In January 1993 our target for a circumnavigation was eighty days but, having been struck halfway between Africa and Australia by an object which holed our starboard hull, we were forced to pull out, and a Frenchman – Commodore Explorer – got round first in just 18 hours under the magic Jules Verne figure. It all seemed to be over, except that we were convinced it could be done more quickly – in seventy-seven days anyway, and perhaps (holding our breath) even seventy-five with some luck. We were keen to have another go at winning the Trophy and fortunately so was our sponsor – the New Zealand Apple and Pear Marketing Board. Preparations began immediately.

This paper, and the following seven papers, were presented at the Institute's NAV94 Conference held at Church House, London, in November 1994. The full proceedings may be obtained from the Director, RIN, price £25.00 (plus p & p).

I should start by explaining that the main purpose of my paper is to pass on the Inmarsat vision of satellite navigation in the future.

But first a little about mobile satcoms, our original reason for being. If you have followed us even at a distance you will be aware of:

• (i) how we started with satcoms for ships;

• (ii) how we contributed to a new maritime safety system;

• (iii) how we developed an aeronautical satcoms system in close cooperation with the civil aviation world;

• (iv) how land-mobile communications now account for one-third of our total traffic.

We have to welcome this initiative to bring together, during these three days of NAV94, system designers, service providers, users and administrations. We are all concerned with the need to contribute to the efficient functioning of the transport system taken as a whole, and the Ministers of Transport have underlined the contributions that can be made by satellite navigation systems and information technology.

Today, no single technology has more broad-reaching potential for worldwide civil aviation than the future applications of satellite technology. These applications represent the greatest opportunity to enhance aviation system capacity, efficiency and safety since the introduction of radio-based navigation systems more than 50 years ago. The foundation for this optimism is the Global Positioning System (GPS), a satellite-based radio navigation system operated and controlled by the United States Department of Defense (DoD). In December 1993, DoD declared GPS to be in initial operational capability (10c), which means 24 satellites are now in orbit, available and usable for satellite navigation. The Federal Aviation Agency (FAA) responded to this potential through initiation of a comprehensive satellite programme involving government, industry and users to expedite research, development and field implementation of satellite-based navigation services.

State-of-the-art avionics achieves very good reliability, and the electronics in the current generation of communication and navigation satellites is sufficiently good to allow a design-life of around 10 years. Nevertheless, failures will arise. The purpose of failure analysis is to identify the consequences if a particular module does encounter a failure, and to ensure that, by system redundancy or through operational procedures, the effect and/or its probability of occurrence will be acceptably safe. This paper is a contribution to the discussion on the strength and weakness of redundancy in satellite-based Communication, Navigation and Surveillance (CNS) systems as envisaged by the International Civil Aviation Organization (ICAO) to be an integral part of the future air navigation system. This particular paper makes a comparison with today's terrestrial-based systems.

Since a paper on Datatrak was presented at Warwick to the NAV90 conference, the system has improved markedly. Each of its three major components has been further developed, giving increased functionality and reliability while allowing the service to be provided at a reduced cost.

It is of historical interest that it was written instructions in the form of periplus, rather than the paper chart, that are recorded as providing the first form of document to guide marine navigators. Therefore perhaps the wheel has turned full circle when it is the digital information rather than the video display that may provide the basic guidance for the navigation of ships in the future. In 1986, when IMO and IHO set out to develop standards and specifications, it was decided that the product to be specified would have to be equivalent to the paper chart. In so doing they were following the guidance of the SOLAS Convention, which requires charts to be carried in Chapter V Regulation 20 and, in Chapter 1 Regulation 5, permits Administrations to substitute equivalents. Regulation V/20 does not state that the charts to be carried be paper but, until recently, it has been assumed that this is what is meant. What is explicit, is that the charts to be carried are to be ‘adequate, up-to-date and necessary for the intended voyage’. Following this guidance, the IMO/IHO Harmonizing Group attempted to specify an electronic system that would be equivalent to a printed paper document. This proved to be no easy task. It was extremely difficult to claim that an electronic system can be as durable and as generally reliable as a sheet of paper. What if the power breaks down? This and many other questions had to be answered before the standards would satisfy the members of IMO.

During the last 5 years there has been a rapid growth in the market for electronic charts. All of the systems that currently use these charts, regardless of their size and complexity, have one thing in common: they are all officially classified as Electronic Chart Systems (ECS). By definition, these systems are not considered to be equivalent to conventional paper charts for the purposes of satisfying SOLAS regulations. For all vessels bound by these regulations, ECS cannot be used in place of paper charts. Consequently, it has been left to commercial companies to provide data for use in these systems. Such data have been of variable quality, and no commercial company currently provides a correction service that matches that provided by most hydrographic offices for paper charts.

This paper discusses the development of Electronic Chart Display and Information Systems (ECDIS) and Electronic Chart Systems (ECS) generally. The role of ECDIS and its implementation is also discussed and compared with the trend by manufacturers to the alternative ECS. International developments in relation to ECDIS and ECS initiatives are looked at briefly and a view on the relationship between government and commercial organizations is presented with reference to the safety of navigation.

Flight trials using an inexpensive Garmin GPS receiver, Century 1 autopilot and a Cessna F172H aircraft to acquire block aerial photography are described. The performance of the whole system in the maintenance of constant sidelap and forward lap in block aerial vertical photography was good. However, the system was not good enough to manoeuvre the aircraft accurately on curved flight paths.

This paper, and the following paper, were presented at the 8th Congress of the International Association of Institutes of Navigation held in Beijing, 6–11 September 1994.

The earliest record of a requirement for ships to carry lights that the author has been able to find is in the Rhodian Laws. These appear to date from about the 3rd or 2nd century B.C., and were certainly incorporated into Roman Law by A.D. 161, although Ashburner suggests that the earliest known copy dates from Byzantine times, A.D. 600–800. The Laws contain a section intended to prevent collisions between vessels under way and vessels at anchor or stopped.

For farming in the future, positional information is of particular importance. Out of a multitude of positioning systems, GPS/DGPS is the most suitable one. This system does not require any additional infrastructure and at the same time guarantees complete coverage of all tilled surfaces. The major application of positioning with GPS/DGPS is to be seen in the area of local information and documentation. By generating both planning and process data, it facilitates the operation and control of work processes (organic and mineral fertilization, plant protection). In the end, positioning leads to navigation, which, in the case of single vehicles and vehicle pools, will in turn provide completely new possibilities for development and application. For the first time, vehicles without drivers are conceivable. Thus, the completion of any kind of work on schedule, without time limitations, would become possible with the least possible stress for soil and environment.

In an earlier paper, the writer attempted a quantitative study of a flow-planning system for aircraft intending to fly across Europe. This paper aims to offer each aircraft a clearance giving a reasonable expectation that, throughout cruising flight at least, there will be no conflict with other traffic. Such a clearance is sometimes termed a ‘tube of flight’. Reference i assumed a pattern of traffic flying along rhumb lines, each flight having a starting position chosen at random in a region roughly the size of Europe. Flight was in a random direction and the flight path length was chosen at random from a plausible distribution.

Traffic regulations have to be clear and strict. Only then can navigators ran their vessels safely. As a complete set of simple rules cannot be developed and introduced within the next decade, suggestions are made to improve the existing rules.

Unlike in the case of airborne and offshore applications, GPS cannot be used continuously for land vehicle navigation due to the loss of satellite signals by obstructions from buildings, trees, etc. With the increasing trend in various sectors of the economy towards efficient fleet management, the challenges of providing a system capable of providing high-accuracy vehicle position and location anywhere, continuously, has led to renewed interest in the area of integrated navigation systems. In order to satisfy these conditions, an integrated system comprising GPS and gyro/odometer dead reckoning has been developed. This paper gives a description of the implemented system and shows some of the practical results that can be obtained using Kalman filtering algorithms.

The delay-lock-loop is a device used in direct-sequence spread-spectrum receivers to track the delay difference between two binary correlated waveforms. This short paper aims to clarify both the interpretation of the S-curve and the sign of the tracking error for such devices, especially those for navigation systems such as GPS.