In this paper, methods of defining heading are enumerated and the limitations of magnetic and gyroscopic devices are analysed in detail. Particular attention is paid to the development of the rotated race principle which is likely to be responsible for a large improvement in the basic azimuth gyro. The gyro-magnetic combination is scrutinized and the errors inherent in this compass system are classified. The possibility and consequent effect of diminishing certain categories of error are presented. The current position is summarized and an attempt is made to suggest possible future trends. The authors are, respectively, with Smiths Aircraft Instruments and the Sperry Gyroscope Company.

Presented at a meeting of the Institute held at the Royal Geographical Society on 15 June 1951.

Shore-based radar stations to supervise or assist the navigation of ships have now been employed for at least a decade. Such stations were more extensively used during the war than they have been since, principally because there had to be large convoy movements along heavily mined coastlines under conditions when, because of wartime limitations, many of the more conventional navigational aids were not available. The most important wartime development in the use of radar in this direction was undoubtedly the introduction of high power centimetric equipment and the plan position indicator. Since the war the use of shore-based radar to assist navigation of merchant shipping has been extremely limited and the only outstanding installation of this type is the Liverpool Harbour Supervision System, which was brought into service in 1948. This system has now been in operation for three years and has provided a great deal of information and has created a world-wide interest.

Summary of a paper presented to the Canadian Institute of Navigation at a meeting held in Montreal on 22 September 1950.

In 1946 and 1947 a great deal was learned about scope interpretation and the use of search radar as an aid to air navigation in the Canadian Arctic. New techniques, differing from those used during the war, when search radar was considered primarily as an aid to bombing and for pin-pointing, were developed and a great deal of information on interpreting the radar presentation of topography at different seasons was obtained. The use of search radar for navigation in the Arctic is described in this paper, which also gives information on the probable appearance of topographical detail on the display at different times of the year.

In the Journal for May 1980, Adlard Coles, author of Heavy Weather Sailingand an Institute Gold Medallist, gave an account of his own investigation into the weather situation which decimated the ocean racing fleet during the Fastnet Race of 1979. Neither the formal report of the Fastnet Race inquiry nor the official meteorological analysis seemed entirely to explain what had happened. Alan Watts, a meteorologist particularly concerned with small craft navigation, from his own analysis of meteorological factors, including the barometric readings of many of the competitors, here suggests an explanation for the particular violence of the seas which was responsible for most of the damage.

To fulfill any specific task a certain navigation accuracy is in general required. If this requirement can be achieved by different systems the cost effectiveness will be decisive. Apart from missions which allow large position errors, medium or high navigation accuracies will normally be desired, obtained either by high technological standards or by an unsophisticated system with an updating procedure. The cost of highly sophisticated systems increases exponentially with increasing accuracy, so that our object was to find an appropriate updating system.

The star sensor field of view varies from several arc-minutes to 20 degrees, which directly determines the star vector orientation in the field of view (FOV). Although the relationship between star vector orientation in the FOV and attitude accuracy has been revealed, the influence mechanism of star vector orientation on the integrated navigation performance of a stellar inertial navigation system has not been analysed. In order to improve the integrated accuracy, the main errors such as star sensor installation error, gyro error and initial platform angle error should be estimated online. It is significant to study the influence mechanism of star vector orientation on estimation of the above errors. In this paper, the star sensor sensitivity and the geometry factor are defined to feature the difference between the optical axis direction and the non-optical axis direction. The formulised mechanism and quantification results between star vector orientation and integration attitude and error estimation accuracy are clearly given. Simulation and ground testing were conducted and it was found that the larger the star vector orientation along the optical axis, the better the error estimation accuracy. In contrast, the attitude accuracy is weakly sensitive to the orientation of the star vector in conditions of appropriate posture adjustment and star observation scheme. This conclusion can offer universal guidance for the design and evaluation of stellar inertial navigation systems with narrow field of view or large field of view star sensors.

Inadequate human actions are still the main cause of all reported accidents and incidents on board ships. The aim of this study is to explore the influence of safety resource activities and other exploratory variables on seafarers’ safety behaviour. For this study, a series of open-ended interviews were conducted to gain insight into how shipping organisations struggle with this issue. Following the interviews, a questionnaire was prepared and distributed to professional seafarers. Two exploratory factor analyses were conducted to identify the underlying factor structure and five factors emerged. Furthermore, three hierarchical multiple regression analyses were conducted to examine the influence of the factors obtained, namely, Company safety orientation and Additional safety incentives on seafarers’ perceived Safety awareness, Job satisfaction, Risk acceptance and other exploratory variables. The study shows that the perceived resource-related activities of the organisation and the demographic characteristics of the respondents can influence the safety behaviour of seafarers.

In the July Journal (14, 362) Klerk and Steensma describe a new and ingenious method of radar plotting. The following comment, sent in at the invitation of the editor of the Journal, follows closely my remarks on a similar article in the Dutch review De Zee (December 1960).

In his detailed and valuable account of the history of the Log (this Journal, 9, 70) Commander Waters is surely at fault as regards the part he ascribes to the Gresham Professor, Gunter. This eminent mathematician delighted in designing instruments with engraved scales, and at first issued the customary Description and Use in Latin, a sufficient indication that he wrote only for fellow scholars. Importuned probably by the instrument-makers, he later published English versions of the tracts (in 1623), and among the numerous ‘uses’ included a couple of chapters on those for navigational purposes.

D. H. Lewis, in his article ‘Ara Moana: Stars of the Sea Road’ in the July 1964 issue of the Journal of the Institute of Navigation (pp. 278–88), speculates on how the Polynesians could have navigated to known distant destinations, but does not explain how the knowledge of die distant destinations on which he relies for his theories was gained by the supposed navigators. Before anybody can navigate to somewhere, someone must first have gone there and come back. Lewis does not tell us how the Polynesians gained their knowledge of the existence, location and size of New Zealand and Hawaii, and of the currents on these courses, on their outward voyages of discovery, and then used this knowledge to get home again. His statement that ‘it seems probable that the Polynesians steered by horizon stars until the zenith star showed that they had reached the right latitude, and then turned east or west’, obviously has no application to voyages of discovery which by definition were made without prior knowledge of the existence, latitude or size of the objectives. The alternative supposition that the discoverers were able to keep account of their courses from bearings on stars which were reputedly aligned with the destinations and the home islands overlooks the fact that such star bearings gave no clue whatever to longitudinal displacement. There was no practicable method whereby the discoverers could have known the longitudinal relationships of their discoveries and their home islands.

Acoustic transponders are employed in underwater navigation in situations in which a high degree of accuracy is required. Typical applications include underwater search, mapping, photography by a submersible or a towed vehicle and positioning of underwater work systems. The network of transponders, of which there may be only two or three, or which may be very extensive, is implanted by a support ship or by a submersible. The network can be located geographically by a satellite navigation equipment to an accuracy of 0·25 nm. This accuracy (or even accuracy within ± 1 mile) is sufficient to locate the network after a period of disuse. Acoustic navigation of a vehicle is accomplished relative to the network, to accuracies of the order of several feet.

At 2215 hours GMT on 21 September 1947 the U.S.A.A.F. All-Weather Flying Centre's Automatic C54 took off automatically from Stephenville, Newfoundland, and twelve hours and five minutes later landed at Brize Norton, England. Neither pilot nor navigator had interfered with the automatic equipment during the entire flight. What, briefly, is the navigation equipment and procedure employed on such a flight?

Equipment. The navigation equipment consists of three magnetic heading selectors, two air log units or AMUS and a radio compass which will automatically switch to a number of preselected frequencies.

British Airways was recently granted permission for its fleet of Boeing 747-400 and 767 aircraft to operate using automatic landing systems in Category IIIB conditions; that is, decision height lower than 50 ft and a runway visual range of less than 200 m. This development might lead some people to think that the weather is no longer a significant factor in aviation operations. However, while these developments are taking place one sees reports such as ‘departure delays are still on the increase’; ‘poor weather slowed airport operations’; ‘BA flight from Singapore delayed by strong winds was five minutes from declaring an emergency’; ‘heavy rain might reduce wing lift when an airliner most needs it’. These reports confirm the realistic state of affairs that the weather, despite the introduction of modern avionics on board the aircraft, and automated instrumentation on the ground assisting aerodrome operations, is still a vital part of aircraft operations decision-making, affecting the safety and efficiency of flying.

Europe is moving towards a more closely integrated air traffic management system through the European ATC Harmonization and Integration Programme (EATCHIP). This paper explains the need for such an approach and how it was brought about by capacity limitations in the current European air traffic system. It describes the key strategy of progressive harmonization and integration by the various States, examines the roles of the European Civil Aviation Conference (ECAC), the International Civil Aviation Organization (ICAO), EUROCONTROL and the European Commission in the management of the Air Traffic Management (ATM) development programmes. It also reviews the longer-term planning of a future system with an enhanced relationship between the air and the ground, and addresses the navigation aspects of ATM systems.

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.

During the last few years much has been learned about the navigational developments and techniques of the English pioneers of colonization in the New World. This has been made possible in some measure by the formation in America of a private library of the books relating to the art of navigation as practised by the Elizabethan and early Stuart seamen. It was in the course of forming his remarkable collection of early Americana that Mr. Henry C. Taylor of New York, purchased copies of Captain John Smith's An Accidence or The Pathway to Experience. Necessary for all Young Sea-men, or those that are desirous to goe to Sea … first published in London in 1626, and A Sea Grammar, with The Plaine Exposition of Smiths Accidence for Young Sea-men, enlarged … first published in London in 1627, subsequent editions of this latter work being entitled The Sea-mans Grammar, etc.

The United States Maritime Administration recently published the results of a study, undertaken by the Norden Division of the United Aircraft Corporation, on automation and the operation of merchant ships. Mr. Clayton, the author of this important report, described the findings of this investigation, in so far as they affect navigation, to an Institute Meeting held in London on 16 November 1962. The paper, which is presented here, was written in association with Mr. Kurz of the U.S. Maritime Administration. It describes navigation systems for partially and fully automated vessels, and discusses the basic system requirements, accuracy and reliability criteria. A command philosophy for automated ships is developed, and finally a marine course computer, which is the first component of a partially automated navigating system already manufactured, is described. This is the first of several equipments being manufactured under contract to the Maritime Administration.

In early 1959 United Aircraft Corporation, led by its Norden Division as systems manager, undertook a company-sponsored study of the technical feasibility of operating merchant ships automatically. The results of this study were circulated throughout the industry. In April 1960 the Maritime Administration awarded a contract to Norden to study the economic and technical feasibility of automating merchant ships. The principal objective of the study was to develop a consistent series of planned, orderly, and reasonable steps towards completely automatic ship operation. The technical feasibility and economic advantage for each significant advance would be thoroughly established and then presented in a form suitable for selective application according to the particular requirements of individual ship operators.