In this paper, a new scene recognition visual descriptor called Enhanced Scale Invariant Feature Transform-based Sparse coding Spatial Pyramid Matching (Enhanced SIFT-ScSPM) descriptor is proposed by combining a Bag of Words (BOW)-based visual descriptor (SIFT-ScSPM) and Gist-based descriptors (Enhanced Gist-Enhanced multichannel Gist (Enhanced mGist)). Indoor scene classification is carried out by multi-class linear and non-linear Support Vector Machine (SVM) classifiers. Feature extraction methodology and critical review of several visual descriptors used for indoor scene recognition in terms of experimental perspectives have been discussed in this paper. An empirical study is conducted on the Massachusetts Institute of Technology (MIT) 67 indoor scene classification data set and assessed the classification accuracy of state-of-the-art visual descriptors and the proposed Enhanced mGist, Speeded Up Robust Features-Spatial Pyramid Matching (SURF-SPM) and Enhanced SIFT-ScSPM visual descriptors. Experimental results show that the proposed Enhanced SIFT-ScSPM visual descriptor performs better with higher classification rate, precision, recall and area under the Receiver Operating Characteristic (ROC) curve values with respect to the state-of-the-art and the proposed Enhanced mGist and SURF-SPM visual descriptors.

Advanced vehicle navigation based on the US Global Positioning Systems (GPS) will play a major role in future vehicle control systems. Contemporary vehicle navigation systems generally consist of vehicle positioning using satellites and location and orientation of the vehicle with respect to the roadway geometry using a digitised map on a CD-ROM. The standard GPS (with Selective Availability) enables positioning with an accuracy of at least 100 m and is sufficiently accurate for most route guidance tasks. More accurate, precision navigation can be obtained by Differential GPS techniques. A new light concept called Adaptive Light Control (ALC) has been developed with the aim to improve night-time traffic safety. ALC improves the headlamp illumination by means of continuous adaptation of the headlamps according to the current driving situation and current environment. In order to ensure rapid prototyping and early testing, the step from offline to online (real-time) simulation of light distributions has been successfully completed in the driving simulator. The solutions are directly ported to real vehicles to allow further testing with natural road conditions.

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.

This paper presents a new method of vessel heave compensation based on a new breed of commercially available low cost GPS receivers that can measure and record the carrier phase observable. The technique is based on the extraction of a highly accurate velocity estimate from standalone receivers using time differenced carrier phase observable. Two trials have been undertaken, one using a Spirent GPS signal simulator and another conducted at sea. The simulator trial thoroughly tested the use of commercially available low cost receivers for this method of velocity estimation through their comparison with higher grade receivers and quantified the errors under varying dynamics. The sea trial tested the heave algorithm against other heave sensors and an accurate reference provided by an Applanix POSRS and showed it to be capable of producing a heave output to rival inertial based heave sensors using commercially available low cost GPS receivers.

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 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.

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.

The spatial distribution of collaborative targets and the information collaboration process are two important factors affecting the efficiency of real-time collaborative navigation. Addressing these factors, this paper presents the following work. First, the collaborative communication process between navigation targets is designed and illustrated with an application example. Second, the feature and error condition of the spatial distribution of collaborative targets is analysed. Then, a method based on CGDOP (collaborative geometric dilution of precision) value is proposed for the evaluation of the actual spatial distribution conditions of collaborative targets. Finally, a simulated experiment is conducted to evaluate the collaborative navigation process and the collaboration effect of the collaborative navigation network in different spatial shapes. Overall, the results of this study optimised the observation and application efficiency of navigation data, and improved the stability and reliability of real-time navigation service through multi-target collaborative navigation.

For torpedo electronic components tested by functional verification, there are characteristics of a few samples and few failures. During service life, it is difficult to analyse and predict the changes in reliability. At present, management's observation of quality is mainly base on failure data, and it is difficult to make predictions about the moments without failure in service life. In this paper, according to the failure data, we consider such factors as performance degradation and detection and use the model of instantaneous failure rate to evaluate the reliability of the detection moments periodically, and predict the reliability of stages through the results of detection moments. The method proposed in this paper, on the one hand, considers the service experience, and on the other combines the detection data, to make the final evaluation result more credible. In addition, this paper predicts the changing trend of reliability between adjacent detection moments, which can provide a useful reference for quality management work.

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.

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.

Systematic error is one of the major factors that affect positioning accuracy owing to the changeable and complex nature of seawater environments. Based on a Global Navigation Satellite System-acoustic intelligent buoys system, whose acoustic array consists of a series of surface buoys, a single-difference method for underwater dynamic positioning is proposed to eliminate systematic error. Positioning configuration optimisation was addressed using dilution of precision (DOP). A simulation of DOP proved that for the single-difference method, a radiation network with a centre-difference reference point was superior to a regular polygon network. The positioning experiment showed that the novel method could effectively eliminate systematic error, improving vertical positioning accuracy from a metre- to a decimetre scale.

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.

This paper, which was originally presented at the Fourth International Symposium on Vessel Traffic Services held in Bremen from 28 to 30 April 1981, here summarizes the results of an investigation into collisions world-wide, with particular emphasis on the circumstances of collisions associated with different types of encounter for conditions of both clear and restricted visibility.

Information relating to the circumstances of collisions is available from various sources but analysis of casualty information has usually been restricted to ships under one flag and been mainly applicable to accidents in restricted waters.

It is expected that the number of military and civil aircraft operating supersonically all over the world may remain the same during the next decade. The problem of sonic boom, which has been by-passed for military aircraft through the assignment of specially allocated ranges for supersonic operation, is still with us and is likely to influence the operation of supersonic transport (SST) aircraft, the Concorde and the Tupolev 144. Concorde is still short of reaching the break-even point, despite the large traffic gain registered on the routes to North and South America. The problem is to get overland routes; the difficulties encountered by the UK in the discussions with India and Malaysia for the establishment of a London–Bahrain–Singapore route are well known.

Before presenting the effects of the sonic boom on the ecology it may be well to summarize the nature and the main features of this phenomenon.

(i) The N-wave signature. A complex body like an aircraft, moving in supersonic flight, generates a pattern of local shock waves which tend to coalesce in two main shock cones, the front (or bow) and tail, as the distance from the aircraft increases. A shock wave is a discontinuity surface for the thermodynamic characteristics of the fluid, the most important being the static pressure jump responsible for the N-shaped pressure signature characteristic of the sonic boom. Other parameters are of minor importance to the environment. A shock signature is denned by the following parameters:

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.

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.

In his Presidential Address at the 52nd Annual General Meeting of the Institute, held in London on 21 October 1998, Air Commodore Pinky Grocott gave an analysis of the causal factors that resulted in the loss of 913 large sailing ships during the period of the Revolutionary and Napoleonic eras (1793–1815). Navigation and weather factors predominated, often aggravated by poor and untimely decision-making. Many of the lessons learnt are equally relevant today.

The basic idea of a dead reckoning personal navigator is to integrate incremental motion information in the forms of step length and step direction over time. Considering that the displacement components are estimated for each step-cycle, it is essential to monitor the integrity of these parameters; otherwise, the error accumulation may render the system unstable. In this paper, a two-stage Kalman Filter (KF) augmented by a neural network is developed to facilitate integrity monitoring. The preliminary results, obtained from several tests performed on simulated and real-word data, indicate an 80% success rate in integrity monitoring.

The lives of sea turtles consist of a continuous series of migrations. As hatchlings, the turtles swim from their natal beaches into the open sea, often taking refuge in circular current systems (gyres) that serve as moving, open-ocean nursery grounds. The juveniles of many populations subsequently take up residence in coastal feeding areas that are located hundreds or thousands of kilometres from the beaches on which the turtles hatched; some juveniles also migrate between summer and winter habitats. As adults, turtles periodically leave their feeding grounds and migrate to breeding and nesting regions, after which many return to their own specific feeding sites. The itinerant lifestyle characteristic of most sea turtle species is thus inextricably linked to an ability to orient and navigate accurately across large expanses of seemingly featureless ocean.

In some sea turtle populations, migratory performance reaches extremes. The total distances certain green turtles (Chelonia mydas) and loggerheads (Caretta caretta) traverse over the span of their lifetimes exceed tens of thousands of kilometres, several times the diameter of the turtle's home ocean basin. Adult migrations between feeding and nesting habitats can require continuous swimming for periods of several weeks. In addition, the paths of migrating turtles often lead almost straight across the open ocean and directly to the destination, leaving little doubt that turtles can navigate to distant target sites with remarkable efficiency.