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.

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.

The latest statistics on maritime accident alerts are again demonstrating a high percentage of false alarms from Emergency Position Indicating Beacons (EPIRBS) in Spanish waters. Of a total number of 243 received distress alarms, only three were real and 123 were never identified; a very similar situation exists in the rest of Europe. To address this problem, as well as IMO Resolution A.814(19)/23.11.95, there is a Spanish proposal to install a receiver (121-5/243/406 MHz) on board ships, so that the seafarer can detect accidental activation of an EPIRB. The installation of EPIRBS, which had seemed to be sufficient to solve the problem of locating vessels in distress, apparently needs the help of other tools. One such tool could be the very high frequency radio direction finder (VHF/DF) proposed in this paper. Recent experiments using VHF/DF carried on board the ships Salvamar Tenerife and Punta Salinas, in conjunction with the traffic control tower of the Rescue Coordination Centre (RCC) of Santa Cruz de Tenerife (Canary Islands), demonstrated a number of advantages which are described in this paper.

This paper proposes a novel method of error mitigation for stereo visual odometry (VO) applied in land vehicles. A non-holonomic constraint (NHC), which imposes physical constraint to the rightward velocity of a land vehicle, is implemented as an observation in an extended Kalman filter (EKF) to reduce the drift of stereo VO. The EKF state vector includes position errors in an Earth-centred, Earth-fixed (ECEF) frame, velocity errors in the camera frame, angular rate errors and attitude errors. All the related equations are described and presented in detail. In this approach, no additional sensors are used but NHC, namely velocity constraint in the right direction , is applied as an external measurement to improve the accuracy. Tests are conducted with the Karlsruhe Institute of Technology and Toyota Technological Institute (KITTI) datasets. Results show that the relative horizontal positioning error improved from 0⋅63% to 0⋅22% on average with the application of the velocity constraints. The maximum and root mean square of the horizontal error with velocity constraints are both reduced to less than half of the error with stand-alone stereo VO.

In the January 1966 edition of this Journal Captain Wylie has given a lucid summary of the factors involved in the presentation on radar displays of true and relative motion. He also stated a conclusion on the combinations of display and ancillary equipment which he considers best satisfy the requirements for use when plotting to avoid collision at sea. Whilst acknowledging with respect all the work he has done to clarify the issues raised on this important but contentious subject over a number of years, a number of us has found it impossible to agree with his latest findings. As these may influence opinion in the shipping industry, the Board of Trade, the Courts of Law and the radar manufacturing industry, both at official and unofficial levels, they should not go unchallenged. Our disagreement concerns the priorities defined for display equipment and the method to be used for plotting. There can be no disagreement on academic principles.

This paper falls roughly into three sections: the inter-relationship between economic forces, technological change and occupations, a brief history of navigation in occupational terms, and the present and future state of the occupation. The conclusions drawn may be open to discussion, since it presents a point of view and not a specific piece of research. It is restricted to the occupation of navigation in the Merchant Navy; naval and aircraft navigation appear to be very different as occupations.

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.

This paper is a sequel to the author's paper under the same title published in the April issue of the Journal.

The statistical relation between wind and temperature in the lower stratosphere is not only of theoretical interest but is of practical concern for the operation of supersonic aircraft since for example the incidence of abnormally high temperature together with strong head-winds could substantially increase the time of flight and reduce the pay-load. Temperature and tail-wind component have been correlated on the great-circle route between London and New York at 50 mb. The route was divided into six legs of approximately 500 nautical miles; at the mid-point of each leg, temperature and tail-wind component for an eastbound flight were obtained from daily charts for the period of the International Geophysical Year and its extension, July 1957 to June 1959 (U.S. Weather Bureau, 1960–63). Seasonal correlation coefficients were evaluated for each leg and for the route as a whole. The seasons in the lower stratosphere in middle latitudes differ from the conventional seasons except in summer (June–August). Although autumn has been taken as September–November, it appears that the transition to the winter type of circulation is usually completed by late October so that November should strictly be included in winter. However, the period December to March has been taken for winter; conditions in March are very variable from one year to another but on balance this month is probably more appropriate to winter than to spring.

The Royal Institute of Navigation has in its possession a remarkable set of works by its late Honorary Member Vice-Admiral Francisco Radler de Aquino. An interesting feature of many of the items of this set is the large number of annotations, made by Aquino, which throw light on the development of his short-method tables—a development which continued throughout Aquino's long career as a distinguished navigator.