Based on a survey of its members in Europe and the Middle East, IATA expects that by 1985 almost half their aircraft will be equipped with Flight Management Systems (FMSs) incorporating 2-D, 3-D or 4-D navigational capabilities. The prime aim of this very significant investment is to increase airline operating efficiency, in particular through fuel saving. Flight Management Systems can perform a wide range of tasks, including flight planning and performance management, for which inputs of meteorological data are required. The more sophisticated systems can accept a number of wind and temperature inputs for the climb and descent profiles plus a wind input at each way-point of the cruise phase. Any estimate of flight progress and fuel requirements based on the use of the most economical aircraft speeds, whether made by the pilot or by an FMS, can only be as good as the knowledge of the wind-vector data pertinent to the flight. Whereas FMS-equipped aircraft in level cruise can often ‘update’ or correct the forecast data relating to the next flight leg, this is not feasible when major changes of altitude are necessary, e.g. during the descent phase. Accurate meteorological data are essential to ensure the optimum results from the FMS.

During the early 1970s, before the fuel crisis began, some thought was being given to the problem of handling the rapidly increasing number of aircraft movements in Europe.

This paper was presented in an elaborated version at a seminar on Safety in European Waters and Progress in the COST-301 Project sponsored jointly by the Institute and the Nautical Institute n i London on 12 December 1984. It reports on the preliminary findings of an independent ‘pilot’ study carried out for the Commission of the European Communities on the legal implications of implementing Vessel Traffic Services (VTS) systems in Western European waters. In particular, it seeks to contribute to wider understanding of the legal position of the VTS authority with respect to the giving of information, advice or instructions to ships, and to assess the possible consequences for legal liability.

Recent growth in air-traffic movements is causing severe traffic congestion problems in terminal areas and en route. To meet these demands for more effective and safe utilization of airspace, separation standards in an air-traffic-control environment are being studied by the Review of the General Concept of Separation Panel (RGCSP) of the International Civil Aviation Organization.

One of the most effective ways of evaluating separation standards would be a mathematical method using a collision-risk model, for which we require data on the navigation accuracy of current aircraft as one of the parameters. At present, the data on navigation accuracy in the vertical dimension (height-keeping error) do not permit us to derive any definite conclusions on the distribution of navigational errors. In order to survey height-keeping errors we have developed a simple height-finding radar system, the Navigation Accuracy Measurement System (NAMS), based on a curve-fitting method. Thanks to this principle, NAMS has an advantage in its comparatively lower cost and simple structure.

The system consists of an antenna whose radiation pattern is a fan beam, a transceiver, a digitizer and a mini-computer. The antenna rotates about a horizontal axis and scans aircraft flying overhead. The height of an aircraft is estimated by processing the data obtained over several scans, using a mini-computer. This paper first outlines the characteristics of NAMS and then gives results of evaluation tests on its accuracy.

This paper was presented at the SASMEX 92 Conference in London, April 7–9 1992. Permission to reproduce it is gratefully acknowledged.

In recent years the problem of preventing collision in the air has become urgent because of increased speeds and traffic densities. Some operators now install what have come to be known, perhaps optimistically, as ‘anti-collision’ lights, and at the meeting of the third Air Navigation Conference of I.C.A.O., it was suggested that one or other of these systems, or some new system, should be adopted internationally. Agreement was not reached at that meeting, and the question was discussed again by the Airworthiness Committee as an ‘exchange of views’ item in July 1958. The present memorandum was prepared mainly for the use of the representative of the United Kingdom at that discussion.

The Global Positioning System (GPS) offers an absolute positioning accuracy of 15 to 100 metres. Inertial navigation complements GPS in that it provides relative positioning and is totally self-contained. These two positioning sensors are ideally suited for system integration for although there is not necessarily an improvement in accuracy, the integration of GPS with inertial navigation systems (INS) does enable an increase in system performance.

A Long-range Secondary Surveillance Radar (LSSR) has been developed and recently used as an Oceanic Route Surveillance Radar (ORSR) in Japan. The LSSR is an SSR (Secondary Surveillance Radar) only system for which the maximum coverage is 250 nautical miles (n.m.). This system utilizes monopulse azimuth estimation techniques for improving the accuracy of azimuth estimation.

Heading angle is a vital parameter in maintaining a vessel's track along a planned course and should be guaranteed in a stable and reliable way. An innovative method of heading determination based on a fisheye camera, which is almost totally unaffected by electromagnetism and geomagnetism, is proposed in this paper. In addition, unlike traditional astronomical methods, it also has a certain degree of adaptability to cloudy weather. Utilising the super wide Field Of View (FOV) of the camera, it is able to simultaneously image the Moon and the horizon. The Moon is treated as the observed celestial body and the horizon works as the horizontal datum. Two experiments were conducted at sea, successfully proving the feasibility of this method. The proposed heading determination system has the merits of automation, resistance to interference and could be miniaturised, making application viable.

In this paper, a simplified and direct computation method formulated by the fixed coordinate system and relative meridian concept in conjunction with vector algebra is developed to deal with the classical problems of celestial navigation. It is found that the proposed approach, the Simultaneous Equal-altitude Equation Method (SEEM), can directly calculate the Astronomical Vessel Position (AVP) without an additional graphical procedure. The SEEM is not only simpler than the matrix method but is also more straightforward than the Spherical Triangle Method (STM). Due to tedious computation procedures existing in the commonly used methods for determining the AVP, a set of optimal computation procedures for the STM is also suggested. In addition, aimed at drawbacks of the intercept method, an improved approach with a new computation procedure is also presented to plot the celestial line of position without the intercept. The improved approach with iteration scheme is used to solve the AVP and validate the SEEM successfully. Methods of solving AVP problems are also discussed in detail. Finally, a benchmark example is included to demonstrate these proposed methods.

NextGen and SESAR have now been under development for several years, but have increasingly complex engineering and operational specifications. A variant Air Traffic Management (ATM) concept is sketched for generating fuel-efficient, very accurate and air-ground synchronized 4D-trajectories by using flight segment groundspeed profiles and linking Global Navigation Satellite Systems (GNSS) data to the aircraft Flight Management Systems (FMS) with feedback control. Is this a flawed concept or a feasible and operationally practical proposition?

An algorithm for Global Navigation Satellite System satellite atomic clock integrity monitoring based on an extended measurement model is proposed. A detection statistic achieved by parity transformation is used to detect clock anomalies, and the concept of the optimal accumulation number, with a method to find it, is provided. Numerical simulations are adopted to verify the validity of detecting two typical anomalies.

With the evolving Global Navigation Satellite System (GNSS) landscape, the International GNSS Service (IGS) has started the Multi-GNSS Experiment (MGEX) to produce precise products for new generation systems. Various analysis centres are working on the estimation of precise orbits, clocks and bias for Galileo, Beidou and Quasi-Zenith Satellite System (QZSS) satellites. However, at the moment these products can only be used for post-processing applications. Indeed, the IGS Real-Time service only broadcasts Global Positioning System (GPS) and Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) corrections. In this research, a simulator of multi-GNSS observations and real-time precise products has been developed to analyse the performance of GPS-only, Galileo-only and GPS plus Galileo Precise Point Positioning (PPP). The error models in the simulated orbits and clocks were based on the difference between the GPS Real-Time and the Final products. Multiple scenarios were analysed, considering different signals combined in the Ionosphere Free linear combination. Results in a simulated open area environment show better performance of the Galileo-only case over the GPS-only case. Indeed, up 33% and 29% of improvement, respectively, in the accuracy level and convergence time can be observed when using the full Galileo constellation compared to GPS. The dual constellation case provides good improvements, in particular in the convergence time (47% faster than GPS). This paper will also consider the impact of different linear combinations of the Galileo signals, and the potential of the E5 Alternative Binary Offset Carrier (AltBOC) signal. Even though it is significantly more precise than E5a, the PPP performance obtained with the Galileo E1-E5a combination is either better or similar to the one with Galileo E1-E5. The reason for this inconsistency was found in the use of the ionosphere free combination with E1. Finally, alternative methods of ionosphere error mitigation are considered in order to ensure the best possible positioning performance from the Galileo E5 signal in multi-frequency PPP.

Marine accidents have many causes but a recurring theme is poor watch-keeping often caused by weak bridge management. Information overload is sometimes blamed for accidents and attempts to reduce information overload may include electronic systems which have been produced for integrating information from various electronic sources so that information is concentrated on fewer screens. This article explores some of the issues facing the designers of such systems. While acknowledgement is given to some of the technical problems, the article concentrates on those issues associated with the user of such systems, in particular, domain knowledge, screen design and user control. Available Marine Accident Investigation Reports for 2004 are used to highlight that, in that year, only one passenger vessel incident was attributed in part to poor data from electronic aids. However, it is accepted that a much wider study of such reports is needed before any firm conclusions can be drawn.

1. Introduction. An air traffic control system maintains adequate separation between aircraft by requiring some aircraft to deviate from the paths which they would otherwise follow. In the absence of such deviations it must be assumed that civil transport aircraft would choose to operate at the most economical combination of airspeed, track and altitude (within the limits set by inaccuracies of weather prediction); A.T.C. deviations therefore involve economic penalty to the operator. It is important to assess the magnitude of such penalties for two reasons:

(a) To provide a yardstick by which to compare different A.T.C. systems.

(b) To give a measure of how much might justifiably be spent on new systems and equipment, to enable separation standards (and hence the penalty of deviations) to be reduced without reduction in safety.

This study summarises the scenario of maritime traffic anomalies, like the increased congestion and U-turn of ships caused by the ship grounding in the Suez Canal in March 2021. Here, satellite automatic identification system based ship trajectories, and Sentinel-1 and Sentinel-2 images based ship positions are analysed after subdividing the study area into seas, lakes and canals. The results show that the blockage affected the maritime traffic for more than three weeks, waiting ship numbers increased from 5 to 122, and daily one to three ships made a U-turn between 23 and 31 March in the Gulf of Suez. Ship density also increased to more than double in Bitter Lakes with a minimum waiting time of 7 days. Hence, to avoid such prolonged waiting of ships, we propose a warning method based on the sharp speed decrease rate, U-turn and congestion.

In this paper we assume that we have measurements of a first difference of a typical satellite navigation carrier phase differential, which is a homogeneous quadratic function of the components of the attitude quaternion. We illustrate the determination of large or sustained attitudes using a dedicated unscented Kalman filter. The unscented Kalman filter structure was chosen for the dedicated filter because of its derivative free nature and other advantages. When a Gaussian distributed vector random variable is transformed to an equivalent quaternion it does not continue to be Gaussian distributed. For this reason, a new predictor-corrector form of the unscented Kalman filter is proposed to maintain the normalization of the unscented mean quaternion estimate in the presence of additive disturbances. The results from our realistic simulations indicate that the large attitude of a spacecraft can be estimated to within 0·1% accuracy over large time frames. The filter is particularly useful for autonomous operations of spacecraft as well as in other applications where the process model is bilinear or second order in the states.

Distance measuring equipment (DME/DME) as the main reversionary method provides alternative positioning, navigation and timing (A-PNT) services for use during a Global Navigation Satellite System (GNSS) outage. Considering the geometry limitation of DME/DME, multi-DMEs with better geometry can be used to increase the accuracy and integrity performance of positioning. This paper discusses the opportunities and challenges related to use of multi-DMEs as an alternate source of positioning, navigation and timing. To support the performance for A-PNT, the basic idea is considering the existing installed equipment. In this paper, barometer altimeter and TACAN are used to help improve the performance of A-PNT provided by multi-DMEs both in accuracy and integrity. Based on the database of EUROCONTROL, the test results demonstrate that 79⋅7% of a reference area roughly matching with the continental European locations achieve RNP 1 using multi-DMEs when the DME measurement accuracy is 0⋅2 NM (95%). When the DME measurement accuracy is 0⋅1 NM (95%), 87⋅9% of the reference area can achieve RNP 1 using multi-DMEs. The usage of barometer/TACAN measurements aided multi-DMEs improves the performance of the accuracy and integrity monitoring.

This paper, and the paper which follows it, were first presented at the IBC '98 Conference ‘Space-Based Navigation Industry’, which was held in London, 11–12 June 1998.

In conventional arable agriculture, position within the field was usually irrelevant! However, the advent of precision agriculture, wherein inputs are targeted according to locally-determined requirements within the field, has opened up a potentially large market for GPS. Indeed, it was the availability of GPS which permitted the development and implementation of precision agriculture – a concept which holds the promise of significant economic and environmental benefits to the farmer. This paper indicates the technical requirements for GPS and presents three case studies where a positioning system is required.

In this paper we introduce a ground monitoring architecture to validate the Integrity Support Message (ISM) parameters to be used by aircraft for Advanced Receiver Autonomous Integrity Monitoring (ARAIM). This work focuses on two critical ISM parameters: Psat, which designates the prior probabilities of satellite faults, and bmax, which is a range domain bound on small faults that may occur at probabilities higher than Psat. We show that the choices of bmax and Psat are not independent. The paper first establishes the relationship between bmax, Psat, Time to Integrity Alert (TIA) and constellation service provider performance commitments. We then provide an example ground monitor design that detects inter-frequency bias faults and code-carrier divergence faults. We show that the performance of the monitor can be used to validate specific bmax and Psat values for ARAIM.

When in 1877 Clements R. Markham edited The Voyages of Sir James Lancaster Kt to the East Indies he remarked that the first log-book with printed headings was that used by Captain Reddell on his voyage in the Samuel & Anna in 1702–3. He does not say that this became standard practice in the ships of the East India Company but it would seem that some of his readers thought that this must have been the case. In The Art of Navigation in England in Elizabethan and Early Stuart Times David W. Waters refers to the Samuel & Anna log and follows it with the comment: ‘The logs of British warships were still ruled and captioned in manuscript in the eighteenth century.’