INERTIAL NAVIGATION DEVICE AND INERTIAL NAVIGATION METHOD

An inertial navigation device that includes a processor that is configured to: assume a vertical velocity and a lateral velocity of a vehicle to be 0, and estimate a roll angle, a pitch angle and an azimuth angle, which are attitude angles of the vehicle, based on angular velocities and accelerations detected by the inertial measurement device, a longitudinal velocity detected by a vehicle velocity sensor, and an initial value of the azimuth angle of the vehicle, and assume the vertical velocity of the vehicle to be 0, and estimate a current position of the vehicle based on the estimated attitude angles, the angular velocities and the accelerations detected by the inertial measurement device, the longitudinal velocity detected by the vehicle velocity sensor, a steering angle detected by a steering angle sensor, and an initial value of a position of the vehicle.