bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Anomalies as a Reference for Ground-speed and Map-matching Navigation
Authors: Tyrén Carl 
Published: November 2009

The Earth's magnetic field has long provided us with a directional reference of almost worldwide usable coverage. This paper examines the use of the magnetic field for ground referenced motion and position measurementsWhere E is the vector representation of an electrical field, v vehicle velocity and B a magnetic field, the electromagnetic law of induction, E = v × B, indicates one possibility for measuring ground speed; the magnetic and electrical fields experienced by vehicle mounted sensors being used to solve the equation for v. This method however only gives the component of v perpendicular to the magnetic field. There are also certain difficulties associated with the measurement of B, which should be only the magnetic field of the Earth at the location of the vehicle, and E, which should be only the electrical field resulting from vehicle motion relative to the magnetic field of the Earth. The main problem appears to be the inseparability of motion dependent and non dependent electrical fields, a problem analogous to that of gravitation-acceleration inseparability for inertial navigation systems. The relative magnitudes of the vehicle-motiondependent E-field, of the order of 10−5 (volt/metre)/(metre/second), and the ever-present and very variable non-motion-dependent E-field between a highly conductive atmospheric layer at an altitude of about 50 km and the surface of the Earth, of some 102 volt/metre, are particularly unfavourable. Another potential basis for a ground-speed measurement system is the heterogeneous character of the intensity of the Earth's magnetic field.
From the Bermudas to Lizard
Authors: Richey Michael 
Published: November 2009

The voyage from the Bermudas, or Somers Isles, to Lizard became in the seventeenth century, following Richard Norwood's use of it in The Seaman's Practice (1637), the standard example to illustrate the principles of great-circle sailing. The title chosen here suggests an association. Norwood, as a matter of interest, carried out the first survey of the islands, and his measurement of an arc of the meridian, from York to London, led to the re-knotting of the log-line to preserve a sea-mile comprising 60 to a degree.(This paper was presented at a meeting to celebrate the tenth anniversary of the Solent Branch held in Warsash on 3 December 1981.)
Helicopter Operations for Norwegian Offshore Installations
Authors: Forssell B. 
Published: November 2009

Before a helicopter takes off from an airport on the Norwegian coast to fly to an offshore installation it is cleared in the usual way and is followed by the air traffic control; even after having left controlled airspace the helicopter gets flight-following and alerting services as long as contact can be kept by vhf radio.When the helicopter approaches its destination it has to enter the platform area by flying over a certain reference point (e.g. an outer platform, Fig. 1), which is to be passed at an altitude of 500 feet and which uses a special frequency for its non-directional beacon (NDB) transmissions; it can thus be easily recognized. Before the reference point is reached, radio contact between the helicopter pilot and the platform area will have been established so that necessary information can be transferred. The pilot then asks all platforms to turn off their NDB's and his destination platform to turn on its own (all NDB's unless otherwise mentioned use the same frequency).
A Computer Simulation of Multi-Ship Encounters
Authors: Davis P. V. , Dove M. J. , Stockel C. T. 
Published: November 2009

In a previous paper a model was outlined for an encounter between two vessels. This paper shows how the model has been developed to include the simulation of the behaviour of more than two ships, the entrance to harbours, and narrow channels.In a previous paper by the authors the concept of a domain was examined. Goodwin's definition of a domain was used, namely, ‘the effective area around a ship which a navigator would like to keep clear with respect to other ships and stationary objects’. The concept of distinct sectors for sidelights and sternlight was modified mathematically so that an area equal to the total of the segments was contained within a circle. By off-centering the position of the ship within this circle, the weighting of the differing areas for the various sectors was retained (Fig. I). A second circle with the ship off-centre was introduced called an arena or ‘sphere of influence’. When a ship is inside the arena a navigator becomes aware of the other ship and decides what action, if any, is needed to keep his own domain unviolated. This resulted in a model which obeyed the Collision Regulations.
A Method for the Analysis and Processing of Marine Collision Data
Authors: Brok J. F. C. , van der Vet R. P. 
Published: November 2009

This paper presents a description of a general method for the evaluation of marine collision risk. The approach differs considerably from existing methods in this area, in that it combines analytical modelling in a special way to analyse historical data. The method makes it possible to find the collision probability of a specific ship in any particular location, taking into account such location factors as area geometry, ship movements and speeds. It also constitutes a basis for worldwide data collection.In view of the growth of marine traffic and the increase in the transportation of hazardous materials over the past two decades, considerable efforts are being made towards the development of maritime risk evaluation methods, the main objective being the quantification of ship collision probability. The methods developed to date can roughly be subdivided into the following two groups: (a) kinematic models (see for instance refs. 1–6); (b) historical data analysis (see for instance refs. 7–17). It is a well-established fact that most collisions are due to human failures, and it is widely accepted that human behaviour cannot be described well by mathematical formulae. Kinematic models are therefore not recognized as suitable for estimating this probability. Historical data analysis estimates the collision probability as the ratio of the number of observed collisions to the number of ship movements. Probabilities estimated in this way are only correct in a probabilistic sense when the assumption is satisfied that every ship movement has the same probability of collision. This assumption is rarely fulfilled since most ships often pass each other without collision danger. In addition, this approach is often hampered by lack of data for a specific traffic area, while the application of worldwide data cannot be considered realistic. As far as we know, there does not exist a method which can transfer, in a statistically justifiable manner, marine traffic data from one area to another. Moreover, neither of the above-mentioned approaches is appropriate to analyse alternative routes in the same area, or under changing circumstances.
Integration of the European Air Traffic Control Network
Authors: Morleigh S. 
Published: November 2009

A large percentage of the air traffic flow in the UK is associated with movement to or from other European countries. It would therefore be unrealistic to consider further development of the UK air traffic control network other than on an inter-European basis, although this would necessarily raise many problems.Throughout Europe, during the period since the Second World War, the various nation states have developed their individual air traffic control systems based on national centres and extending to the boundaries of their own Flight Information Regions (FIR). The movement of aircraft across the FIR boundaries of neighbouring states is at present governed by a series of bilateral agreements, whilst attempts to reach international agreement on integration of the European ATC system have not as yet met with much success.
A Table of Latitude Parts
Authors: Turner R. J. 
Published: November 2009

It is always reassuring to find a kindred spirit thinking along the same lines as oneself. R. Williams's proposal for a table of latitude parts (34, 247) is a reiteration of my paper of twelve years ago (23, 233).The equations of a rhumb-line track were established by Sadler (9, 371) and it always seemed to me to be a more elegant solution to solve the equations themselves rather than to apply corrections to inaccurate equations, hence the approach suggested in my paper.
Collision Threat Parameters
Authors: Ratcliffe S. 
Published: November 2009

Lenart derives boundaries of a Collision Threat Parameters Area (CTPA), which defines the range of velocity and heading which own vessels must not adopt if it wishes to maintain a specified minimum spacing from a given threat. Lenart's treatment of the problem is algebraic, and a geometric demonstration of the validity of the CTPA boundaries may be of interest.In Fig. 1, O is the position of own vessel. OX and OY are Cartesian axes, fixed in direction as own vessel manoeuvres. T is the position of a threat, whose velocity is represented on the diagram by a line TT´ whose length gives the distance the threat will travel, relative to own vessel's present position, in some time τ, 0·2 hours, say.
Air Navigation Systems: Chapter 6. Navigation and the Pioneering Flights: Part I
Authors: Steele Philip 
Published: November 2009

This paper is the sixth chapter of a series on the history of air navigation systems which have appeared from time to time in the pages of theJournalsince 1988. Part II of this chapter will appear in the next issue of theJournal.The author acknowledges the assistance of Bath College of Higher Education and, in particular, Dr Terence Rodgers, The Royal Aeronautical Society, The Royal Air Force Museum, and Philip Saxon of the Royal Air Force Historical Society.
‘Columbus's Method of Determining Longitude’
Authors: Pickering Keith A. 
Published: November 2009

I am pleased to see that, in light of my critical evaluation, Arne B. Molander has reevaluated a number of points in his analysis, and has revised his proposals of Columbus's alleged use of the Moon for determining his longitude. However, it is disappointing that these latest proposals again do not seem to have been thoroughly considered.Since it is clear that Columbus's East–West position fixes are not correlated with visible lunar-planetary conjunctions, Mr Molander's latest hypothesis is that Columbus observed a dark-horizon moonrise or moonset near each conjunction – which usually can be done whether or not the conjunction itself is visible. However, it is entirely unclear how such an observation can be converted into a longitude. Reading attentively, we can glean a few details of this process: only a single observation is required, since some positions are computed within a few hours of the purported observation; and Columbus apparently used the Ephemerides of Johann Miiller, since errors in that ephemeris are alleged to have caused errors in the computed longitude. In his 1992 paper, Mr Molander asserted that timing of the conjunction is not required by this method, because Columbus somehow utilizes the Moon's daily topocentric motion. But how this datum is utilized, and in fact all details of the longitude determination itself, are entirely obscure.
Traditional Aids to Navigation: The Next 25 Years
Authors: Turner Neil MacDonald 
Published: November 2009

The authors of this paper are the three General Lighthouse Authorities (GLAs) of the United Kingdom and the Republic of Ireland. It was presented on their behalf at the RIN-96 conference by Captain Turner. The paper gives a brief overview of the policy of the GLAs (i.e. the Corporation of Trinity House, the Northern Lighthouse Board and the Commissioners of Irish Lights) regarding the provision of an aids to navigation service with emphasis on the future prospects of traditional aids to navigation over the next 25 years. The three GLAs have recently carried out a consultation exercise on marine aids to navigation into the 21st century. The results of this consultation exercise are discussed. It should be noted that, for clarity, the General Lighthouse Authorities (GLAs) refer to the systems that they provide as ‘aids to navigation’ (AtoN), to differentiate their provision from the equipment carried on board ships for navigational purposes which are referred to by the GLAs as ‘navigational aids’. This paper therefore in the main deals with AtoN.The coastlines within the GLAs' areas of responsibility rank with the most heavily trafficked and dangerous in the world. The coastlines vary from isolated rocks and the steep, Atlantic coastline, to the low-lying relatively featureless coastline of south-east England, off which are shifting sandbanks and channels. The tidal range in GLA waters is significant and tidal streams can reach 10 knots or more in a number of places.
Air Navigation Systems: Chapter 6. Navigation and the Pioneering Flights Part II
Authors: Steele Philip 
Published: November 2009

Part I of this chapter was included in the January 1997 issue of the Journal, Vol. 50, p. 65.The Smith Brothers, 1919. Captain Ross M. Smith, of the Australian Flying Corps based in Palestine, flew a Handley Page 0/400 late in 1918 on a special flight to Baghdad and beyond, carrying as passenger Major General W. G. H. Salmond, the RAF's Middle East Commander. Flying as co-pilot was Brigadier-General Borton, Commander of the Palestine Brigade. Smith had been flying, in support of Lawrence's forces, another 0/00 which Borton had brought from England.
Political Aspects of the Charting of the Seas
Authors: Haile T. C. 
Published: November 2009

This paper is an abridgement of the paper presented at an Ordinary meeting of the Institute held in London on 20 February 1980 with Captain G. Dudley in the Chair. Captain T. C. Haile of the School of Navigation, City of London Polytechnic, illustrates some past instances when political issues have involved hydrographic surveys, before discussing the delicacy of position fixing in off-shore oilfields.The political implications of hydrography can be traced back at least to the close of the fifteenth century, when the great discoveries of the Portuguese, promoted by Prince Henry the Navigator, and the discovery of America by Christopher Columbus brought to a head the rivalry between the two powers for the control of the Spice Islands of the east.
Computer Model of a Collision-Avoidance System for Air Traffic Control
Authors: Morleigh Sidney 
Published: November 2009

Among the major problems encountered in the control of air traffic are those concerned with conflict prediction and resolution. An interesting method by which many of the associated difficulties could probably be overcome would be by employment of a suitable type of computer-controlled Airborne Traffic Situation Display (ATSD). This would operate in a manner similar to that described for the Fully Automated Pilot-Monitored ATC, utilizing information derived from an ATC Centre via ground/air data link.In addition to the ATSD and the associated digital computer the airborne equipment required for this system includes an electronic data display (EDD) and a bulk storage unit for enabling flight plan and map data to be set up on the relevant display. The ground-based ATC subsystem could automatically provide the pilot with information concerning other air traffic in the vicinity, warning him of any potential conflict situations and advising him of an appropriate evasion manoeuvre. The air traffic data could automatically up-date the back-up information for both the ATSD and the EDD, whilst details of any proposed collision-avoidance manoeuvre could appear on the EDD. The pilot would be able to employ his airborne computing and ATSD system for monitoring the situation. He should therefore be able to confirm the likelihood of a collision, to check the time available before a potential impact and to determine the most suitable manoeuvre for collision avoidance. This manoeuvre will generally agree with that selected by the ground system.
The Avoidance of Accidents at Sea
Authors: Phillips Robert 
Published: November 2009

The problem of collision avoidance at sea would be an important one even if accidents were rare, but the evidence suggests that they are much more common than one might expect. In the eight years leading up to May 1963 there were 60 collisions in the English Channel area and in the following eight years the number increased to 94. With the development of navigational aids such as radar one might have hoped for a decrease. The suggestion that the increase is quite likely attributable to the possession of radar is ironic indeed. It would appear that having the use of this ‘safety’ equipment allows the mariner to take greater risks, but that the risks which are in fact taken are greater than the equipment allows. We would do better to go back to fog horns alone. Even if over-confidence is not the only factor responsible for the increase in accidents, it does, nevertheless, illustrate the importance of the psychological variable in any man–machine system.Collisions at sea, however, are not simply due to errors in a man–machine system, It is, of course, the hardware that actually collides, but the cause of the interaction lies in the decisions and indecisions of the two human agents controlling the vessels. It is essentially a social encounter. It is for this reason that the work initiated by Captain Kemp is greatly to be welcomed.
The VHF Radio Lighthouse
Authors: Johannessen R. 
Published: November 2009

In this paper, which was presented at the seminar on Coastal Navigation referred to on p. 448, the author describes a new system of radio navigation particularly suited to small craft and coastal vessels.This paper reviews the objectives of a new radio aid termed the Radio Lighthouse and describes its scope and use. The results achieved to date are given, as well as plans for the immediate future. A consideration of the options available in implementing the system and methods of obtaining navigational data from the system conclude the paper.
II—The First Year of MNPS
Authors: White F. A. 
Published: November 2009

The adoption by the International Civil Aviation Organization of the MNPS requirement in the North Atlantic Region was based on two premises:(i) The need to maintain an acceptable level of safety in an ATC environment in which a major systems change was taking place—the withdrawal of the Loran A Navigational System on 31 December 1977.(ii) The evidence of an option to take economic advantage of the provision of advanced navigation systems now being used by the majority of traffic operating in the Region. This advantage would be a reduction in the lateral separation minima.
Edward J. Johnson and the early History of Ship Magnetism
Authors: Cotter Charles H. 
Published: November 2009

During the months of October and November 1835 a series of magnetic observations was made, under orders of the Lords Commissioners of the Admiralty, on board the iron steamshipGarryowenby Commander Edward J. Johnson R.N. The results of Johnson's observations paved the way to Airy's solution to the crucial problem of compass management on board an iron ship.Johnson related in a paper in which he described his experiments, that he proceeded to Ireland taking with him the necessary instruments for ascertaining the deviation of the magnetic needle produced by the local attraction of an iron steam-vessel, together with instruments for measuring dip and magnetic intensity. Every facility was afforded him by the owners of theGarryowen, the City of Dublin Steam Packet Company, and by the builders of the vessel, Messrs. Laird of Liverpool.TheGarryowen, built in 1833, was a paddle steamer of length 130 ft, breadth 21 ft 6 in and depth 11 ft. She was equipped with two engines each rated at 85 h.p. and her tonnage was 281 tons burden. She was fitted with four water-tight transverse bulkheads of wrought-iron ¼ in thick. Her hull and boilers were of malleable iron and the total weight of iron in her structure amounted to 180 tons.
Interaction at Sea
Authors: Dand Ian W. , Paget P. J. V. 
Published: November 2009

Dr Corlett's paper on hydrodynamic interaction (Journal, 32, No. 2, May 1979) is of great interest, coming as it does from a practising naval architect with considerable experience of dealing with complex issues arising from casualty investigations. His paper gives an insight into the causes of interaction and the practical illustrations given in the paper add weight to his arguments.Model experiments to study interaction between ships in shallow water have been undertaken at the National Maritime Institute for some years now and many of the results obtained agree with conclusions reached by Dr Corlett. For example experiments carried out with models close to sloping surface-piercing and flooded banks have shown that at moderate to high speeds the side forces and turning moments induced by the banks vary not as the square of the speed, but as the speed raised to a power greater than two. It is of interest to note that the rudder force used to counteract these bank effects varies roughly as the square of the speed, so that when close to a bank at too high a speed, use of the rudder is less likely to maintain control than would be the case at a more moderate speed.The author correctly emphasizes the advantages of a ‘kick ahead’ with a single screw ship, but it is well to bear in mind that this device is not applicable to some ships, notably those with twin-screws and a single centreline rudder.
An Analysis of Error Distributions in Navigation
Authors: Hsu D. A. 
Published: November 2009

This paper first presents some of the results of my recent work on error distributions in navigation which may be worth summarizing for navigation practitioners. Some further explanations and insights in the second part may be useful for future studies on the subject.Discussion on this subject was initiated by E. W. Anderson who questioned the adequacy of the gaussian distribution as the probability model for navigational position errors. He observed that empirical position error distributions are usually long-tailed (i.e. with raised skirts) compared to the gaussian and have a strong tendency to form an exponential function of error magnitude, especially in the far tail-region. Attempts to explain this phenomenon have been made by Abbott, Crossley, Lloyd, Parker, Lord, O. D. Anderson, etc., based on various aspects of navigation performance. To provide a general structure for characterizing the error distributions, Anderson and Ellis made a significant step forward in suggesting ‘Student's t’ distributions as error models. As pointed out by Parker, however, this suggestion has to be taken with reservation and requires further verification based upon empirical data. My own recent work has indeed taken the direction advocated by Parker and has attempted to fill a theoretical deficiency in Anderson and Ellis's work, to provide examples of empirical model fitting and to discuss the merits of Student's t distributions relative to the double exponential model. The main findings are summarized below.