This paper reviews the use of the air for the police in their operations to fight crime throughout the UK. There is a description of the job of the aircrew, the role and navigation systems and the aircraft used in daily operations. There is an examination of the use of both the helicopter and fixed wing aircraft concentrating on their suitability for police operations in which the weather and cost constraints are seen to be major factors to be considered in striking the balance to obtain the best effectiveness.

This article is based on a lecture to the Royal Institute of Navigation History of Air Navigation Group at Tangmere Museum on 12 May 2004. The author served as a navigator-radar – or a radar bomb aimer – within RAF Bomber Command during the mid-1960s. This article is based on his experience of this time in Bomber Command and describes how the Medium Bomber Force would have carried out their war operations had nuclear deterrence failed. In its day these plans were TOP SECRET.

A new ICAO Policy on Airborne Collision Avoidance Systems is needed, which recognizes it to be an integrated part of the air traffic management system's safety defences; and that should be fully included in hazard analyses for the total system's design safety targets.

In the immediate aftermath of WW2 there sprang up an international argument over the relative merits for aerial navigation of area-coverage radio navaids versus point-source systems. The United States was in favour of point-source whereas the UK proposed area-coverage, systems for which had successfully been demonstrated under very adverse conditions during the war. It rumbled on for many years, not being finally settled until the ICAO Montreal Conference of 1959 decided for point-source. Since then, VOR/DME/ADF/ILS have been the standard aviation radio navaids and there seems little likelihood of any change in the near future, GNSS notwithstanding, if one discounts the phasing-out of ADF. It now seems sufficiently in the past to perhaps allow a dispassionate evaluation of the technical arguments used at the time–the political ones can be left to another place and time.

This paper describes the United States Coast Guard's efforts regarding Long Range Identification & Tracking (LRIT) of ships. Among those elements included in the LRIT plan, automatic identification systems (AIS), typically envisioned as a short-range system, may also play a long-range role. AIS vessel tracking may be accomplished through high elevation shore sites allowing reception of AIS signals to nominally 24 nm that loosely puts it in the category of a short-range sensor. Additionally, the US Coast Guard is conducting research and development efforts to determine the feasibility of using AIS receive capability on low earth orbit (LEO) satellites and high altitude, long endurance (HALE) airships or balloons. In parallel with the developing technical capabilities, the US approach with the International Maritime Organization (IMO), and domestic legislation and regulations are also addressed. Finally, a vision for the implementation of LRIT is offered. The paper was presented on 9 November 2004 at Church House, London during the Institute's NAV 04 Conference.

An Automatic Identification System (AIS) was implemented in the St. Lawrence Seaway during 2003. This paper reports the results of a trial conducted pre- and post-AIS implementation to examine the impact of AIS adoption in a safety-critical system. Analysis of the impact on three types of operators, ship's masters, mates and shore-based traffic management system operators showed that overall AIS significantly improved voyage plan monitoring, contributed to improved monitoring vigilance and offered significant aid to decision making. Recommendations include follow-on studies to include a steady state evaluation of the technology impact once the system is mature and a broadening of the pool of subjects to include a less experienced, more international and less well educated group of operators.

This paper was the basis of a presentation given on 9 November 2004 at Church House, London during the Institute's NAV 04 Conference. The author argues that AIS has been proven as a valuable aid to safe navigation, but requires comprehensive training to ensure its proper and effective use. Furthermore, he supports those concerned that using AIS in support of “homeland security” will make ships more vulnerable to attack.

Albatrosses are known for their extreme navigation performance enabling them to locate isolated breeding islands after long-distance migrations across open seas. Little is known about the migration of young albatrosses and how they reach the adults' navigation and foraging skills during the period of immaturity lasting several years and spent permanently flying across the open ocean. We tracked by satellite telemetry the dispersal and migration of 13 juvenile wandering albatrosses from the Crozet Islands during their first year at sea. The young albatrosses covered an average distance of 184,000 km during the first year, restricting their dispersal movement to the unproductive and low wind subtropical Indian Ocean and Tasman Sea. The juveniles initiated the migration by an innate phase of rapid dispersal encoded as a fixed flight direction assisted by southerly winds towards north and northeast. Thereafter each individual restricted its movement to a particular zone of the ocean that will possibly be used until they start breeding 7–10 years later and return in contact with breeding adults. This dispersal in young birds corresponds well with movements observed for adult non-breeding wandering albatrosses. The results show clearly an inherited ability to navigate back to already visited areas in young wandering albatrosses. The juvenile dispersal behaviour and migration at sea suggest a genetically based migration program, encoding navigation to a destination area used throughout the life.

In this paper, a novel method of sensor based pedestrian dead reckoning is presented using sensors mounted on a shoe. Sensor based systems are a practical alternative to global navigation satellite systems when positioning accuracy is degraded such as in thick forest, urban areas with tall buildings and indoors. Using miniature, inexpensive sensors it is possible to create self-contained systems using sensor-only navigation techniques optimised for pedestrian motion. The systems developed extend existing foot based stride measurement technology by adding the capability to sense direction, making it possible to determine the path and displacement of the user. The proposed dead-reckoning navigation system applies an array of accelerometers and magneto-resistive sensors worn on the subject's shoe. Measurement of the foot's acceleration allows the precise identification of separate stride segments, thus providing improved stride length estimation. The system relies on identifying the stance phase to resolve the sensor attitude and determine the step heading. Field trials were carried out in forested conditions. Performance metrics include position, stride length estimation and heading with respect to a high accuracy reference trajectory.

This paper presents an overview of results from the two year REGIONAL project. The aims of REGIONAL were to undertake research to enable landmarks to be an integral feature of future vehicle navigation systems. Results from the project, including five empirical road-based trials, are summarised. The main findings were: landmarks were widely used by drivers as key navigation cues; the incorporation of good landmarks within navigation instructions has the potential to considerably enhance vehicle navigation systems; although a wide range of landmarks are potentially useful to a driver, only a limited set, which displayed key characteristics, were consistently effective as navigation cues.

Vehicle navigation systems use various sensors and the global positioning system (GPS) to locate a vehicle. This location is then matched to a map database to provide navigation information. Between GPS updates, the vehicle's heading angle and forward speed are used to “dead reckon” its position. Heading angle is often measured by integrating the output of a rate gyroscope. For this measurement to be equal to the vehicle's heading angle, the vehicle should not experience any rotation about its roll or pitch axes. For an automobile, the roll and pitch angles are small and may be neglected for the purposes of navigation. This article demonstrates that this same assumption is not true for a motorcycle. Through simulation, it is shown that for a motorcycle, obtaining a meaningful heading angle from a single angular rate measurement requires accounting for the motorcycle's roll angle. Methods to estimate roll angle and heading angle from available navigation measurements are presented, and two possible sensor configurations are compared. A motorcycle navigation scheme based on these roll angle estimation methods is shown to produce exceptional results in a simulation environment.

Automatic Identification System (AIS) has recently become the leading issue in maritime navigation and traffic management worldwide. The present AIS solution, based on a VHF data communications scheme, provides AIS functionalities for SOLAS (AIS Class A) vessels only in a limited environment defined by radio propagation properties. Here we present a novel approach in AIS development based on current mobile communication technologies. It utilises existing mobile communications equipment that the majority of targetted end-users own and are familiar with. A novel AIS concept aims to offer a transition of AIS data traffic to mobile Internet. An innovative AIS architecture supports AIS data processing, storing and transferring to authorised parties. This enhances not only the operational area, but also provides the global AIS with data transfer security and an improved aids-for-navigation service, with all legally traceable vessels (both AIS Class A and AIS Class B) included in the system. In order to provide the development framework for Internet AIS, a set of essential four use-cases, a communication protocol and the first Internet AIS prototype have been recently developed and are briefly introduced in this article.

In general, a Reference Station calculates differential corrections which are valid for that exact location (zero baseline) at that particular epoch (age of corrections zero). However, DGPS users may be located as far as 200 nm away from the Reference Station and some of the errors compensated for by the Reference Station vary with space, namely satellite ephemeris, tropospheric and ionospheric errors. Therefore, the corrections calculated at the Reference Station suffer certain accuracy degradation as the separation distance increases, because of a decreasing relevance of the Reference Station data to the user. The error growth with increasing distance to the beacon is accentuated by the inability of Reference Station and user to see the same satellites, commonly termed the lack of intervisibility. The error growth with distance is the most important factor determining DGPS accuracy, but surprisingly very little has been done to assess it. US official documents and IALA state that the achievable accuracy degrades at an approximate rate of 1 m for each 150 km (80 nm) distance from the broadcast site, but this value is based on a theoretical prediction, made back in 1993. To estimate the error growth with real data, 6 DGPS receivers were placed along the Portuguese coastline at approximately 50 nm intervals from Sagres Broadcast Station, in a South – North direction. This paper describes the results of the trial.

The focus here is on the performance of and interaction between the Traffic Alert and Collision Avoidance System (TCAS) and the controller's short-term conflict alert (STCA) system. The data source used is UK Airprox Board Reports of close encounters between aircraft, and the focus is on commercial air transport aircraft using UK controlled airspace with a radar service. Do the systems work well together? Are controllers surprised when they find out that a pilot has received a TCAS resolution advisory? What do TCAS and STCA events say about collision risk? Generally, the systems seem to work together well. On most occasions, controllers are not surprised by TCAS advisories: either they have detected the problem themselves or STCA has alerted them to it. The statistically expected rate of future mid-air collisions is estimated by extrapolation of Airprox closest encounter distances.

Although there have been improvements to the interface design of marine systems, there are still calls for increased usability as designers are blamed for systems that users find difficult to operate. This paper examines some of the issues and constraints that the designer faces when attempting to design a usable interface. The approach to designing that the developer may take is considered as well as more practical issues such as the limitations of using design principles. The importance of domain and context knowledge is stressed as well as other issues such as safety and culture. The paper concludes that design is a complex compromise but user involvement throughout the lifecycle can improve the ease of using marine systems.

Errors of different positioning algorithms for tracked targets used in the ARPA systems and their influence on estimated speed of targets is analysed. Examples show their significance in tracking targets at low ranges.

The Disaster Monitoring Constellation (DMC) is an international Earth observation programme to provide a rapid global remote sensing service for the monitoring and mitigation of natural and man-made disasters. Although the Global Positioning System (GPS) was originally designed for terrestrial and air applications, satellite operations have benefited greatly from the use of on-board GPS receivers. This paper describes the GPS receiver operations on the DMC satellites, performance analysis, lessons learned, and upgrades planned for the future.

This paper reviews currently existing fault-tolerant navigation system architectures and data fusion methods used in the design and development of integrated aircraft navigation systems and also compares their advantages and disadvantages. Four fault-tolerant navigation system architectures are reviewed and the associated Kalman filter architectures and algorithms are discussed. These techniques have been used in most integrated aircraft navigation systems. The aim of this review paper is to provide a guide for navigation system designers to develop future aircraft multisensor navigation systems.

The purpose of this paper is to describe a statistical method for modelling and accounting for the heavy tail fault-free error distributions that have been encountered in the Local Area Augmentation System (LAAS), the FAA's version of a ground-based augmentation system (GBAS) for GPS. The method uses the Normal Inverse Gaussian (NIG) family of distributions to describe a heaviest tail distribution, and to select a suitable NIG family member as a model distribution based upon a statistical observability criterion applied to the FAA's LAAS prototype error data. Since the independent sample size of the data is limited to several thousand and the tail probability of interest is of the order of 10−9, there is a chance of mismodelling. A position domain monitor (PDM) is shown to provide significant mitigation of mismodelling, even for the heaviest tail that could be encountered, if it can meet certain stringent accuracy and threshold requirements. Aside from its application to GBAS, this paper should be of general interest because it describes a different approach to navigation error modelling and introduces the application of the NIG distribution to navigation error analysis.

Extensive ionospheric scintillation and Total Electron Content (TEC) data were collected by the Institute of Engineering Surveying and Space Geodesy (IESSG) in Northern Europe during years of great impact of the solar maximum on GNSS users (2001–2003). The ionospheric TEC is responsible for range errors due to its time delay effect on transionospheric signals. Electron density irregularities in the ionosphere, occurring frequently during these years, are responsible for (phase and amplitude) fluctuations on GNSS signals, known as ionospheric scintillation. Since June 2001 four GPS Ionospheric Scintillation and TEC Monitor receivers (the NovAtel/AJ Systems GSV4004) have been deployed at stations in the UK and Norway, forming a Northern European network, covering geographic latitudes from 53° to 70° N approximately. These receivers compute and record GPS phase and amplitude scintillation parameters, as well as TEC and TEC variations. The project involved setting up the network and developing automated archiving and data analysis strategies, aiming to study the impact of scintillation on DGPS and EGNOS users, and on different GPS receiver technologies. In order to characterise scintillation and TEC variations over Northern Europe, as well as investigate correlation with geomagnetic activity, long-term statistical analyses were also produced. This paper summarises our findings, providing an overview of the potential implications of ionospheric scintillation for the GNSS user in Northern Europe.