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A MODEL BASED APPROACH FOR ORIENTATION IN URBAN ENVIRONMENTS 
D. Klinec 
Institute for Photogrammetry, University of Stuttgart, Geschwister-Scholl-Str. 24, Stuttgart, Germany 
darko.klinec@ifp.uni-stuttgart.de 
ThS 19 
KEY WORDS: Photogrammetry, Location-based Services, Integration, Multisensor, Matching, Orientation, Camera 
ABSTRACT: 
At the Institute for Photogrammetry (ifp), Stuttgart University, current research aims at the development of tools and applications for 
Location Based Services (LBS). As location based access on information is a key parameter of these applications, the current user's 
position and orientation is essential for information access. Usually, human beings navigate and locate themselves by integrating 
viewpoint information (landmarks) into a coherent mental representation of the traversed environment. In urban environments with 
unknown, difficult and complex building structures natural orientation fails very often, because the navigator's viewpoint does not 
encompass the environment in its totality. Thus, intuitive automatic positioning and navigation becomes necessary. 
Usually GPS is used for positioning, but in urban areas GPS is jammed by multipath effects and signal loss, compasses suffer by 
electro magnetic fields. As pedestrians intuitively use viewpoint information to locate themselves, the idea is to use the surrounding 
objects (buildings) as landmarks to automate this process. In this paper an approach will be presented which uses visual information 
(images) collected by a digital camera, 3D city models and photogrammetric methods to provide improved orientation information in 
urban environments. The principle of the process for positioning by viewpoint information is the overlay of a 3D city model to the 
corresponding primitives in the real word. The end result of this overlay process is the accurate determination of the actual position 
and orientation of the user. Within this paper our approach for positioning with images will be described in more detail pointing out 
the whole process as well as aspects for automation. 
KURZFASUNG: 
Gegenwärtige Forschungsarbeiten am Institut für Photogrammetrie der Universität Stuttgart, zielen darauf ab, verschiedene 
Funktionalitàten für Location Based Serives (LBS) bereitzustellen. Die Hauptfunktionalitát solcher Dienste ist der ortsbasierte 
Zugriff auf Informationen. Aus diesem Grund ist die gegenwärtige Position eines mobilen Nutzers eine grundlegende Information. 
Üblicherweise bestimmt ein Mensch seine Position, indem er markante Objekte (Landmarken) visuell erkennt und diese einer 
vorhandenen, mentalen Karte zuordnet. Innerhalb einer komplexen und unbekannten, städtischen Umgebung versagt diese Arte der 
Orientierung in der Regel, da der mobile Nutzer über keine mentale Karte der Umgebung verfügt. Vielmehr müsste diese Karte erst 
antrainiert werden. Eine intuitive und automatische Positionierung und Navigation kann hier hilfreich sein. 
Vielfach wird GPS zur Positionierung verwendet, dessen Empfang aber innerhalb städtischen Umgebungen durch Multipatheffekte 
und abreißende Signale gestört wird, digitale Kompanden zur Bestimmung der Orientierungsparameter werden dagegen durch 
elektromagnetische Felder gestört und sind auch nur begrenzt Einsetzbar. Da der Mensch üblicherweise visuelle Information für 
seine Lokalisierung und Navigation verwendet ist die Idee, umgebende Objekte (Gebäude) als Landmarken zu verwenden. 
Nachfolgend wird ein Verfahren vorgestellt, dass Bilder (erzeugt von einer digitalen Kamera) in Kombination mit einem 3D 
Stadtmodell verwendet, um die äußere Orientierung mittels photogrammetrischer Methoden zu ermitteln. Das Prinzip dabei ist die 
Überlagerung von 3D Stadtmodelldaten mit den entsprechenden Objekten der realen Umgebung. Durch einen derartigen 
Zuordnungsprozess kann dann die genaue Position und Orientierung eines mobilen Nutzers abgeleitet werden. Innerhalb des Papers 
wird das Verfahren der Positionierung mittels Bildern detaillierter beschrieben, sowie Automatisierungsansätze diskutiert. 
1. INTRODUCTION phone network, GPS (Global Positioning System) or another 
type of positioning system, e.g. proprietary indoor positioning 
During the hype of the “new market” many scenarios were used systems. For user support by overlaying the reality with 
to show the need of digital systems, which are able to supporta additional information or for interaction with surrounding 
mobile user in different situations. At this time also the idea of objects, these techniques are not sufficient. There are several 
LBS (Location-based Services) arose and in the meantime techniques in Augmented Reality (AR) to solve these problems 
simple LBS are offered from various sides for users of cell but often they are limited for indoors use, as the environment 
phones, etc. . With an emerging availability of small and has to be equipped with appropriate sensor technology. 
powerful devices different types of applications become Outdoors we cannot assume the same prepared environment like 
feasible. They enable us to access on data stored on remote indoors. The approach being developed at the Institute for 
Systems or to stay in contact with other persons. People can get Photogrammetry therefore takes into account a model of the 
guiding support to the next restaurant, and even friend finder environment to support the process. 
functionality is provided. For these applications the mobile 
devices (cell phones) can be localized by use of the cellular