Forty years ago Sir Harold Spencer Jones, Astronomer Royal, gave the first Presidential Address on the ‘Development of Navigation’ so it seems appropriate on this anniversary to address a related theme from a different perspective.

This paper formed the 1988 Anderson Memorial Lecture, and was presented to the Boscombe Down Branch on 17 March.

Wing Commander Anderson, in addition to his many distinctions connected with our Institute (a Founder Member, President, Gold Medallist, Honorary Member and frequent office holder) was above all an indefatigable worker for the science and artistry of navigation, which he regarded as a basic activity of all mankind. In 1939 he was headmaster of a school and by 1945 had become one of the most outstanding operational navigators in the Royal Air Force. In that year he was chosen as navigator of the research aircraft, Aries I, for those epic flights over the North geographic and magnetic poles, investigating compass performance in high latitudes.

A mainly theoretical study has been undertaken to demonstrate how the extent of cover from a hyperbolic navigation system chain can be evaluated. The impetus for the study was the need to assess how Loran-C could be extended over Western Europe, particularly in the South western Approaches, North Sea, English Channel and Bay of Biscay sea areas.

The technique described in this article leads to an accurate determination of the electric field strength at a distance from each transmitting site and takes into account the complexities of the ground-wave propagation path. This field-strength contour is combined with the geometric effects of station siting (expansion factors) to yield a constant S/N contour (–10 dB) which defines the ¼n.m. error and hence the limit of cover for the hyperbolic chain under study.

In order to exercise the analytical methods a hypothetical Loran-C chain was studied comprising a master station at Lessay (France), with secondary stations at Soustons (also in France), at Sylt (dual rated; off the North Sea coast of Germany, near the Danish border) and at a fourth station located in north-west Britain on the Hebridean island of Barra. The study indicated that such a hypothetical chain would significantly improve Loran-C cover over much of western Europe.

The magnetic field of the Earth originates in the motions of the fluid core of the planet. By good fortune it is predominantly dipolar and so has a simple topography. The core motions cause the field to change with time, and once charted it has to be charted again and again. Mathematical models can be made which represent the geomagnetic field to an accuracy of about one degree globally. Higher accuracy demands advanced techniques such as satellite surveys, and also attention to the detail of external fields caused by solar activity which disturb the main field, restricting the accuracy of mapping and producing magnetic deviations from the mean value from day to day. Understanding such effects is essential in preparing magnetic reference data for navigation.

Though now losing ground to other methods, magnetic compasses still have a valuable role to play in many situations, so long as the limitations are fully appreciated and taken into account. Modern technology in standard geomagnetic observatories offers ways of updating a datum very accurately in automatic navigational systems and even of forecasting disturbances, and may bring magnetic reference back to the forefront of many navigational systems.

In mid-1985 the 20 metre outrigger canoe Sarimanok, built in the Southern Philippines from tropical forest materials, sailed out of Bali, Indonesia, to follow the direct east-west Indian Ocean track which the first Austronesian settlers of Madagascar may have taken.

It was on the river Rhine that radar started its inland waterway career, followed almost immediately by the inland waterways in the Netherlands. In those days the inland waterway fleet was composed of ships owned by a few large companies and ships owned by their skippers.

Global satellite navigation systems have been under development by the United States and the Soviet Union for many years. The US Navstar GPS system saw its first launch in 1978 and the USSR's Glonass system followed 4 years later. The US space shuttle, which was foreseen as the launch vehicle for Navstar spacecraft, received an enormous setback in 1986 as a result of the Challenger accident. In the meantime, Glonass launches, which carry three spacecraft at once into orbit, have proceeded without incident (until the failure on 24 April 1987). Both systems are currently still in test phase and can be expected to reach operational status in 3 or 4 years' time. In the meantime, the idea of combining Navstar and Glonass into a single civil programme has many attractions for all concerned. Some aspects of Glonass orbital characteristics and signal structure are discussed with this end in view. In addition, features of the data message content of Navstar and Glonass are also compared, to gain a better understanding of the feasibility of a dual satellite navigation system.

The chief failing of surface astronavigation in its traditional form is reliability – it needs clear skies! Any solution to this limitation must therefore centre on a more weather-independent means of both detecting and identifying astronomical objects. This implies that the detection process should be conducted not in the optical but in the radio waveband, although radio astronomy makes it clear that the rather simple distribution and ‘point’-like images seen visually do not exist at radio wavelengths.

The purpose of this paper is to identify and discuss official British general charts of New Zealand. The principal development period of the general chart ended when the fourth chart was published in 1885; this edition was not superseded until 1964.

On ne sait pas pourquoi ils s'echouent parfois sur la plage; car on assure qu'ils le font assez souvent, quand la fantaisie leur en prend, et sans aucune cause appréciable.

This paper is the first of a series on Air Navigation Systems during the fifty years from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. These papers are intended as critical commentaries. A definitive history has yet to be written. The writer would be grateful to receive criticisms of the paper or comments on the subject.

This paper was originally presented at a meeting of the International Omega Association in October 1987. It describes the operational use of the Omega system for daytime air-pollution monitoring and control, and for night-time low-level pest-spraying operations in South Africa.

The ability of visually impaired individuals, especially when blind, to locate themselves in an urban or rural environment with respect to road intersections, prominent landmarks, etc. has always been a serious problem. In addition, and of equal importance, is the inability to communicate their location to a central control facility in the event of their needing any additional assistance.

With the advent of high accuracy global positioning many applications, which heretofore had been considered highly futuristic and discussed only in the most tentative terms, are now being researched. One such application is the use of differential Navstar GPS and its capability as an aid to the visually impaired. The concept envisions a small device that can be worn by the user. This device will have the means for providing Navstar GPS phase information accurate enough to be converted to a specific street location. Inherent in the concept is means by which the users can be instantly apprised of their location and/or can communicate with a central location for other purposes.

To establish feasibility of such an application, it was necessary to understand the limitations of Navstar GPS. In particular those that may result from its use in an urban environment. Accuracies of the Navstar GPS system tend to depend on the sophistication of the receiver to be used. At the time there was some question as to future developments of a small enough package for the intended use. Along with this was the question of the suitability of differential positioning for increased accuracy. This article deals with the initial field tests that were run and the conclusions drawn from this work.

Similar work was previously accomplished in 1985 by the US Department of Transportation, Transportation Systems Center. The referenced effort included both the use of Navstar GPS as well as Loran-C which our effort did not but did confirm a number of our findings relating to the limitations of Navstar GPS in an urban environment and attenuation in the presence of foliage, it did not centre on differential Navstar GPS as did our work.

This paper represents a follow-up of work previously reported at an Ordinary Meeting of the Institute and published in the Journal in May 1986 under the title ‘Navigational Aspects of JTIDS’.

Technical studies on JTIDS for the airborne applications are being directed by the Royal Aircraft Establishment (RAE), Farnborough and by the Admiralty Research Establishment (ARE), Portsdown, for maritime use, for which Systems Designers Scientific is providing technical support in a number of areas. One such field is Relative Navigation (relnav). As part of this MOD-funded work a relnav simulator has been developed at the RAE. This simulator is currently in use for the assessment of the relnav capability and has been used to produce the results presented in following sections.

This report gives a brief description of JTIDS relnav and presents some basic features of relnav performance in simple communities. Then a description of relnav performance in fragmented and loosely coupled communities is presented. Finally a brief summary of the main points and conclusions is given.

The Institute’s NAV 88 Conference, with the above title, was held in London from 22 to 24 March. It included nearly 40 papers concerned broadly with the way ahead for radionavigation in Europe. The Jull proceedings of the Conference are available on application to the Director, price £30 (plus £3 p & p) for Members (£60 plus p & p for non-Members). A summary of the Conference is presented below, and this is followed by one of the Conference papers which describes a rationalization of radionavigation in the USA.

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

This briefing presents an overview of one section of a recently enacted Statute (US Public Law 100–223 signed into Law by the President of the United States on 30 December 1987) which directs the US Secretary of Transportation to effect certain improvements in US-provided radio navigation systems.

This paper describes a computer aided method which has been developed for assessing impending platform contacts (Impact). Some preliminary results are presented.

The 1987 Conference of the Institute was held at the Penta Hotel, London, in the autumn. A selection of nine papers from the Conference is reprinted here, following an introductory summary.

The complete proceedings, comprising some 40 papers, may be obtained from the Institute price £25 to Members (£50 to non-Members).

Weather-related ship loss statistics are assessed as a proportion of total losses to ascertain the requirement for route planning. A routeing assessment for suitability of on-board application is undertaken and a moveable grid is then proposed incorporating a time optimization procedure for the on-board system.