Accelerometer and fiber optic gyro measurements of an instrumented cylinder used to study impact burial

The impact burial of anti-ship bottom mines in soft seafloors is dependent on the sediment properties and the velocity and orientation of the mine at the time of impact. A full-scale instrumented mine has been constructed to measure descent trajectory and velocity for ground truthing of hydrodynamic model predictions. A dynamic measurement unit (DMU) supplied by Crossbow Technology is the primary sensor employed for this measurement. The six channels of data provided by the DMU are three orthogonal DC coupled accelerations, and three angular rates (about the axis system defined by the accelerometers). We develop a signal processing algorithm that converts the raw DMU data into a time history of the mine's position and orientation during deployment. The algorithm is then tested on DMU data gathered from well-characterized instrument motion to quantify the accuracy of our measurement capability.