The increase in the number of commercial flights highlights the need for air traffic to follow air procedures. Unfortunately, general aviation aircraft used for recreational purposes keep entering controlled and restricted airspace without obtaining permission from air traffic services. Given the safety and operational problems this could potentially cause, this paper examines the underlying reasons for these incidents occurring. In particular, it analyses airspace infringements between 2008 and 2017 involving general aviation flights that were recorded in airspace in which a large number of commercial flights also fly in Europe and America. The reports were analysed based on an initial assessment of their quality. Information was latent in the narrative and subsequently both qualitative (content analysis) and quantitative methods (descriptive statistics) of analysis were used. The analysis revealed that airspace infringements were related to the pilot's flight planning, that is, flight-route choice, navigation skills and communication, in addition to requirement to adhere to airspace procedure. The findings could be used by national authorities and flying clubs to promote safe flying in these regions.

Airborne-Pseudolite (A-PL) systems have been proposed to augment Global Navigation Satellite Systems (GNSSs) in difficult areas where GNSS-only navigation cannot be guaranteed due to signal blockages, signal jamming, etc. One of the challenges in realising such a system is to determine the coordinates of the A-PLs to a high accuracy. The GNSS Precise Point Positioning (PPP) technique is a possible alternative to differential GNSS techniques such as those that generate Real-Time Kinematic (RTK) solutions. To enhance the A-PL positioning performance in GNSS challenged areas, it is assumed that inter-PL range measurements are also used in addition to GNSS measurements. When processing these new measurements, cross-correlations among A-PL estimated states introduced during measurement updates need to be accounted for so as to obtain consistent estimated states. In this paper, a distributed algorithm based on a Split Covariance Intersection Filter (SCIF) is proposed. Three commonly used means of implementing the SCIF algorithm are analysed. Another challenge is that real-time GNSS PPP relies on the use of precise satellite orbit and clock information. One problem is that these real-time orbit and satellite clock error corrections may not be always available, especially for moving A-PLs in challenging environments when signal outages occur. To maintain A-PL positioning accuracy using GNSS PPP, it is necessary to predict these error corrections during outages. Different prediction models for orbit and clock error corrections are discussed. A test was conducted to evaluate the A-PL positioning based on GNSS PPP and inter-PL ranges, as well as the performance of error prediction modelling. It was found that GNSS PPP combined with inter-PL ranges could achieve better converged positioning accuracy and a reduction in convergence time of GNSS PPP. However, the performance of GNSS PPP with inter-PL ranges was degraded by observing A-PLs with limited positioning accuracy. Although the performance improvement achieved by the SCIF-based distributed algorithms was smaller than that by the centralised algorithm, greater robustness in dealing with deteriorated observed A-PLs' trajectory data was demonstrated by the distributed algorithms. In addition, short-term prediction models were analysed, and their performance was shown to reduce the effect of error correction outages on A-PL positioning accuracy.

Four manuscript charts of British ports, and notes on them, were made in the 1590s by an English Catholic pilot, N. Lambert. They were sent to Don Juan de Idiáquez, Philip II's secretary, through the mediation of an English Jesuit exile, Robert Persons (or Parsons). Lambert also offered to pilot Spanish ships and guide Spanish troops in raids on the coasts of England and Wales, and prepared a list of appropriate targets. Being some of the earliest charts of the ports concerned, and hitherto unpublished, they are here presented with relevant background material.

This paper was presented at a meeting of the Institute in London on 21 January 1981 with W. H. McKinlay in the Chair. The views expressed do not necessarily represent CAA policy, but Mr Attwooll discusses the derivation of fuel-uplift requirements from considerations of safety and regularity of the flight, using additional information on the probability of various adverse contingencies such as headwind or ATC delay. Methods of safely reducing fuel reserve requirements are discussed, including improvements in navigation and the on-board decision-making process.

The lane-level map, which contains the lane-level information severely lacking in widely used commercial navigation maps, has become an essential data source for autonomous driving systems. The linking relations between lane-level map and commercial navigation map can facilitate an autonomous driving system mapping information between different applications using different maps. In this paper, an approach is proposed to build the linking relations automatically. The different topology networks are first reconstructed into similar structures. Then, to build the linking relations automatically, the adaptive multi-filter algorithm and forward path exploring algorithm are proposed to detect corresponding junctions and paths, respectively. The approach is validated by two real data sets of more than 150 km of roads, mainly highway. The linking relations for nearly 94% of the total road length have been built successfully.

Many discussions have taken place regarding the feasibility of plotting when using radar in reduced visibility and it soon becomes apparent that there is confusion in what each of us considers by the term ‘plotting’.

These notes are to suggest definitions of the various stages of plotting and to consider the conditions under which each is necessary.

Radar plotting can be divided into three stages:

(a) Record plotting

(b) Deductive plotting

(c) Forecast plotting.

Mr. Bell and Professor Stratton have in the October Journal shed interesting light on the nature of inertial navigation as applied to navigation around a planet. It is a pity that Mr. Bell has repeated that in such inertial systems vehicle position and velocity are deduced from measurement of acceleration. This idea is certainly misleading so far as understanding error propagation in these systems is concerned, if not actually wrong.

When geophysical measurements are made from the air, it is important to know the position of the aircraft. The position at any time is usually known from a combination of position-fixing and dead-reckoning systems. In-flight optimization of this combination is a well-studied subject. When post-flight track plotting is required for geophysical survey, use can be made of both the initial and terminal position fixes to correct the dead-reckoning track and hence improve on the in-flight version. This technique is applied to compute the track of aircraft conducting ice thickness measurements in the Antarctic, and the effect of certain errors is evaluated. The algebraic results are equally applicable in parts of the world where better navigational aids are available. A relation is derived between the track plotting errors and die errors in the geophysical measurement such that the precision of one is not degraded by errors in the other.

Although the economic theory of congestion as applied to road traffic has been known since at least the time of Pigou its application to marine problems has been much slower. It is the purpose of this paper to remedy this somewhat by interpreting the theory in a marine context and to suggest some of the practical implications of taking proper account of congestion effects.

This paper is concerned with the legislative change which would have to take place if an automatic collision avoidance system were to be implemented.

The principle of complementary action, and the role of coordination in achieving that action is considered. Current collision avoidance practice is discussed, noting the coordination attributes of the International Regulations for the Prevention of Collision at Sea, and the responsibility placed on the mariner by the regulations. The processing element of an automatic collision avoidance system is considered in the light of current judicial practice.

The paper concludes that the implementation of an automatic collision avoidance system is incompatible with the current collision regulations and the supporting judiciary. It is suggested that successful implementation will require the recognition of a discrete rule base.

The Federal Aviation Administration (FAA) is developing the Local Area Augmentation System (LAAS) as a public use local area differential GPS system. The LAAS is required to support all categories of precision approach navigation. The purpose of this paper is to summarize the FAA's LAAS technical activities and programme plans. First, the complementary roles of the Wide Area Augmentation System (WAAS) and LAAS are summarized. Then technical activities are discussed, including requirements, system architecture, and flight tests. The paper concludes with a summary of the FAA's plans for LAAS, including the planned schedule of major programme activities.

The views expressed in this paper are personal to the author, and not intended to represent official policy of the UK Hydrographic Office.

With the ever increasing use of electronic charts in the small craft sector, this paper is designed to give some background to developments at the United Kingdom Hydrographic Office. Included is a short review of the state of the market, with the author's view of possible future progression. The various formats of data are discussed, with a summary of the legislative background within the commercial market. This discussion is relevant, as it will ultimately shape the future market for small craft users

This paper is based on a presentation at a seminar on the History of Navigation in the Royal Air Force, held at The Royal Air Force Museum, Hendon, on 21 October 1996. The seminar was organized by the Royal Air Force Historical Society in Association with the Guild of Air Pilots and Air Navigators and the Royal Institute of Navigation. The complete proceedings of the seminar are being published in 1997.

The earliest record of a requirement for ships to carry lights that the author has been able to find is in the Rhodian Laws. These appear to date from about the 3rd or 2nd century B.C., and were certainly incorporated into Roman Law by A.D. 161, although Ashburner suggests that the earliest known copy dates from Byzantine times, A.D. 600–800. The Laws contain a section intended to prevent collisions between vessels under way and vessels at anchor or stopped.