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).

Although early meteorological records were naturally confined to the weather experienced at the surface of the Earth, as soon as meteorology began to be a science it was realized that what went on above the surface was important and that the physics of the air needed to be studied in three dimensions. An obvious illustration is the use made of cloud observations—the nature and structure of clouds, the method of their formation and their movement. Something could be learnt on those questions by observations from the ground, aided by such a simple instrument as the nephoscope. Most people, and certainly all concerned with navigation, know that the movement of clouds may be very different from the wind at the surface. It was also realized that since the atmosphere is a heat engine a knowledge of the temperature of the upper air was required. Anyone who has climbed a mountain knows that the temperature falls, and this was confirmed for the free atmosphere by observations with kites. It was clearly of interest to know whether the fall of temperature was maintained until the absolute zero was reached, and if not, why not. It is in the measurement of temperature and wind in the upper air that balloons have found their chief use.

This paper first considers the characteristics of the supersonic transport aircraft (S.S.T.) as established by various international authorities and, on the basis of these characteristics, endeavours to deduce the operational requirements for a navigation system. An indication is then given of the extent to which low frequency radio aids (such as Decca and Harco) can meet these requirements in the subsonic, transition and supersonic flight regimes, whilst discussing the relationship of these ground-based systems to self-contained aids. The paper was presented, in a fuller version, at the meeting of the Deutsche Gesselschaft fiir Ortung und Navigation held in Berlin, 22–7 April 1963.

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.

The problem of collision avoidance at sea would be an important one even if accidents were rare, but the evidence suggests that they are much more common than one might expect. In the eight years leading up to May 1963 there were 60 collisions in the English Channel area and in the following eight years the number increased to 94. With the development of navigational aids such as radar one might have hoped for a decrease. The suggestion that the increase is quite likely attributable to the possession of radar is ironic indeed. It would appear that having the use of this ‘safety’ equipment allows the mariner to take greater risks, but that the risks which are in fact taken are greater than the equipment allows. We would do better to go back to fog horns alone. Even if over-confidence is not the only factor responsible for the increase in accidents, it does, nevertheless, illustrate the importance of the psychological variable in any man–machine system.

Collisions at sea, however, are not simply due to errors in a man–machine system, It is, of course, the hardware that actually collides, but the cause of the interaction lies in the decisions and indecisions of the two human agents controlling the vessels. It is essentially a social encounter. It is for this reason that the work initiated by Captain Kemp is greatly to be welcomed.

Dr. David Lewis, better known for his own remarkable feats of navigation, which include single-handed transatlantic passages, illuminates the background to various theories on early Polynesian navigation. Reviewing the evidence, which includes the wide dispersion of the Polynesians and their culture as well as methods of navigation and seamanship that were still practised at the period of European contact, Dr. Lewis concludes that they could determine both course and, in effect, latitude with sufficient accuracy to make a landfall within the area of a known island group, and so proceed to any intended destination.

This is an abstract of a paper commissioned by the Lights Advisory Committee and published in June 1987.

To fulfill any specific task a certain navigation accuracy is in general required. If this requirement can be achieved by different systems the cost effectiveness will be decisive. Apart from missions which allow large position errors, medium or high navigation accuracies will normally be desired, obtained either by high technological standards or by an unsophisticated system with an updating procedure. The cost of highly sophisticated systems increases exponentially with increasing accuracy, so that our object was to find an appropriate updating system.

Since the advent of large-scale commercial aviation in the mid 1940s, a system of routes has been developed between airports serving the major conurbations of the world. To prevent collision between aircraft using these routes and off-route traffic, protection is provided to the routes and to the vicinity of airports by means of controlled airspace, airways (AWYS), control areas (CTAS) and control zones (CTRS). Zones commence at ground level and the base an area is at a defined altitude. Inside this controlled airspace certain rules apply which are more stringent than those applied outside, and all movements are subject to Air Traffic Control (ATC).

The Royal Navy employs naval architects to design its ships and a number of establishments exist to advise the Director General, Ships, on various specialist subjects connected with warship design. The Admiralty Experiment Works at Haslar, near Gosport, (AEW) which was founded in 1872 by the father of modern naval architecture hydrodynamics, William Froude, advises the Director General on all aspects connected with hydrodynamics. Froude's activities and those of his son R. E. Froude, who succeeded him as Superintendent, covered a wide field but the study of resistance and propulsion in calm water occupied most of their energies. William Froude was indeed responsible for the first real understanding of the mechanism of ship resistance and was able to demonstrate that the resistance of a ship could be accurately predicted from model experiment results.

The past 10 years have seen an explosion in the use of high speed marine craft. This explosion has been in most sectors of operation, leisure, passenger carrying and military, and is now poised to expand into the cargo carrying sector. The sizes of the new generation of fast craft can range from small 60 knot, 7 metre leisure craft up to fast ferries which are 140 metres long with speeds of 40 knots. Future developments encompass 40 knot large cargo ships, 100 knot passenger and cargo vessels and very high speed military craft. Added to this galaxy of high speed concepts is the 200 knot wing-in-ground (WIG) craft, which, because it flies close to the sea surface, will interact with other marine traffic.

A great deal has been written, especially in the last few years, on the subject of collision at sea. The increase, however, in the speed of ships and in the density of traffic so magnifies the complexity of the problem that even closer and more earnest study is still called for. Three fields of inquiry demand our attention: technical advances, procedure, and the human factor. Of these, the widest and most promising might seem to be the first. Its importance is undeniable, and I am by no means the only one to have pointed out that with the new difficulties it raises it supplies also the appropriate solution. Even wider, however, and more complex is the field of human study; this covers both the others, for in this the final objective is to enable men to master what they have won for themselves, and this they cannot do—here we meet the familiar problems of philosophy, ethics and religion—unless they first learn to master themselves.

Compared with these two fields, the technical and the human, that of procedure must at first seem quite insignificant. Can one seriously imagine that there is in fact some new method of avoiding collisions, so abstruse that no one has yet been able to discover it? In my small book on the use of radar I wrote: ‘The Regulations envisage two ways of avoiding collision:

1. A movement carried out in concert with the other vessel.

2. A reduction of speed, if necessary to zero.

For many generations mariners have been taught the law of storms and the rules for avoiding their centres. This paper describes some of the practical difficulties of avoiding hurricanes in the south-west Pacific area, and the failure of meteorologists to appreciate the dangers and difficulties of the mariners.

About half the tropical storms observed conform roughly to the parabolic track of the law of storms. They form about 10° South of the equator during the north-west monsoon, (from December to April), and travel west-south-west, south-west and south-south-west as they gather strength and speed to a maximum; at 20° South they pause, recurve through south-south-east and south-east as they diminish in force and pass out of our consideration at 30° South.

A dual channel microwave Doppler-Sensor-Module for 24 GHz is presented. This front end is well suited for true ground speed and distance measurements in all kinds of automotive applications. The microwave components such as oscillator, mixer, antenna and their characteristics in the MIC are discussed. The influence of the antenna pattern and the road surface on the Doppler spectrum is treated in a 3D-field theoretical simulation. This simulation takes the antenna nearfield and the distributed scattering of the road into account.

During the summer months of 1994 the yacht Jester undertook a seagoing investigation into some of the navigational problems that would have confronted the Portuguese discoverers of the thirteenth and fourteenth centuries returning to mainland Portugal from the coasts of Africa and the Atlantic archipelagos. The investigation was made at the suggestion of the maritime historian D. W. Waters to illuminate one aspect of how astronomical navigation was first introduced at sea in the west.

Civil aviation authorities have a requirement for the application of devices which are capable of determining the geometric height of aircraft above flight level 290 with a high degree of precision. These devices, called height monitoring units (HMUS), should pave the way for a safe and expeditious introduction of reduced vertical separation of 1000 ft above flight level 290.

In this paper the design philosophy as well as the prototype development of such a device, which is called the dual-synchronized autonomous monitoring system (DAMS), are outlined. This device operates fully independently of any airborne equipment such as secondary surveillance radar transponders.

The configuration basically consists of two standard marine radars with both axes of revolution situated in a horizontal plane. With this configuration it is possible to determine the trajectory of an aircraft and, in particular, the geometrical height above ground level within typical radar slant range coverage of some 18 km. The basic application of this equipment will be in the field of height monitoring of aircraft targets in environments with reduced vertical separation standards of 1000 ft above flight level 290, but a wider application of this concept is foreseen for local precision tracking of aircraft targets.

Recent advances in the speed and capability of miniature computers have made possible a strapped-down mechanization for airborne inertial navigation systems. The implementation of this mechanization is critically dependent on the availability of suitable accelerometers and gyroscopes able to measure, and yet withstand, the effects of vehicle motion. The laser gyroscope is now considered a major contender for angular measurement in that it offers the possibility of a cheap, reliable instrument with the wide dynamic range required for strapped-down implementation.

During the last few years much has been learned about the navigational developments and techniques of the English pioneers of colonization in the New World. This has been made possible in some measure by the formation in America of a private library of the books relating to the art of navigation as practised by the Elizabethan and early Stuart seamen. It was in the course of forming his remarkable collection of early Americana that Mr. Henry C. Taylor of New York, purchased copies of Captain John Smith's An Accidence or The Pathway to Experience. Necessary for all Young Sea-men, or those that are desirous to goe to Sea … first published in London in 1626, and A Sea Grammar, with The Plaine Exposition of Smiths Accidence for Young Sea-men, enlarged … first published in London in 1627, subsequent editions of this latter work being entitled The Sea-mans Grammar, etc.