The 2007 Annual General Meeting of the Royal Institute of Navigation was particularly significant; not only did it celebrate the 60th anniversary of the founding, but also celebrated the granting of the Royal Charter of Incorporation to the Institute by Her Majesty Queen Elizabeth II. Our President, Professor David Last, marked the occasion with his Presidential Address which is recorded here.

Squadron Leader Douglas Fraser, a Fellow and Life Member of the Institute holding RIN membership number 6, was one of the founder members joining when the Institute was formed on 25th June 1947. Sixty years later, on Friday 29th June 2007, at our first Annual General Meeting since being granted our Royal Charter, he was invited by our President to make a short presentation on the birth of our Institute. Squadron Leader Fraser was unable to travel from his home to attend the AGM in person, but with great foresight had planned for such an eventuality and prepared a short video of his speech. This paper is a verbatim account of his message.

This work investigates the utilisation of Particle Swarm Optimisation (PSO) for the non-deterministic navigation of Unmanned Aerial Vehicles (UAVs), allowing them to work cooperatively toward the goal of protecting a wide area against airborne attack. To negate the PSO's inherent weakness in dynamic environments, a neighbourhood scheme is proposed that not only enables the efficient interception of targets several times faster than the UAVs but also facilitates the maintenance of effective airspace coverage. Empirical results suggest that these techniques may indeed be of use in autonomous navigation systems for UAVs in air defence roles.

This article presents efficient and practical methods for path planning of optimal interceptions on two-dimensional grids with obstacles, such as raster charts or non-distorted digital maps. The proposed methods search for optimal paths from sources to multiple moving-targets by a novel higher geometry wave propagation scheme in the grids, instead of the traditional vector scheme in the graphs. By introducing a time-matching scheme, the optimal interception paths from sources to all the moving-targets are obtained among the combinations with linear time and space complexities. Two optimal path planning methods for multiple one-to-one interceptions, the MIN-MAX and MIN-AVG, are applied to emulate the real routing.

In densely-populated cities or indoor environments, limited visibility to satellites and severe multipath effects significantly affect the accuracy and reliability of satellite-based positioning systems. To meet the needs of “seamless navigation” in these challenging environments an advanced terrestrial positioning system is under development. This system is based upon Ultra-Wideband (UWB) technology, which is a promising candidate for this application due to good time domain resolution and immunity to multipath. This paper presents a detailed analysis of two key aspects of the UWB signal design that will allow it to be used as the basis of such a high performance positioning system: the modulation scheme and the multiple access technique. These two aspects are evaluated in terms of spectral efficiency and synchronisation performance over multipath channels. Thus this paper identifies optimal modulation and multiple access techniques for a long range, high performance terrestrial positioning system using UWB.

This paper discusses human error from two perspectives: errors made by operators on the one hand and errors made by designers and manufacturers of technological aids on the other. The question of operators' reliance on technological aids is discussed, as well as the concept of “overreliance” in connection with technologically aided presentation of navigational information. The accident investigation report following the grounding of the M/V Royal Majesty in 1995 is taken as an example. In that and many reports, designers and technology were not investigated as carefully as the operators on site. In that report, total responsibility for the accident was attributed to the mariners, while unreliable, incorrectly designed or incorrectly mounted technological aids, as well as the constructors, manufacturers and technical expertise behind it, were not investigated. This biased praxis when investigating human error is questioned and another investigative approach is suggested, in which operators and technology are treated equally and where the people behind the technologies can also be scrutinised. Such an approach would have a great beneficial impact on safety at sea.

This paper is intended as an historical document describing the entry and success of the Decca Radar Company into the production of Doppler-based navigation units. It is based on an original personal paper written in about 1970 by Trevor Gray, then Head of Doppler Department, Decca Radar, updated and edited with additions by Walter Blanchard (past President of the RIN) assisted by Trevor Gray in May 2007. The paper first covers the basic theory and principles of Doppler radar systems, continues through the setting up of the Decca Doppler Department in the mid-1950s and the production of the first transistor-based Doppler system. Success led to the development of both civil and military Doppler systems culminating in the Decca Doppler 70 Series which was fitted to some 30 types of aircraft and helicopters, worldwide.

The integration of GPS and INS observations has been extensively investigated in recent years. Current systems are commonly based on the integration of INS data and the double differenced GPS measurements from two GPS receivers in which one is used as a reference receiver set up at a precisely surveyed control point and another is as the rover receiver whose position is to be determined. The requirement of a base receiver is to eliminate the significant GPS measurement errors related to GPS satellites, signal transmission and GPS receivers by double differencing measurements from the two receivers. With the advent of precise satellite orbit and clock products, the un-differenced GPS measurements from a single GPS receiver can be applied to output accurate position solutions at centimetre level using a positioning technology known as precise point positioning (PPP). This then opens an opportunity for the integration of un-differenced GPS measurements with INS for precise position and attitude determination. In this paper, a tightly coupled un-differenced GPS/INS system will be developed and described. The mathematical models for both INS and un-differenced GPS measurements will be introduced. The methods for mitigating GPS measurement errors will also be presented. A field test has been conducted and the results indicate that the integration of un-differenced GPS and INS observations can provide position and velocity solutions comparable with current double difference GPS/INS integration systems.

After Selective Availability (SA) was turned off, the rate of change with time of the DGPS common errors (atmospheric delay, satellite orbit and clock error) became quite slow. This inevitably leads to a requirement to modify various configurations of DGPS correction message broadcasting, and reference station (RS) managers need to examine the characteristics of GPS measurement errors with SA-off. GPS error sources are temporally and spatially decorrelated, so the DGPS user position accuracy is varied by the baud-rate of the RS, the distance between the user and the station, and the noise statistics of the receiver. We identify the minimum and maximum size of correction data, interval time, the coverage range and the baud-rate that are required to maintain the existing DGPS service. Moreover, the compatibility and accuracy can be assessed to meet the users' requirements without measurements being needed. The results in this paper are used in the study and testing for the redesign of United States Coast Guard (USCG) RS. We hope that our study will be a great help in determining the flexible factors of both the RS and the user.

Severe space weather conditions affect the performance of numerous modern technical systems, causing problems not only for national and global economies, but for everyday life as well. Satellite navigation systems are particularly vulnerable, despite the fact that systematic monitoring of space weather in general is still performed on a global scale. Space weather effect correction models applied within the standard satellite positioning service are not capable of tackling the effects of severe space weather conditions and local ionospheric characteristics. Severe space weather effects on the GPS ionospheric delay are intensely studied in order to provide advanced models of the space weather effects on GPS positioning performance.

Here one study of severe space weather conditions and its consequences on the GPS ionospheric delay in Croatia is presented. The study takes advantage of the availability of the space weather indices and the GPS pseudorange measurements (taken at the reference site at Osijek, Croatia) related to a major severe space weather event lasting from early October 2003 to late November 2003. This paper presents the reconstruction of the severe space weather conditions and the development of ionospheric disturbances. Based on these reconstructions, the dynamics of the GPS ionospheric delay has been derived. The comparison of actual (measured) and modelled (according to standard GPS model) GPS ionospheric delay has been performed, with the aims of identifying actual behaviour of GPS ionospheric delay and examining the ability of standard (Klobuchar) GPS model to describe the GPS ionospheric delay in severe space weather conditions. Two interesting experimental models derived from the data analysis are presented, addressing the direct relations between the GPS ionospheric delay and the parameters of space weather activity (sunspot number and solar flux), as observed at the reference station Osijek, Croatia.

The paper concludes with the plans for further research activities related to the regional GPS ionospheric delay model development for south-eastern Europe.

This study provides both a spherical understanding about autonomous ship navigation for collision avoidance (CA) and a theoretical background of the reviewed work. Additionally, the human cognitive abilities and the collision avoidance regulations (COLREGs) for ship navigation are examined together with water based collision avoidance algorithms. The requirements for autonomous ship navigation are addressed in conjunction with the factors influencing ship collision avoidance. Humans are able to appreciate these factors and also perform ship navigation at a satisfactory level, but their critical decisions are highly subjective and can lead to error and potentially, to ship collision. The research for autonomous ship navigation may be grouped into the classical and soft computing based categories. Classical techniques are based on mathematical models and algorithms while soft-computing techniques are based on Artificial Intelligence (AI). The areas of AI for autonomous ship collision avoidance are examined in this paper are evolutionary algorithms, fuzzy logic, expert systems, and neural networks (NN), as well as a combination of them (hybrid system).

On February, 15th 2005, Gondán S.A. shipyard in the north-west of Spain handed over the escort tractor Voith tug “VELOX” to the Norwegian shipowner Østensjø Rederi AS, the first of this type in the world to incorporate a bulbous bow. After generally making a reference to the benefits obtained by the incorporation of a bulbous bow regarding the reduction of the ship's resistance, we specifically analyse the consequences derived from the incorporation of this appendage in an escort tractor Voith tug concerning its real operating conditions when carrying out escort tasks, especially when using the indirect towing method.

According to the mid-term review of the EU White Paper on Transport, short sea shipping is expected to grow at a rate of 59% in metric tonnes, from 2000 to 2020. If we consider that the overall expected growth in freight exchanges is of some 50%, sea transport is one of the most feasible ways to reduce traffic congestion on European roads. High speed vessels are a possible way to compete with road transport on certain routes; however, these ships are highly affected by heavy weather. This paper analyses the weather influence on several short sea shipping routes to be served by fast ships.