Weather routeing of ships has taken roughly three chronological steps. Originally, seasonal climatological weather charts, bearing little resemblance to actual conditions, gave standard routes. This somewhat passive activity was superseded by the measurement and subsequent forecasting of atmospheric and oceanographic data. Weather routeing became more complex as telex and radio facsimile routeing messages could be regularly transmitted to the ship. This form of routeing is still operational; masters can obtain radio facsimile sea and pressure charts and perform their own routeing, or employ specialist organizations which transmit the relevant routeing advice.

A realistic runway capacity study for two major airports, namely Frankfurt (EDDF) and Chicago O'Hare (ORD) is presented, assessing the effect of optimal scheduling on the runway capacity and air traffic delays. The maximum position shift (MPS) runway scheduling algorithm, used in the study, was developed by Trivizas at the Massachusetts Institute of Technology (1987).

EDDF is studied in the context of 160 major European airports, with a real traffic sample from 6 July, 1990. ORD is studied in the context of 26 major US airports using a large traffic sample from 1 March, 1989. Secondary airport traffic has been assigned to the geographically nearest major hub and time compression has been used to extrapolate to an artificially denser scenario.

The results show that optimal scheduling can bring about capacity improvements of the order of 20 percent, which in turn reduce delays up to 70 percent. These results are the product of a dynamic traffic management process which has been visually validated by observing animated runway operations and monitor functions.

The study has been conducted with TMSIM, a comprehensive, object-oriented simulation tool that allows one to build an understanding of the structure and functionality of the air traffic control system, by modelling its components, their functionality and interactions, and measuring component and system performance. It features interactive route network editing (using menu/mouse techniques), complete route and airport structure modelling, independent flight and ATC objects, 3-D animation, advanced algorithms for scheduling, routeing, flow management, airspace restructuring (sectorization) and performance (capacity and communications workload) analysis.

Navigation systems on ocean-racing yachts have developed significantly over the last ten years, due to advances in communications systems, position fixing systems, and computer systems. This paper looks at the systems being used on boats competing in offshore racing events, discusses some of the shortcomings of existing technology, and also looks at areas of future development. We take the term ocean racing to cover events of such duration that the weather systems along the route are not able to be known in advance. Thus, for example, this excludes most Royal Ocean Racing Club (RORC) races, as these finish within a day or two of starting.

The trend in the western military towards ‘superiority through technology’ has led towards the requirement for more mobile and efficient forces and equipments to address their defence needs in an increasingly unstable and unpredictable post-‘cold war’ world.

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.

The achievement of the goals of the International Civil Aviation Organization (ICAO) Future Air Navigation System (FANS) is essential for the continued development of the airline industry. A recently completed movement study for the North Atlantic Track area forecast that the previously anticipated aircraft movements for 2010 would now be achieved by 1999. Peak time capacity growth for the region is now reliant on the introduction of Reduced Vertical Separation Minima (RVSM) scheduled for January 1997. Similarly, Europe had an all-too-evident capacity problem though some alleviation should follow from the introduction of precision area navigation (PRNAV) routeings in early 1998. However, despite the introduction of these developments, the restrictions on flow rates imposed by capacity variations in adjacent areas will remain. Quite obviously, an enhanced and fully capable Air Traffic Management (ATM) environment is required to solve many of the problems that commonly exist today. Nevertheless, more could be achieved through the application and exploitation of advanced navigation equipment such as the aircraft Flight Management Computer System (FMS) that is in widespread use today – a theme that will be returned to later in the paper.

The purpose of the study on which this paper is based was to establish whether there was a maritime requirement for a Global Navigation Satellite System (GNSS) integrity monitoring and warning service in UK and Irish waters, and, if so, how best it could be established and operated.

The scope of the study extended to all maritime users: merchant ships; fishing vessels; pleasure craft; and all aspects of the voyage: harbour/harbour approach; coastal and ocean passage.

It has been assumed that the United States Global Positioning System (GPS) would be the system adopted, since it is the closest to an operational state. However, most of the technical considerations would apply equally to the Russian GLONASS or any future replacement system under international control.

The views expressed are those of the author, and should not be taken to represent the policies of the Department of Transport or any of the other bodies mentioned.

This paper derives a fast satellite selection algorithm; that is, an algorithm to select the best subset of satellites to use for positioning in circumstances whereby a satellite navigation receiver is not capable of using all satellites in view. The algorithm adopts the weighting factor concept to determine the contribution of each satellite to the overall positioning accuracy. Selection by this algorithm is shown to be especially efficient when the number of available satellites is large, so it is likely to be particularly useful for receivers capable of making combined measurements to GPS and GLONASS satellites.

The objectives for a Global Navigation System (GNS) may be simply stated as the provision for all users, air, sea and land, wherever they may be on or above the surface of the globe, or beneath the sea, with the navigation means of going about their business in a safe and economic manner.

This paper examines first a statistical modelling of the number of navigational accidents (collisons, groundings and strikings) involving tankers and freighters in Canadian waters; it then looks at a direct method of modelling oil spill frequency and magnitude, given a navigational accident. The former is used to examine various hypotheses in the literature regarding the impact of various factors on navigational risk. The latter is based on a direct probability tree analysis which allows the estimation of detailed oil spill impacts by facilitating the examination of representative spill sizes.

Sweden and some other countries are currently evaluating and verifying the potential impact of a newly developed, satellite-based GNSS transponder system on future CNS/ATM and ATN systems.

The concept provides the possibility to introduce a distributed, mobile, real-time data processing system, for all properly equipped users in the global civil aviation community being interacting members (air/air, air/ground and ground/ground).

My background is that of a professional navigator but, although I have spent a lifetime at sea, my experience as a harbour master gathering knowledge about problems in inshore waters has been limited to only the last three years. My aim is to be moderately – but deliberately – provocative in order to help stimulate discussion, though I suspect, with the strongly held views on the subject, this may not be necessary. I do not suppose there is anything new in what I am going to say and far greater minds than mine have been hard at work for many years in seeking solutions to some of the problems I will outline. Given all the diverse interests in this subject, there will perhaps never be a perfect answer but one of the important things is that the dialogue is ongoing, and embraces many organizations and authorities. This paper reflects the problems we perceive in the area of the Solent and, although some issues can be read across in general terms for other areas in the UK, the Solent is a unique area with perhaps unique problems. So what better place to start-Before I outline the scope of the problem, I must stress that the views I expound in this paper are my personal views, and should not in any way be considered official MOD policy. I would also like to say (and some readers may take issue with this by the end) that I believe my views are impartial – my main task as Queen's Harbour Master is to protect the interests of the Ministry of Defence and, once that duty is fulfilled, I have no commercial or financial axe to grind. When I look at some of the maritime safety problems, I can do so free from hindrance or pressure.

For centuries, celestial navigation was the main method of determining a ship's position at sea, especially when sailing into more exotic areas. Later on, vast areas of the oceans were only covered by the Omega system and there was still every opportunity of finding a position by using the sextant. Nowadays, with GPS coverage worldwide, we consider celestial navigation as an interesting back-up.

Human error accounts for a number of collisions at sea; nevertheless, it is widely accepted that vessels are inclined to produce widely varying ranges of radar echo strengths in real sea conditions, in contrast to their ‘true’ anechoic strength, which tends to be minimal for a small and structurally non-reflective craft; even for the calmest possible water conditions.

In this paper experimental results for small craft will be presented and analysed in an exploration of potentially influential parameters in such cases. These results are based on three series of sea trials. Furthermore, an attempt is to be made to portray the inherent, theoretical and/or practical, limitations in the radar detection of small craft in real (estuary) sea conditions.

The almost complete constellation of GPS satellites now provides excellent positional information for aircraft, with typical worst-case errors of the order of 100 metres. The low frequency waves used for Omega navigation have wavelengths of the order of 30 kilometres and thus, even in an aircraft moving at varying speeds up to around 500 km per hour, it is now a simple matter to measure VLF phase with a significance at the 1 degree level. This paper describes the use of GPS to provide accurate positional information to VLF receivers located on aircraft of the Royal New Zealand Airforce (RNZAF) en-route to Antarctica. The marked phase irregularities on signals from La Reunion and Argentina, observed north of the icecap in earlier studies using aircraft fitted with inertial navigation systems, have been confirmed and described with much greater precision. Smaller phase anomalies have also been observed on signals from Omega Australia and Omega Hawaii, whilst flying directly over the Antarctic icecap. The latter signal was previously regarded as unperturbed and used in earlier studies as a phase reference. Small-scale periodic variations of phase and amplitude have also been recorded on signals propagating from Omega Australia. These variations are considered to be caused by the reflection of the VLF waves at discontinuities in the height (e.g. mountains) or the lower boundary conductivity of the Earth-ionosphere waveguide. Reflections of smaller amplitude have also been observed flying over the open ocean before reaching Antarctica.