PocketSLAM based on the principle of the FootSLAM algorithm

Infrastructureless indoor navigation remains a challenging research area in spite of the fact that multiple low cost sensors suitable for positioning recently became available even in mobile phones. Since Global Navigation Satellite Signals (GNSS) are often unavailable indoors, the use of Inertial Measurement Units (IMUs) seems to be promising for indoor navigation. Auspicious results are available when the sensor is placed on the foot in indoor positioning applications, but still many problems remain when the drift error during stance phases cannot be reduced. An indoor navigation solution is the so called FootSLAM algorithm, where reliable positioning (positioning error below 1 meter in the case of loop closures) is possible assuming that the sensor is fixed on the foot. More recently, another navigation system was proposed where the sensor is located in the pocket of a pedestrian. Since no special fixation or no special shoe is needed, this location of the sensor is more convenient for mass market users. But also this system suffers from a remaining drift that needs to be compensated. In this paper, we propose a combination of the pocket navigation system with the FootSLAM approach and show that it is also possible to reduce the remaining drift with this combination.