Abstract: A method for determining a current estimated gyroscope bias of a gyroscope configured to output rotation rate data includes receiving first rotation rate data associated with a first time from the gyroscope, the first rotation rate data comprising a first rotation rate reading that indicates a rotation rate of the gyroscope about a first axis; calculating a rotation rate moving average and a rotation rate moving average associated with a second time earlier than the first time; calculating a moving standard deviation based on the first rotation rate data, and a moving standard deviation associated with the second time; determining if the moving standard deviation associated with the first time is less a threshold moving standard deviation; and in response the moving standard deviation being less than the threshold moving standard deviation, using the first rotation rate reading to update the current estimated gyroscope bias.

Abstract: A method for calibrating respective estimated joint axis directions for each of a pair of body mounted sensors, one of the pair of sensors being located to each side of the joint comprising a joint axis, the sensors each calculating a pitch angle about respective first sensor axes and a roll angle about respective second sensor axes, the first and second sensor axes together with a third sensor axis orthogonal to the first and second sensor axes forming a sensor frame, the method comprising: receiving orientation data for each of the two sensors, the orientation data being associated with at least two different poses of the joint for each of the two sensors and the orientation data comprising the pitch angle and the roll angle of the sensor for each pose; calculating a sensor frame estimated gravity vector for each pose associated with each sensor based on the pitch and roll angles for each pose associated with each sensor and a gravity vector running along a vertical direction; and determining the estimated

Abstract: Disclosed is a method for determining an unworn state of a sensor system comprising a pair of sensors configured for mounting on first and second body parts either side of a joint. The method comprises: obtaining one or more measurements from each sensor; calculating a relative angle between the two sensors using one or more of the obtained one or more measurements; calculating, using one or more of the obtained one or more measurements, a joint angle between the first and second body parts, where the joint angle is defined in a plane of normal bending of the joint; and determining, based on the calculated angles, whether either of the sensors is not mounted and if so, determining that the system is in an unworn state. Also disclosed is a system for providing information about a joint.

Abstract: A method for determining a current estimated gyroscope bias of a gyroscope, the gyroscope being configured to output rotation rate data, the method comprising: receiving first rotation rate data associated with a first time from the gyroscope, the first rotation rate data comprising a first rotation rate reading that indicates a rotation rate of the gyroscope about a first axis; calculating a rotation rate moving average associated with the first time based on the first rotation rate data and a rotation rate moving average associated with a second time earlier than the first time; calculating a moving standard deviation associated with the first time based on the first rotation rate data, the rotation rate moving average associated with the first time, and a moving standard deviation associated with the second time; determining if the moving standard deviation associated with the first time is less a threshold moving standard deviation; and in response the moving standard deviation being less than the thresho

Abstract: A method of calibrating a pair of body mounted sensors, the method comprising the steps of: (a) in a baseline position of a joint to be measured, determining a first offset between a measured joint angle and an angle between pair of sensors, one mounted on each side of the joint to be measured, so as to calibrate the sensors; (b) after at least one of the sensors has been removed and reapplied, placing the joint back into the baseline position such that the sensors are in a second configuration relative to each other; and (c) determining a second offset between the measured knee angle and an angle between the pair of sensors in the second configuration in order to recalibrate the sensors such that, in each of the first and second configurations, the same joint angle for the baseline position is reported.