An inertial measurement unit (IMU) is a device that measures and reports an object's specific force, angular rate, and sometimes magnetic field. It typically consists of accelerometers, gyroscopes, and sometimes magnetometers, which work together to provide data about the object's motion and orientation in three-dimensional space. IMUs are widely used in various applications, including aerospace, automotive, and robotics. They help in navigation, stabilization, and control systems by providing real-time information about movement and position, making them essential for technologies like drones and smartphones.