flight which we are anxious to establish. I believe that a secondary radar, giving an all-round horizontal view, would probably go a long way to meet the stated requirement; although, of course, only one giving a spherical view could give 100 per cent safety. Even with pilots who can see exactly where they are going, along clearly defined tracks over country abounding in natural navigational aids, it is true to say that the really effective variable is the track and not the timing. This lateral scatter is due to inaccurate steering data and to the many other inaccuracies affecting the actual path of an aircraft through the air, quite apart from wind-finding errors. Even with the best primary navigational aids, tracks cannot be flown with absolute precision. It follows that collisions are at least as likely to arise from errors of track as from errors of timing. So I would suggest that what we really need is a secondary radar which will give us an all-round horizontal view and I think that we must not delude ourselves into thinking that even the finest primary navigation aid will provide an accuracy in the air by which all aircraft proceeding along one route will remain only fore-and-aft of each other.
Loran Accuracy Diagrams for Four-station Fixes
Authors: Hasegawa K. 
Published: January 2010

The idea of portraying the accuracy of a navigational system by means of contours is very old and was first introduced to readers of this Journal by Jessell and Trow. Later writers, Sameshima, Namikawa and Hasegawa, have published accuracy contours for Loran chains. This note is a further contribution in this direction and its aim is to investigate what sort of accuracy can be achieved by marrying a position line from one chain with a position line from another.N. Sameshima has studied the accuracy contours arising from a hyperbolic system where position lines are obtained from two pairs of stations, each pair having one station, the master station, in common. Y. Namikawa and K. Hasegawa, in a later article, constructed accuracy contours for a number of Loran chains, mainly in the Pacific, but also in the Atlantic areas. This article discusses the more difficult case where fixes are obtained through using pairs with no common station, and indicates what improvement may be expected through introducing a fourth station in a number of selected instances.
Integrated Navigation
Authors: Ramsayer Karl 
Published: January 2010

Each navigational aid has its advantages and disadvantages and for that reason the optimum aid will be a combination of several aids. The best way of combining the aids seems to be by means of an automatic dead reckoning computer which continuously computes position from true air-speed and wind-speed and other data which can be fed into the existing navigational aids by means of a data transformer. Data from the integrated system can be transmitted by data link to air traffic control to correct the flight programme, &amp;c. This paper, which was presented at Dusseldorf at the German Navigation Society's meeting (5–7 June 1962), surveys the field of integrated navigation systems and describes a number of possibilities. Formulae are derived for the accuracy of Vortac and D.R. and Vortac and doppler. It is published with the kind permission of the German Navigation Society.If we look critically at the navigational aids which are available today we find that all have advantages and disadvantages, and that no one aid can be claimed to be suitable for all purposes. This situation will still exist for many years. Therefore it seems very advantageous to combine the available navigational aids to form an integrated navigation system in such a way that the possibilities may be fully utilized.
The Ground in the Western Approaches
Authors: Cotter Charles H. 
Published: January 2010

Judging from what is written in early Sailing Directions and navigation manuals it would appear that seamen of North-west Europe laid great store in their knowledge of the nature of the bottom in the seas in which they traded. And indeed, even at the present time, mariners are provided (although they may seldom use it) with fairly detailed information about the sea-bed, designedly to assist them in pilotage. A navigator may read, for example, that:‘The bottom in the Western Approaches appears to consist, mainly of fine or coarse sand, a great deal of broken shell, occasional patches of pebble, gravel, small stones, and, now and then, mud. The sand is mostly white, but in numerous places yellow sand and also black specks are met with…. The greater proportion of yellow sand is found to lie southwards of 49°30′ N and the far larger portion of black specks northwards of that line. This peculiarity is so marked, especially between 9°40′ and 7°30′ W that the mariner running eastwards, and supposing his vessel to be to the southwards of this parallel, should certainly suspect his having been set northwards of his reckoning if the soundings disclose this mixture of black specks to any great extent and with any frequency.’
The Case for Revision of Routing
Authors: Harrison W. L. S. 
Published: January 2010

On page 533 of the October 1970 issue of the Journal (23, 4), the following passage appears:‘At a recent meeting of the Safety of Navigation Committee of the Board of Trade, those present were advised by the Mercantile Marine Service Association that they had independently circulated a simple form of the present plan and the proposed reversal of routing to some 2300 Masters of their Association. Of the 500 replies received at that time, two-thirds supported the plan for reversal’
A Comparison of Two Systems for Avoiding Collision
Authors: Calvert E. S. 
Published: January 2010

In the last number of the Journal (14, 243) Hollingdale showed mathematically that anticollision manoeuvres for the case of two craft moving in a plane can be formulated on a rigorous logical basis; and that a simple set of manoeuvres could be devised to meet all the geometrical requirements for anti-collision. The convention adopted was that each craft should manoeuvre so that if the other craft stood-on, the sight-line (the line joining the two craft) would always rotate in an anti-clockwise direction. The analysis showed that, mathematically, this was the complete and only answer to the basic problem.The author of the present paper compares systems, such as that represented by the Collision Regulations and the Rules of the Air, based on onus to avoid, with a system based on a convention as to the direction of rotation of the sight-line. The first type of system, he holds, is defective for visual sightings and almost useless for radar sightings. The system put forward in the paper can be applied to both visual and radar sightings whether unilateral or bilateral by orientating a simple diagram with own course. A means of inter-communication is desirable but even without it such a system can, the author believes, safely be employed in the greater proportion of encounters.The collision problem as a whole is beset by operational factors which are entirely distinct from the geometry of the situation, and for that reason no purely mathematical approach can, in isolation, be entirely valid. Nevertheless, there can be no doubt that studies such as the present one, based on a proper understanding of the geometry, can contribute greatly to the solution of this most pressing problem of navigation.
A Navigation Device for Steering Vehicles on the Polar Ice-Cap
Authors: Black H. P. 
Published: January 2010

Precise navigation upon the ice-cap depends largely upon the accurate steering of a chosen course. This operation can be rendered difficult by three major problems commonly faced by Arctic and Antarctic expeditions. First, the absence of topographic features as points of reference; secondly, the loss of precision of the magnetic compass inside a moving vehicle and in areas adjacent to the Magnetic Pole; thirdly, the dependence of the astro-compass and similar instruments upon an unobscured Sun.A simple method by which these difficulties are overcome was tested and found satisfactory during an inland traverse from Wilkes Station in November–December 1960 into an area not previously explored by land. The principle of this method is the use of a periscope-like arrangement of mirrors combined with a suitable sighting system to enable the driver to use his track astern to steer a straight course ahead.The original device was installed upon a vehicle (a ‘Weasel’), already fitted with an astro-compass and a magnetic compass in order to function as the navigation vehicle of the train. The rear vision mirror taken from a ‘Traxcavator’ was used as the main ‘Track mirror’. It was pivoted at its centre point through the shorter axis. The mirror was mounted on a frame of two half-inch steel pipes bolted on to the vertical wall of the well between the windscreen and the forward hatch of the Weasel.
II—Some Possible Aids
Authors: Hansford R. F. 
Published: January 2010

The problem of navigating a vessel under conditions of bad visibility in open sea and in coastal waters has in recent times been largely solved by the advent of modern aids. The problem in pilotage waters, however, still remains severe and the handling of a sizeable ship in estuaries and harbours in bad visibility is today the exception rather than the rule.The lack of progress in this field is due mainly to two causes. The first of these causes is the lack of a clear understanding of the pilotage requirements; the discussion at this meeting may help to shed some light on this problem. The second is referred to later. Commander Akerman has stated some of the pilot's requirements and the object of the present paper is to illustrate and further clarify the problem by examining some of the possible systems available to aid its solution. The paper will concentrate on radio systems since these seem the ones most likely to aid in solving the bad-visibility problem.
Traffic Capacity
Authors: Fujii Yahei , Tanaka Kenichi 
Published: January 2010

Traffic capacity is the capability of a waterway to deal with the traffic and when the traffic volume exceeds this limit traffic flow stops, as is often experienced on congested roads.According to the U.S. Government Highway Capacity Manual the capacity of a highway with four or more lanes and free from conditions hindering smooth traffic flow has a maximum value of V/Ymin per lane, where V is the speed of a group of vehicles and Ymin is the average minimum separation of cars. Since Ymin is a function of V and increases rapidly and continuously with speed, there is a maximum value for V/Ymin which is a function of the speed. This is called basic capacity. Several examples of capacity together with the speeds of the transportation facilities are given in Table I.
International Charts
Authors: Pascoe L. N. 
Published: January 2010

In his Presidential Address Admiral Ritchie referred to the two series of charts in 79 small-scale sheets which 16 member states of the International Hydrographic Organization have undertaken to produce; some of them will be published this year. This new development, and how it will affect mariners who now use our Admiralty charts, may be of some interest.The two small-scale charts for ocean and offshore navigation require a comparatively limited effort and with the enthusiasm and interest shown by all participating nations it is expected that both could be completed within a reasonable period, probably before the end of 1974. When these charts are published it will be possible to withdraw many small-scale Admiralty charts, some of which were originally published more than a century ago and have subsequently received only partial correction, and much criticism as being out-of-date. But it will not usually be possible to replace them chart for chart as each individual new International Chart is published, because replacement of existing charts can best be made when the whole scheme or at least a complete regional area has been completed. This applies not only to the United Kingdom but to all the world charting authorities and will result in their still having to maintain many existing charts until the new coverage is complete. This problem of ‘block’ replacement, rather than individual chart replacement, will assume serious proportions in the subsequent larger-scale stages of the International Chart.
‘Manning Reductions and the Cost of Navigation’
Authors: Bingley P. T. 
Published: January 2010

After studying Captain J. S. McKenzie's very interesting paper on the above subject (Journal24, 174), and recognizing the need for an improvement in the safety of navigation, it would seem worthwhile considering whether safety could be improved while still reducing costs.Using Captain McKenzie's assumed costs, and his Table III as a model, the accompanying table shows the costs and savings for two versions of an all officer bridge manning scheme.
Collision Avoidance in a Traffic System
Authors: Calvert E. S. 
Published: January 2010

In 1960 Dr. Calvert published a paper in the Journal (13, 127) which proposed a fundamentally new conception of how to avoid collision between single craft at sea or in the air, based on work carried out by the Mathematics Department of the Royal Aircraft Establishment. Later Hollingdale (14, 243) published a rigorously mathematical explanation of Calvert's ideas. The following paper to some extent draws together the arguments that have ranged so widely over this subject during the last ten years or so.The chief criticism which has always been made against the existing Collision Regulations and is now being made against the revised ones, is that, except for the end-on encounter, no directives are given as to how a vessel should manœuvre to ‘keep out of the way’. Their role, it has been said, is not so much to prevent collisions as to enable lawyers to apportion blame after collision has occurred. The explanation usually given is that ‘the infinite variety of encounters which may arise at sea does not yield to a uniform treatment’.
Manœuvring Large Ships in Shallow Water—I
Authors: Hooft J. P. 
Published: January 2010

Dr. J. P. Hooft who is a Vice-President of the Netherlands Ship Model Basin at Wageningen, discusses the hydrodynamic forces which act upon a large ship sailing in shallow water. Their effects on the manœuvrability and control of the ship include a smaller response to a given rudder angle, a shift of the pivoting point aft towards the centre of gravity, a larger turning circle and less reduction in speed when turning. In general a ship becomes more sluggish in shallow water.Since manœuvres with large ships are usually only performed in the proximity of harbours while in deep water the ship is kept on course by means of an autopilot, it will be difficult to compare the manœuvrability of large ships in shallow water with their manœuvrability in deep water. The influence of water depth on the hydrodynamic characteristics of the ship will therefore be the main subject of the present paper; the consequences of these ship characteristics on manœuvrability will then be considered. This term ‘manœuvrability’ is often replaced by ‘controllability’. In this respect a ship is said to be controllable when the navigator is able to manœuvre the ship with ease in such a way that departures from the anticipated manœuvre remain within acceptable limits.
Improvement of Navigation Lights and Signals
Authors: Lindsay Douglas J. 
Published: January 2010

In recent years there has been growing concern over the adequacy and distinctiveness of navigation lights in use at sea. This has expressed itself in a series of modifications to the lights shown by various specialized vessels, and by and large the more unusual users of the sea are now clearly and distinctively lighted by night. However, despite the noise being made about it, little has so far been done to improve ordinary ship's navigation lights. There can be little doubt that something urgent does need to be done about them; the survey carried out by Shell International Marine1 indicated this statistically, and any practising navigator need only think of the difficulties encountered at sea from other ships showing wrong or inadequate lights to realize it.The range of navigation lights in general is the first and most obvious matter for improvement. The present statutory ranges were laid down when oil lamps were still the normal means of providing light, and when in addition ships were much smaller and slower than the average today. In view of the current size and speed of ships, and the obvious fact that in the future they are going to get even bigger and faster, it seems senseless to have their navigation light ranges prescribed on a datum established by oil lamps. The mind boggles at the prospect of two crossing supertankers, each with side-lights visible for no more than the statutory 2 miles, maintaining course and speed until each saw the other's side-lights (a common practice at sea).
The Metrication of Navigation
Authors: Cotter Charles H. 
Published: January 2010

THE following notes stem from Ronald Turner's somewhat controversial paper on the metrication of navigation.The unique feature of the nautical or sea mile as a unit of distance is that it is directly related to a commonly-used unit of angular measure. To be more precise, the nautical mile may be defined as the length of a meridianal arc of the terrestrial sea-level surface, the geographical latitudes of the end points of which differ by one-sixtieth of a degree. In other words, the sea mile is a minute-mile, and the resulting convenience to mariners is one that is not too lightly to be sacrificed on the altar of the metric system.The association of the seaman's unit of distance with the unit of angular measure and with the size of the spherical Earth, became a serious consideration soon after the initiation of the Age of Discovery by the Portuguese navigators sponsored by Prince Henry. Before this epoch, and indeed for some time after, seamen used landsmen's units of measure: units derived from homely, but certainly non-scientific, standards such as the length of a thumbjoint, forearm, foot and pace, and in no way related to the size of the Earth.The inconveniences in trade and commerce caused by a wide variety of units of length and weight must always have prompted men to suggest standardizing these units.
A Simple Area Navigation Display
Authors: Honick K. R. 
Published: January 2010

A simple inexpensive optical projection map display is described which converts the range and bearing signals available from ground-based beacon aids such as TACAN or VOR/DME into a continuous map indication of present ground position without additional computing. This provides an area navigation system from such aids within their limits of accuracy, which increases with decreasing range from a beacon.The display, which is self-synchronous, employs a series of circular map micro-transparencies, each of which is centred on a TACAN or co-located VOR/DME beacon and which can be changed in flight. The transparencies are automatically orientated with reference to beacon magnetic north on insertion, by a notch in the rim. The transparency is rotated by the bearing signal and is translated radially by the range signal to give a continuous indication of present position.
The Accuracy Contours of a Running Fix
Authors: Namikawa Y. , Yamazaki Y. 
Published: January 2010

An accuracy contour can be defined either in terms of a locus of constant radial error or a locus of constant probability density. A short comparison of the two concepts is given in reference 3.The object of this note is to define contours of constant probability density in the case of a two-position-line running fix; the outcome is of interest in that it enables the navigator to plan his observations so that the accuracy is optimized. In Fig. 1 the object observed is S. The transferred position line corresponding to the first observation is drawn from the point S′, where SS′ is the vector corresponding to the ship's run during the time between the two observations. The fix is at O.
The Terminal Area Problem at London
Authors: Briggs J. H. 
Published: January 2010

The rate of growth of air traffic in the London Terminal Area (T.M.A.) is such that the existing airports will be unable to handle it for more than a few years. If a safe and expeditious flow of traffic is to be maintained, even if more airports of the existing type are provided, ways must be found to increase the capacity of individual airports. In any case, it will be necessary to improve the marshalling of traffic between the airports and the air routes to prevent harmful interaction between the various activities. One solution put forward, tacitly assumed that the growth potentials of Heathrow and Gatwick airports were so limited, that a third, and subsequently a fourth, airport of similar design and capacity would be required.The alternative solution relying on ideas yet to be proved, is more difficult to assess, since possible improvements in technology must be taken into account together with the changes in A.T.C. procedure which their adoption would permit. By 1967, this task had not received the comprehensive study afforded to en-route (Mediator) problems, and no specific operational requirements existed for electronic aids related to this T.M.A. problem.For this reason, the fairly substantial amount of work which could have a bearing on T.M.A. problems being carried out in various R. & D. establishments and industry could not be directly related to the users' needs.