This paper is concerned with the legislative change which would have to take place if an automatic collision avoidance system were to be implemented.

The principle of complementary action, and the role of coordination in achieving that action is considered. Current collision avoidance practice is discussed, noting the coordination attributes of the International Regulations for the Prevention of Collision at Sea, and the responsibility placed on the mariner by the regulations. The processing element of an automatic collision avoidance system is considered in the light of current judicial practice.

The paper concludes that the implementation of an automatic collision avoidance system is incompatible with the current collision regulations and the supporting judiciary. It is suggested that successful implementation will require the recognition of a discrete rule base.

This paper and the following six papers were presented at the NAV95 Conference held in London, November 199j. The full proceedings, under the title containing 30 papers, can be obtained from the Director (£25 to Members, £35 to Non-Members).

In a paper delivered to Geo '89, a NATO symposium, Wing Commander G. T. Scard was tempted to summarize RAF requirements for digital geographic information as ‘raster now, vector later’.1 He avoided that temptation. However, it is still easy to assume that supplying raster data is today's quick solution to the problem of providing geographic information, and that soon raster products will be replaced by a new generation of vector products. Six years on, raster digitized mapping is becoming firmly established as a major geographic information product supplied by the Military Survey Defence Agency. Although vector data is becoming widely available, there are no defined RAF requirements to procure map displays based on vector products. It is apparent that raster data will remain an important source of displayed geographic information on which the RAF will rely for a long time. However, supplying raster mapping is not easy. There are technical problems which need further work to find solutions. This work is urgent. Systems using raster data are already in service and we cannot wait for vector data to replace raster data at some unspecified future date.

Electronic navigation systems are now well established on commercial vessels throughout the world. In a big ship it is entirely feasible (and probably necessary) to design the system to suit the ship. Budgets are large and there are few space constraints, so that many separate displays may be used on a bridge which would not look out of place on the USS Enterprise. This is definitely not so for a small sailing cruiser or powered leisure craft. Neither is it true for many fishing vessels. It is to those with an interest in these small boats that I address this paper.

The last few years have seen the launch of several new navigation-related products to the market; TrafficMaster is an excellent example of technical innovation and marketing skill which assists drivers to make decisions about travelling. There are many other products in development targeted at differing user groups for a wide range of applications.

This paper presents a brief overview of current human factors research into route guidance systems. A short description of different interface styles is given and a review of two road-based studies of three existing route guidance systems is provided. A general discussion then highlights a range of issues of relevance to driver-system interfaces, drawing on results both from the studies carried out, and other research. Specific aspects addressed include the content and means of presenting route guidance information, and the potential effect of interface design on driver visual behaviour and performance.

This paper considers the effect of receiving a secondary source of information upon ability to acquire and use spatial knowledge (i.e. the formation of a cognitive map). Participants watch videos of three journeys through an unfamiliar area. They then perform tasks measuring ability to integrate the routes into a cognitive map of the area. Subjects viewing the routes whilst hearing route guidance information performed consistently worse than those receiving no guidance. The presence of non-salient information, however, did not impair performance.

Existing studies highlighting differences between gender and age groups regarding spatial ability receive only partial support: the results suggest that ability to drive negates these effects. Female drivers perform as well as, if not better than, their male counterparts, and outperform male non-drivers. This same ‘driving’ effect was also evident in the over-55s group, with both male and female drivers performing significantly better than non-drivers in this age group. The results also show that driving ability enhances ability to cope with and use guidance information, suggesting that systems’ designers should make varying levels of spatial information available for less experienced drivers.

Maps are familiar objects that need little introduction. By strict definition, a map is a diagrammatic representation of the spatial environment – for example, the Earth's surface, the stars or parts thereof. The techniques of map-making, or cartography, are basically concerned with reducing the spatial characteristics of large surface areas to a form that makes them observable. Cartography has been considered as both a science and an art. As an art form and craft tradition with printed maps, cartography traditionally has sought to address aesthetic criteria for human appreciation and visual attractiveness, in addition to considerations of functional utility.

This paper and the following paper were presented at a meeting organized by the Institute's Land Navigation Group in October 1995. The meeting was on Loction Technology Applications in Public Transport. Copies of the proceedings can be obtained from the Director (£10 to Members, £15 to Non-Members).

This short paper discusses briefly the role of the current forms of bus priority used in the United Kingdom and how these strategies are incorporated within our urban traffic control systems.

The philosophy behind the SCOOT (Split, Cycle and Offset Optimization Technique) demand-responsive signal timings program is discussed, and the latest results from the bus priority trials carried out in London by the University of Southampton and London's Traffic Control Systems Unit (TCSU) are appraised. The system installed in London is compared with current dead reckoning vehicle location systems and the major differences highlighted.

This paper was presented at a Workshop organized by the Institute in London in October 1995 on the subject of GPS Interference – Is it a Problem? Copies of the Workshop Notes can be obtained from the Director (£50 to Members, £75 Non-members, £10 to students).

This year marks the twentieth anniversary of the introduction of Concorde into commercial airline service. The first commercial flights were on 21 January 1976 – British Airways from Heathrow to Bahrain and Air France from Paris to Rio via Dakar. Later in that year commercial flights to Washington/Dulles began on 24 May. Services to New York were delayed until 22 November 1977. The first flight of Concorde was some seven years earlier. The prototype took off out of Toulouse on 2 March 1969 and this was followed by 002 from Filton to Fairford on 9 April. At the time it was anticipated that this was the beginning of an era when supersonic flight would be the normal way to travel long distances. Now, in 1996, Concorde is still the world's only supersonic commercial passenger airliner in airline service. This is an extraordinary achievement. The Boeing SST proved to be too ambitious and the programme was halted in 1971 after the United States Government withdrew support, while the Russian TU 144 was beset with problems. One TU 144 crashed at the Paris Air Show in 1973. The aircraft entered internal airline service in December 1975, flying supersonically between Moscow and Alma-Ata, capital of Kazakhstan, carrying mail and freight, but it did not have the range to operate viable intercontinental passenger serives. Certainly by 1985, if not many years before, the TU 144 was out of service.

On any surface which fulfils the required continuity conditions, the shortest path between two points on the surface is along the are of a geodesic curve. On the surface of a sphere the geodesic curves are the great circles and the shortest path between any two points on this surface is along the arc of a great circle, but on the surface of an ellipsoid of revolution, the geodesic curves are not so easily defined except that the equator of this ellipsoid is a circle and its meridians are ellipses.

Vessel Traffic Services (VTS) advise vessels navigating the waterways, VTS communications provide to the mariner timely, pertinent, and accurate information that would assist in safe manoeuvring of the vessel.

Following several oil spills in 1989, Congress passed The Oil Pollution Act of 1990 (Public Law 101–380). The Act requires the “Secretary to conduct a study…to determine and prioritize the US ports and channels that are in need of new, expanded, or improved vessel traffic service systems.…”

As required by the Act, the US Coast Guard analysed historical vessel casualties and their consequences and projected future vessel casualties and consequences for 23 study zones. The study uses a benefit–cost approach, VTS benefits are defined as the avoided vessel casualties and the associated consequences. The avoided consequences are measured in physical units and are assigned monetary values, VTS costs are defined as the initial federal investment for a state-of-the-art VTS system in each study zone and its annual operating and maintenance costs. Both the benefits and costs are expressed in the 1993 Net Present Value of annual stream over the life cycle at 10 percent basic annual rate. The study recommends VTS design by rank-ordering the zones by net benefit.

In this paper, we use alternative methodologies for offering better assistance in making VTS design decision-making. First, we perform ABC analysis on the zones; that is, we classify them into three groups: The A group deserves a state-of-the-art, full-fledged VTS presence, the B group could use an intermediate level of VTS services, and the c group deserves an elementary level of VTS services, as and if the budget permits. This analysis assumes that VTS services can be offered at various levels with correspondingly changing costs. Secondly, we perform resource allocation analysis; that is, for a given budget and given criterion (e.g. maximize the total benefit), select the optimal zones in which the VTS services should be offered. This analysis, done for various levels of budget, would form a useful decision aid for the VTS design.

First, a brief description is given of an algorithm for the generation of carrier-adjusted differential corrections. Next, the relationship between satellite elevation and the precision of GPS code observations is investigated, on the basis of data collected by TurboRogue SNR-8000, Trimble 4000 SSE and Trimble 4000 SST receivers. It is concluded that the precision of code observations decreases with decreasing elevation, particularly at low elevation and that the relationship can quite well be modelled by an exponential function. For different types of receivers and different types of code observables, this relationship may not be the same.