bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Accurate Determination of Aircraft Altitude
Authors: Warner J. 
Published: January 2010

A method of obtaining aircraft altitude to within 50 feet at altitudes of 10,000 to 20,000 feet is described. This accuracy is necessary in a few special cases. The method consists of determining the height of a pressure level at some convenient point by radar or other means, and then calculating from a knowledge of the wind vector the change of height of this pressure level between the check point and the point at which an accurate altitude is required. The limitations of alternative methods of height finding, such as the use of an aneroid altimeter corrected for temperature at the upper level, are discussed.For most purposes the aircraft type aneroid altimeter gives a sufficiently accurate indication of height, provided corrections are made for the temperature at flight level. In the application of radar to topographical surveying, however, it is necessary to know the altitude of the aircraft used in the measurement to within 50 feet when flying at heights of 10,000 to 20,000 feet. This can be achieved only by special techniques. The method here outlined has been used extensively during investigations into the use of radar for surveying. It is simple and appears to give satisfactory results.
Equivalent Head Winds on Air Routes
Authors: Crossley A. F. 
Published: January 2010

1. Introduction. A detailed paper describing the theory and calculation of equivalent head winds on air routes has been prepared by J. S. Sawyer and is being published as a Meteorological Report. The present paper is a simplified account which draws largely on Mr. Sawyer's paper.When regular air services over a route are being planned, the wind at the chosen level of flight is an important factor. From the long term point of view, aircraft require to be designed so as to operate economically against adverse winds, if not on all occasions at least on all but a small percentage of occasions; for example, British Overseas Airways Corporation usually specify an 85% regularity of operation as a minimum. Similarly, for short term planning, wind information is necessary for the computations regarding the averages and extremes of fuel consumption, payload, time of flight, and so on. The aircraft operator consequently requires to know the frequency distribution of winds on any given route at any time of the year.
Jet Streams and their Importance to Air Navigation
Authors: Durst C. S. , Davis N. E. 
Published: January 2010

Jet streams are fast moving air streams which appear at times in the levels between 15,000 and 40,000 feet; they are located in the tropical air above the polar front. In this paper examples are given and certain occasions are noted on which they have seriously influenced air navigation.Early in 1948 when a few charts of the 225 mb. level were drawn to show temperature variations over an air route it was noticed that a very strong stream of air was seen along the line where the tropopause appeared to cut that level. This stream seemed of very considerable length and little width.
Magnetic Compass Problems— A Fresh Approach
Authors: Harvey G. N. 
Published: January 2010

This paper describes a number of proposals concerning the correction of the errors of magnetic compasses. The first proposal concerns the correction, by means of special soft iron correctors, of the deviating effects of both vertically and horizontally induced magnetization.A scheme for removing constant error without having to use algebraic addition or even having to record the existing deviations is next described.A scheme is then suggested whereby, provided no constant deviation is present, a compass may be corrected for the effects of permanent magnetism in four operations, each of which consists of the complete removal of deviation on a particular heading by a particular corrector.Possibilities of putting compasses below decks without seriously affecting their performance are also discussed; these particular suggestions cannot apply to merchant ships in which magnetic cargo is being transported. Suggestions are also made of correcting the compass by modifying the disposition of the magnetic material in the bridge structure instead of by adding a corrector to the compass binnacle.Finally, a scheme is introduced to maintain an aeroplane compass mounting parallel to the surface of the Earth during a level turn by using the centrifugal force due to the turn.This paper puts forward five separate suggestions concerned with the correction and siting of magnetic compasses. The suggestions are unrelated to each other except in the fact that they have all resulted from viewing the problems from a deliberately unconventional standpoint. Some of the solutions proposed may be of interest to those concerned with magnetic compasses in ships, aircraft and vehicles.
The Influence of Echo Sounding
Authors: Hughes A. J. 
Published: January 2010

Throughout the history of marine navigation it has been recognized by seamen that soundings of the sea bed are a most natural and valuable aid to safe passages. Yet it is probably true to say that the methods of obtaining such soundings and for recording and using the information so obtained remained relatively primitive for longer than any of the other arts or systems used by seamen.Records can be found which indicate that the earliest navigators used poles or lines and plummets to measure the depths of water on the coasts and in the rivers. An example of the use of soundings by Phoenician seamen is recorded by Strabo, who relates that the captain of a Phoenician ship on a voyage to the Casseterides for tin thought himself too closely followed by a Roman ship and deliberately sought a shoal which he knew of on which to run his vessel to avoid capture and the loss of his precious secrets. Then Hanno, the famous Carthaginian admiral of about 500 B.C., at his furthest point south on the West Coast of Africa, outlined the contours of the River Niger, and the Greek admiral Nearchus at the same time made his voyage from the Indus to the Euphrates by soundings in the rivers and on the coast.
The Birth of the Compass
Authors: May W. E. 
Published: January 2010

It seems probable that the magnetic compass, the mariner's compass as it is often called, first made its appearance at some time between the tenth and twelfth centuries A.D. Attempts have been made to prove that the compass was in existence earlier, and that some of the early voyages could not possibly have been performed without its help; but there is no evidence to support this contention and a certain amount to show that other methods were used.Again, it has been suggested that some obscure remarks by certain classical writers could be explained if the author were assumed to be describing the use of a compass, whilst having only the haziest notion of what it was. Among such is the legend of Abaris, the Hyperborean priest, who visited Greece, some say from Britain, many centuries B.C., and had with him a mysterious arrow which showed him the way. If we cut out the fancies of some writers who credited him with the possession of a kind of aircraft (capable of supersonic speeds), it is not difficult to imagine that the arrow may have been a magnetized needle. The difficulty is in understanding how no one down the centuries which followed came to write of the compass. There is, of course, little doubt that much scientific knowledge was possessed by the ancient priestly cults and the knowledge of the compass may have been kept secret for their own ends. If the great library of Alexandria had not been destroyed we might have had the answer to the riddle; but perhaps there is none and the whole tale of Abaris is a fabrication.
An Aircraft Approach Procedure: Some tests with aircraft using Distance Measuring Equipment and the Multiple Track Radar Range
Authors: Downes J. G. 
Published: January 2010

This paper describes tests of an approach procedure in which aircraft approach the airport on a radial track, circle the airport on an orbit and finally approach to land on another radial track in line with the runway. Ninety-six approaches were made with a representative selection of airline pilots in an aircraft fitted with the Australian Distance Measuring and Multiple Track Range Equipment.The flight tests provide information as to the accuracy with which pilots can follow a set track, both for track accuracy and turning, when provided with adequate navigation aids. The average time for the particular procedure used was 18 minutes, and 90% of all times were within ±1 minute of the average. Maximum departures from the correct track occurred during orbiting where the average track was 0·2 mile inside the nominal orbit, and in 90% of approaches the departure did not exceed ±0·8 mile. Detailed analysis of the turns is also given in which it is shown that, on the average, turns occupy ¾ minute instead of the ½ minute required for a correctly executed Rate 1 turn.
Some Profiles for the Future in Coastal and Port Approaches
Authors: Richardson R. B. 
Published: January 2010

The following article is a summary of a paper presented by the author to a meeting of the Liverpool branch of the Institute on 26 January 1968.Many people believe that there is a compelling need to discuss much more seriously than we do the whole way ahead into a new era in the conduct of ships; to scale the heights that lie above the chaos of detail and the log-jams of orthodoxy, and to discover where the truth is most likely to lie in this respect, for obsolete thinking is far more harmful to progress than obsolete equipment and this thinking, therefore, can often become a dominant factor.
‘The Metrication of Navigation’
Authors: Turner R. , Sadler D. H. , Horscroft A. D. , Fifield L. W. J. 
Published: January 2010

Mr. Sadler rightly emphasizes one aspect of time: that is to say time is one coordinate of a space-time set of coordinates that locate an event. The other aspect is that of time interval and it is this that the S.I. second defines. Thus if S.I. units are used the time interval between two events is measured in S.I. seconds; the orbital period of the Earth on its axis (referred to a specified frame of reference) is a certain number of S.I. seconds and, in this context, unless this happens to be 86,400 it is surely incorrect to call this interval a day.Charles Cotter says my note is controversial. I do not think this is so. The controversy lay in the decision to adopt S.I. units. My purpose was to indicate the implications of this decision. The S.I. unit of plane angle is the radian and hence the argument for the retention of a unit of distance related to the minute of arc is not relevant. The problem involved in adapting rhumb-line sailing to S.I. units is not difficult and has already been dealt with with great clarity. The advantages of a single universal coherent system cannot be over-emphasized and it is to be hoped that difficulties will not be prolonged by isolated areas of resistance.
The Improvement of Navigation Lights and Signals
Authors: Lindsay Douglas J. 
Published: January 2010

The Forum comments about small craft lights by Bernard Hayman clearly shows up a shortcoming in the original argument put forward. In relegating the single white light to small craft, and then forgetting it, I have failed to develop this particular argument to its conclusion.Although I cannot agree with Mr. Hayman's reasoning, the shortcoming must be rectified. To this end, may I propose that: ‘Vessels of less than 65 ft., propelled by any means (sailing vessels by definition are excluded from this), to show a single white light, visible all round the horizon for a distance of at least 5 miles. This light to be not less than 9 ft. above the gunwale. These vessels also to show sidelights prescribed in Rule 7(a(ii)), or if less than 40 ft. in length, may show in lieu the lantern prescribed in Rule 7(d).’
Guidance and Control Philosophy for All-weather Landing
Authors: Jones S. S. D. 
Published: January 2010

This paper, which was presented at an Institute meeting held in London on 21 January 1970, suggests a range of philosophical implications which result from the interaction of guidance and control systems in the context of all-weather landing of fixed-wing aircraft. It then attempts to deduce the considerations which must be applied to the approach to the engineering solution to the guidance and control problem.In the context of this paper the terms guidance and control have specialized connotations which have achieved the status of common usage.As they are used in the all-weather operations (AWO) jargon they are easier to define as adjectives than as nouns; the ‘guidance system’ is the system which defines the flight-path which the landing aircraft must follow and the ‘control system’ is that part of the aircraft equipment which enables the aircraft to follow the flight-path which has been defined by the guidance system.
An Examination of some Ship Radars with Automatic Computation
Authors: Wylie F. J. 
Published: January 2010

It is generally accepted nowadays that, to obtain full value for anti-collision purposes from the use of radar by a ship proceeding in poor visibility, it is necessary to plot, or to compute in some other way, the raw data which may be obtained from the radar. It is also usually conceded that, for this to be done effectively in frequented areas, without the aid of mechano/electronic devices, a great deal of time and expertise is demanded from the radar observer and a great deal of responsibility thereby rests upon his shoulders.To reduce the load of work and the possibility of human error and to give the observer more time to use his intelligence in appraising the situation and keeping it under review, radar engineers are already pressing forward the development of automatic devices which, in one way or another, produce computed informatioa in the form ultimately needed.
Radar Usage and Speed in Fog
Authors: Robb E. M. 
Published: January 2010

The use of radar in relation to the Rule of the Road at sea is a subject over which there is still a great deal of controversy. An examination of the main problems involved was made in this Journal (Vol. 3, No. 1, January 1950) by Captain F. J. Wylie who concluded in his paper that the use of radar might justify a more liberal interpretation of the term ‘moderate speed’ than has hitherto been countenanced; and a recent amendment to theKing's Regulations and Admiralty Instructionsclearly accepts the use of radar as an existing circumstance within the meaning of Article 16.No attempt, however, has so far been made to arrive at a precise definition of ‘moderate speed’, and it may well be that the reasons which prevented a definition being made in the non-radar case are in fact given more force when radar, with its added variables, is used. On the other hand it is unlikely that any progress in the matter can be made without a full discussion of the factors involved, and Captain Robb's paper, though it may be possible to dispute some of his conclusions, is presented here as an interesting attempt to achieve a definition which can serve as a guide to shipmasters.—Ed.
Optimum Flight Paths
Authors: Fraser D. O. 
Published: January 2010

A condensed version of a paper presented to the Centre Beige de Navigation, Brussels, 9 January 1950.The fact that the most expeditious route between two points on the Earth's surface is not necessarily a great circle is no new discovery. In the days of sailing ships courses were set to take maximum advantage of the wind; the trade winds were so called because they made the voyages of the trading ships possible. To a large extent they dictated the sea lanes and it was not until the arrival of the steamship that more direct routes across the oceans could be followed.
Winter Navigation through the Strait of Belle Isle
Authors: Simmons R. E. G. 
Published: January 2010

The shortest route from the Great Lakes and St. Lawrence River to Europe passes through the Strait of Belle Isle. The alternative routes pass through the Cabot Strait and are between 100 and 400 miles longer according to the European port of destination. The Strait of Belle Isle is, however, normally closed to navigation from the end of December until the middle of July due to the presence of pack ice and icebergs.Air reconnaissance patrols flown over the Labrador, Belle Isle and East Newfoundland areas seem to indicate that, for the past few years at least, ice conditions have not been so severe as to hamper navigation throughout the normal period of closure. Consolidated ice is only present from the third week of January to mid-February and clears in mid-April to mid-May; only icebergs present a problem in May and June. It is hoped t o show that with proper air reconnaisance at the beginning and end of the ice season, navigation through the Strait could be extended to eight or nine months of the year, or even longer, instead of the present short season of only 5½ months.
The Bordeaux Port Radar
Authors: Girardin A. 
Published: January 2010

At the end of 1963, to assist ships making use of the extensive facilities in the Gironde estuary, the port of Bordeaux installed surveillance radar covering the mouth of the Gironde. As it is still too early to assess its potentialities, this paper describes the technical arrangements and makes some general comments on the use of radar, suggested by the new installation.Ships approaching the Gironde estuary from the open sea follow the buoyed channel from the landfall buoy BXA, 18 kilometres west of Pointe de la Coubre. After picking up the pilot they enter the western or outer entrance passage, whose seaward termination lies 8 kilometres from the coast. This provides a dredged channel, 800 metres wide and 3500 metres long, running east–west. The depth of 12 metres at low water springs enables ships to cross the annular river bar separating the deep water on the seaward side from the mud banks at the mouth of the inner channel.
The Minimum Navigational Equipment for Supersonic Transport
Authors: Hardouin J. 
Published: January 2010

The navigational problems presented by supersonic aircraft do not differ essentially from those with modern four-jet aircraft. Navigation will still entail three main tasks:i. To ensure that the crew knows the position of the aircraft at any given moment, within a reasonable time, and with the necessary accuracy.ii. To ensure that the aircraft is operated under the best conditions of route, speed and height for profitable operation.iii. To ensure compliance with air traffic control.
Anti-collision Radar Sectors
Authors: Garcia-Frias J. 
Published: January 2010

Both the argument and the geometry in this paper require careful study before they can be appreciated; it is hoped that the following notes, which are restricted to purely geometrical considerations, will assist readers to understand them.The author's fundamental argument is that it is geometrically impossible for ships A and B, at distance r apart and moving with constant speeds v and u, to approach each other more closely than distance d (less than r) if the courses of ships A and B are each restricted to a semi-circular anti-collision sector, depending only on the angle δ sin δ = d/r, and on an agreed universal convention. This is illustrated in Fig. 1 in which the two sectors are indicated by vv' for ship A and uu' for ship B. Adopting the convention that the ships pass ‘port to port’, the permissive anti-collision sector for each ship is, relative to the bearing of the other ship, from δ to starboard, increasing to 180° and to port from 180° to 180° −δ . This is equivalent to restricting the course so that the other ship bears more than δ to port or more than 180°−δ to starboard.
Matthew Flinders, Hydrographer
Authors: Ritchie G. S. 
Published: January 2010

In the bicentenary year of the birth of Matthew Flinders at Donington, near Boston in Lincolnshire, it is my privilege to present to Members of three notable British societies some details of the life and work of this great hydrographer.His surveying and charting impact was made entirely in Australian waters and he is probably better remembered in that country today than he is in his homeland. It is my hope that my discourse, added to the many activities that have been arranged in Britain this year, will do something to rectify this situation. My talk will attempt to tell the brief story of Flinders' 40 years of life and work, beset in his later years by many misfortunes. I will also examine in some detail how Flinders conducted his surveys by taking a few isolated examples, and finally briefly review the results of his labours.
Systems Engineering Aspects of the Proposed Channel Navigation Information Service
Authors: Griffiths P. F. C. , Jarman D. R. 
Published: January 2010

This paper, by the head and the deputy head of the Civil Marine Navigational Aids Division of the Admiralty Surface Weapons Establishment, deals with certain problems relating to the proposed Channel Navigation Information Service, including radar coverage, the transmission of information, computer assistance and information display. The paper was read at a meeting of the Institute held in London on 30 January 1974 with the President in the Chair.Much of the background to marine traffic problems in the Dover Strait has already been discussed in previous issues of this Journal. It was decided in 1971 that some radar surveillance of the area would be appropriate. The first steps were taken when a radar trial was conducted by A.S.W.E. in the St. Margaret's Bay area near Dover in 1971. As a result of these trials the Coastguard station at St. Margaret's was fitted with a standard marine radar as an interim solution.
The Quantitative Description of a Traffic Control Process
Authors: Ratcliffe S. , Gent H. 
Published: January 2010

A practical traffic control system can be envisaged as a hierarchy of control loops, each serving to convert a traffic demand into a potential traffic flow. Each loop is concerned with problems that can be foreseen to arise at some time in the future and the distinctive characteristic of any loop is the distance ahead, in time, to which it prognosticates. Although this model is probably applicable to most traffic systems the present note will apply it in the context of air traffic control.Figure 1 shows a whole family of possible control loops. (Not all of these are present in all A.T.C. systems.) In each loop there is a mechanism for the prediction of future traffic. This prediction is compared with certain internal criteria and, if these are not satisfied, some control action is taken to coerce the traffic pattern into some more acceptable form. It is characteristic of most of these loops that they cannot be proved to be capable of safely handling all conceivable traffic demands; there is an implicit assumption that the superior elements of the control system will not tolerate a traffic demand which is beyond the handling capability of the inferior loops, but that a residue of unsolved problems can generally be left to be handled further down the chain.
The Manœuvrability of Ships as Influenced by Environment and Human Behaviour
Authors: Hooft J. P. 
Published: January 2010

This paper by the Vice-President of the Netherlands Ship Model Basin presents the results of a study performed on the N.S.M.B. ship manœuvring simulator aimed at the development of criteria for the manœuvrability of ships sailing in a current. Six pilots navigated four types of 250,000 d.w.t. tankers in sixteen different conditions of current.Ships have grown so large that it is no longer taken for granted that they can be manoeuvred as required. The problem can be split up in two aspects, the ship's inherent manoeuvring ability, which is mainly a technical problem, and the mariner's ability to manœuvre the ship, which is mainly a psychological problem.