A description is given of the basic principles and method of operation of a single-channel automatic blind landing system developed by the Blind Landing Experimental Unit. The system uses the internationally accepted radio aid ILS for approach guidance to the point where more accurate information is required and then two new guidance elements, magnetic leader cable and radio altimeter, are introduced for the final landing. One of the great advantages of the system is its flexibility and if new guidance elements are developed the system will be easily adapted.

Extensive flight tests have been made in all weathers and the performance achieved is much better than that obtained in manual landings in good visibility.

In considering the application of the system to civil aviation the outstanding problem Is that of safety and reliability. Various suggestions are discussed briefly and the possible requirement for an independent pictorial monitor is mentioned. Early thoughts on a monitoring system are described.

The Navigation with Indian Constellation (NavIC)/Indian Regional Navigation Satellite System (IRNSS) is an emerging satellite navigation system that provides an independent navigation system for positioning and timing services in India and up to 1,500 km from its borderline. The dual frequency NavIC system uses the L5 frequency and S-band for navigation. These navigation signals are extremely weak and susceptible to interference when they are received on Earth's surface. Moreover, the performance of these bands may be degraded by other band or out-of-band communication systems, which can become the major threat to the performance of a NavIC receiver. The main focus of this paper is to detect real-time interference of Wi-Fi signals in the S-band of the NavIC receiver. The results are prepared with respect to the Power Spectral Density (PSD), execution of acquisition stage and the detection of Wi-Fi interference with two sample hypothesis testing methods including the Kolmogorov-Smirnov (KS)-test, the t-test and the Variance (var)-test. A performance analysis of the p-value is used to measure the evidence of interference existence for hypothesis testing, decision hypothesis and probability of detection are evaluated for each hypothesis method. The results show the severity of the Wi-Fi signal as a potential source of interference for future NavIC applications.

Satellite based navigation system integrity monitoring is essential both for liability and safety critical services. The threats to system integrity are the potential failure modes that could occur at system, operational and user sensor levels. Research on identification, characterisation and modelling of such failure modes, suggests that failures that grow slowly over time (e.g. ramp error less than 2 m/s), also referred to as slowly growing errors (SGE) are the most difficult to detect early. Conventional snapshot algorithms detect SGEs when the test statistic crosses the threshold usually after relatively long periods of time. A recent concept based on the average of residuals over time has been found to have a significant weakness. This paper proposes a “difference test” algorithm capable of detecting SGEs early. In this method, the test statistic is the difference between the norm of current residuals and the norm of the residuals at a previous epoch. The distribution of the test statistic is over-bounded by a normal distribution whose parameters are derived from two Chi-distributions. Results show that the new algorithm results in a significant reduction in detection time compared to conventional methods.

Global Navigation Satellite Systems (GNSSs) are easily influenced by the external environment. Signals may be lost or become abnormal thereby causing outliers. The filter gain of the standard Kalman filter of a loosely coupled GNSS/inertial navigation system cannot change with the outliers of the GNSS, causing large deviations in the filtering results. In this paper, a method based on a χ2-test and a dynamically adjusting filter gain method are proposed to detect and separately to suppress GNSS observation outliers in integrated navigation. An indicator of an innovation vector is constructed, and a χ2-test is performed for this indicator. If it fails the test, the corresponding observation value is considered as an outlier. A scale factor is constructed according to this outlier, which is then used to lower the filter gain dynamically to decrease the influence of outliers. The simulation results demonstrate that the observation outlier processing method does not affect the normal values under normal circumstances; it can also discriminate between single and continuous outliers without errors or omissions. The impact time of outliers is greatly reduced, and the system performance is improved by more than 90%. Experimental results indicate that the proposed methods are effective in suppressing GNSS observation outliers in integrated navigation.

The volume of air traffic has increased considerably in the United Kingdom in recent decades and with further predicted increases, there is concern that safety is not compromised. In the UK, the number of occurrences is a key safety performance indicator. An occurrence can be thought of as a failure in the chain of operations in the air traffic system. Some of these occurrences result in a loss of separation between aircraft, varying from a slight loss of separation posing no danger of collision to a very serious loss with a significant risk of collision, known as an airprox. However, in the UK this definition is extended to include controller overload that does not necessarily involve a loss of separation. This paper analyses recent occurrence trends in the UK airspace attributed to air traffic control during the period 1998 to 2000 using data from the Civil Aviation Authority and the United Kingdom Airprox Board. The results indicate a decline in the rate of occurrences over the period 1990–1999 due to safety aids on board aircraft and in control rooms. Furthermore, the different conditions under which airproxes occur have been explored and observations made on duration and causes of controller overloads.

The new Global Positioning System (GPS) Civil Navigation Message (CNAV) has been transmitted by Block IIR-M and Block IIF satellites since April 2014, both on the L2C and L5 signals. Compared to the Legacy Navigation Message (LNAV), the CNAV message provides six additional parameters (two orbit parameters and four Inter-Signal Correction (ISC) parameters) for prospective civil users. Using the precise products of the International Global Navigation Satellite System Service (IGS), we evaluate the precision of satellite orbit, clock and ISCs of the CNAV. Additionally, the contribution of the six new parameters to GPS Single Point Positioning (SPP) is analysed using data from 22 selected Multi-Global Navigation Satellite System Experiment (MGEX) stations from a 30-day period. The results indicate that the CNAV/LNAV Signal-In-Space Range Error (SISRE) and orbit-only SISRE from January 2016 to March 2018 is of 0·5 m and 0·3 m respectively, which is improved in comparison with the results from an earlier period. The ISC precision of L1 Coarse/Acquisition (C/A) is better than 0·1 ns, and those of L2C and L5Q5 are about 0·4 ns. Remarkably, ISC correction has little effect on the single-frequency SPP for GPS users using civil signals (for example, L1C, L2C), whereas dual-frequency SPP with the consideration of ISCs results have an accuracy improvement of 18·6%, which is comparable with positioning accuracy based on an ionosphere-free combination of the L1P (Y) and L2P (Y) signals.

There are three aspects of collision avoidance in the air which require mathematical investigation:

• (a) discovery and evaluation of the risk;

• (b) the remedial manœuvre;

• (c) the probabilities associated with (a) and (b).

Marine traffic survey is a fundamental part of marine traffic engineering. In the assessment of the safety or effectiveness in particular water areas, the distribution of ship tracks is always included as one of the most significant results of a marine traffic survey. In this paper, methods of marine traffic survey are discussed and an appropriate method is selected to obtain the traffic data considering the available research circumstances in China. A semi-automatic artificial way of plotting a distribution diagram of ship tracks is presented with illustrations. Details of the diagram plotted by using the collected traffic data are described for reference.

In this paper, the ship manoeuvring problems particular to maritime search and rescue are investigated. A solution to such problems is necessary for successful ship handling to save human life. A fuzzy gain scheduling Proportional Derivative (PD) controller, using a back-propagation algorithm, is developed to solve these maritime search and rescue problems. The parameters of the proposed PD controller are determined on-line by fuzzy rules and adjustable fuzzy reasons. The proposed controller is self-adaptive and can accommodate the effects caused by wave or wind disturbance. Some computer simulations are provided to illustrate the use of the main ideas.

This paper presents a taxonomy of human wayfinding behaviours. For the purposes of this paper, wayfinding is purposeful navigating in everyday life, in man-made environments, traversing an environment or aiming for an objective with which the individual is unfamiliar. The taxonomy is developed through a review of wayfinding literature from research and practice, user studies conducted specifically for this research and a process of thinking by designing. This taxonomy can also be applied to navigating in documents printed on paper and on-screen, but this paper concentrates on behaviours in environmental space. This taxonomy creates twelve categories of behaviour differentiated by the characteristics of the information that they use. The categories of behaviour are also separated into three groups: social, semantic and spatial. This paper briefly describes and gives examples of each of the categories of behaviour. This is followed by insights into the behaviours from user studies conducted by the author. (This paper borrows its title from Cohen, 2015).

Ship domain is an important theory in ship collision avoidance and an effective collision detection method. First, several classical ship domain models are used in experiments. The results show that the alarm rate is too high in busy waters, leading to greatly reduced practicality of the model. Potential collision risk cannot be detected effectively, especially for a ship with restricted manoeuvrability, which is usually regarded as an overtaken ship due to its navigation characteristics. Therefore, it is necessary to fully consider the interference of other ships to ships with limited manoeuvrability in an encounter situation. A novel ship domain model for ships with restricted manoeuvrability in busy waters is proposed. Considering the navigation characteristics of a ship with restricted manoeuvrability and the influence of the ship–ship effect, an algorithm to determine the boundary of the ship domain model is given by force and moment equations. AIS trajectory data of the North Channel of the Yangtze River Estuary are used to perform a comparative experiment, and four classical ship domain models are employed to perform comparative experiments. The results show that the alarm rates of the novel ship domain model are 7⋅608%, 15⋅131%, 55⋅785% and 7⋅608% lower than those of the other four classical models, and this outcome can effectively reduce the high false alarm rate produced by other models in this environment.

Besides offset biases (such as range, the gain of range, azimuth, and elevation biases), for mobile radars, platform attitude biases (such as yaw, pitch, and roll biases) induced by the accumulated errors of the Inertial Measurement Units (IMU) of the Inertial Navigation System (INS) can also influence radar measurements. Both kinds of biases are coupled. Based on the analyses of the coupling influences and the observability of 3-D radars’ error registration model, in the article, an Attitude Bias Conversion Model (ABCM) based on Square Root Unscented Kalman Filter (SRUKF) is proposed. ABCM can estimate 3-D radars’ absolute offset biases under the influences of platform attitude biases. It converts platform attitude biases into radar measurement errors, by which the target East-North-Up (ENU) coordinates can be obtained from radar measurements directly without using the rotation transformation, which was usually used in the transition from platform frame to ENU considering attitude biases. In addition, SRUKF can avoid the inaccurate estimations caused by linearization, and it can weaken the adverse influences of the poor attitude bias estimation results in the application of ABCM. Theoretical derivations and simulation results show that 1) ABCM-SRUKF can improve elevation bias estimate accuracy to about 0·8 degree in the mean square error sense; 2) linearization is not the main reason for poor estimation of attitude biases; and 3) unobservability is the main reason.

Conventional underwater navigation and positioning methods for Autonomous Underwater Vehicles (AUVs) either require the installation of acoustic arrays, which make AUVs less independent, or result in cumulative errors. This paper proposes an Underwater Terrain Positioning Method (UTPM) using Maximum a Posteriori (MAP) estimation and a Pulse Coupled Neural Network (PCNN) model for highly accurate navigation by AUVs. The PCNN model is used as a secondary discriminant to effectively identify pseudo-anchor points in flat terrain feature areas and to find the true positioning point, which significantly improves the matching positioning accuracy in these areas. Simulation results show that the proposed method effectively corrects Inertial Navigation System (INS) cumulative errors and has high matching positioning accuracy, which satisfy the requirements of AUV underwater navigation and positioning.

In this paper, the operability of the GMDSS is studied to identify those aspects that are hindering its successful use. Particular emphasis is placed upon the operator-equipment interface within the working environment of the ship's bridge. The results of a relevant survey, based on the opinion of recently G.O. certified navigation officers, indicate that – despite the automation in GMDSS and the resulting reduction of the human factor – there is a definite need to improve the knowledge-based proficiency of the operator. The current design of the system, and the increasing workload on the ship's bridge, constitute the main drawbacks to operability and dictate the requirement for improved knowledge and hence improved certification and refresher training for operators.

A weather routing tool is presented based on forecasted weather data along the route and considering safety aspects. The tool aims to determine the optimal path for the minimisation of the fuel oil consumption, ensuring a safe passage. It is developed in MATLAB and considers detailed ship characteristics. Specifically, ship's motions and fuel oil consumption of the main engine during a potential path are estimated. For the latter, a physics-based model for a specific vessel is developed where tools of different level of detail are utilised to calculate the various resistance components. A speed management strategy along the route is specified as well as safety criteria representing acceptable limits of ship's responses. When the set criteria and constraints have been set, a genetic algorithm is used to find the optimal route by means of ship's heading or by considering both heading and ship's power settings as variables to minimise the fuel oil consumption. The search space of the algorithm lies within a predefined envelop, but still the evolutionary optimisation approach used has no pre-assigned values to any possible candidate waypoint.

In the maritime community, a runner-up will undertake this typical process to catch up with the front runner; first, as a nation's economy grows its domestic crew costs rise, creating a gap with those abroad, which in turn depresses the international competitiveness of shipping companies. Then, to maintain their economic strength, shipping companies have their ships fly a “flag of convenience” relying on increasing amounts of cheap foreign labour. As a result, the nation gradually loses domestic seafarers, which, in the worst case, leads to a depletion of national human resource needed for its maritime cluster to continue to exist. In that sense, the personnel shortage issue is a fate for top runners in the marine transport world, where international competitiveness is inevitable. The Japanese maritime sector is just facing this issue. In this paper, the current situation in the maritime sector and its dependence on foreign labour, the cause and process of the change and the problems of the outcomes are explained, and the possible solutions in terms of the social mechanism of personnel development and utilization are discussed.

This paper offers an algorithm for enhancement of positioning accuracy of a quad-rotor flying robot, based on jerk and jounce of motion. The suggested method utilises the first and second numerical derivatives of the vehicle's acceleration and augments the mathematical model in the estimation process. For this purpose, the Kalman Filter (KF) is implemented for integration of a Strapdown Inertial Navigation System (SINS) and Global Navigation Satellite System (GNSS). The required data are collected from a low-cost/quality Micro Electromechanical Sensors (MEMS) during an assisted flight. For increasing the precision and accuracy of the collected data, all instruments including accelerometers, gyroscopes and magnetometers are calibrated before the experiments. Moreover, to reduce and limit the measurement noises of the MEMS sensor, a low-pass filter is applied; this is while sensors in the autopilot are affected by high levels of noise and drift, which makes them inappropriate for accurate positioning. The experimental results exhibit an improvement in positioning and altitude sensing through augmentation of the loosely coupled SINS/GNSS navigation method.

Recent work has revealed that increasing numbers of drivers now receive driving instructions using a portable navigation system. A 2×2×2 (position×display decrease mode×voice) factorial experiment was executed to compare driving performance when using a portable navigation system (PNS). Thirty-two subjects were paid to participate in this field study, and a smart phone was adopted as the portable navigation device. The results indicated that drivers using the PNS under the conditions up position and with voice instruction performed better in terms of trip duration, mean speed, and the standard deviation of speed.

The issues in this paper are a continuation of those presented previously by the authors in The Journal. In this paper we discuss the changes in maritime navigation and their consequences. We show the changes taking place in the ship's navigation process and in development of Maritime Navigation Safety and Efficiency System (MNSES). The relations between these two processes are examined. As the result, a probable scope of the competencies required by future navigators is proposed.

Unlike in the case of airborne and offshore applications, GPS cannot be used continuously for land vehicle navigation due to the loss of satellite signals by obstructions from buildings, trees, etc. With the increasing trend in various sectors of the economy towards efficient fleet management, the challenges of providing a system capable of providing high-accuracy vehicle position and location anywhere, continuously, has led to renewed interest in the area of integrated navigation systems. In order to satisfy these conditions, an integrated system comprising GPS and gyro/odometer dead reckoning has been developed. This paper gives a description of the implemented system and shows some of the practical results that can be obtained using Kalman filtering algorithms.