bluuebunny/crossref_metadata_2025_split huggingface dataset:
I—The Requirement
Authors: Davies W. P. 
Published: January 2010

The following papers were presented at a meeting of the Institute held in London on 12 March 1965. Mr. W. P. Davies (Polhemus Associates) first outlines the height measurement requirements for a supersonic transport aircraft. The other speakers review the available techniques: Mr. R. Whalley (Ferranti) dealing with inertial techniques, Mr. B. Cape (S. Smith & Sons) with pressure measurement techniques and Mr. W. L. Garfield (Standard Telephones and Cables) with radio altimetry. Mr. G. E. Beck (The Marconi Company) describes a recently developed radio altimeter.1. Introduction. In outlining requirements for height measurement in supersonic transport aircraft it should first be said that not all the requirements are special to supersonics. Some of the requirements are the same as already exist, or will exist in the 1970's, for subsonic aircraft. The main problem in supersonic aircraft will be to maintain the same accuracy over increased measurement ranges of height and height rate and in an environment of higher speeds and temperatures. Where-ever possible then, the requirements are of the same standard expected for subsonic aircraft of the 1970's. More stringent requirements are stated only where they are considered necessary; there are enough real problems in the advance to civil supersonic operations without creating artificial ones.
Shore Radar Control in the Port Entrance Area
Authors: van Hooff J. F. Drijfhout 
Published: January 2010

The paper discusses the measure of control to be exercised by the Port Authority in a Port Entrance Area where shore radar enables tracks to be made of all ships present. The problem becomes acute where great numbers of ships are trying to enter and leave in restricted visibility, creating danger and confusion.In a previous paper presented at the conference, Commandant R. Betton, Captain of the Port of Le Havre, suggested that it was perfectly possible for shore-based guidance radars to be used to reduce collision risks at the entrances to harbours, provided this supplementary function is precisely denned in terms of how much authority harbour administrations can exercise over ships outside the harbour. Betton stipulated that any control should only be exercised by experienced seamen and that they should not have the right to interfere in manœuvres for which masters should have sole responsibility.
Refraction at Low Altitudes
Authors: Sadler D. H. , Scott W. A. 
Published: January 2010

The analysis of low-altitude observations of celestial bodies specially made for the purpose, indicates that no significant amendment is required to the refraction corrections published in the (Abridged) Nautical Almanac.In recent years there has been an increasing interest in low-altitude astronomical sights, particularly in regard to the accuracy of observation and of the corrections to be applied for atmospheric refraction. As a result of the analysis of many thousand observations made under different conditions, Professor C. H. Smiley had deduced tabular refraction corrections which differed significantly from those in current use and also from those deduced from modern theories. Suspecting some systematic error in Smiley's results, possibly associated with the phenomenon of irradiation, Dr. G. M. Clemence of the U.S. Naval Observatory undertook an independent investigation using observations made at his request by ships of the U.S. Merchant Navy. Although the number of observations was rather small, leading to a fairly large uncertainty in the deduced refractions, there was little possibility of any source of systematic error; the observed values agreed with the theoretical values well within their observational uncertainty, and differed significantly from those of Smiley. A systematic difference between the observed altitudes of the upper and lower limbs of the Sun was ascribed to irradiation (the spreading of a bright image on the retina of the eye, making the diameter of a bright object appear larger than it is) and, taken in conjunction with a similar phenomenon depressing the visible horizon, was allowed for by subtracting 1.2 from the observed altitudes of the Sun's upper limb and leaving those of the lower limb unchanged. This correction was later incorporated in the altitude correction tables of the (Abridged) Nautical Almanac.
A Microwave Position-fixing System
Authors: Smyth H. R. 
Published: January 2010

Shortly after merchant marine radar came into use as a navigational aid, it was felt that some consideration should be given to the development of electronic aids for vessels too small to use radar, such as tugs and fishing vessels. It was obvious that the use of the microwave frequencies of radar would best suit the development of a small directionfinding receiver. The final system developed by the National Research Council used a compact 3-cm. pulse transmitter on a shore site, such as a lighthouse, or harbour breakwater. The antenna was designed to radiate energy across the water from all angles of approach.The receiving equipment was built into a case on the back of a small radar antenna consisting of a six-inch slotted waveguide at the focal plane of a parabolic cylinder. The receiver used a radar crystal detector and transistorized audio amplifier for reception on phones or a speaker. The receiver could be hand held or mounted on a pelorus head, and rotated around the horizon to take a bearing on the shore transmitter. The signal from the shore is audible over an arc of only about six degrees, and can be maximized with an accuracy of ± 1 degree.
A System of Automatic Navigation
Authors: Britnell C. 
Published: January 2010

A computer known as the Radio Track Guide, of which both air and ground trials have been held, is described. As a system it can provide accurate automatic guidance for all anticipated operational conditions in a manner which is of value for both navigational and movement-control purposes. Mr. Britnell's paper was presented at the Paris convention on automatic navigation.The criterion for assessing the efficiency of a navigational aid must include a reference to the ease and precision with which it enables a vehicle to maintain a specified track. In aircraft navigation the most accurate tracks are, of necessity, those made in the vicinity of the runway during the landing and take-off phases. At such times the errors must be limited to a few feet and such small values are a result of the pilot using an ideal reference frame for lateral guidance purposes. This is centred upon the runway and within it he is able to detect, with a high degree of accuracy, the two quantities necessary for precise track keeping. These two quantities are the displacement and rate of displacement from the required track.
A Route Direction-finder
Authors: Gaudillère Colonel P. 
Published: January 2010

The route direction-finder is a device giving an accurate directional reference. It uses two distant transmitters, A and B, radiating two continuous waves, the frequencies of which are different but very proximate. The paper was presented at the Paris convention on automatic navigation.Classical methods of navigation by dead reckoning have been considerably improved in recent years by the use of autonomous systems such as doppler and inertia which enable true speed to be measured. When using these systems, the principal cause of errors is the unreliability of the directional reference, which may be the meridian or any arc of a great circle, since it is with respect to this that the speed vector is obtained. The directional reference is given by the magnetic compass which often has an error of up to several degrees or is given by gyroscopic devices which can have considerable drift after several hours' operation. Errors in directional reference are especially marked in polar regions where magnetic or gyro compasses cannot be used.
The Metrication of Admiralty Charts
Authors: Hall M. 
Published: January 2010

By 1966 it was obvious, the Government having announced its intention for the country to go metric, that we had to think seriously of the metrication of Admiralty charts. With some 3500 navigational charts, many additional special charts, plotting sheets and other publications the task was unquestionably a formidable one, but it was decided that it could be done and a start should be made as early as possible.It could be tackled in two ways, either by a gradual process, whereby charts would be converted as they came up for correction or where it was necessary to produce a new chart; this would mean slow progress and result in a haphazard geographical distribution. Alternatively such resources as were available could be concentrated in one area at a time and blocks of charts produced in metric units. This would avoid, to some extent, the difficulty to the mariner of having to jump about from fathoms and feet to metres and back again as he changed charts, and we eventually decided on this method—but in true British fashion are doing a bit of both.
The U.K.–Australian–New Zealand Charting Arrangement
Authors: Russom D. 
Published: January 2010

In July 1963 the Hydrographic Department published a Notice to Mariners announcing the integration of charting arrangements between Great Britain, Australia and New Zealand.Because of the historical associations, the Hydrographer of the Navy was the primary charting authority in Australian and New Zealand waters until comparatively recently. Local Hydrographic Offices were set up, and these, not unnaturally, began to turn out products strongly resembling British Admiralty charts, to such an extent in fact that we were clearly wasting effort in recompiling British charts which virtually duplicated the originals. Facsimile reproduction seemed an attractive proposition. Unfortunately the normal arrangements for use of another authority's charts, as laid down by the International Hydrographic Bureau, do not allow for facsimile reproduction but special agreements can get round this difficulty.
Two Years of Routing in the Dover Strait
Authors: Beattie J. H. 
Published: January 2010

On 1 June 1967 routing was established in the Dover Strait. In the two years since then much experience has been gained and some of this has been reported already. The most significant fact to emerge so far is the sharp reduction in the number of accidents especially in relation to the amount of fog.In the years 1961–7 before routing there was an average 14·3 collisions per annum, the lowest years being 1962 and 1965 with only 12 and the worst being 1961 with 23. In the first year since routing between 1 June 1967 and 31 May 1968 there were only 5 collisions, an all time low, and in the second year between 1 June 1968 and 31 May 1969 13 collisions with two after the 31 May 1969. Since most accidents in this area, but not as a whole, occur in fog it has long been established that a good measure of the safety record here is to examine the collisions per fog day. To do this in the Dover Strait, the amount of fog reported at the South Goodwin and Varne light vessels has been established from Trinity House and averaged to give an index for the Strait.
Changing the Collision Regulations
Authors: Dickson A. F. 
Published: January 2010

Tentative arrangements have now been made for the International Maritime Consultative Organization (Imco) to call an International Conference in 1972 to examine the international regulations for prevention of collision at sea and to make proposals for change where appropriate. It would therefore seem timely for members of the Institute with views on how the Collision Regulations might be amended to air these views so that all the aspects of the problem can be considered prior to the Revision Conference.It would seem essential first to consider whether the rules as at present structured are broadly correct, which would indicate simply a review of each rule to see whether and to what extent amendments or improvements may be desirable, or alternatively whether some of the underlying basic premises on which the present rules are based are in need of revision, which would obviously mean very much more radical change. In the author's opinion the rules as now drafted do not seem to be correctly structured for modern navigation by the great bulk of ships on the high seas.
Collisions between Radar-equipped Merchant Ships U. S.
Authors:   National Transportation Safety Board
Published: January 2010

This study by the United States National Transportation Safety Board was undertaken to determine why ship collisions persist despite the use of radar and what recommendations could usefully be made to prevent collisions between radar-equipped vessels. The samples analysed cover the fiscal years 1963–7. An Appendix giving details of these collisions is omitted.1. Introduction. The National Transportation Safety Board's review of the investigation of the collision between the S.S.Arizonaand the M.V.Meiko Marudirected attention to collisions of vessels equipped with radar. In this case, the Masters of both vessels were navigating by radar to the exclusion of the Rules of the Road and the requirements of good seamanship, and neither was utilizing properly the radar to best advantage by plotting the relative motion of targets.
The Edge of a Needless Collision
Authors: Bell Frank Coffman 
Published: January 2010

Commandant L. Oudet in his contribution ‘Lessons from a Needless Collision’ (Journal,20, 30) may not have gone so far as to suggest that at no time ought eitherTenacious or Placidto have altered course or speed then obtaining. Yet from his account this is plainly the case, a fact for which there must be some technical explanation, although he does not fully disclose it, saying rather, ‘We have not sought to teach but only to stimulate thought among Masters and their shipowners.’ No doubt others are not excluded. His pars. 2 &amp; 3 give the facts in summary and the statement concerning the verdicts ofTenaciousthat ‘at 1330 she finds the bearing is steady’ plus some muttering about even worse than steady at 1340. This summary he later on amplifies slightly as to the facts:(1) in par. 16, ‘between 1344 and 1349 …Placidmade no (careful) observation.’(2) in par. 18, ‘Placiddid not detect this alteration (byTenaciousat 1340, from 130° to 160°).’
Selecting the Moon's Limb
Authors: Wright Frances W. 
Published: January 2010

This paper describes two methods of determining whether a sextant observation of the Moon should be of the upper or lower limb. The first method requires the use of a celestial globe or planisphere; the second is mathematical and requires a certain amount of computation, but is exact.The line which separates the dark portion of the Moon's disk from the illuminated portion is known as the terminator, and the straight line joining the ends of the terminator is that used in this problem. This line is always perpendicular to a line from the Moon to the Sun (the horns being always turned away from the Sun), so that its position can be predicted from the geometrical relations of the Earth, Sun and Moon. This enables the limb to observe to be determined.
The Approach Channels to Southampton
Authors: Macmillan D. H. T. 
Published: January 2010

The conservancy problems of any modern major terminal port are governed by certain features. In this paper the Port of Southampton is examined within the context of these features and certain significant facts are recorded; recent work to improve the facilities of the port is then described and possibilities of further long-term development are discussed. The features referred to may be classified as:(i) The geological history.(ii) The tidal regime. In particular the spring lunitidal interval and range, the times, direction and rate of maximum tidal streams and relation to local high water, duration of slack-water periods and particularly that phase of the tidal stream which is dominant in rate.
Some Observations of Refraction at Low Altitudes and of Astronomical Position-line Accuracy
Authors: Peterson B. Chr. 
Published: January 2010

No account of the observations described in this paper has previously been published, though they were made nearly eighteen years ago. The author has kindly presented the Institute with all the data he obtained from them and with a detailed description of the investigation. We print here a short account of the observations and of the principal results obtained, which it is felt should go on record.—Ed.Largely as a result of discussions with Dr. Per Collinder of the Swedish Hydrographic Service and Dr. Knut Lundmark, Professor of Astronomy at Lund, the author undertook, between June and August 1934, a series of sextant observations to determine the degree of refraction at low altitudes, the normal accuracy of sights at sea, the accuracy of twilight and night observations and possible elevations of the horizon at noon. 1908 observations were taken during the period.
A Survey of Navigation Systems and Instrument Aids
Authors: Adams D. E. , Uttley A. M. 
Published: January 2010

An abbreviated version of a paper read before a joint meeting of the Institute and the Royal Aeronautical Society.The usefulness of a particular aircraft may well depend upon the availability or simultaneous development of equipment. Safe, reliable, economic and speedy operation in the civil field may rest, for instance, on facilities which enable all-weather operation to be undertaken—including navigation, traffic control, approach and landing facilities. Military operations, even more directly, will be determined by the instrument aids available.
The Effect of Doppler on Navigation System Accuracy
Authors: Willis D. C. , Powell P. G. 
Published: January 2010

This paper discusses navigation system accuracies achieved on North Atlantic routes by Air Canada, and the effect of doppler on the accuracy of navigation. Data are presented on track maintenance performance with doppler inoperative and operative, on performance over a prolonged recent period combining all results, whether doppler operative or inoperative, and on the frequency of gross errors.Doppler was installed by Air Canada with the primary aim of reducing the gross track maintenance errors which seemed otherwise inevitable at jet speeds and altitudes. A comparison of the results given below indicates the deterioration which resulted when the DC-8 was introduced and no doppler was available, and show the improvement achieved after some experience with doppler.
Compass Swinging without Rotating the Aircraft
Authors: Baker Donald H. , Skaar Martin 
Published: January 2010

The principle of applying controlled direct current to the flux valve to simulate rotation of the aircraft in a compass swing is discussed. The validity of the technique is demonstrated for the measurement of single cycle error and the MC-1 and MC-2 are shown as implementations of this technique. Work is now in process to eliminate calibration procedures, and to extend the technique to the pilot's standby compass and to aircraft with significant soft-iron error.The precise navigation of modern aircraft requires an accurate source of heading information. In the primary mode of operation this signal is often obtained from an inertial reference, but the advent of inertial navigation has not eliminated the role of accurate magnetically slaved systems. A flux valve is often used to provide magnetic information to platform systems for use in initial alignment or in standby modes of operation and a magnetically slaved compass system, teamed with a doppler navigator, is still an excellent reference for long flights. For both applications full performance can only be obtained if the signal from the flux valve is carefully compensated in a compass swing.
Charting for the Dynamic Map Display
Authors: Murlin James A. 
Published: January 2010

Present criteria for aeronautical charts need further investigation in preparation for S.S.T. operations in respect to the facilities to be charted, the format for supplemental information, symbols and scale. For projection displays the negative presentation has decided advantages, while the use of colour has both advantages and disadvantages. Pre-loaded film cassettes for quick insertion into the dynamic display system can be maintained in libraries at S.S.T. terminals, which will also facilitate the frequent updating of the material.In recent years the interest in dynamic map display systems has increased with the advent of S.S.T. planning and higher speed tactical aircraft. There are several approaches including a static chart with a mechanically driven ‘bug’, a moving paper chart with a static ‘bug’ in the form of a stylus, and several projected displays utilizing 35 mm. and 70 mm. film. This paper is chiefly concerned with projected displays.
I.—The Redesign of the Abridged Nautical Almanac
Authors: Sadler D. H. 
Published: January 2010

The design of an almanac is a highly technical matter in which principles may have to yield to practical detail. In order that the proposals shall be fully appreciated and fairly discussed the basic principles that have led to the present proposals, and their practical alternatives, will be indicated as briefly and as objectively as possible.In the Nautical Almanac Office we have much experience in the presentation of astronomical and numerical data; but we are not navigators and we have little experience of the practical use of the Abridged Nautical Almanac. While all criticisms will be welcomed, those relating to practical requirements will therefore be particularly valuable.
The Presentation of the Fixing Accuracy of Navigation Systems
Authors: Trow G. H. , Jessell A. H. 
Published: January 2010

AbstractThe paper discusses the way in which the accuracy provided by different navigation systems can best be presented diagrammatically, and it is concluded that contours of constant 95% radial error give the best general picture of a system. Where a more detailed picture is required error ellipses can be added at suitable points in the system. The 95% radial error of fixing is calculated for radial, rθ, azimuthal and different hyperbolic systems, and graphical methods are developed for drawing contours along which the 95% error is constant, and also for drawing 95% ellipses. Diagrams show typical results for the different systems.
Hariot's Meridional Parts
Authors: George Frank 
Published: January 2010

Thomas Hariot's recently discovered manuscript ‘The Doctrine of Nauticall Triangles Compendious’ was the subject of a paper in this Journal by Professor Taylor and D. H. Sadler which poses but leaves unanswered the intriguing question of the method he employed in his computation. Sadler shows that the method depends on the fact that if sequences of meridional parts are in arithmetic progression the corresponding values of tan (45° − ½φ) will be in geometric progression. This is at once obvious from the modern formula for meridional parts:But how did Hariot, writing before 1596, discover the relationship when neither logarithms nor the integral calculus had yet been invented; and was he able to prove it? It is the purpose of the present paper to supply a proof which requires neither logarithms nor the calculus. It is not claimed that this was necessarily the method that Hariot employed, although the manuscript reveals several points of similarity.