The Great Elliptic Sailing (GES), which can reduce sailing distance, is important to navigators. Whether a Great Ellipse (GE) is worth using depends on whether the distance saved is significant. Otherwise, the Rhumb Line (RL) is easier to steer. We propose a simple criterion to evaluate the difference in distance between the GE and the RL. The criterion is that the GE is worth using when the vertex lies between the departure and destination. In order to take the advantage of shorter distance, the GE is usually approximated as a series of waypoints. Unlike currently practised methods, we propose the Longitude Bisection Method (LBM) which determines waypoints with varying intervals. This approach can establish the appropriate number of waypoints to approximate the GE effectively. The proposed criterion and the LBM are demonstrated in practical examples.

This study is a brief report of the only re-sailing of Columbus' 1492–1493 Voyage following the data in his log in a scientifically controlled research voyage by a professional and experienced global and ocean navigator. The study is follow-on to the article: “The Controversial Skill of Columbus as a Navigator: An Enduring Historical Enigma,” published in The Journal of Navigation (2009) Vol. 62, 417–4251.

To evaluate the aptness of a navigation system in a particular application, the designer needs to assess its performance over typical trajectories travelled by the vehicle itself. Moreover, he or she may be required to judge which components of the kinematics state may be better estimated (and which will not). The main contributions of this work are two novel and complementary performance measures that, in concert, allow for the assessment of a navigation system within the actual context of its application over specific trajectories. For a given on board instrumental configuration, the “excitability metric” permits the isolation of the contribution of the information conveyed by the vehicle's motion itself, while, the “sensability metric” measures the resultant overall quality of the kinematics state estimation. The same tools could help the designer planning appropriate vehicles manoeuvres in order to obtain a required precision for each estimated component. While emphasis is given on the mathematical justification of those metrics, their use is also illustrated with real flight data recorded from a sounding rocket.

To encourage compatibility of national and global precise positioning of GPS surveys in Great Britain, Ordnance Survey is providing access at no cost to the new National GPS Network, via a website first available in June 2000. By requiring the use of this infrastructure to provide ETRS89 control station coordinates at a stated level of precision, survey clients can be assured that any commissioned survey will be precisely consistent with any other, even if the two are widely spaced in location and time. All such surveys will also be precisely consistent with the Ordnance Survey large-scale base mapping, using the precise National Grid Transformation and National Geoid Model. This is now the Ordnance Survey recommended ‘standard method’ of creating new National Grid coordinate datasets, eventually to replace completely the traditional national control networks of triangulation stations and height bench marks.

This paper, and the following five papers, were presented during the Telematics Automotive 99 Conference held at the National Exhibition Centre, Birmingham, 13th to 15th April 1999. This first paper sets the scene for the more detailed technical aspects of the later papers. Copies of the full proceedings of Telematics Automotive 99 are available on loan from The Cundall Library.

Globalisation of both markets and supply has been nowhere more obvious than in motor cars. These vehicles create not only the most free economic pipeline known to man but also a revolution in personal freedom. They are unlikely to go away; we have to find ways of living with them by coping with the environmental problems and the many forms of traffic problem: congestion, driving and support skills and car crime. In other areas, notably manufacturing and commerce, automation and advanced communications have enabled radical improvements in quality, productivity and environmental impact. This effect has yet to reach road transport in volume; the environmental and traffic problems are growing at least as fast as the populations of vehicles grow. The risk with such an important enabler as telematics is that it is seen as a plaything for gadget-minded users, rather than a key enabler for ongoing use of the car in the face of unrelenting pressures of congestion and environmental damage.

The ever-increasing number of vehicles on the road has created a serious demand for traffic information not only on the move but also at the planning stage of a journey. While on the move, the driver will be able to re-route his/her journey avoiding traffic congestion, but this information could be even more valuable before starting the journey. Today there are differences between the three main ITS markets (USA, Japan and Europe). Japan is leading the way, with the introduction in 1995 of the Vehicle Information Communication System (VICS), which is a free service. Vehicles are equipped with VICS receivers taking information from a network of road beacons installed on main roads, transmitting traffic flows by infrared rays, wave beacons, and FM multiplex broadcast. Europe has been involved in driver information systems from the early '90s when RDS was developed, which is another free service, and most of the car radios sold in Europe are able to process RDS signals. Since then, new free services have been developed – for example, RDS-TMC. In the UK, the private sector has been heavily involved recently, its major player being Trafficmaster. The Trafficmaster system is based on a network of traffic detection sensors, which covers all major UK motorways and most of the major A roads, with plans to expand into the continent. Trafficmaster collects road traffic flows and disseminates this information to its subscribers via a range of technologies, including GSM. The quality of the information supplied by the free and subscription services can be improved by being fully integrated with on-board navigation systems and by providing more detailed and wider types of information. All current methods are described/analysed and compared in this paper, with future enhancement highlighted. One of the main limitations lies in current data transmission routes, which are not fast enough to support the data required for an optimal use of the system. Some technologies available will potentially allow the many service providers to transmit information.

Digital electronics have caused massive changes to navigation technology in the latter half of the twentieth century. This paper presents an alternative view to much of the commentary on the future of electronic navigation. It is written from a small craft perspective, although the principles are of value to commercial and naval shipping. Essentially, it proposes the development of environmental simulation as the basis for computer-hosted charting systems on vessels. This is drawn from the author's experience of developing the DyGeo system for environmental simulation, of which the navigation version forms a part. It stresses that much of the additional data we have placed on charts this century has been cultural in content, and necessitates a large bureaucratic system for its maintenance. An environmental system requires different types of inputs, but can be largely self-maintaining. The advent of the inexpensive, portable, personal computer has put this sort of facility in the hands of the leisure mariner as well as professional navigators.

In the middle years of the 20th Century, few merchant ships were fitted with radar and, on those that were, shipmasters often looked upon it as a distraction from a watchkeeper's proper duties rather than as a useful aid to navigation.

For shipmasters of that persuasion, the only place to keep watch was outside the wheelhouse on an exposed bridge wing; mostly the starboard wing because the COLREGS (‘Collision Regulations’ or, more properly, ‘The International Regulations for Preventing Collisions at Sea’) required us to give way to ships approaching from the starboard side. Well, the bridge wing was an attractive place to spend a few hours on a calm, tropical night, but it could be highly disagreeable and sometimes, I thought, actually dangerous, in a North Atlantic rainstorm.

This paper discusses the knowledge and culture of astronomy possessed by the Maya civilisation and how this might have been used for marine navigation in the 8th Century. Comparison is made with the European view and use of celestial positioning.

This paper details the current status of the development of an ‘automatic’ low-cost system based on wireless communications technology to provide continuous tracking of the location of devices in all environments. This task requires a multi-disciplinary approach combining communications systems design, digital signal processing to extract ranges and, importantly, approaches from the field of geodesy to develop novel network positioning techniques for ad-hoc networks. Such a network will support a number of services relevant to crime management where seamless tracking is required. The paper discusses the process for developing the system, christened intelligent pervasive location tracking (iPLOT), with a particular reference to user and system requirements, and how these have been used to explore a network positioning strategy.

When the Society for Nautical Research was founded in 1910, one of its objects was to work for the foundation of a National Maritime Museum. To many this must have seemed an unattainable star on which to focus their hopes, especially when a few years later the First World War broke out. However, fortune changed, and in 1928 the great Macpherson Collection of maritime prints and drawings came on the market. A fund was started to purchase it for the nation, but Sir James Caird, a wealthy shipowner, stepped in and bought the entire collection. Matters now really began to move. The Admiralty was anxious for more space in the Royal Naval College at Greenwich and this could only be obtained by removing the Royal Naval Museum, which had been transferred from Somerset House, and the Greenwich Hospital collection of paintings, which had been started in the Painted Hall in 1824. A new home was needed for these and for the Macpherson Collection, and then in 1933 the Greenwich Hospital School was moved to Holbrook, and the great range of buildings just across the road from the Royal Naval College became available. In the next year the National Maritime Museum was established by Act of Parliament and the conversion of the buildings was begun; but already fresh acquisitions had begun to come in. Sir James Caird bought such treasures as came on the market and, capably advised by the distinguished naval historian, Sir Geoffrey Callender, who was to become the first director of the museum, laid the foundations of a collection which has become the envy and admiration of maritime nations.

Shiphandling training simulators have come into use since 1967. Several such simulators, with differing technical characteristics and training goals, are now in use around the world. They are commonly used to familiarize already competent masters with new vessels, restricted water areas, or some form of standard bridge procedures. Acceptance of these simulators by highly experienced master trainees has been predominantly favourable. Ship radar simulators have been in use for a somewhat longer time. They are typically used for training entry level officers as well as experienced masters.

The aviation and nuclear reactor industries, with a greater experience of simulator technology and its training value, use simulators for both training and licensing. The military (e.g. Navy) and other government agencies (e.g. National Aeronautics and Space Administration) have extensively used simulators for training and qualification. It has been suggested (Schumacker, Madsen and Nicastro, 1972; IMCO Standards of Training and Watchkeeping Convention of 1978, Resolution 17) that simulators could be used for proficiency demonstration on the part of mariners. The US Port and Tanker Safety Act of 1978 requires standards for licence qualifications by use of simulators.

The United States Coast Guard and Maritime Administration have funded research into the role, technology, and effectiveness of ship-handling simulators. Depending partly on conclusions from this research, the Coast Guard will consider partial credit toward licences for successful completion of approved simulator training. The Maritime Administration may assist maritime training academies to design and procure simulator-based training systems.

This is an abstract of a paper commissioned by the Lights Advisory Committee and published in June 1987.

It would be interesting and profitable to look back to see how closely the applications of science to the sea had followed its developments and technical achievements ashore. In contrast to the wealth of literature on the classical geography of the oceans and the achievements of the early voyagers there is no balanced account of the scientific investigation. Such an account would include the work of men like Boyle, who, in his observations and experiments about the saltness of the sea (1672), gave the first satisfactory explanation of this phenomenon, and showed th at it would be necessary to make a great number of observations in different climates and different parts of the world to determine the degrees of saltness with any certainty. He arranged for travellers to collect samples for him. Lavoisier (1772) and Bergman (1777) analysed samples of sea water and named the principal dissolved salts. In 1812, Alexander Marcet, a London physician, made the remarkable discovery that although the total amount of salt varied from place to place according to the balance of evaporation and precipitation, the principal constituents were always present in the same proportions. Although this was almost a premonition based on the analysis of not more than fourteen samples from different parts of the Atlantic Ocean, it has stood the test of time.

This paper describes two methods by which lines of position may be obtained by observation of stars (in pairs) without the use of instrumental scale readings either for altitude or for azimuth. These lines of position represent arcs of great circles of the Earth. An instantaneous observation is proposed.

Great circles determined by star positions form, on the celestial sphere, a lattice which is not deformed by precession. Whether or not he be at rest relative to the rotating Earth, the observer's zenith traverses this lattice, which thus may serve in celestial navigation precisely as does a well-marked terrain in contact flying over land, or as do ranges and markers in coastal and harbour navigation. Observation of the zenith-transit of an element of this lattice is akin to the process of noting the moment when an aircraft crosses a coastal line or other visible terrestrial mark or to the recognition of when a vessel near shore is on a certain range. Observation of this type is as rapid as the navigator may be able to make it since it is the observation of the occurrence of an instantaneous situation.

The national SAR (search and rescue) objective is to prevent loss of life and injury through search and rescue alerting, responding and aiding activities. Specific objectives under the SAR Branch's five year R & D (research and development) plan are: reduction of search time, improvement of rescue technology, and systems integration. The project described in this paper falls under the first objective – reduction of search time.

This, and the following five papers, are a selection from those presented at the RIN91 Conference on Small Craft Navigation. The Conference was held at the Warsash Campus, Southampton, over the weekend 6–7 April 1991. Copies of thecomplete proceedings are available from the Director, price £30 to non-members and £20 to members (exc. postage and packing).

1. INTRODUCTION. The North Atlantic air traffic system is the busiest and most important long-range system in operation today with a current total of 127 000 flights“annum. The combined effects of the total flight time and the difference in time zones on either side of the Atlantic makes it desirable for most passengers to fly westward in the day-time. Conversely, it is most convenient (or least inconvenient!) to fly eastbound during the hours of darkness. Thus the Atlantic traffic system is strongly tidal with the flow predominantly (though not entirely) westbound during the day and eastbound overnight. Currently the central core of the traffic in the busiest hours is organised into a parallel track structure – the Organized Track Structure (OTS), though nearly half the aircraft operate so-called random routes clear of the OTS.