Whilst unmanned aircraft (UMA) can be said to encompass missiles, targets for weapon training, preprogrammed reconnaissance drones and civilian systems such as radio-controlled models used to carry cameras, for the purpose of this paper we will restrict ourselves to aircraft which are capable of sustaining autonomous flight and accepting navigation commands whilst airborne. The terms applied to unmanned aircraft are variously UMA, remotely piloted vehicle (RPV), Drone and Unmanned Aerial Vehicle (UAV).

Operational research has been developed and introduced into air transportation problems since the late 1940s, mainly in the U.K. and the U.S.A., and simulation techniques have also been used for designing or evaluating air traffic control systems. Some data on the actual operations are needed for carrying out these studies. The data on the time and motion of taxiing aircraft, especially jet aircraft, were collected at Tokyo International Airport (TIA) in 1975 and 1976 and the relation between average taxi speed and taxi distance was stated on the basis of the observed data. In this paper, a theoretical method for estimating the average taxi speed of departing aircraft is considered, using simplified models, and the results are compared with the empirical data.

Waves, tides and ocean currents might not be expected to produce electric currents, but by moving water, as a conductor, through the Earth's magnetic field they do in fact produce measurable voltages and flows of electricity. Young, Gerrard and Jevons, who made the first detailed study of this phenomenon, thought it conceivable that measurements of electric potential gradient might be used to estimate the drift of a ship at sea, and Von Arx showed how indications from electrodes towed behind the Research Vessel Atlantis were used to keep her on a direct course from Bermuda to Woods Hole, across the Gulf Stream. In recent years the method has been used extensively in studies of ocean currents and more ships might use it if the necessary equipment were readily available.

This paper and the following three papers were presented at the EURNAV92 Conference on Digital Mapping and Navigation. This was held in London and was jointly sponsored by the RIN and the DGON. Forty-five papers were presented at the Conference and copies of the complete proceedings may be obtained from the Institute, priced at £65 for Members and £85 for Non-Members.

The Amoco Cadiz and the Work of the Institute. Seaborne trade calls for international agreement but it is not a matter that attracts much public attention. That is why, as Beattie has pointed out very clearly in his paper ‘Traffic Routing at Sea 1957–1977’ presented to the Institute on 14 December 1977, all the major steps taken to bring some order into the regulation of maritime traffic have been due to the initiative of mariners or maritime organizations. International action was only taken later, to give a legal sanction to such proposals as were felt to be necessary. In any case there was no international authority until 1958 when IMCO (the Inter-governmental Maritime Consultative Organization) took over the direction of maritime affairs between the International Safety of Life at Sea Conferences, and these were not convened at regular intervals. One can easily see that under these conditions progress was slow, depending as it did on either the initiative of seafaring people or on some turn of events that demanded a new approach.

Each navigational aid has its advantages and disadvantages and for that reason the optimum aid will be a combination of several aids. The best way of combining the aids seems to be by means of an automatic dead reckoning computer which continuously computes position from true air-speed and wind-speed and other data which can be fed into the existing navigational aids by means of a data transformer. Data from the integrated system can be transmitted by data link to air traffic control to correct the flight programme, &c. This paper, which was presented at Dusseldorf at the German Navigation Society's meeting (5–7 June 1962), surveys the field of integrated navigation systems and describes a number of possibilities. Formulae are derived for the accuracy of Vortac and D.R. and Vortac and doppler. It is published with the kind permission of the German Navigation Society.

If we look critically at the navigational aids which are available today we find that all have advantages and disadvantages, and that no one aid can be claimed to be suitable for all purposes. This situation will still exist for many years. Therefore it seems very advantageous to combine the available navigational aids to form an integrated navigation system in such a way that the possibilities may be fully utilized.

This paper is concerned with the effect on airline operation of the introduction of inertial equipment, from the engineering viewpoint. It is difficult to avoid entirely all operational considerations but the main object here is to stress the economic and engineering aspects arising from the use of this equipment.

Over the past few years several papers have been written based on the results of surveys of marine traffic in different parts of the world. The general knowledge of the overall picture of the behaviour of ships at sea has increased considerably but there are still many aspects which need to be explored. One of the main fields of interest of the Marine Traffic Research Unit at the City of London Polytechnic is the use that mariners make of available sea room. For any particular area the navigational difficulties are going to vary considerably in situations where ships enter the area at different points, travelling indifferent directions, from situations in which the ships tend to keep to a number of defined routes through the area. If ships do tend to adopt a routing structure through an area, the next question of interest is how wide the various routes are, given no physical limitations for their width. The behaviour patterns may vary for different types of ship, and speed is another variable which may affect the situation. Answers to all these questions would be needed if one wanted to analyse the efficiency and safety aspects of marine traffic in an area.

The author of this paper, which was presented at a meeting of the Institute in London on 16 March 1977 with Captain B. J. Calvert in the Chafr, is the President of Jeppesen Sanderson Inc. He traces the history of the Jeppesen Company's charts from their early beginnings when map reading and dead reckoning were the only aids to air navigation to their adaptation to modern automated airborne systems.

This article treats integration of navigation data from a variety of sensors in a submarine using extended Kalman filtering in order to improve the accuracy of position, velocity and heading estimates. The problem has been restricted to planar motion. The measurement system consists of an inertial navigation system, a gyro compass, a passive log, an active log and a satellite navigation system. These subsystems are briefly described and models for the measurement errors are given.

Four different extended Kalman filters have been tested by computer simulations. The simulations distinctly show that the passive subsystems alone are insufficient to improve the estimate of the position obtained from the inertial navigation system. A log measuring the velocity relative to the ground or a position determining system are needed. The improvement depends on the accuracy of the measuring instruments, the extent of time the instrument can be used and which filter is being used. The most complex filter, which contains fourteen states, eight to describe the motion of the submarine and six to describe the measurement system, including a model of the inertial navigation system, works very well.

Radar transponders and radar target enhancers have been in use in a variety of applications for many years. Perhaps the most widely-known applications of radar transponders are in Identification Friend or Foe (IFF) and its civilian counterpart, secondary surveillance radar for air traffic control, and as racons in marine navigation and, most recently, as Search And Rescue Transponders (SART) in the Global Marine Distress and Safety System (GMDSS).

This paper describes how it was found possible to estimate the accuracy, under operational conditions, of navigators' wind-determinations by the 3-course drift method. This was done by studying the self-consistency of the set of three drifts logged by the navigator; the technique which was developed, using the size of the circle inscribed in the ‘triangle of error,’ can be used expeditiously by persons with no special training. This technique is applicable to other position line problems. Of the total inaccuracy of the winds found by the navigators, three quarters was contributed by the errors of observation of the drifts, and one quarter by the process of deriving the wind from the set of drifts, using the Dalton Computor.

The validity of the method was checked by comparing wind measurements by the 3-course drift method with the value obtained from Air Position Indicator readings taken in the course of practice bombing exercises; the accuracy of the latter value was also estimated from internal consistency. The check was satisfactory; and in particular, contrary to widely held belief, showed that the navigators did not systematically underestimate drift angles.

The paper is divided into two parts. The development of ship-borne compasses is reviewed in Part I; in this section some of the difficulties due to bad siting, &c., are mentioned and certain solutions such as the use of repeating compasses and improved methods of correction are described. Part II surveys the development of the aircraft compass and shows how its phases of development have corresponded to those of the marine compass. Some recent forms of aircraft compass and methods of development are also described.

Secondary surveillance radar is a combined radar and communication system, which provides aircraft position (range and azimuth) on the radar side and identity and height on the communication side. It is a main working tool in Air Traffic Control today and the information it produces is an ingredient in providing separation between aircraft in flight. This paper is concerned only with the reliability of the identity (Mode C) and the height (Mode A) data, and not with the radar position data as such. ‘Reliability’ is taken to mean ‘can the values reported by the SSR be relied upon?’ Consequently we are not concerned with cases where an interrogation elicits no response, but only with responses which are present but not correct. Furthermore, a ‘Mode C discrepancy’ is defined as a read-out that disagrees with the altimeter reading observed by the pilot, so that we are not concerned with altimeter errors, but only with the faithfulness (or otherwise) with which the SSR reproduces the altimeter reading. In cases where the Mode C read-out is obviously wrong, but no pilot's report is available, it is not always possible to distinguish between an altimeter error and a Mode C discrepancy.

The Home Office in January 1977 invited submissions for inclusion in the United Kingdom proposals to the World Administrative Radio Conference 1979 (WARC 1979.) Prior to that, in August 1976 in Boston, U.S.A., the member Institutes of the International Association of Institutes of Navigation had agreed to exchange views on matters of concern to the world's navigational community which in particular might be considered by WARC. It was envisaged that any approach by the various national Institutes would be through their own administrations.

The weather is rarely out of the news. Weather can be hazardous at times almost anywhere on Earth, and the media are always keen to report dramatic events. On the global scene, weather, climate and the environment are issues of great international public concern at present because of the likely implications of increases of greenhouse gases in the atmosphere. The contributions of the meteorologist to the understanding of this global problem are increasingly recognized, as is the progress which has been made in the accuracy of day-to-day forecasts. This paper provides a brief résumé of our present ability to model and forecast the behaviour of the global atmosphere and the ocean surface, and also demonstrates how these models are applied to the practical problems of operational ship-routeing by the UK Meteorological Office. It is worth remembering that it was the very high incidence of losses at sea in the 1850s which brought about the establishment of the UK's first meteorological service.

Since the inauguration of the B.O.A.C. Return Ferry Service, the principles of pressure pattern flying have been followed on the North Atlantic as regards flight planning. In co-operation with the forecaster the practice developed of working out a number of flight plans to achieve the shortest possible flight time, and eventually it became possible to select the most favourable route with a reasonable degree of precision.

The advent of the radar altimeter furthered development of the pressure position line theory which I believe was first propounded by R.A.E., Farnborough, and has since been elaborately garnished and enthusiastically tested by our American friends during recent years. The words ‘altimetry’ and ‘aerologation’ have been added to our generally common language to cover flight techniques that might perhaps be more simply described as ‘pressure comparison navigation.’