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 is concerned with potential improvements in the way man interacts with machines, maps and charts. Particular motivation comes from the new navigational challenges provided by the increasingly widespread use of electronic position-fixing aids in the marine field. Whilst automatic plotting tables and moving light spots have provided part of the solution in larger ships, much recent investment has been witnessed in the development of ‘electronic chart’-based systems.

For a number of practical reasons, among which are the lack of available data bases for these systems and little updating and distribution infrastructure for them, it is believed that there is unlikely to be a wide acceptance of such equipment as the primary or sole plotting aid for a considerable number of years to come.

Yeoman, a navigation plotting system which uses existing conventional charts, was conceived and developed to provide a simple and effective man–chart interface with few drawbacks. This paper provides the background for the development, the product and potential future evolution.

This paper describes preliminary studies towards a navigational Knowledge-based System currently in progress within the School of Engineering and Technology Management at Liverpool Polytechnic.

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.

In this paper, methods and formulas for testing ARPA (Automatic Radar Plotting Aid) equipment according to IMO requirements are developed. The International Maritime Organization (IMO) and International Electrotechnical Commission (IEC) requirements for tracking accuracy are also discussed.

Instrument landing systems (ILS) and the upcoming microwave landing systems (MLS) are (or are planned to be) very important navigational aids at most major airports of the world. However, their performance is directly affected by the features of the site in which they are located. Currently, validation of the ILS performance is through costly and time-consuming experimental methods. This paper outlines a powerful and versatile analytical approach for performing the site evaluation, as an alternative to the experimental methods. The approach combines a multi-plate model for the terrain with a powerful and exhaustive ray-tracing technique and a versatile and accurate formulation for estimating the electromagnetic fields due to the array antenna in the presence of the terrain. It can model the effects of the undulation, the roughness and the impedance (depending on the soil type) of the terrain at the site. The results computed from the analytical method are compared with the actual measurements and good agreement is shown. Considerations for site effects on MLS are also outlined.

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.

In this paper two devices as applied to a marine sextant are presented. A night viewer replaces the usual telescope to allow observation of the horizon in darkness. In addition an automatic reading of altitude is made practicable by a ten-bit encoder mounted on the index arm. In this way the proposed Celestial Navigation Automated Global System may be included within an integrated navigation system.

This paper was presented at the Annual Meeting of the US Institute of Navigation held in Annapolis, June 1988

The following is an assessment of Area Navigation Systems, or RNAV, as they apply to regional aviation.

Regional aviation, in this context, refers to that third sector of the airline industry which concentrates on short haul, high frequency, so-called ‘hub and spoke’ operations. Now amounting to over j per cent all airline passenger traffic, regional operations by their nature have more to gain from the use of RNAV than any other segment of the airline business. In particular we look at how RNAV systems provide business opportunities to regional operators, not only to manage aircraft more effectively, but in the process to improve a firm's viability.

Hairawa in the Journal made the statement that there is no easy method of calculating the length of a geodesic line on the surface of a spheroid and this is true. Nevertheless, it is the purpose here to attempt to devise a method and then to leave it to the reader to judge whether or not the amount of work involved justifies the method as an alternative to the correction methods of Andoyer and Lambert and to the work of Hairawa himself.

An account of the calculation of the geometry of collision zones surrounding vessels engaged in overtaking and meeting encounters is given. The zones are calculated for a range of mariners' decision times corresponding to clear and restricted visibility. The determination of encounter risk from the size of the zones is discussed.

In situations where the use of a magnetic compass has disadvantages, it is sometimes possible to use successfully a suncompass. All known suncompasses use the clock time. This paper introduces a method of orientation which does not use clock time and which surpasses the accuracy and usefulness of the Cole suncompass.

de Wit has produced an analysis of the apparent spontaneous yaw of a ship when undergoing combined rolling and pitching. This analysis produces a set of four first-order simultaneous differential equations which govern the motion. In de Wit the numerical solutions of these equations for a couple of representative examples are given, as well as the corresponding analytical solutions to the linearized equations. In this communication it is shown how two of the four equations can be solved analytically; these solutions can be used to obtain approximate analytical solutions to the remaining two equations.