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.

In an earlier study, the author attempted to give some quantitative estimates of the problems that free flow might face in Europe. The study was based on a traffic sample from the Eurocontrol Route Charges Office for a busy day in 1991. More recently, they generously made available a similar sample for a day in 1997. Using this new data, the study has been extended to cover wider aspects of the free flow problem. The central problem is that of ensuring safety. This will require a mechanism to detect collision threats and safely to resolve the problems. Possible tools are ground-based surveillance and/or airborne systems. This paper will use computer modelling to predict the loads that these detection and resolution systems must face.

Using GPS for animal tracking applications presents many significant challenges; not least the integration of the antenna in what is usually a miniature device. This paper describes a test setup that has been constructed to allow the user to perform something close to a full antenna gain pattern test using a simple turntable and relying on the GPS satellite motion to collect all angles required for a 3D gain plot. This has proved invaluable when predicting the expected performance of various antenna/packaging options for animal tags.

The Eva G. R. Taylor Lecture is jointly sponsored by the Institute with the Royal Geographical Society, the Hakluyt Society and the Society for Nautical Research to enable a lecture to be given every year by a distinguished scholar in one or other of the branches of knowledge to which Professor Taylor made such notable contributions. The 1999 lecture was presented at a meeting held at the Royal Geographical Society on 30 November 1999. Michael Richey first describes the events leading up to the dramatic announcement by Yale University in 1974 that the famous Vinland Map it had acquired some nine years before might well be a fake; and then the steps taken to try to rehabilitate it. Professor Taylor was almost certainly the first scholar to set down in detail the reasons for believing the map to be a forgery. The map remains a mystery, for while the evidence seems for the most part to point towards forgery, who by and when and why remain in the air. Michael Richey is a Gold Medallist and a former Director of the Institute.

This article is based on a lecture to the Royal Institute of Navigation History of Air Navigation Group at Tangmere Museum on 12 May 2004. The author served as a navigator-radar – or a radar bomb aimer – within RAF Bomber Command during the mid-1960s. This article is based on his experience of this time in Bomber Command and describes how the Medium Bomber Force would have carried out their war operations had nuclear deterrence failed. In its day these plans were TOP SECRET.

This, and the following three papers, were first presented at GNSS 2000, the Third European Symposium on Global Navigation Satellite Systems held in Edinburgh, Scotland from 1st to 4th May 2000.

This paper presents the methodology and a practical implementation approach to perform GNSS Safety Assessment and Certification with due consideration of the satellite navigation system users. It places Galileo GNSS in a total system that includes vehicles, on-board equipment, crews and traffic controllers and defines the necessary organisation for implementing safety analyses right from the early design phases of navigation systems. Civil aviation has very demanding requirements based on objectives for air navigation safety. It is much better organised on a worldwide basis than other GNSS users and is considered in this paper as the leading study case. Some methods are then proposed to build a bridge between all user organisations and to set up a common approach to certification.

Liquefied natural gas (LNG) offers negligible NOx and SOx emissions as well as reductions in CO2 compared with other liquid hydrocarbons. LNG is a significant player in the global energy mix, with a projection of 40% increase in demand for the next two decades. It is anticipated that the expected rise in demand will cause the fleet of LNG carriers (LNGC) to expand. This work concentrates on steam-powered LNGC, which accounted for 47% of the LNGC fleet in 2018. It performs an empirical analysis of continuous monitoring data that provide high levels of accuracy and transparency. The analysis is done on data collected from 40 LNGCs for over a year to estimate the fleet's operational profile, fuel mix and energy performance. The findings of this work are relevant for bottom-up analysis and simulation models that depend on technical assumptions, but also for emission studies such as the upcoming Fourth International Maritime Organization Greenhouse Gases study.

There is still fierce debate in the international community regarding the use and standards of electronic chart data and equipment. Whilst the standards for ecdis are now virtually complete and type-approved equipment will be entering the market during 1998, there is currently no IMO/IHO compliant enc data service from any national hydrographic office. It is expected that it will be 1 to 2 years before there is any appreciable quantity of enc data supported by a proper update service. It will be many more years before enc data becomes available to match the present coverage of paper charts, but we can expect that most major routes and the port entries of the majority of the world's trading nations will be available within a few years. This situation is examined, together with the ideas that IMO is considering to improve the availability of official electronic chart data. In addition, the distribution of electronic charts is discussed and the future trends in navigation that will occur with the availability of ecdis equipment and related data are explored.

This, and the following four papers, were first presented at the NAV99/ILA28 Conference on ‘Loran-C, Satellite and Integrated Systems for the 21st Century’ held at Church House, Westminster, London, 1st–3rd November 1999.

Just 25 years ago, the author presented a paper at the 30th Annual Meeting of the United States Institute of Navigation (ION) entitled ‘Radionavigation in North America, the Next 25 Years’. The paper received much attention and was given the ION's Burka Award for the best paper of the year. The author attempted to predict the worldwide implementation of Loran-C and Omega while acknowledging that satellite technology was on the horizon. ‘Global Radionavigation – The Next 50 Years and Beyond’ builds on the previous paper and is an attempt to define the future of global radionavigation based upon a mix of terrestrial and satellite systems. The time it takes for satellite systems and augmentations to mature and the reasons for this extended period provide the foundation of the paper. Also discussed are: the time to achieve a full constellation of space vehicles having signal specifications that meet the requirements for safety-of-life, the political complexities to achieve international harmonisation of service, and the use of a common worldwide protected frequency spectrum. The need for terrestrial complements is presented from the standpoint of supporting satellite systems and as a back-up in the event of loss of satellite services.

There is increasing pressure from commercial interests to obtain radio bandwidth for both terrestrial and satellite radio-communication applications. Existing civil radio-navigation and military radio-location bands are now being scrutinised by these interests. This background paper is about those pressures and the factors that marine navigators need to be aware of now and will need to deal with in the future.

This paper considers the need for better detectability of small targets at sea using marine radars in the 3 and 9 GHz bands. The problems of using radar reflectors and radar target enhancers to improve radar cross section, particularly when clutter is present, are discussed in detail. The IMO carriage requirement and the lack of suitably robust specifications are highlighted, and a proposal is made for a standard family of radar reflectors to meet the requirement. Radar target enhancers are also considered together with how these and radar reflectors should be mounted for best effect.

Heading errors caused by gyroscope drift affect the positioning precision of pedestrian dead reckoning, and these errors are even greater for smartphone-based reckoning. In this study, an optimised improved heuristic drift elimination (O-iHDE) method is proposed to correct the heading errors on a smartphone gyroscope. Based on an analysis of the improved heuristic drift elimination (iHDE) and enhanced improved heuristic drift elimination (E-iHDE) algorithms, the quaternion method is used to update the attitude and angle threshold judgement conditions, and a method for correcting the quaternion is added to eliminate the heading errors caused by random gyro errors. The analysis of multiple sets of experiments shows that the new method improves the ability to discern and correct the walking route, and the heading accuracy is improved by more than 90%, which extends the effective operation time of pedestrian dead reckoning positioning based on the step-by-step system.

COMPASS or BeiDou is the new satellite navigation system under construction in China. In this paper, the standalone performance of COMPASS is compared to the Global Positioning System (GPS), including: Single Point Positioning (SPP), differential positioning (DGPS and Differential COMPASS) and single epoch ambiguity resolution and positioning. Based on the results, it was found that COMPASS SPP performance is clearly worse than that of GPS, due to larger broadcast orbit and satellite clock errors, especially the latter. Differential positioning performance of COMPASS and GPS are essentially similar, with GPS marginally better. COMPASS single epoch ambiguity resolution performance is obviously better than that of GPS due to more observed satellites and the single epoch positioning performance of COMPASS and GPS are similar.

This paper addresses a simple implementation technology for localising a group of mobile nodes using the Peer-To-Peer (P2P) ranging measurements obtained from a Mobile Wireless Sensor Network (MWSN). In recent years, MWSN-based multi-target localisation technologies have been investigated with alacrity. However, it is difficult to implement P2P ranging and data transformation for multi-target localisation iteratively using single channel MWSN. Also, there are critical problems in the conventional localisation algorithms associated with the estimation errors owing to the erroneous linearization of a nonlinear range equation and bad relative locations of the reference nodes and target node. In this paper, very simple P2P ranging and connection data sharing procedures that can be easily implemented in single channel MWSN are established. Moreover, an adaptive localisation algorithm is presented to reduce the estimation errors that may occur in the conventional localisation algorithms. To verify the performance of the presented implementation technology, a localisation system prototype is developed and the presented procedures and algorithm are embedded in the prototype. Through actual experiments, the validity of the localisation system containing the proposed procedures and algorithm is demonstrated.

GNSS relative positioning technique is an important field of study, in which the standard ‘GNSS Baseline Model’ is often used. Differencing between observation equations is used to construct the mathematical model, since this method can eliminate some common errors in the GNSS signal measurements. The ‘Orthogonal Transformation’ method can also construct the GNSS Baseline Model. However, as is described by some scholars, this model may avoid some drawbacks of Double Differencing (DD) while maintaining all the advantages. For comparison purposes, this model is evaluated and the theoretical equivalence of both approaches is proved for the short baseline from two aspects: the Integer Ambiguity Resolution and the conditional least-squares baseline vector.

Currently, most of the studies on unmanned aerial vehicle (UAV) automatic landing systems mainly depend on image information to determine the landing location. However, the system requires a camera, a gimbal system and a separate image-processing device, which increases the weight and power consumption of the UAV, resulting in a shorter flight time. In addition, a large amount of computation and slow reaction speed can cause the camera to miss a proper landing moment. To solve these problems, in this study, the moving direction and relative distance between an object and the automatic landing system were measured using a receive signal strength indicator of the radio-frequency (RF) signal. To improve the movement direction and relative distance estimation accuracy, the noise in the RF signal was minimised using a low pass filter and moving average filter. Based on the filtered RF signal, the acceleration of the multicopter to reach the object was estimated by adopting the proportional navigation algorithm. The performance of the proposed algorithm for precise landing on a moving vehicle was demonstrated through experiments.

With reference to Captain Emden's paper in the April 1975 issue of this Journal, in which he refers to the control and identification of shipping passing through the English Channel, and the numerous articles by Captain Wylie on the subject of computerized shipborne collision avoidance systems, why not adapt the ship-borne radar systems for land based control of Channel traffic ? A modified shore based system would, with present and predicted traffic movement, be ideally suited to this type of application. As to the problem of operator traffic identification and control, the present civil air traffic control procedures would seem to provide the ideal solution; if all shipping were required to carry dual channel multi-code transponders in addition to the current obligatory navaids.

Whether Henry Ford or someone else gave us this famous quote, ‘If I had asked people what they wanted, they would have said faster horses’, we may agree that it implies there is a limit to what we can expect from the performance of an existing solution. Science and technology always try to push the boundaries and ‘improve’; improving the quality of our lives or improving the quality of technologies. We, as researchers in the area of navigation, are no exception; we want to improve the quality of navigation services. And there are many ways to do so, and challenges and limitations to those attempts. Some researchers look to improve the accuracy, the reliability, the integrity through different approaches. Some try to reduce or model noise, some try to minimise human error, and some use novel techniques and algorithms for better prediction. Of course, when ‘our horses cannot go any faster’ and there is not much space for improvement for a certain technology or service, researchers may come up with a completely new solution, such as an automobile. Almost all new technologies go through the same exploration period; at the beginning, we want to see how and if it works so we try simple tasks, but then we become more ambitious (or greedier!) and so we introduce it to more difficult challenges until it hits the breaking point. At this point, curious researchers and inventors try to push the boundaries and make the technology better, and if improvement is not possible, they build (invent) a new solution. But what is the ‘quality’ that many of us want to improve? How the quality of a technology or service can be measured in the first place?

It seems unfortunate that with the great advances made in modem navigation, the elementary and basic problems have been left unstandardized, incomplete and to a certain extent misleading, causing needless confusion to the student.