Signal processing issues in indoor positioning by ultra wide band radio aided inertial navigation

The difficulties and possibilities connected to indoor positioning suggest using several sources of navigational information. Apart from the signal processing of the individual sources this gives rise to the need for information fusion. This article aims at presenting and describing the signal processing methods and issues faced when constructing a navigation system based on a local ultra wide band (UWB) ranging system and an inertial navigation system (INS). The signal processing methods within the individual systems are described together with techniques for fusing the information from them. Finally, filtering results of experimental data is presented with expected convergence properties and positioning accuracy of below ±4 cm.