Vessel Traffic Services (VTS) advise vessels navigating the waterways, VTS communications provide to the mariner timely, pertinent, and accurate information that would assist in safe manoeuvring of the vessel.

Following several oil spills in 1989, Congress passed The Oil Pollution Act of 1990 (Public Law 101–380). The Act requires the “Secretary to conduct a study…to determine and prioritize the US ports and channels that are in need of new, expanded, or improved vessel traffic service systems.…”

As required by the Act, the US Coast Guard analysed historical vessel casualties and their consequences and projected future vessel casualties and consequences for 23 study zones. The study uses a benefit–cost approach, VTS benefits are defined as the avoided vessel casualties and the associated consequences. The avoided consequences are measured in physical units and are assigned monetary values, VTS costs are defined as the initial federal investment for a state-of-the-art VTS system in each study zone and its annual operating and maintenance costs. Both the benefits and costs are expressed in the 1993 Net Present Value of annual stream over the life cycle at 10 percent basic annual rate. The study recommends VTS design by rank-ordering the zones by net benefit.

In this paper, we use alternative methodologies for offering better assistance in making VTS design decision-making. First, we perform ABC analysis on the zones; that is, we classify them into three groups: The A group deserves a state-of-the-art, full-fledged VTS presence, the B group could use an intermediate level of VTS services, and the c group deserves an elementary level of VTS services, as and if the budget permits. This analysis assumes that VTS services can be offered at various levels with correspondingly changing costs. Secondly, we perform resource allocation analysis; that is, for a given budget and given criterion (e.g. maximize the total benefit), select the optimal zones in which the VTS services should be offered. This analysis, done for various levels of budget, would form a useful decision aid for the VTS design.

This article is partially based on the Doctoral thesis (Reference 1) entitled (in English) Working aboard and job-related accidents: Health and safety conditions on merchant vessel. Divided into four sections, the paper includes: issues relating to legislation, an analysis of accidents, the research that has been done about accidents and risk factors for falling on board. The main causes of accidents are examined. Moreover, conclusions are drawn by analysing work-related accidents in the Spanish maritime transport sector through a study covering the period between 1999 and 2003. The text was updated in 2004, with the latest official data, figures which may be equally applicable to the maritime sector throughout the European Union.

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 17 November 1961, discusses aspects of high-speed, high-altitude navigation which will have a bearing on the selection of a navigation system and control philosophy for supersonic transports. The effects of certain separation criteria on systems accuracy are described, as are meteorological factors bearing on operation of the aircraft. Estimated performance capabilities which relate to traffic control and navigation are described. An analysis is offered of the effects of particular system accuracies on the selection of components of a navigation system and, finally, an integrated system is described, with arguments presented for certain levels of redundancy, reliability and automation.

In the second issue of the Journal a system of grid navigation was described. This system warrants serious consideration because of its application to polar navigation and because it offers a means of simplifying navigation in high-performance single-seater aircraft of long range. These aircraft are going to present extreme difficulties, particularly in naval aviation, where fixing facilities and pilotage are limited.

In this paper, the accuracy of astronomical (astro) navigation will be considered against the wide variety of factors that affect it. A series of practical observations will be analysed and astro positions compared with GPS positions and the reasons for the differences discussed. The paper will reach the conclusion that only by understanding the processes of astro navigation can its accuracy be fully understood and properly used by a practical navigator.

The existence of marine science is commonly believed to date from the great Challenger Expedition which sailed in 1872. Indeed John Young Buchanan, the Expedition's chemist, held that oceanography started on one particular day in 1873, the day of Challenger's Station I when she first dredged in the depths of the North Atlantic south of Tenerife. In fact, as anyone who has read Margaret Deacon's Scientists and the Sea knows very well, marine science has grown gradually over the centuries, at rates depending on individuals and the environment in which they found themselves.

Marine traffic engineering is a new field of navigation study with a history ranging over some fifteen years. The first traffic survey fully deserving of the name was carried out by Yamaguchi et al in 1963 in Japan; more than 30 surveys a year are nowadays being carried out with the cooperation of the Maritime Safety Agency, the Japanese Association for Preventing Sea Casualties and the Marine Traffic Engineering Research Group. The number of papers on the subject in the Journal of the Japanese Institute of Navigation has increased correspondingly. Table I gives a breakdown of theoretical studies of marine traffic engineering. A general account of Japanese activity in these fields has been published in different papers in the Journal of Navigation, London, and emphasis in this paper is based on activities since 1970.

FOR traffic proceeding in random directions on a plane surface the frequency of collisions, if no avoiding action is taken, is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the craft. Avoiding action is normally taken and the rate of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collision-avoidance rules, the competence of personnel, the manoeuvrability of the craft and the efficiency of radar and other equipment.

In the post-war years there has been a considerable increase in the number of merchant ships. The number of vessels of ioo tons gross and upwards increased from less than 30,000 in 1948 to over 65,000 in 1976. When considering the population of ships at risk it is necessary to deduct special types of non-trading vessels and ships laid up. The number of trading ships in service has increased by approximately 100 per cent since 1950 (Fig. 1) and the greatest increase has been for large ships. The average length of trading ships has increased by approximately 40 per cent in the same period and there has also been an appreciable increase in the mean speed of ships.

Efforts to determine the mean size of ship ‘domains’ from measurements of the distribution of ships in the vicinity of an individual ship have been made by several workers, particularly by Goodwin, who made extensive observations in the Sunk Lightship area of the North Sea. The work involved plotting the positions of vessels at time intervals of a few minutes to estimate the number of ships in an annulus about a central ship, or alternatively the number per unit area at various distances from a central ship. These figures were used to obtain distribution curves from which the average domain could be estimated. The work of Curtis and Barratt on the validation of simulator studies of passing manoeuvres in fog, in which the nearest point of approach of ship's tracks was determined, serves to illustrate an alternative method based on the distribution of the density of tracks. In both procedures use is made of the point at which the distribution function first returns to the value which would obtain if the distribution were uniform, that is, if ship domains were absent. Some doubts have been expressed as to the validity of using the position of the cross-over point as a measure of the average domain size, and also whether it would be more appropriate to employ the position of the maximum value of the functions.

Anyone concerned with navigation, be he practising navigator, design or development engineer, teacher, or amateur yachtsman, will be aware that the great majority of developments took place prior to Captain Cook's epic voyages (1768–1779) or after 1904 when the first radio time signals were transmitted. During the first period the science of astro-navigation had been developed and such aids as log, chronometer, sextant and Nautical Almanac were available. The methods developed during that period differ very little from the traditional methods which are still in use today.

Concerning the minimum fuel routeing, the algorithm stated in Section 2 is very effective in the calculation of the (sub)optimum route for most environmental conditions. However, when the weather around the great circle route is extremely severe and the final isochrone bends backwards sharply near the destination, there is a possibility that the route passing through the other side of the great circle causes less fuel consumption than the calculated minimum fuel route. In such a case, to investigate the fuel consumption of that alternative route it is necessary to apply the algorithm for only the other side of the great circle route.

This paper formed the basis of a highly successful talk at the RIN's AIS 03 in Church House London on 24th/25th November 2003. The authors are Tees Bay Pilots and have used their expertise and knowledge to survey and examine the introduction and progress of AIS.

This paper is presented as a think piece and poses the introduction of a new type of high-speed craft to represent the growing number of fast manoeuvrable craft that could safely maintain their speed in heavy traffic areas. A method of defining such craft is introduced and a proposal made for a corresponding amendment to the COLREGS.

An integrated GPS/GLONASS system was employed in this study to support the re-design of road networks and the adjustment of traffic control. The system was used to update road maps, and to determine the velocity and acceleration of a test vehicle. The vehicle ran along the traffic stream at designated times of a day, for specific time spans, to identify traffic conditions in urban areas of uncontrolled intersections such as roundabouts. Issues addressed included: transformation of GLONASS satellite coordinates from PZ-90 to WGS-84, the presence of the receiver clock error in the GLONASS double-differenced measurements, and the impact of the carrier wavelength variation on the ambiguity resolution. Two tests were carried out in an urban environment using the combined GPS/GLONASS system. The first test included updating a road map of a test area by an RTK approach. Results were checked by comparing them with an accurate map of the area, previously determined by conventional methods. The second test comprised determining position, velocity and acceleration of a moving vehicle representing the traffic flow for a selected area. Different solution schemes were investigated, including: RTK, DGPS, and post-processing of phase measurements. The impact of GLONASS augmentation and the quality of GPS satellites on solution feasibility and accuracy were also examined. Test results showed the benefits of adopting the integrated approach. These included: improving productivity and economics of map production, and improving availability, integrity, and accuracy of determining the velocity and acceleration, linked to positions on the road networks.

This paper presents the thoughts and experiences of marine navigators of the mid-20th century in their use of compasses during the transition from magnetic to gyro compasses.

An aircraft wing is the carrier of imaging payload (interferometric synthetic aperture radar (SAR) or array SAR) of a high-resolution aerial remote sensing system, and high-precision estimation of wing deformation is the key. There are two main traditional modelling methods for wing deformation, namely stochastic theory modelling and material mechanics modelling only dealing with single disturbance, of which the model parameters are derived from empirical values. Aiming at the complex multi-source disturbance of an aircraft wing, this paper separately probes the influence of external disturbance (air disturbance) and internal disturbance (engine vibration) based on the real-time observation of sensors and classifies the wing deformation on the basis of auto-regressive (AR) modelling for parameter identification. With the authentic flight data of a certain types of aircraft, the experimental analysis shows that the wing deformation under the influence of engine vibration is the 14th-order AR model, and the wing deformation under the influence of turbulence is the fifth-order AR model. Meanwhile, this paper also provides an experimental verification idea for the wing deflection modelling built on the second- or third-order Markov model.

Stochastic models are essential for precise navigation and positioning of the global navigation satellite system (GNSS). A stochastic model can influence the resolution of ambiguity, which is a key step in GNSS positioning. Most of the existing multi-GNSS stochastic models are based on the GPS empirical model, while differences in the precision of observations among different systems are not considered. In this paper, three refined stochastic models, namely the variance components between systems (RSM1), the variances of different types of observations (RSM2) and the variances of observations for each satellite (RSM3) are proposed based on the least-squares variance component estimation (LS-VCE). Zero-baseline and short-baseline GNSS experimental data were used to verify the proposed three refined stochastic models. The results show that, compared with the traditional elevation-dependent model (EDM), though the proposed models do not significantly improve the ambiguity resolution success rate, the positioning precision of the three proposed models has been improved. RSM3, which is more realistic for the data itself, performs the best, and the precision at elevation mask angles 20°, 30°, 40°, 50° can be improved by 4⋅6%, 7⋅6%, 13⋅2%, 73⋅0% for L1-B1-E1 and 1⋅1%, 4⋅8%, 16⋅3%, 64⋅5% for L2-B2-E5a, respectively.

This paper describes a camera simulation framework for validating machine vision algorithms under general airborne camera imperfections. Lens distortion, image delay, rolling shutter, motion blur, interlacing, vignetting, image noise, and light level are modelled. This is the first simulation that considers all temporal distortions jointly, along with static lens distortions in an online manner. Several innovations are proposed including a motion tracking system allowing the camera to follow the flight log with eligible derivatives. A reverse pipeline, relating each pixel in the output image to pixels in the ideal input image, is developed. It is shown that the inverse lens distortion model and the inverse temporal distortion models are decoupled in this way. A short-time pixel displacement model is proposed to solve for temporal distortions (i.e. delay, rolling shutter, motion blur, and interlacing). Evaluation is done by several means including regenerating an airborne dataset, regenerating the camera path on a calibration pattern, and evaluating the ability of the time displacement model to predict other frames. Qualitative evaluations are also made.

‘Close-quarters situation’ is a term used in the International Regulations for Preventing Collisions at Sea. As the term is not precisely defined, this paper analyses the interpretations and definitions of the term by various authors or courts, based on judicial processes and judgments. In the end, the authors suggest their own definition of the term ‘close-quarters situation’. Knowing the minimum distance from another ship and the time to the closest point of approach at which collision may still be avoided by one's own manoeuvre is information that every ship's officer needs to know. In accordance with the proposed definition of the term ‘close-quarters situation’, minimum distances between ships and time to the closest point of approach in which the ship can still take action to avoid a collision by its own manoeuvring are determined by means of simulations on a navigational simulator. A total of 168 simulations were performed with three fine-form vessel sizes and three full-form vessel sizes. Due to the extensive amount of data, the paper presents the results for one vessel only.

A priori attitude information can improve the success rate and reliability of Global Navigation Satellite System (GNSS) multi-antennae attitude determination. However, a priori attitude information is nonlinear, and integrating a priori information into the objective function rigorously will increase the complexity of an ambiguity domain search, such as the Multivariate Constrained-Least-squares Ambiguity Decorrelation Adjustment (MC-LAMBDA) method. In this paper, a new method based on attitude domain search is presented to make use of the a priori attitude angle information with high efficiency. First, the a priori information of pitch and roll is integrated into the search process to derive the analytic search step for attitude angle, and the integer candidates are determined by traversal search in the three-dimensional attitude domain. Then, the objective function is parameterised with Euler angles, and a non-iterative approximate method is utilised to simplify the iterative computation in calculating objective function values. Experimental results reveal that compared to the MC-LAMBDA method, our new method has the same success rate and reliability, but higher efficiency in making use of a priori attitude information.