Gait State Classification by HMMS for Pedestrian Inertial Navigation System

보행용 관성 항법 시스템을 위한 HMMS를 통한 걸음 단계 구분

  • 박상경 (울산대학 전기전자정보시스템공학부) ;
  • 서영수 (울산대학 전기전자정보시스템공학부)
  • Published : 2009.05.01


An inertial navigation system for pedestrian position tracking is proposed, where the position is computed using inertial sensors mounted on shoes. Inertial navigation system(INS) errors increase with time due to inertial sensor errors, and therefore it needs to reset errors frequently. During normal walking, there is an almost periodic zero velocity instance when a foot touches the floor. Using this fact, estimation errors are reduced and this method is called the zero velocity updating algorithm. When implementing this zero velocity updating algorithm, it is important to know when is the zero velocity interval. The gait states are modeled as a Markov process and each state is estimated using the hidden Markov model smoother. With this gait estimation, the zero or nearly zero velocity interval is more accurately estimated, which helps to reduce the position estimation error.


Pedestrial Navigation System;Zero Velocity Updating; Hidden Markov Mode


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