This paper, and the following five papers, were presented during the NAV 97 Conference held at Church House, Westminster, London on 11th and 12th November 1997. A full listing of the Conference, and how to obtain a copy of the proceedings, is shown on Page 279.

The Government of the Russian Federation has made available, subject to certain conditions, the GLONASS satellite radionavigation system for civil use. Use of the system is free and there is no intention to introduce coding or to cause any deterioration to the accuracy of the signals. Discussions are currently taking place between the European Commission and the Russian Federation on cooperation concerning the implementation of a navigation satellite system for civil purposes. Discussions are also taking place between interested European Governments and the Russian Federation into the possibility of developing joint Chayka/Loran-C chains wherever this is feasible, and in particular, to cover the Barents Sea, the Baltic Sea and the Black Sea. The development of a concept on integration of radionavigation systems would probably be a significant contribution to the European Radionavigation Plan.

Marine radiobeacons have been used to broadcast differential corrections for global navigation satellite systems (DGNSS) for nearly a decade. The method has become the accepted international standard for maritime applications. The background to the development of the system is described and the current status of radiobeacon DGNSS services around the world reported. The applications are discussed, including the function of radiobeacon DGNSS as the position sensor within integrated systems, together with the performance requirements imposed by associated systems such as ECDIS and Automatic Identification Systems. The advantages and disadvantages of the radiobeacon system in regulatory, administrative and technical terms are discussed and the potential for development of the system is considered. The future role of radiobeacon DGNSS in the overall mix of systems is assessed taking into account the introduction of geo-stationary overlays, and possibly Loran-C, for provision of DGNSS corrections.

This paper gives details of the failure rates and the failure modes experienced with SPS GPS receivers certificated for aviation use to the TSO-C129 specification. These failure rates are significant compared to those from other modern avionics and the rates are comparable to that currently experienced from un-scheduled failures in the GPS signals-in-space. To achieve certification, Flight Management System (FMS) design should consider the way in which the satellite navigation receivers fail. The paper also gives details concerning the 2-D errors that have been experienced with these receivers, and indicates further work that needs to be done with C 129a receivers.

This paper covers the wide area and short range locational technologies that are available for vehicle tracking in particular and mobile user security in general. It also summarises the radio communications services that can deliver information to the user. It considers the use that can be made of these technologies, when combined with procedures for delivering a response, in the security field, notably in relation to personal security, high-value load protection and the after-theft tracking markets.

This paper addresses two aspects of high accuracy GPS positioning : single point positioning and real-time kinematic positioning. In both cases, it is shown that use of the correct models significantly improves the quality of the resulting positions. In the first case, emphasis is placed on physical models, especially the satellite orbit, and in the second case, emphasis is placed on the stochastic model, i.e. understanding the statistics of the GPS observables.

This paper gives an overview of navigation and positioning requirements of the European offshore oil industry in the context of consideration now being given to the role of GPS in the European Radio Navigation Plan. An outline is given of how these requirements are currently achieved and of the criticality of the operations.

There is no generally accepted definition of the difference between a map and a chart. A widespread feeling probably exists favouring the old saying that maps are to look at and charts to work on. It is true that the term ‘aeronautical chart’ gained a general currency over alternative terms as contact flying gave way to aerial navigation. But, in this paper, the terms ‘map’ and ‘chart’ will be used as seems appropriate to each occasion, without attempt to conform to any particular definition.

We can get an idea of what was available to the earliest aviators by looking at an Ordnance Survey reprint of one of their nineteenth century maps (Fig. 1). They are printed in one colour only, black on white. By far the predominant feature is the hill shading. Quite gentle hills are hachured with a heaviness which tends to obscure both natural features like rivers, lakes and woodlands and man-made constructions such as towns and villages, roads, canals and railways. Hills are, of course, very important features to those on the ground, since they limit the extent to which other features can be seen. To the soldier, the significance of high ground is self-evident, and it was principally for the ordnance requirements of soldiers that these maps had been developed. But when men began to view the ground from the air, the perspective changed. Hills appeared flattened out and, provided that you knew the height of the tallest in the area and were sure none would impede your take-off or landing, were of minor significance. Lakes and woods, though, were spread out before you in their distinctive shapes, while railway lines and canals presented bold straight lines and curves, and rivers their unique courses, to your view. The need was for new kinds of maps which would give due prominence to such features.

A simulator experiment was conducted to determine the potential benefits of path prediction on the navigational performance of channel-bound vessels. Channel pilots had to sail an approach channel under critical conditions in a deep-draught vessel. For the navigation task, basic radar information was used, supplemented by three different path predictors. Predictor (a) was based on an accurate fast-time hydrodynamic model of the vessel and showed the exact future path of the vessel. Both other path predictors were less accurate, relatively simple extrapolators; predictor (b) was based on a speed and rate of turn extrapolator and showed a curved representation of the future path; predictor (c) was based on a linear speed and course extrapolator and showed the ground velocity vector. Navigational performance was determined in terms of deviation from the planned route. The results indicate that the relatively simple extrapolator (b) supported the navigational task as effectively as the highly accurate path predictor (a). In comparison with the linear extrapolator (c), the navigational accuracy increased by a factor of two. It is concluded that support in anticipating the vessel's rate of turn is essential for accurate navigation. Implications of the use of path prediction for ship control are discussed.

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 discusses the necessity and feasibility of the application of Pulse Doppler Radar in vts through analysing the limitations of the non-coherent, single frequency, radar and the advantages of PD radar.

After a brief overview of Loran-C system operation and performance, the present situation of the system in Europe is described. Loran-C is now in operation under the NELS agreement in north-western Europe in newly established chain configurations with old and new transmitter positions. Parallel to Loran-C the Russian equivalent, Chayka, is also operating, with three chains in Europe. There is an agreement between Norway and Russia concerning cooperation and possibly joint chain operations between the two system providers in the north; similar agreements in the Baltic and Mediterranean/Black Sea areas are being worked on. The situation around the Iberian peninsula has not yet been clarified. Being the only long/medium-range terrestrial system in Europe in the 2000+ time frame, Loran-C could be seen as a supplement to satellite systems. Due to the good penetration properties of its low-frequency signals, it can be used in many circumstances where satellite systems fail because of limited satellite visibility. Integration of Loran-C and (differential) satellite receivers, where Loran-C is calibrated by the satellite system as long as there are enough visible satellites, could in fact give the best of both worlds. For this reason, Loran-C is being considered in the perspective of a future international, civil satellite navigation system, initiated in Europe.

This paper presents results from a doctoral dissertation (reference 12), on the problem of scheduling with Maximum Position Shift (MPS) constraints. The problem typically arises in a queueing system, when the service rate depends on the sequence in which customers are handled by the server. Such a queueing system is the airport runway system, where it has been shown (references 3, 10, 12) that rearranging the sequence of landings and takeoffs affects the runway capacity – that is, the rate of runway operations. An optimal Dynamic Programming (DP) scheduling algorithm is developed that takes as input the set of currently known flights, their desired time of operation, basis of the First Come First Served (FCFS) sequence, and a matrix of Air Traffic Control (ATC) minimum time separations, in order to produce an optimal schedule defined as runway and threshold time assignments maximizing runway capacity.

Most reference books or monographs about the history of the gyrocompass portray individual inventors, each as an inventive genius, respected as a national hero and probably depicted creating novelties in ‘brooding meditation’. This seems to be an accepted, rather comfortable point of view, as the subject covers the invention of a ‘black-box’-type too. But the invention, development and the adaption of this gyro instrument in a complex technological and social system was not achieved on the basis of a ‘single-handed’ venture.

If emerging technologies are not only scientific, but also involve social or cultural requirements, then communication along the networks of knowledge between inventor, mechanic and mathematician, the code of patent lawyers and financiers and – last but not least – navigation officers and the red tape of a navy must play an influential role. I would thus like to sketch out the subject of invention as communication and present the inventor as a navigator, someone who leads his crew through all currents, shallows and drifts and, while keeping ahead of other competitors, arrives at some still uncertain location.

Air Vice-Marshal Wilfrid Oulton, who died on 31 October 1997, aged 86, was one of that select group of distinguished Royal Air Force pilots who became equally distinguished navigators. Much of his early Service experience in World War II was spent in Coastal Command, where his natural flying ability combined with his acquired navigator's knowledge and skill led to exceptional operational achievements.

In 1943, German submarines were taking a devastating toll of Allied shipping in the North Atlantic and Wilf Oulton was flying long-range patrols over the Bay of Biscay. In May of that year, commanding a Halifax bomber which had been converted for maritime operations, he attacked with depth charges and sank two U-boats and shared in the destruction of a third. For these outstanding successes, which helped mark the Battle of the Atlantic turning in our favour, he was awarded the DSO.

Later, and completely different, with the cessation of hostilities, Oulton was jointly responsible for the introduction of the first Air Traffic Control system at Heathrow. And, different again, his ability to inspire confidence and co-operate extremely well with others led to the most challenging peace-time appointment as Joint Task Force Commander of ‘Operation Grapple’, which supported the British hydrogen bomb tests at Christmas Island in the Pacific Ocean.

The 1997 International Conference of The Royal Institute of Navigation was held at Church House, Westminster, London on 11 and 12 November 1997. The full proceedings, which includes the following papers, can be obtained from the RIN Director (£40 to Members, £60 to non-Members).