bluuebunny/crossref_metadata_2025_split huggingface dataset:
A History Recording Radar Display with Prediction
Authors: Embling C. A. , Stewart J. P. 
Published: January 2010

The paper describes a method by which ‘history’ in the form of tracks of all vessels appearing on the PPI is projected on a flat plotting surface, and the use that can be made of such information to ascertain either the true or relative tracks of all such vessels and also the effects of own ship alterations of course or speed or both on the relative tracks of other vessels.In a recent survey of collisions and from experience on board ships it has been found that, in heavily congested waters and low visibility, even vessels with sophisticated radar equipment and associated plotting facilities and sufficient personnel may find themselves ‘saturated’. Vessels with simpler radar and plotting facilities and less staff consequently become saturated in less heavy traffic conditions.
Velocity Measurement in Tanker Berthing
Authors: Bulman P. J. 
Published: January 2010

Dr. Bulman's paper (which is Crown copyright) was presented at an Institute meeting held in London on 19 February 1970 with the Hydrographer of the Navy, Rear Admiral G. S. Ritchie, C.B., D.S.C., in the Chair. The paper, which describes work undertaken by the Royal Radar Establishment on the measurement of ship movement for berthing very large vessels, was presented at the same time as the paper read by Mr. M. J. Tucker, National Institute of Oceanography, and the discussion relates to both.When a 200,000-ton tanker hits a jetty at more than about 24 ft./min., that is, nearly a quarter of a knot, some damage is likely to be caused. However, the problem of measuring the speed of the ship starts much sooner than that. One could say that from the moment the log is retracted on entry to the estuary some other form of assistance ought to be made available. Traditionally pilots and masters have relied on visual estimation—on the appearance of the passing land and passing landmarks in order to judge the speed over the ground while travelling up an estuary. This has been adequate for smaller ships where the height of eye, length of ship, width of ship were all considerably less than they are now on the largest tankers, and where the critical velocities were higher. Now, however, it has proved very difficult to judge by eye the speed of a very large ship from a station some 80 ft.above the water to the accuracy required, the accuracy being of the order of ± 3 ft./min. It is in this spirit that the Esso Petroleum Company approached the Royal Radar Establishment (R.R.E.) some two years ago or so to tackle the problem.
Errors of a Simple Doppler Computer due to the Spheroidal Form of the Earth
Authors: Williams J. E. D. 
Published: January 2010

Doppler-operated computers which perform plane D.R. navigation are currently offered to the airlines. A datum track and distance to go are set; from the time of selecting ON, the computer resolves small elements of distance run (input doppler and heading reference) as follows:Change in across-track dist. = element of dist. run × sin (actual tr. − set tr.)Change in along-track dist. = element of dist. run × cos (actual tr. − set tr.)These relations are true for a plane Earth.
The Changing Navigation Routes of the Thames Estuary
Authors: Robinson A. H. W. 
Published: January 2010

Reference to a chart of the Thames Estuary will show that the dominant feature of the submarine morphology is the series of elongated banks, of which the Barrow, Sunk and Long Sand are the most important. Between these banks, and with the same north-east to south-west trend, are the navigable channels of the Swin, Barrow and Black Deep (Fig. 1).The alignment of the channels suggests that they originated as a result of tidal-stream scour of a fairly uniform sheet of fine silt and sand. In each tidal period, streams enter the estuary from the north and flow on the flood in a south-westerly direction parallel to the Essex coast. After about six hours they slacken, turn and flow out of the estuary in the reverse direction. This continuous flood and ebb stream action, with a maximum velocity varying from 2·3 to 2·9 knots depending on whether the tide is neap or spring, has apparently scoured out channels to depths which exceed 10 fathoms in places. If the channels largely arose in this way, the banks represent the modified remnants of the initial surface. These banks are constantly being extended seaward as more riverine silt is emptied into the estuary by the Thames, Medway and the rivers of Essex. The distal end of Long Sand alone has grown almost ½ mile in the past 100 years (see Figs. 1 and 4).
High Altitude Observations at Sea
Authors: Verstelle J. Th. 
Published: January 2010

The method of taking high-altitude observations at sea described by A. N. Black in the April number of theJournalis not widely known and is undoubtedly of practical value, though it is not new. In his article Mr. Black regretted that he had had no opportunity of testing the method under practical conditions as his cruising range did not extend into the tropics. For this reason the results of some actual observations taken by the present writer some twenty-five years ago using this method may be of interest to Mr. Black and to readers of theJournal.The author is in entire agreement with the first ten lines of Mr. Black's paper, though the termslant altitudeorinclined altitudemight express better what is being measured thanhorizon distance, which may be misleading. He does not however agree that the method is sound in theory for ‘normal’ altitudes, as will be explained. The method is in fact both practically and theoretically restricted to use with zenith distances of about i°, which is the limit actually considered in Mr. Black's paper.
III—The Meteorological Limitations on Pressure Pattern Flying
Authors: Sawyer J. S. 
Published: January 2010

The preceding papers indicate that the theory of pressure pattern flying assumes that the wind satisfies the conditions imposed by the geostrophic wind equation and that the atmospheric pressure distribution is not changing. These conditions are not satisfied in the atmosphere, and the errors caused by their non-fulfilment are discussed in the following paragraphs.Effect of departures of wind from geostrophic. The geostrophic wind equation is derived on the assumption that the wind blows uniformly without acceleration and without friction. These conditions are never satisfied in the atmosphere, nevertheless the practising meteorologist has found that the geostrophic wind represents a useful approximation to the true wind. There are certain exceptions of which the most important are in low latitudes and at levels below 2000 feet.
The Second International Meeting on Radio Aids to Marine Navigation New York and New London
Authors: Michell R. B. 
Published: January 2010

At the first International Meeting on Radio-Aids to Marine Navigation held in London in May 1946 some 105 delegates of twenty-three maritime nations met to discuss and witness demonstrations of some of the remarkable advances made in radio-navigation during the war and to consider the progress made in relation to their peacetime uses for marine transport.At the invitation of the U.S. government a second meeting was held a year later, in New York and New London, to show the progress made in America, to illustrate, with demonstrations, the U.S. policy and to pave the way to international standardisation. The U.K. delegation was led by Sir Robert Watson-Watt.
Navigation and Strategy in Ocean Racing
Authors: Illingworth J. H. 
Published: January 2010

The technical processes of navigation are much the same in all craft, but there are certain requirements and problems which are peculiar to ocean racing. Compared with big ship navigation, the principal differences are:(1) The ship's speed is irregular and is not always exactly known; it is also much lower so that the tidal streams and other sets play a much more important role.(2) The course steered is often a constantly varying one, particularly when the vessel is on the wind, or before the wind.(3) Leeway is a far larger factor.(4) The violence of the motion and the lack of space greatly increase the difficulty of plotting and calculating.(5) The methods of fixing the ship are generally less exact and less readily available.
I—Decca for Helicopter Operations
Authors: Adam J. G. 
Published: January 2010

For a number of years helicopter operations will mainly take place at operating altitudes between 500 and 2000 ft. Due to the inaccuracies of existing pressure altimeters vertical separation less than 1000 ft. cannot be applied and therefore maximum use will have to be made of lateral and longitudinal separation possibilities if the development of helicopter operations in high density areas is not to be impeded. As far as possible helicopter operations will be kept apart from fixed-wing traffic but this may be difficult to achieve in terminal areas where departing and arriving fixed-wing aircraft are at low altitude and the available airspace is restricted.It is, therefore, essential that the navigational aid on which air traffic control base safe separation should be one which enables the helicopter pilot to adhere strictly to his pre-determined track and also provides him with an accurate measurement of progress along track. Quite apart from the air traffic control aspect, since the helicopter flies low, frequently in poor horizontal visibility and low cloud-base conditions, accurate track keeping is essential from the standpoint of avoiding obstructions or high ground in the vicinity of the route. Accurate and solid coverage over a wide area at low altitude is therefore an important requirement of any helicopter aid system, particularly in a high traffic density area such as western Europe.
Operational Performance Standards for Civil Aircraft
Authors: Gillman R. E. 
Published: January 2010

Throughout the history of aircraft design, a trend that has remained quite constant up to the present time is the steady increase of wing loading with successive types. This feature with its consequent raising of stalling speed, and therefore landing and take-off distances, has resulted in techniques rather more scientific than those used in the early days of civil flying. With take-off distances of anything up to 6000 feet, the pilot in deciding whether a particular airfield is adequate for a given aircraft is no longer the sole arbiter; the rule of thumb must give way to the slide rule.The pilot is, of course, still responsible for the safety of a particular operation, and to help him in this respect, performance information for his particular type of aircraft is supplied in graphic form with the safety factor already built in. It is the purpose of this paper to explain why and how this is done.
Navigation in the Days of Sail
Authors: Shaw A. R. Perry 
Published: January 2010

At the turn of the century I served in two four-masted barques under three captains hailing respectively from Nova Scotia, Liverpool and Glasgow. All three were rather elderly and their practice of navigation did not exhaust the theory even then included in the syllabus for second mate. However, it may be interesting to recall their methods.The captains personally had to supply, in addition to sextants and nautical tables, chronometers, charts, ‘Pilots’, patent logs and nautical almanacs. I doubt if they bothered about tide tables. These were all kept in the captains' bedrooms. Each of these captains rented and insured two chronometers. In port, if convenient, these went ashore to a chronometer dealer and just before sailing were brought on board, each with a card showing its maker's name and number with error of instrument and its daily rate. If at sea it was possible to get a longitude by bearings of the land and also longitude by sights, they would be checked and error and rate corrected. Of course in sail it was impossible to maintain an even temperature in the chronometer compartment. It was generally assumed that, owing to effect of change of temperature on the lubricating oil, a chronometer ran slower in cold weather and faster in hot. I don't know when they were cleaned. Perhaps if a ship did return to where the chronometers' owner had his place of business they might be cleaned before being issued to some other ship.
The Work of the Institute
Authors: Irving Edmund 
Published: January 2010

Presidential Addresses over the years have covered a variety of subjects, mainly scientific and generally devoted to navigation. Being neither a scientist nor, strictly speaking, a navigator, I have chosen the work of the Institute as the subject of my Address. Today, the Institute celebrates its twenty-first anniversary and we can suitably reflect on its growth and achievements. We are immensely proud of the fact that Your Royal Highness consented, as long ago as 1952, to become our Patron. We are always honoured and delighted that you have been able to attend so many of our Annual General Meetings and to take the Chair. You inspire us, Sir, to keep in full view the objects of the Institute, which were laid down in 1947 and which are:‘To unite in one scientific society those interested in navigation’ and ‘To advance the science and practice of navigation and its associated sciences’.
Future Requirements for Autopilots at Sea
Authors: Wepster A. 
Published: January 2010

Some forty years ago, in the early days of automatic steering, autopilots were looked upon as a mere addition to the gyro-compass equipment. It was a black box, which was said to be able to reduce fuel consumption. It was also a gadget that amused passengers. The original introduction of the autopilot was based on these two aspects and its application was consequently confined to a small number of large passenger vessels.Yet the name autopilot clearly indicates the possibility of automating an important element of the ship's routine, the steering. However, at this stage shipping in general was not ready for this aspect. The cost of labour on board played a less important part then than it does today. It took another twenty years before it became clear that it was precisely the labour-saving capacity of the auto- or gyro-pilot which would play such an important role in the rationalization of the ship's manpower requirements.
Ground Movement Guidance and Control at Major Airports in Low Visibility
Authors: Harrison G. 
Published: January 2010

The practical feasibility of blind take-off, landing and rolling to a stop has been adequately demonstrated, and both ground and airborne facilities are now being provided which will permit its progressive implementation operationally. Thus, one of the major questions remaining to be answered is the extent to which supporting airfield facilities are required to be improved in order to match the landing capability.The present paper represents a contribution to discussion of the problems involved in ensuring that airport ground movements of both aircraft and vehicles can continue efficiently, and of the various measures which can be taken to minimize these problems. The conclusions drawn represent the opinions of the Blind Landing Experimental Unit, based upon the limited information which so far is available on this topic, and thus do not necessarily reflect firm U.K. policy since this must involve further study and investigation.
Distance by Vertical Angle—Height Unknown
Authors: Sayers P. H. 
Published: January 2010

An interesting, easy and useful method of finding the observer's distance from a ship, buoy or isolated lighthouse, the height of which is unknown, is by measuring the angle between its waterline and the horizon. To this is added the angle of dip for the height of eye.From the figure it can be seen that the angle so obtained is equal to the angle at the object between the observer's height of eye and his own waterline.
The Use of Radio Sextants in Automatic Navigation Systems
Authors: Cade C. M. 
Published: January 2010

The basic principles of radio sextants are reviewed and their application is compared and contrasted with that of infra-red and visual wavelength sextants. For maximum versatility an automatic sextant should be able to operate both on radio wavelength and at one of the others. A complete automatic system requires not only a means of making automatic celestial observations but also a means of carrying the data forward—that is to say, as inertial reference. In the paper presented in Paris the development of inertial systems was briefly reviewed with particular reference to linear vibration gyrostats which lend themselves readily to light and compact systems where the highest accuracy is not required.It is suggested that future developments in automatic navigation may well see novel forms of inertial reference coupled to radio sextants of millimetre wavelengths.
Height Information from Doppler Navigators
Authors: Beck G. E. 
Published: January 2010

The possibility of obtaining altitude as additional information from an airborne doppler navigation equipment is reviewed, and some of the design problems involved are discussed briefly. These relate to the form of modulation used for transmission, the aerial beam shape and the direction of the aerial beams.It is concluded that an accuracy of ±5 per cent. ±2 ft. over the range of 10–100 ft. might be possible. The work is in an investigational stage, and no specific design is described.
The Reduction of Weather Minima and the Improvement of Scheduled Regularity
Authors: Majendie A. M. A. , Gorham J. A. 
Published: January 2010

The inter-relationships between the application of such airborne devices as automatic landing, head-up instrument displays, flare-out computers, and the like, their effect on operating weather minima, and the consequential benefits that may be derived in scheduled regularity, are very involved. The purpose of this note is to set out in simple terms the more important factors so as to provide a framework for further discussion. A cardinal theme of this discussion is the close association between the techniques needed to improve regularity, and those needed to improve safety.The landing of a transport type aircraft is a task of a routine and repetitive type. It takes place within a fixed envelope of conditions that can be fairly strictly defined, and a high order of precision is needed compared with other phases of normal flight. The repetitive consistency that can be achieved by automatic means makes it natural to consider such a solution. Once such a system has been developed to a satisfactory level, the accuracy and consistency of the landing manœuvre will undoubtedly be much better than can be achieved by a human pilot.
On the Stopping Distances of Giant Vessels
Authors: Tani H. 
Published: January 2010

This paper considers a practical solution to the stopping distance of ships, with particular reference to modern giant tankers. One solution to the problem has already been evolved by Captain H. Topley of the Honourable Company of Master Mariners. The present paper tackles the same subject from quite a different viewpoint.The basic assumptions on which the mathematical treatment has been based is presented in Section 1, which also includes the calculation formulae of the speed and distance run at any time in a manœuvre, without proofs. Section 2 deals with clarifying the essential differences between Captain Topley's theory and the author's. The validity of the theories is examined in Section 3 by comparison with the results of actual ship tests. Section 4 presents calculation diagrams prepared by the author.The only reliable data available by means of which captains can predict the stopping behaviour of their ships after ordering STOP ENGINES are the results of inertia tests conducted at the sea trials when the ships were built.The inertia tests, however, are usually performed for only one case in which the approach speed is assigned to HALF AHEAD or the so-called manœuvring full ahead speed. Therefore most masters are glad of any knowledge of how to predict the movements of ships from any reduced speed.
III—The Voyage of Sputnik
Authors: Porter J. G. 
Published: January 2010

The Russian Sputnik travels rather faster than the Mayflower or even a transatlantic racing yacht, and the launching of this artificial satellite is truly a wonderful achievement. I want to tell you why I think so, and what it means for the future.The satellite, which was launched on 3 October, has already made 300 revolutions about the Earth. Its speed is about 17,000 miles/hour, which is about 280 miles a minute, and it makes one revolution about the Earth in 96 minutes—that is, 15 revolutions a day. Its track is inclined to the equator at an angle of about 65 degrees, so that at one time it goes up to the Arctic Circle, and at the other end of its path down to the Antarctic.
Time Data and Navigation
Authors: Smith Humphry M. 
Published: January 2010

In 1972 an atomic time standard based on the fundamental properties of the caesium atom is being substituted for Greenwich Universal Time, based on the rotation of the Earth on its axis, as the ultimate control for international time signals. Greenwich Time and longitude are inseparable, so that any necessary correction to the time signals he receives will be of vital importance to the navigator.This paper was presented at a meeting of the Institute in London on 27 January 1970 with the Hydrographer of the Navy, Rear-Admiral G. S. Ritchie, C.B., D.S.C., in the Chair. Mr. Humphry Smith, head of the Time Department at the Royal Greenwich Observatory and Chairman of the Directing Board of the Bureau International de l'Heure, reviews the relationship of uniform time systems to the precise astronomical observations that determine the irregularities of the Earth's rotation. He outlines the current proposals for time signals, their correction to Universal Time and the implications for the navigator.
Low Light Television and its Application to Navigation
Authors: Corps R. J. , Hicks A. G. 
Published: January 2010

This paper was presented at a joint meeting of the Institute and the R.A.F. Specialist Navigation & G.D. Aero-Systems Course Association in London on 21 April 1971, with Group Captain D. F. H. Grocott, C.B.E., A.F.C., in the Chair. At the meeting the paper was illustrated with many slides which greatly facilitated understanding of some passages. Only a proportion can be reproduced here.Obviously there are many occasions when the navigator would like to retain a full visual capability at night; this is certainly so in the military context where it may be essential that aircraft operations shall be fully effective under night conditions. It is similarly a truism that the acuity of the human eye, that is the ability to resolve fine detail in the image, decreases as night falls and the illumination level is reduced. Because of this there have been many research programmes over the years to develop sensors to extend the capability of the human eye, and one of the most important developments has been the use of low light television (LLTV) systems as an aid to night vision.