A method for determining the rotational rate of a movable member using an array of inertial sensors is provided. The method includes defining a hidden Markov model (“HMM”). The HMM represents a discrete value measurement of the rotational rate of the movable member. A transition probability of the HMM accounts for a motion model (linear or non-linear) of the movable member. An observation probability of the HMM accounts for noise and bias of at least one of the inertial sensors of the array of inertial sensors. A processor receives input from the array of inertial sensors. The processor determines the rotational rate of the movable member by solving for an output of the HMM using the input received from the array of inertial sensors. The processor may use a forward algorithm, a forward-backward algorithm, or a Viterbi algorithm to solve the HMM.