Bernhard Hofmann-Wellenhof

Global pose estimation using multi-sensor fusion for outdoor Augmented Reality

Outdoor Augmented Reality typically requires tracking in unprepared environments. For global registration, Global Positioning System (GPS) is currently the best sensing technology, but its precision and update rate are not sufficient for high quality tracking. We present a system that uses Kalman filtering for fusion of Differential GPS (DGPS) or Real-Time Kinematic (RTK) based GPS with barometric heights and also for an inertial measurement unit with gyroscopes, magnetometers and accelerometers to improve the transient oscillation. Typically, inertial sensors are subjected to drift and magnetometer measurements are distorted by electro-magnetic fields in the environment. For compensation, we additionally apply a visual orientation tracker which is drift-free through online mapping of the unknown environment. This tracker allows for correction of distortions of the 3-axis magnetic compass, which increases the robustness and accuracy of the pose estimates. We present results of applying this approach in an industrial application scenario.

Surveying with GPS

This chapter is mainly concerned with the practical aspects of GPS surveying and addresses planning, performance, and in situ data processing. Overlapping with other chapters is intentional to provide complete information in a single chapter for readers more interested in practical considerations.

River Information Services

SummaryRiver Information Services (RIS) represent the most substantial modernization of river infrastructure aiming at information services to support planning and managing of traffic and transportation operations on waterways. The RIS concept is based on tracking and tracing of the vessel positioning and the monitoring of relevant vessel data. The innovative concept and the ongoing implementation are presented in this paper.ZusammenfassungDas Konzept eines Schiffsinformationssystems verfolgt die Bereitstellung eines Überblicks über das aktuelle Verkehrsgeschehen auf Schiff und an Land zur Verkehrssteuerung sowie die Online-Verfügbarkeit eines umfassenden Informationssystems für alle Belange der operativen Binnenschifffahrt. Die Implementierung dieses modernen Konzepts wird in diesem Beitrag beschrieben.

Image-based navigation

Image-based navigation aims at navigating objects by processing series of image data. These image data may be recorded with passive sensors like digital cameras or active instruments like laser scanners. Image-based navigation allows to extend the definition of navigation beyond the so far primarily geometric task. Due to the interaction of the sensor with its surrounding, sophisticated techniques may be developed permitting autonomous vehicles to find their way even within unknown surroundings. Image-based navigation has the potential of complementing traditional tasks of navigation with intelligent problem solutions. Thus, current fields of application often refer to robot technology, covering the operation and control of industrial robot arms up to the guidance of mobile robots. In many of today’s realizations, image-based navigation serves as one component of a multisensor navigation system and is responsible for specialized tasks like collision avoidance.

GNSS interference detection, classification and localization using Software-Defined Radio

This paper presents details about the theoretical background as well as implementation of a GNSS interference monitoring system that can be used to continually monitor the GNSS frequency bands and thus alert users depending on the reliability of GNSS measurements. As shown in the results section, events of intentional GNSS interference are successfully detected and the system can also be used to classify different types of interference as well as localize the source of the disturbing signals.

Routing and guidance

According to the basic definition, navigation consists of two fundamental components: positioning and guidance. Thus, many applications within intelligent transportation systems (ITS) are not only based on position determination but are also essentially dealing with problems of vehicle and traffic guidance. This applies to land-based systems and maritime and aeronautic applications as well. Guidance in its turn is very often based on routing problems as the optimal path, the traveling salesman problem (TSP), etc.

GNSS-based trajectories for demanding applications

The Institute of Navigation and Satellite Geodesy of the Graz University of Technology is involved in many projects and developments to determine GNSS-based trajectories for demanding applications. Examples demonstrating the capabilities and limits of GNSS-based positioning under detrimental conditions are: positioning and guidance of visually impaired pedestrians, search and rescue applications, trajectory and attitude determination for airborne platforms, positioning and orientation of a mobile augmented-reality client, and trajectory and velocity determination in ski jumping. This paper gives an overview of each of the applications followed by a special insight into the last example which is characterized by high kinematics, partly shadowing of satellites, and updates of high frequency.

Vehicle and traffic management

The tools of navigation serve a broad spectrum of applications. One of the main topics refers to the wide range of vehicle and traffic management, which is characterized by a high degree of interdisciplinarity. The navigational components are correlated with tools of transportation and traffic sciences, telematics, geoinformatics, and of many other disciplines. Navigation is inherent in any kind of traffic and transportation. For example, questions like “where am I?” and “how to go?” are associated with the main tasks of navigation, namely, positioning and guidance of individual vehicles or a collective of vehicles. In addition, vehicle and traffic management requires an adequate infrastructure for processing and transmitting traffic-related data and information. In this respect, (traffic) telematics contributes essentially to the success of a traffic management system. Covering topics of telecommunications as well as informatics, telematics strongly cooperates with geoinformatics, which mainly focuses on the collection, administration, evaluation, and visualization of geographic data. In connection with traffic telematics, geographical information systems (GIS) handle data and information about vehicles and objects of the traffic infrastructure associated with a position or location on land, at sea, or in the air. Meanwhile, a good deal of the GIS applications cover topics of traffic and transportation.

Terrestrial radio navigation

The main objective of terrestrial radio navigation is position fixing. Referring to a transmitter with known position and a rover to be determined, specific navigation systems give information on directions, angles, distances, pseudoranges, and combinations of these types of information. Considering these quantities as measurements, the term line of position (LOP) as explained in Sect. 3.2.2 becomes fundamental. Depending on the LOPs involved, various kinds of position fixing exist, see Figs. 3.7, 3.8, and 3.9 in Sect. 3.2.2.

Satellite-based navigation

A short remark on the terminology is given to avoid misinterpretation. “Satellite-based navigation” means navigation based on satellites, i.e., using signals transmitted by satellites. Quite often, this full nomenclature is shortened to the expression “satellite navigation”. This could be misleading because the navigation of satellites could be associated. Primarily, this book implies satellite-based navigation and the authors tried to use the correct denotation. Frequently, the term global navigation satellite system (GNSS) is used to refer to the current global systems.