Hybrid positioning system combining angle-based localization, pedestrian dead reckoning and map filtering

We present a hybrid indoor positioning solution combining angle-based localization, pedestrian dead reckoning, and map filtering. The angle-based localization system provides absolute location estimates, whereas pedestrian dead reckoning (PDR) results in accurate shape and length of the traversed route without absolute location and heading information. PDR movement and angle-based location estimates are fused together with a building vector map in a fusion filter, which in this study is implemented through a particle filter. When the fusion filter has been initialized with absolute position data and has converged, it can run also on PDR and map filtering, independently of the angle-based localization system, in areas that are not illuminated by multi-antenna arrays. In principle the same fusion design could accommodate location estimates also from other positioning sources, for example WiFi, or GPS in outdoor-to-indoor transitions. By combining information from various positioning modalities, different types of indoor environments can be provided with seamless positioning coverage with reasonable accuracy and infrastructural investments.