It is perhaps appropriate, on this the exact 187th anniversary of the death of Admiral Lord Nelson at Trafalgar and in the year in which so many celebrations have taken place to commemorate the 500th anniversary of Christopher Columbus's arrival somewhere in the West Indies, to consider the progress which has been made towards international co-operation and achievements in hydrographic surveying and nautical cartography, particularly since the formation of the International Hydrographic Bureau in 1921, and to look at the problems facing international hydrography in the immediate future.

Many animals have some kind of ‘home’ –a nest, a burrow, etc. This applies to insects that build nests and provide their larvae with food just as much as to numerous species of vertebrates. Rodents and moles are known to dig burrows; most other mammals, reptiles, amphibians and even many fresh-water fish do not roam around randomly either, but have well-defined home ranges with favourite resting places in particular cavities, under rocks or in dense thickets. Birds build nests for their young and fly out searching for food. All these animals permanently face orientation problems: they have to move swiftly and efficiently within their home range, and they must be capable of returning home when they have left their familiar area while exploring, fleeing, etc.

The constraints imposed by the regulatory authorities give flight crews more tasks to perform at the flight planning stage for an Extended Range Twin Operations (ETOPS) flight than for a non–ETOPS flight. Among the additional checks the flight crew has to make are the following:

(i) That the aircraft will at all times be within the distance, calculated using the still–air single engine speed for the certified time, from the nearest ‘ suitable ’ airfield.(ii) That the ETOPS planning minima, which are typically three times the Category 1 operating minima in terms of forecast cloud base and visibility, are attained for each of the ‘suitable’ airfields used.

(iii) That the weather at each of the ‘ suitable’ airfields used is forecast to be above the planning minima, not just for the time of passing, but for a period, termed the time window, from one hour before to one hour after the expected time of arrival of the aircraft at this airfield.

(iv) That there is sufficient fuel, using the most critical fuel scenario, to take the aircraft from the critical point to any ‘ suitable’ airfield used in the calculation of the route.

This paper and the following three papers were presented at the EURNAV92 Conference on Digital Mapping and Navigation. This was held in London and was jointly sponsored by the RIN and the DGON. Forty-five papers were presented at the Conference and copies of the complete proceedings may be obtained from the Institute, priced at £65 for Members and £85 for Non-Members.

A GEC Marconi Avionics/MoD joint–funded integrated, digital terrain system called ' PENETRATE ' (passive enhanced navigation with terrain referenced avionics) is in its fourth year of flight trials on a Hunter fast–jet aircraft at the Defence Research Agency, Farnborough. Although originally designed to enable military aircraft to penetrate enemy defences at low level in poor weather conditions and at night, the system also has a direct read across to civil air transport operations. The heart of the PENETRATE system is a digital data–store housing a three–dimensional model of the terrain including cultural details, obstructions and tactical intelligence information.

PENETRATE incorporates terrain-referenced navigation to provide accurate position information relative to the ground contours. A sophisticated digital map displays navigation information and includes intelligence and intervisibility overlays. Head-up visual enhancement options are provided which can be tailored to the outside visibility. These comprise monochrome skeletal perspective displays which are superimposed on the outside world view and also on the forward-looking infra-red (FUR) scene. The display enhancements range from obstruction cues through ridge line overlays to skeletal perspective terrain presentations.

This paper covers the philosophy and architecture of PENETRATE together with details of the demonstration system. It also discusses the capability of this digital terrain system to enhance the safety of civil aircraft approaches into difficult airports such as Kathmandu and Hong Kong.

In the 1990s, digital maps are being used for a wide variety of applications. In the world of digital road maps, the most notable applications are in the area of theIntelligent Vehicle Highway Systems (IVHS). In the USA IVHS is involved with five basic interrelated applications:

(i) Advanced Traffic Management Systems.

(ii) Advanced Vehicle Control Systems.

(iii) Commercial Vehicle Operations.

(iv) Advanced Public Transportation Systems.

(v) Advanced Traveller Information Systems.

The AN/SSN-6 Navigation Sensor System Interface (NAVSSI) Project is a new system being designed with two primary objectives; to serve as the central distribution computer for navigation data to shipboard combat/weapon systems and to serve as the electronic chart display and information system (ECDIS). The NAVSSI will operate the digital nautical chart (DNC) database being developed by the Defense Mapping Agency (DMA). Our goal is for the digital nautical chart to replace the paper chart as a legal means of ownship navigation plotting. This paper will introduce the project and will primarily explore the use of digital nautical charts for ownship navigation with NAVSSI.

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.

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.