Abstract: A method for initializing an inertial measurement unit (IMU). The IMU is associated with an accelerometer frame. The accelerometer frame corresponds to an inertial frame. The method includes generating variations in rows of a gravity disturbance matrix of the IMU by rotating the IMU about a rotation axis and estimating an optimal transformation matrix from the accelerometer frame to the inertial frame by minimizing the variations of the rows of the gravity disturbance matrix. The rotation axis passes through a center of the accelerometer frame. A column of the gravity disturbance matrix includes a gravity disturbance vector at an initialization moment of an initialization time. The gravity disturbance vector is associated with a gravity vector of Earth.

Abstract: A method for initializing an inertial measurement unit (IMU) is disclosed. The IMU includes a plurality of accelerometers and a plurality of gyroscopes and is associated with an accelerometer frame and a gyro frame. The accelerometer frame includes a first orthogonal set of axes, and the first orthogonal set of axes includes an xa-axis, a ya-axis, and a za-axis. The za-axis is associated with a gravity vector of Earth. The gyro frame includes a second orthogonal set of axes, and the second orthogonal set of axes includes an xg-axis, a yg-axis, and a zg-axis. The accelerometer frame and the gyro frame correspond to an inertial frame. The method includes generating variations in rows of a gravity disturbance matrix of the IMU by rotating the IMU about a rotation axis and estimating an optimal transformation matrix from the accelerometer frame to the inertial frame by minimizing the variations of the rows of the gravity disturbance matrix of the rotated IMU.