Abstract: A method and a system include a first inertial measurement unit (IMU) is positioned on a first member of a joint and a second IMU is positioned on a second member of the joint, where the first IMU and the second IMU each lack a magnetometer unit. A processing device receives first IMU sensor data and second IMU sensor data. The first IMU sensor data is inputted into a quaternion computation algorithm (QCA) to compute a first quaternion. The first quaternion and the second IMU sensor data are inputted into the QCA to compute a one second quaternion, where the inputting of the first quaternion imposes yaw constraints. A calibration parameter algorithm determines a mobility metric of the joint based on the first and the second quaternions, and an orientation and position of the first IMU on the first member and of the second IMU on the second member.

Abstract: Systems and methods for calculating mobility metrics associated to a plurality of wearable sensors in various arrangements comprising a plurality of communicatively-connected sensors comprising inertial measurement units (IMU) attached to connected bodies of a hinge or ball joint in communication with a computing device. Systems and methods for quaternion calculations comprising a first sensor's quaternion output as estimate into another sensor's quaternion calculation to improve the other sensor's quaternion estimate and vice versa. Systems and methods for data synchronization of a plurality of sensors involving building an external reference time vector and interpolating the sensor's data based on the reference time vector. Systems and methods for calculating a sensor's orientation and position based on the inertial measurements captured by the wearable sensors during hinge or ball joint movements to, at least, calculate a joint angle.

Abstract: Systems and methods for calculating mobility metrics associated to a plurality of wearable sensors in various arrangements comprising a plurality of communicatively-connected sensors comprising inertial measurement units (IMU) attached to connected bodies of a hinge or ball joint in communication with a computing device. Systems and methods for quaternion calculations comprising a first sensor's quaternion output as estimate into another sensor's quaternion calculation to improve the other sensor's quaternion estimate and vice versa. Systems and methods for data synchronization of a plurality of sensors involving building an external reference time vector and interpolating the sensor's data based on the reference time vector. Systems and methods for calculating a sensor's orientation and position based on the inertial measurements captured by the wearable sensors during hinge or ball joint movements to, at least, calculate a joint angle.