Building information systems based on precise indoor positioning

Abstract

During the last 10 years, many modern IT-based applications have developed inside buildings. Many of those applications would benefit by the ability to locate people and/or objects inside the building (indoor positioning). However, most of today's indoor positioning systems are not able to deliver precise position information (<10 cm) along with quality parameters. Ultra wide band (UWB) is a new radio-based technology that allows the determination of distances in indoor environments with a very high spatial resolution even through building materials. At the Institute of Geodesy of TU Darmstadt, a high-resolution UWB positioning system (UWB-ILPS; ILPS, indoor local positioning systems) based on trilateration principle has been developed to estimate the position of a mobile station precisely. To benefit from knowing the position and orientation, it is necessary to select and merge data linked to the user's location for indoor location services. By this means, the visitor to a public building may benefit from the system as his position is shown on a digital floor plan generated dynamically or by retrieving location-based information inside the building. Mixed reality systems also offer advantages for a mobile building information system. For this purpose, a webcam was replaced by the digital camera in the UWB-ILPS prototype. Knowing the camera's location in space and its view direction, one is able to merge the real world taken by the webcam with the virtual world represented by a 3D CAD model of the building.