In the mid-16th century the English began to expand their merchant and fighting navies to sail beyond the waters of north-west Europe. This necessitated mathematical navigation, charts, and written and illustrated sailing directions; all, from the 1580s, were embodied in the printed ‘waggoners’ of the Dutch and were used in translation by the English seamen.

This paper was presented at the RIN89 Conference on Orientation and Navigation – Birds, Humans and other Animals. The conference was held in Cardiff in 04 1989. The printed proceedings contain some 27 papers and are available by application to the Director. The price is £30 (RIN Members) or £35 (Non-Members).

This paper was presented at the RIN89 conference on Orientation and Navigation – Birds, Humans and other Animals held in Cardiff in April 1989.

Around 1992 Navstar/GPS will become fully operational. Public access is then provided in the Standard Precision Service, SPS, at a reduced accuracy of 100 metres for 95 per cent of the fixes. The exclusively US military-operated system and the deliberately introduced degradation (SA, selective availability) of the attainable accuracy have some drawbacks for European navigation. Neither the probability density function of the error amplitude, nor its power spectral density function is known. So, using Navstar/GPS as a sole-means precise and reliable navigational aid for high-risk transports is not possible.

A number of factors need to be understood initially.

(1) Alignment is based upon the use of light, though not on being able to see where you are going!

(2) The theory relies upon three dimensional co-ordinate geometry.

(3) The knowledge that junction error will increase with distance, together with the commercial need to keep construction time short, normally means tunnelling from the ends towards a junction in the middle.

(4) Difficulties arise because of short baselines and no intermediate fixes.

(5) Terminology needs some explanation. Thus desired alignment is designed and then set out in the tunnel. Post-construction, a wriggle diagram is prepared and final alignment computed.

Accurate navigation, better described as precise positioning, is essential to efficient mine countermeasure operations. This paper will describe the basic principles of mine hunting, mine sweeping, mine classification, mine disposal and mine avoidance. The paper will describe the methods employed for precise positioning in the past, at present, and a method for the future. The sea mine has the capability of being a very cost-effective weapon, which can be deployed in peacetime for future remote-controlled activation. Events in the Red Sea and the Arabian Gulf in recent years have demonstrated that fact.

This paper deals with an analytical method for establishing a separation minimum for air traffic control using a monopulse SSR (Secondary Surveillance Radar), namely the Long Range SSR (LSSR), of which coverage is extended to 250 n.m. The azimuth estimation accuracy of the monopulse SSR was significantly improved compared with that of conventional SSR.

As an index of a collision risk due to azimuth errors of the LSSR, the close approach probability (CAP) associated with the probability of overlap of aircraft in azimuth is used for evaluating the safety of the surveillance system. The CAPs for both the LSSR and the conventional SSR are estimated by modelling and comparing distributions of azimuth errors. The CAP for the LSSR is significantly smaller than that for the conventional one under 5 n.m. separation minimum.

The objective of ground collision avoidance systems (GCAS) is to assure the separation of aircraft during flight operations, GCAS can be divided into tactical and strategic systems. The term tactical implies conflict prediction made after every radar scan and with approximately a one minute look ahead time. The aim of the study is to build up a mathematical model which uses only radar information and predicts potential conflicts within a fixed time, p, which may differ in different areas.

Navigation at sea and navigation in the air have much in common. There is, however, a marked limitation for the ship (with the exception of a submarine), as that kind of navigation is restricted to the surface of the sea. The ship has to navigate within areas defined by two dimensions only, always bearing in mind that the depth of the water has to be more than the draught of the vessel.