A method of pedestrian dead reckoning using action recognition

We present a method of estimating the location and orientation of a pedestrian which simultaneously recognizing his/her actions with a single low-cost inertial measurement unit (IMU) mounted at the waist of the user. Some of the actions other than walking locomotion, such as standing up from/sitting down on a chair, and bending over to slip through obstacles, taken by the pedestrians can be mostly seen at the particular locations where the objects and building facilities to induce the actions are placed. Conversely, by knowing the current location and its attribute about possibly taken actions, the action recognition process can be improved with the contextual information since prior knowledge about occurrence of actions is given as the attribute in the map. Additionally, when the posture (such as sitting, standing and getting to one knee) of the pedestrians is known, falsely recognized actions can be rejected. Experimental results show that accuracy of the action recognition on six types of the action (forward walking, backward walking, side stepping, sitting down on/standing up from a chair, going downstairs/upstairs and bending over) is more than 95% by cross validation test on the training data set, and the results also show that error rate of the PDR localization is reduced from 4% of the walking distance to 2% in the total scenario within the office environment by using the results of action recognition to adjust the estimated location.