int32 RELATIVE_TIMESTAMP_INVALID = 2147483647 # (0x7fffffff) If one of the relative timestamps is set to this value, it means the associated sensor values are invalid
float32[3] accelerometer_m_s2 # average value acceleration measured in the FRD body frame XYZ-axis in m/s^2 over the last accelerometer sampling period
uint32 accelerometer_integral_dt # accelerometer measurement sampling period in microseconds