bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordinate Systems: How to Get Your Position Very Precise and Completely Wrong
Authors: Ashkenazi V.
Published: October 2009

Positioning by navigation satellites is carried out in three-dimensional geocentric cartesian coordinates, X, Y, Z. This applies to both the Transit System, which has now been in operation for over 20 years, and the Global Positioning System which is being tested and is due to become operational in 1988. Traditionally, the cartographer, the seafaring navigator and the geodetic surveyor have always expressed their coordinates in geographical terms, i.e. latitude and longtitude, whereas the land-based civil engineer, surveyor and the foot (or mechanized) soldier preferred theirs in terms of projection grid coordinates, i.e. northings and eastings. Transformations between these various coordinate systems involve not only complex algebraical formulae, but also some very specific numerical parameters, which are appropriate for different countries and continents and which can only be determined empirically. Moreover, the treatment and interpretation of the different systems of coordinates may frequently involve some very basic conceptual misunderstandings. These include confusing astronomical latitudes and longitudes with their geodetic counterparts, treating projection northings and eastings as if they were ordinary plane coordinates and, in the case of positions derived from observations to Transit satellites, applying the wrong set of transformation parameters or using inappropriate geoidal contour maps. These are typical examples of the sort of common misconceptions leading to gross errors and affecting even the most precisely determined absolute positions. Relative positioning, with respect to another point or a framework of points with known coordinates, eliminates some of the worst effects of these systematic sources of error, and is commonly used in geodetic surveying. However, instantaneous navigation (especially by using satellites) is most likely to be based on continuously determined, successive absolute positions and will therefore inevitably be affected by reference system errors. This is particularly important in the case of land navigation where much higher accuracies will be expected. This is a review paper with definitions and descriptions of the various types of coordinate systems and their mutual relationships. Geographical and geodetic coordinates are discussed in section 2, and projection grid coordinates in section 3. This is followed, in section 5, by a description of three-dimensional cartesian coordinates used in conjunction with navigation satellites. A brief discussion on current and proposed navigation satellite systems is given in section 6 and the paper is concluded in section 7.
Navigation of Spacecraft on Deep Space Missions
Authors: Jordan James F.
Published: October 2009

Spacecraft which are sent on deep space missions to the planets must be accurately navigated in order to achieve the correct flight path. Navigation analysts use precise measurements and large computational software systems to determine a spacecraft's position throughout the mission and compute the velocity corrections for its guidance through space. When the spacecraft is launched into deep space on its voyage, it is impossible to know with great precision where it is headed. Imperfections in both the launch vehicle's terminal velocity and the uncertainty in the knowledge of the parameters which will affect the spacecraft trajectory contribute to errors in the predictions of the total flight path. Continuous navigation of the spacecraft achieves an ever-evolving prediction of its orbit from the reduction of radiometric and astrometric observations of the craft. Control of the spacecraft is achieved by computing and signalling to the craft a series of propulsive, velocity correction commands, which manoeuvre the craft to its desired course.
Sea Trials of a Navigation System Based on Computer Processing of Marine Radar Images
Authors: Austin G. L. , Bellon A. , Ballantyne E.
Published: October 2009

A system which yields the automatic positioning of a ship from computer analysis of marine radar images of nearby coastlines has been tested on data from the survey vessel Maxwell while proceeding in and out of Halifax harbour. Differences between radar-determined position fixes and those obtained by a microwave navigation system with an error of the order i o m show little evidence of additional error when the origin of the radar images used as ‘reference map’ is within 500 m of the actual position. As the distance increases the accuracy slowly decreases.
Coordinate Conversion Techniques in Microprocessor-based Receivers for Hyperbolic Radio-navigation Systems
Authors: Last David , Scholefield Christopher
Published: October 2009

Traditional receivers for the low-frequency, hyperbolic radio-navigation systems – Loran-C, Decca Navigator and Omega – are expensive and are operated manually. They either display position fixes in hyperbolic coordinates for plotting by hand on navigation charts printed with hyperbolic overlays or they plot tracks automatically, often on distorted charts. Recently, low-cost receivers have been developed for marine navigation which operate wholly or largely automatically and which display position measurements in geographical coordinates – latitude and longitude – or as headings and distances to waypoints which are entered by the navigator in geographical coordinates.
Practical Weather Routing of Sail-assisted Motor Vessels
Authors: Hagiwara H. , Spaans J. A.
Published: October 2009

This paper reports on a study conducted during the academic year 1985–6 by Assistant Professor H. Hagiwara of the University of Mercantile Marine in Tokyo and Professor J. A. Spaans of Delft University of Technology.
Worldwide Navigation into the 21st Century – An Airline View
Authors: Moore P. , Page D. M.
Published: October 2009

The navigation and control of commercial aircraft has developed in an almost random fashion during the past forty years. Now circumstances have produced an opportunity, through the ICAO Special Committee on Future Air Navigation Systems, for the industry to put time aside from more immediate problems to plan ahead for the future. Although our current methods and procedures are immeasurably better than those of forty years ago there is now little scope for further refinement and it is very apparent that by the end of the century present systems will be unable to cope efficiently with the traffic in the world's high-density areas. In addition our current methods do not permit us to operate our aircraft as efficiently as we would wish.
Planning of the Navigational Channels in the Gulf of Suez Following IMO Regulations
Authors: Mokhtar G. A. , Hussein I.
Published: October 2009

This is an abridged version of a paper which was presented at the NAVIGOS Seminar held in Cairo in October 1986. It describes the development of ship routeing in the Gulf of Suez since 197J. Dr Mokhtar is Director General of the Arab Maritime Transport Academy and Commodore Hussein is a consultant at the same Academy.
The Navigator – Man or Machine?
Authors: Maybourn Ralph
Published: October 2009

This paper formed the 1987 Anderson Memorial Lecture, and was presented to the Bristol Channel branch on 24 March.
Navigational Ideas and the Yorkshire Ripper Investigation
Authors: Kind Stuart S.
Published: October 2009

This paper describes the application of navigational ideas during a late stage of the Yorkshire Ripper investigation. The conclusions reached were irrevocably recorded before the ultimate facts were established by the arrest and conviction of the killer. The reader is invited to assess the degree of success of the method and to rework the data supplied according to his own navigational ideas. The suggestion is made that navigational concepts may become a valuable weapon in the field of crime investigation.
The Navigation of Navigation Satellites
Authors: Ashkenazi V. , Moore T.
Published: October 2009

The orbits of navigation satellites have to be determined very precisely. The Transit broadcast (predicted) ephemeris, which is computed by the US Navy Astronautics Group, has an estimated orbital positional accuracy of the order of 25 m in each direction. By contrast, the precise (post-mission) ephemeris, which is determined by the US Defense Mapping Agency, from tracking data collected by the global TRANET network, reaches accuracies of the order of 10 m. These orbital precisions affect the navigation and (static) positioning accuracies which can be achieved by users of the system. The same is true of the GPS system which will become fully operational some time during 1988—89. However, unlike Transit, GPS will allow quasi-instantaneous absolute positioning (i.e. real-time navigation) as well as very high relative positioning accuracies. The latter will be obtained by using special operational and processing techniques (e.g. ‘differential GPS’ and ‘GPS interferometry’).
Developments in Inertial Navigation
Authors: Smith S. G.
Published: October 2009

Inertial navigation systems represent the ideal in automatic navigation. They operate entirely without external assistance, other than information as to their starting conditions, which makes them of great interest to both military and civil operators.
The Cost-effectiveness of Terrestrial Radio-navigation
Authors: Pearson M. G.
Published: October 2009

It is generally acknowledged that the present terrestrial radio-navigation facilities are in need of updating. Furthermore, satellite navigation offers great potential benefits to all classes of user. One of the factors to be taken into account is cost, and with this in mind it would be useful to establish how much the present spectrum of terrestrial radio-navigation aids itself is costing and what it provides for the money. This is a difficult task which has been attempted before. Each attempt makes a dent in the armour of impenetrability that is inherent in the problem. This paper adopts a fresh approach which it is hoped may make a dent slightly greater than some of the others.
Presidential Address: The Provenance of Navigational Science
Authors: Williams J. E. D.
Published: October 2009

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.
The Position-fixing Needs of Merchant Ships: An Assessment in the Area Portland Bill to the Thames Estuary
Authors: Strange J. L.
Published: October 2009

This is an abstract of a paper commissioned by the Lights Advisory Committee and published in June 1987.
Omega – An Industrial Resource
Authors: Rousseau A. P.
Published: October 2009

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.
Land Navigators – Where are They?
Authors: Fudge R. E.
Published: October 2009

The need for maritime navigation is obvious and the subject has a long history, indeed the science of navigation was mainly developed for maritime purposes. The areonautical requirement is nowhere near as old as the maritime, in the early days it was sufficient to follow roads or railways, the need for navigation came when crossing seas or not being able to see the ground for a large part of the journey. Space navigation requirements are even younger.
Airborne Data Bases — A Quiet Revolution
Authors: Terpstra James E.
Published: October 2009

The data base has become the heart of many of our businesses. This discussion will begin with an overview of the many aspects of how the data base is used and manipulated at Jeppesen Sanderson. The core of NavData has been named the Flight Information Master Data Base.
Civil Marine Radar Colour Displays
Authors: Ibbetson E. R.
Published: October 2009

Marine radars, introduced generally for merchant ships immediately after World War 2, play a vital role in ship navigation and collision avoidance. They are now considered to be essential to a ship's safe operation and internationally agreed carriage rules and performance specifications exist for most classes of vessels.
Integrated Flying Aid and Mission Displays for Modern Combat Aircraft Incorporating a Digital Data Base
Authors: Whitehead A. M. , Thomas W. P. , Wilkins M. P.
Published: October 2009

Electro-optic sensors – forward-looking infra-red and night vision goggles – are today providing a dramatic enhancement of low-level operational capability, but causing increased demands for precision navigation, situation awareness and advanced displays. Digital map displays, also available today, offer the flexibility of map presentation that is needed. In the future, terrain-referenced systems incorporating digital data bases hold the promise of the integrated flying aid and mission displays that are required for ‘all-weather’ operations. This paper describes first the fit and usage of the EO systems likely in a future combat aircraft and goes on to review the status of data-base systems. It establishes the baseline against which digital map systems and later terrain-referenced displays that exploit an elevation data base might be integrated into the aircraft.
Redesign of Bridge Layout and Equipment for Fishing Vessels
Authors: Stoop J.
Published: October 2009

The safety on board medium-sized fishing vessels in relation to working conditions on the bridge is analysed by means of a problem-solving method developed by the Safety Science Group of the Delft University of Technology. The potential of the method is illustrated by a number of case studies on selected aspects of the bridge design, since a complete application of the method is not yet available.
Subsatellite Point Positioning for Synchronous Circular Polar Orbits
Authors: Lucarelli G. , Santamaria R. , Troisi S. , Turturici L.
Published: October 2009

In this paper the authors obtain analytical expressions for the ground traces of synchronous polar satellites on the polar orthographic projection, confirming that they are circles and pointing out a simple graphic method for the mapping of the subsatellite point.
Hunters and Herders: Chukchi and Siberian Eskimo Navigation Across Snow and Frozen Sea
Authors: Lewis David H. , George Mimi
Published: October 2009

The tip of the Chukotskiy Peninsula in the Soviet Far East is 86 km from mainlandAlaska and its mountains are clearly visible from St Lawrence Island. It is a ruggedtreeless land that straddles the Arctic Circle between the Bering Sea and the ArcticOcean. In winter it is snow-covered and the sea stays frozen until May.
External Ground Monitoring v. Receiver Monitoring
Authors: Johannessen R.
Published: October 2009

The transmissions from GPS and GLONASS navigation satellites include information about the state of those transmissions as perceived by the control centre. In the case of GPS, for example, this information is contained in the data stream in Subframe 1 Word 3. However, with some of the failure conditions that can arise there is a delay of the order of half an hour before this message is altered to signal that a failure exists. A situation can therefore arise when the satellite signals that all is well, whereas in fact it is not. The very high levels of integrity which civil aviation require before satellite navigation can be used with confidence therefore means that the warning messages from the satellite must be augmented by some other form of monitoring. Two alternatives exist: (1) to have a monitor at some fixed and surveyed ground location which broadcasts a warning to the navigating aircraft when there is a malfunction (ground monitoring), or (2) to arrange for the navigating receiver to perform its own internal monitoring, known as receiver autonomous integrity monitoring (RAIM). Each alternative is beneficial in its own way.
ALV Navigation Using Terrain Databases
Authors: Blackman C. P. , Maclachlan I. R.
Published: October 2009

A navigation strategy for an autonomous land vehicle (ALV) based on the Defence Geographic Database is currently being developed under the auspices of. the Mobile Advanced Robotics Defence Initiative (MARDI). The database is hierarchically structured, and supports the storage of an unlimited number of attributes for each geographical feature. It also expressly identifies the interconnectivity of adjacent features, making it ideal for automatic route calculation. Tactical battlefield information is being combined with the database resulting in a composite link-node map which will be searched for optimum routes using standard algorithms. Both military and geographical criteria will be simultaneously optimized. Waypoints suitable for machine vision techniques will also be extracted and used to confirm the ALV location.
Flowers and Satellites
Authors: Lucarelli G. , Santamaria R. , Troisi S. , Turturici L.
Published: October 2009

In this paper some interesting properties of circular orbiting satellites' ground traces are pointed out. It will be shown how such properties are typical of some spherical and plane curves that look like flowers both in their name and shape. In addition, the choice of the best satellite constellations satisfying specific requirements is strongly facilitated by exploiting these properties.
Air Traffic Control Today and Tomorrow
Authors: Stonor Thomas
Published: October 2009

Life is more intense today than was shown in the film, and direction finding is somewhat more precise. We now know where aircraft are, rather than where they were some minutes earlier, (for at least most of the time!) and not every air traffic controller we employ speaks like an early BBC announcer.
Study Towards a 21st-Century Intelligent Ship
Authors: Iijima Yukito , Hayashi Shogo
Published: October 2009

The current state of the shipping and ship-building industries indicates that they are having difficulty surviving. This is especially so in Japan, which imports oil, ores, food and most of the materials used in manufacturing products for the domestic and foreign markets. The issue of maintaining stable and effective transportation overseas is, therefore, vital.
A Dynamic System for Fuel Optimization Trans-Ocean
Authors: Calvert S. , Deakins E. , Motte R.
Published: October 2009

Increased fuel costs necessitate a careful consideration of consumption when planning voyages trans-ocean. A model is formulated whereby ship response algorithms are matched with forecast environmental conditions expected for the duration of a voyage. A discrete system allows an optimization routine to minimize fuel costs for a trans-atlantic passage, using dynamic programming techniques.

These are simulated by using an on-board boosted micro-computer. The results are discussed and limitations of the system considered.
Applications of a Methodology to Demonstrate the Relative Effectiveness of Different Navigation Aids
Authors: Fletcher Tony
Published: October 2009

Criteria and a methodology for evaluating the relative effectiveness of different navigation aids in a coastal region, taking account of the ship-borne equipment, human factors and the needs of the navigator, have been discussed in the Nautical Institute' recently-published book on Pilotage and Shiphandling. The method is based on the product of the probabilities that the equipment will be fitted, that it will be available (in reliability terms), that it will be properly used and that it will provide the required information.
The Future of Area Navigation in Western Europe
Authors: Perry Bernard
Published: October 2009

The following two papers were presented at a joint Royal Aeronautical Society/Royal Institute of Navigation conference on ‘European Navigation into the 21st Century’ on Tuesday 12 February 1991.

The existing system of point-source radio navigation aids deployed throughout the European Region (e.g. VOR, DME, NDB), is inherently inflexible and suffers from a number of problems which degrade its efficiency; providing little scope for route capacity expansion. Area Navigation (RNAV) is seen to offer the answer to many of these deficiencies. Many aircraft are already fitted with RNAV – a system of navigation that allows track maintenance to defined levels of accuracy without the need to overfly point source aids. However, the full benefits of RNAV, including the introduction of more direct fuel efficient routes, arrivals and departures, and substantial increases in route capacities made possible by the application of reduced lateral and vertical separation criteria, cannot be fully realized until virtually all aircraft are equipped to a precision RNAV standard, and minimum aircraft systems performance specifications are introduced. This is unlikely to be practicable before 1998.

Timescales have been established for the progressive implementation of RNAV capability. High levels of cooperation between European states should ensure that operational implementation is achieved in a coordinated, efficient, orderly and safe manner. Certification and operational standards are being developed jointly and European guidance material, developed under the auspices of ICAO, is soon to be adopted by ICAO RGCSP for global application. Appropriate legislative amendments are being developed in the United Kingdom and elsewhere in Europe. All the present indications are that the implementation of RNAV in Europe will proceed successfully on an evolutionary basis, between now and the turn of the century.
The Accuracy and Coverage of Loran-C and of the Decca Navigator System — and the Fallacy of Fixed Errors
Authors: Last David
Published: October 2009

The proposal to develop an extensive North-West European Loran-C system, replacing many existing chains of the Decca Navigator System (DNS), has led to an intensive debate on the merits of the two navigation aids, especially in the United Kingdom. The paper reviews the principal sources of random and systematic position errors in the two systems. The wide range of DNS random errors, predominantly due to skywave interference, are compared with the Loran-C random errors, and typical coverage limits of acceptable repeatable accuracy are presented. The paper also identifies the factors which control the magnitudes of Loran-C and DNS systematic effects due to land paths. It demonstrates that differences between the two systems are substantially less than are predicted by simple models. Loran-C and DNS techniques for dealing with land paths are compared and the errors experienced by Loran users are shown to be reduced by modelling and publishing ASF values.

This paper is based on a presentation made by the author at a technical symposium of the Wild Goose Association.
A Brief Description of the Major Second World War Navigational Aids
Authors: Kendal Brian
Published: October 2009

During the 1939–1945 conflict, the development of navigational aids, particularly for the purpose of bombing the opposing nation, took place at an unprecedented rate. The life of any system was only the period of time it took scientists of the opposing nation to determine the nature of the aid and devise an appropriate countermeasure. So much so that in several cases, the time from conception to operational service could be measured in months.
The Development of Ship Collision Avoidance Automation
Authors: Jingsong Zhao , Fengchen Wang , Zhao-lin Wu
Published: October 2009

This paper reviews the history and the evolution of international ship collision avoidance research. The direction which research should take in the Chinese People's Republic is discussed and the authors recognize that new ideas may be needed to take account of the conditions in their country.
GPS/GLONASS User Systems in Sweden
Authors: Nilsson Johnny
Published: October 2009

A research and development programme performed in Sweden over a period of 9 years has created a substantial know-how on the design of satellite navigation user systems. Thus, a basic user system, called the GP & c Total System has been developed and tested over 3 years. This system can serve as a basis for the tailoring of an almost endless number of applications. The system is currently using data from the GPS satellites, but can also be operated with combined GPS/GLONASS receivers. The Swedish GP & c System is an example of how the communication, navigation and surveillance (CNS) concept and the various elements (ADS, ATM, etc.) for a new global Air Navigation System published by the ICAO FANS Committee can be implemented and integrated into a user-friendly operational system. The ICAO 10th Air Navigation Conference (5–20 September 1991) endorsed the FANS concept in which the main elements are based on the implementation of satellite navigation technology.
The 21st Century Navigation Station
Authors: Grocott D. F. H.
Published: October 2009

This paper formed the 1992 Anderson Memorial Lecture. It was presented by Air Commodore Grocott at a meeting of the Solent Branch at the Warsash Campus of Southampton Institute of Higher Education on 12 March.
Optimization of Time Saving in Navigation Through an Area of Variable Flow
Authors: Lunnon R. W. , Marklow A. D.
Published: October 2009

In planning routes between well-defined points of departure and arrival, both aircraft and ships can take into account forecast values of certain geophysical parameters so that the route chosen is in some sense optimized. For aircraft flying the North Atlantic, the methods used are described in the papers by Attwooll, Bennett, and Monk (all 1982). There have been a number of papers on ship-routeing; they were reviewed by Motte and Calvert (1988). It should be noted that whereas for aircraft the dominant consideration is the wind (for which the maritime equivalent is the current), ship-routeing on the trans-oceanic scale is dominated by considerations of waves. However, on smaller scales, currents can be the dominant consideration: for example, see the paper by Fales (1991). That paper does not make use of the basic theory that was applied to the aeronautical problem in the 1940s. Although the work reported here is orientated to aeronautical applications, it clearly has ramifications for certain maritime problems.
The ECDIS Paradox: A Controversial View on Navigation, Freedom and Safety at Sea
Authors: Bianchetti Fosco
Published: October 2009

The unexpected commercial success of electronic charting systems has put an unusual pressure on the regulatory organizations to come up with some accepted international standard for this new technology. Unfortunately, the scope of this issue is far-reaching and touches the most sensitive nerves of maritime tradition and culture. This cumbersome legacy was noticeable from the very first US RTCM meetings on the subject and has conditioned the development of recommendations ever since.

This paper, written by an outsider, tries to look at the whole issue with an unprejudiced eye, arriving at a conclusion which casts heavy doubts on the wisdom of the current course and which advocates a different approach to take advantage of the incredibly powerful potential of this new technology – a technology which could radically change the rules and laws of commercial navigation to the benefit of safety and economy.
Mercator – 425 Years Not Out
Authors: Hughes Terry
Published: October 2009

The development of an electronic system which can be used for navigating water-borne craft has been going on for well over two decades. In fact, various digital representations of navigational maps have been in use since the concept of computers. The word ‘map’ is intentional, for in some cases, apart from the land outline and some navigational marks, they bore little resemblance to the paper navigational chart.
Blinking Detection Methods for Loran-C
Authors: Nieuwland André
Published: October 2009

To ensure integrity of the Loran-C radionavigation system during non-precision approaches, an automatic blinking system notifies the user when the system is not functioning within specifications. To be certain that timely detection of this blinking can be guaranteed, one of the requirements imposed on an airborne Loran-C receiver is that it should flag an alert when the signal to noise ratio drops below –6 . This paper addresses some blinking detection methods, that will ensure safe operation beyond this –6 dB limit. A preliminary version of this article was presented at the Wild Goose Conference in Birmingham, August 1992.
Design and Operation of a Computerized, On-Board, Weather Routeing System
Authors: Motte R. H. , Fazal R. , Epshteyn M. , Calvert S. , Wojdylak H.
Published: October 2009

Weather routeing of ships has taken roughly three chronological steps. Originally, seasonal climatological weather charts, bearing little resemblance to actual conditions, gave standard routes. This somewhat passive activity was superseded by the measurement and subsequent forecasting of atmospheric and oceanographic data. Weather routeing became more complex as telex and radio facsimile routeing messages could be regularly transmitted to the ship. This form of routeing is still operational; masters can obtain radio facsimile sea and pressure charts and perform their own routeing, or employ specialist organizations which transmit the relevant routeing advice.
The Discovery of an Early Bearing-Dial – Further Investigations
Authors: Thirslund S.
Published: October 2009

The first part of the above title was used in the Journal in 1953 for a paper by Captain Carl V. Solver. His special interest was to discover how the Norse navigators of the Viking age found their way across the North Atlantic. He was the first person to interpret the small wooden disc shown in Fig. i as a fragment of an early bearing-dial and investigations since his paper was published provide considerable supportive evidence. At the time, there was some strong opposition to his views, but he persisted with his theory and wrote a book, Vestervejen. This formed a basis for other researchers to carry his work further and, as a result, there have been many international contributions over some 40 years. The archaeological find from southern Greenland seems to show that the Norse navigator used the path of the Sun's shadow during the day as the basis of a compass.
A history of visual approach guidance indicator systems in Australia
Authors: Clark B. A. J. , Antonenko P.
Published: October 2009

Approach and landing are the phases of flight most associated with accidents and near accidents, especially when external visual cues are sparse. At what is now Australia's DSTO Aeronautical Research Laboratory, research on ways of reducing the hazard incidence resulted in the development and testing of several ground-based visual approach slope indicators. The T-VASIS landing aid was an outcome of this work, T-VASIS, which has been in international use for over twenty years, is now under potential threat of displacement by PAPI which is a more recent UK development. The research which led to the implementation of T-VASIS is described here, along with subsequent events leading to the introduction of PAPI to Australia. A glossary of abbreviations is included at the end of the paper.
The Orientation and Navigational Skills of Young Children: An Application of Two Intervention Strategies
Authors: Walsh S. E. , Martland J. R.
Published: October 2009

Orienteering is a navigational sport using large–scale maps (1: 15000) and a compass to locate, as quickly as possible, a series of control points in a pre–defined order. Orientation of self and map are fundamental skills in the sport of orienteering. The traditional teaching or coaching of this skill is based on a hierarchical model. This model introduces the concept of location of self by initial reference to landmarks, then routes linking individual landmarks followed by configurations of these landmarks and routes. This model quite clearly aligns with the hierarchical model of spatial reference systems suggested by Seigal & White (1975). However, it is proposed that the process-oriented model offered by Downs & Stea (1977) may be more appropriate to orienteering. The model is based on orientation and then develops through route choice, route monitoring and route recognition. Orienteering behaviour, which is based on using map and compass information to select and follow a novel route in a multi-choice route following task, appears to follow this model.
The Value of GNSS to Aircraft Operators
Authors: Senechal C. G.
Published: October 2009

This paper, and the following 2 papers were presented at the 17th Annual Meeting of the International Omega Association held on 3—7 August at Amsterdam. Permission to reproduce these papers is gratefully acknowledged.
The Duke of Edinburgh Lecture: International Hydrography
Authors: Haslam David
Published: October 2009

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.
ECDIS Research in China
Authors: Depeng Zhao , Dongli Wu , Wenli Sun , Chengnang Chu , Yuanhui Li
Published: October 2009

abstract

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.
What do we know about the Genetic Basis of Bird Orientation?
Authors: Helbig A. J.
Published: October 2009

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.
Some Institutional Factors and Aspects Relating to a Civil Global Navigation Satellite System
Authors: Asbury M. J.
Published: October 2009

This paper and the following 5 papers were presented at the Institute's NAV93 Conference on The Application of Advanced Systems. The conference was held in London in November 1993. The full Proceedings, containing some 42 papers, are available on application to the Director, price £30 for Members and £40 for Non-Members.
A Route Planning and Driver Information System for PLEIADES
Authors: Ness Michael , Herbert Martin
Published: October 2009

This paper describes a low-cost, in-vehicle route planning and driver information system being developed for use within the DRIVE PLEIADES (London–Paris corridor) project. The system integrates vehicle position information from a GPS receiver, traffic condition messages broadcast from both RDS-TMC and radio paging, and road network information from a route planning system. Instructions describing the route to be followed are presented to the driver on a dashboard-mounted LCD and in spoken form. The system tracks the calculated optimum route and gives instructions for the next section of the route to be covered. The optimum route is continuously recalculated, reacting to TMC messages and the vehicle's location.
The Use of a GPS-Equipped Aircraft as a Mobile Platform to Study the Propagation of Omega Navigation Signals
Authors: Barr R. , Armstrong T. R. , Arrell S.
Published: October 2009

The almost complete constellation of GPS satellites now provides excellent positional information for aircraft, with typical worst-case errors of the order of 100 metres. The low frequency waves used for Omega navigation have wavelengths of the order of 30 kilometres and thus, even in an aircraft moving at varying speeds up to around 500 km per hour, it is now a simple matter to measure VLF phase with a significance at the 1 degree level. This paper describes the use of GPS to provide accurate positional information to VLF receivers located on aircraft of the Royal New Zealand Airforce (RNZAF) en-route to Antarctica. The marked phase irregularities on signals from La Reunion and Argentina, observed north of the icecap in earlier studies using aircraft fitted with inertial navigation systems, have been confirmed and described with much greater precision. Smaller phase anomalies have also been observed on signals from Omega Australia and Omega Hawaii, whilst flying directly over the Antarctic icecap. The latter signal was previously regarded as unperturbed and used in earlier studies as a phase reference. Small-scale periodic variations of phase and amplitude have also been recorded on signals propagating from Omega Australia. These variations are considered to be caused by the reflection of the VLF waves at discontinuities in the height (e.g. mountains) or the lower boundary conductivity of the Earth-ionosphere waveguide. Reflections of smaller amplitude have also been observed flying over the open ocean before reaching Antarctica.
DGPS Emergency Location System for Vehicles
Authors: Vogel Dietmar , Harrer Stefan
Published: October 2009

Even today much time is lost in bringing effective help when an accident with a truck carrying dangerous goods occurs. The location of the accident is often not well described by the people reporting it. Often it is difficult to determine what sort of freight a lorry is carrying, for example when the vehicle is burning, and sometimes the fire brigade does not bring the appropriate extinguishing equipment for the first help approach. Now an emergency location system is under development which will remove all these disadvantages. For immediate help on car accidents, an automatic alert message is transferred from the crashed vehicle via the emergency call centre to the fire brigade, the police station or the headquarters of an ambulance. The alert is initiated by a crash sensor within the car or the truck. The data channel between vehicle and base can be a radio link or, for longer distances, a mobile telephone connection using CNET or GSM. AS help is faster and more effective with this system, environmental damage caused by dangerous goods can be reduced.

In Stuttgart the mobile part of the DGPS-based emergency location system has been integrated in several vehicles. The full system is being tested within a field trial of a pilot project called STORM (Stuttgart Transport Operation by Regional Management), which is part of a programme of the European Community. The results of these tests are summarized in this paper. The integration of the system into fleet management applications is also considered.
A Fast Satellite Selection Algorithm for Combined GPS and GLONASS Receivers
Authors: Mok Esmond , Cross Paul A.
Published: October 2009

This paper derives a fast satellite selection algorithm; that is, an algorithm to select the best subset of satellites to use for positioning in circumstances whereby a satellite navigation receiver is not capable of using all satellites in view. The algorithm adopts the weighting factor concept to determine the contribution of each satellite to the overall positioning accuracy. Selection by this algorithm is shown to be especially efficient when the number of available satellites is large, so it is likely to be particularly useful for receivers capable of making combined measurements to GPS and GLONASS satellites.
The Use of Airborne Differential GPS to Detect Coordinate and Calibration Errors in DME Navigation Aids
Authors: Ashkenazi V. , Hill C. J. , Moore T. , Ochieng W. Y. , Storey J. , Rawlings R. , Cleasby C. V.
Published: October 2009

In May 1993, in support of Eurocontrol's WGS 84 Implementation Programme, a project was undertaken to assess the accuracy of navigation aid coordinates. The exercise involved flying a route over a number of European countries, in an aircraft which was equipped for multi-DME ‘data puddle’ position updating, and which also carried Global Positioning System (GPS) receivers. This test flight, carried out under contract to Eurocontrol, involved two parties, namely the Defence Research Agency (DRA) Bedford, who provided the airborne trials facility and DME data, and the Institute of Engineering Surveying and Space Geodesy (IESSG) at the University of Nottingham, who provided an analysis of the DME coordinate accuracy.

The aim of this test flight was to assess whether it is possible to determine independently the (WGS 84) coordinates of DME ground stations from the air, by using the same DME range measurements which are used to update aircraft position information in-flight. The procedure used to determine DME coordinates involves reversing the position updating principle. Instead of taking the DME ground station coordinates as known points and using the DME range measurements to determine the aircraft's position, the aircraft's position is independently determined (from DGPS) and the range measurements are used to estimate the coordinates of the DME ground stations.
Civil GNSS : The Inmarsat Vision for the 21st Century
Authors: Lundberg Olof
Published: October 2009

This paper, and the following seven papers, were presented at the Institute's NAV94 Conference held at Church House, London, in November 1994. The full proceedings may be obtained from the Director, RIN, price £25.00 (plus p & p).

I should start by explaining that the main purpose of my paper is to pass on the Inmarsat vision of satellite navigation in the future.

But first a little about mobile satcoms, our original reason for being. If you have followed us even at a distance you will be aware of:

(i) how we started with satcoms for ships;

(ii) how we contributed to a new maritime safety system;

(iii) how we developed an aeronautical satcoms system in close cooperation with the civil aviation world;

(iv) how land-mobile communications now account for one-third of our total traffic.
GPS and DGPS as a Challenge for Environmentally-Friendly Agriculture
Authors: Auernhammer Hermann , Muhr Thomas , Demmel Markus
Published: October 2009

For farming in the future, positional information is of particular importance. Out of a multitude of positioning systems, GPS/DGPS is the most suitable one. This system does not require any additional infrastructure and at the same time guarantees complete coverage of all tilled surfaces. The major application of positioning with GPS/DGPS is to be seen in the area of local information and documentation. By generating both planning and process data, it facilitates the operation and control of work processes (organic and mineral fertilization, plant protection). In the end, positioning leads to navigation, which, in the case of single vehicles and vehicle pools, will in turn provide completely new possibilities for development and application. For the first time, vehicles without drivers are conceivable. Thus, the completion of any kind of work on schedule, without time limitations, would become possible with the least possible stress for soil and environment.
Interpretation of S-Curve and Tracking Error in a Delay-Lock-Loop
Authors: Warner E. S. , Last J. D.
Published: October 2009

The delay-lock-loop is a device used in direct-sequence spread-spectrum receivers to track the delay difference between two binary correlated waveforms. This short paper aims to clarify both the interpretation of the S-curve and the sign of the tracking error for such devices, especially those for navigation systems such as GPS.
Marine Accident Frequencies – Review and Recent Empirical Results
Authors: Rømer Hans , Petersen H. J. Styhr , Haastrup Palle
Published: October 2009

Marine accident frequencies reported in 20 different sources have been studied and compared. Further than this, comparisons were made with an analysis done by the present authors. There seems to be consistency within the sources in the use of the terms total loss, casualty and accident/incident. The rates were observed to decrease by an order of magnitude going from accident/incident to casualty and likewise from casualty to total loss. The overall frequencies were found to be in the range of 0·0009 to 0·07 total losses per 106 ship miles, 0·03 to 1 casualties per 106 ship miles, and 0·5 to 13 accidents/incidents per 106 ship miles. It was found that the frequency depends on visibility, brightness, geographical environment, age of vessel and size of vessel. Collision and grounding frequencies were found to increase with decreasing visibility, brightness and more restricted waters. Collision frequencies were found to increase with increasing size of vessel. Fire/explosion and structural damage frequencies were found to increase with increasing age, and collisions to decrease with increasing age. No firm trend was found from the effect of flag state or type of vessel.
MOBIC: Designing a Travel Aid for Blind and Elderly People
Authors: Petrie Helen , Johnson Valerie , Strothotte Thomas , Raab Andreas , Fritz Steffi , Michel Rainer
Published: October 2009

This paper presents the research for the development of a new travel aid to increase the independent mobility of blind and elderly travellers. This aid will build on the technologies of geographical information systems (GIS) and the Global Positioning System (GPS). The MOBIC Travel Aid (MOTA) consists of two interrelated components: the MOBIC Pre-journey System (MOPS) to assist users in planning journeys and the MOBIC Outdoor System (MOODS) to execute these plans by providing users with orientation and navigation assistance during journeys. The MOBIC travel aid is complementary to primary mobility aids such as the long cane or guide dog. Results of a study of user requirements are presented and their implications for the initial design of the system are discussed.
A Review of the Prediction of Squat in Shallow Water
Authors: Millward A.
Published: October 2009

Recent evidence has shown that the effect of a ship moving in shallow water and the resultant squat are not well understood. This paper reviews the general problem of a ship in shallow water and illustrates the corresponding resistance, trim and sinkage at both sub-critical and also at super-critical speeds.

The paper then reviews the various methods of predicting the squat of a ship in shallow water in the sub-critical range, which is applicable to most ships. It is suggested that the simple rule-of-thumb methods are, at best, unreliable and the paper gives examples of empirical methods which have been tested against various sets of data and seem to give more representative answers. A summary of the notation used is given at the end of the paper.