This paper, and the following 5 papers, were presented at the RIN93 Conference on “Orientation and Navigation - Birds, Humans and other Animals.” This took place in Oxford in April, and included some 40 papers. Copies of the complete Proceedings, priced £25 for RIN members and £35 for non-members, are available from the Director.

This is the concluding part of a series of three papers for this Journal, documenting the European studies into the feasibility of 1000 ft vertical separation minima above FL290. This paper outlines the results from European data collections other than the main precision radar data collection and expands upon the factors affecting height-keeping performance. The development of a Minimum Altimetry System Performance Specification (MASPS), necessary for a reduced vertical separation minimum above FL29O, is presented. A number of implementation issues, in particular monitoring, are also discussed.

The contents of this paper reflect the views of the authors; they do not necessarily reflect the official views or policy of the NLR, CAA or EUROCONTROL.

A model avian compass is formed if magnetite crystals are included among the statoconia loading some of the hair cells in the vestibular system. The magnetite is used as a null detector to detect the direction in which the magnetic couple acting on the magnetic crystal is zero. The location of the north/south plane and the angle between the directions of the gravitational and the magnetic fields are detected at a single site.

The US Coast Guard has a project to provide a differential global positioning system service for harbour and harbour approach (HHA) areas of the coastal United States. The Great Lakes, Puerto Rico and most of Alaska and Hawaii will also be covered by the service. The Coast Guard's DGPS system will fulfil the 8–20 metre navigation accuracy requirement for HHA with an availability of up to 999 percent. The Coast Guard intends to provide this service to the general public and other government agencies, as well as use the system for its own missions. This capability is expected to enhance maritime safety in keeping with the National Transportation Policy by providing an all-weather radionavigation service to supplement existing radar and visual techniques, as well as a highly accurate position sensor for future electronic chart displays. This paper describes the Coast Guard's programme. Background and historical information on the development of pseudorange differential GPS is presented first, followed by a description of currently available technology. Various aspects of the Coast Guard's plan for implementing DGPS are then described, concluding with a rough project time line and a statement concerning Federal DGPS policy.

According to comprehensive theories of navigation, animals navigate by using two complementary strategies: (1) dead reckoning informs the subject in a continuous manner on its actual location with respect to an Earthbound or absolute coordinate system; while (2) long-term associations between particular landmarks and specific locations allow the animal to find its way within a familiar environment. If the subject structures familiar space as a system of interconnected places – the so-called ‘cognitive map’ – it may know through dead reckoning where it is located on its map and relate its route-based expectations to the actually perceived scenario of local cues.

Recently, integration of different radionavigation systems has become very popular, since it improves system integrity, availability, accuracy and reliability. This paper discusses a new, flexible and cost-effective approach to system integration, centred on a single-chip application specific processor (ASP). An overview of this integrated system is presented and the application of the ASP for the implementation of a six-channel GPS, OMEGA, Loran-C and MLS receiver is given. The ASP is currently being implemented on a 180000 transistor 1·6μ, m CMOS Sea of Gates chip, and is expected to run at 100 MHz clock speed.

Jester, in the course of her fourteenth transatlantic crossing, was abandoned on 15 July 1988 in position 39° 08′ N., 58° 43′ W., some 470 nautical miles southeast of Halifax, NS. The circumstances leading up to this melancholy event were described in an article I wrote for the Journal, which also gave, I believe, some indication of the distress the loss of the boat had caused me. Jester had been knocked down in a storm with the loss of one of her side hatches which left her open to the seas and led me to believe I would require assistance to sail on. I sent out a distress call, an act that culminated in the coastguard rescue services urging me, in view of the deteriorating weather situation, to abandon the voyage and take passage in the ship that had come to my assistance. I finally concurred but later, when the boat was lost under tow, reflected bitterly that in the circumstances the coastguard's advice could scarcely have been otherwise and that in any case the safest course is not always the right one to take. From then on, like Conrad's Lord Jim (not the most sympathetic of his characters), I was assailed by doubts.

This paper presents a prototype ECDIS as developed by the Research Group on ECDIS (RGE) of Dalian Maritime University (DMU). It describes the configuration, the functions and the characteristics of the system. The results of sea and land trials are also presented.

Projected requirements for automatic dependent surveillance (ADS) include the downlinking of certain aircraft flight parameters periodically and upon command from the ground. This will require a primary source of the data such as a flight management system (FMS) and, of course, a radio datalink. This paper provides a description of an existing system that could fulfil much of the interim airborne ADS equipment requirements by using GPS/OMEGA/INS/ACARS for existing aircraft which are not equipped with, or envisioned to be equipped with, SATCOM, FMS or IRS.

It is now well established that homing pigeons (Columba livia) use a variety of mechanisms and cues to help them find their way home. It is far more difficult to determine the relative importance attached to such mechanisms and cues by pigeons during homing. As a step towards this quantitative stage in our understanding of homing behaviour we consider if cues contribute significantly to homing speed. In particular we attempt to assess the role of visual landmarks. Using pigeons released from familiar release sites, we demonstrate that birds home faster if they can view their surroundings from inside a Perspex box for 5 minutes prior to being released, compared to birds denied this view. Pigeons released from unfamiliar sites, however, do not show a similar improvement. We suggest that seeing familiar visual landmarks before release allows pigeons to become more certain of their current location with respect to home. Simply viewing the release site is not sufficient to produce a faster homing speed; the pigeons must be able to recognize that the release site is familiar.

Migratory directions of birds have long been assumed to be at least partly ‘innate’ that is, genetically determined. In recent years much progress has been made toward understanding the genetic basis of several components of the orientation system. An important distinction has to be made between a bird's ‘knowledge’ of which direction to migrate, and its ability to use certain compass systems to find this intended direction. Both processes, establishing an intended direction and the subsequent compass orientation, have a partly genetic basis. The present review will be concerned only with the first of these processes, and the way it allows evolutionary changes of migratory routes to occur.

A variety of different techniques has been developed for the weather routeing of sailboats. These have varied according to whether the technique is intended for yachts or for sail-assisted powered vessels, whether the routeing is for long or short time periods, and whether the routeing is used for navigation or design purposes.

The techniques that have been implemented to date are reviewed, comparing their strengths and weaknesses. Ways in which these problems may be overcome in future implementations of weather routeing are also discussed

Over the last two decades, my colleagues and I have sailed a modern reconstruction of a Polynesian voyaging canoe some 40 000 nautical miles through Polynesian waters. This programme has been driven by two intertwined goals: one experimental – to test the sailing technology and navigational methods of the ancient Polynesians in order to resolve issues in Polynesian prehistory; and the other cultural – to enable contemporary Polynesians to relearn the means by which their ancestors found and settled their islands, and thereby gain a better sense of their uniquely maritime heritage and, ultimately, themselves. This paper focuses on the effort to rediscover how to navigate without instruments, and how that rediscovery is helping both to change scientific thinking about the colonization of Polynesia and to transform the selfimage of contemporary Polynesians.

This paper is based on one presented by the author at the Maritime Technology 21st Century Conference held at the University of Melbourne in November 1992.