inertialsensors

Inertial sensors are devices that measure motion and orientation by detecting linear and angular accelerations. They are the core components of inertial measurement units (IMUs) and, when combined with other sensors, form inertial navigation systems (INS) used for dead reckoning and attitude estimation. The sensors most commonly found in IMUs are accelerometers and gyroscopes, with magnetometers used in some configurations to provide a heading reference.

Accelerometers measure linear acceleration along their axes, reporting the non-gravitational component of motion as well as gravity when stationary. Gyroscopes measure angular rate around their axes, providing information about rotation. Magnetometers measure magnetic field strength and direction, aiding orientation relative to Earth's field. Other specialized inertial devices include optical or fiber-optic gyros (ring laser gyros, FOGs) and quartz or MEMS-based sensors.

MEMS sensors dominate consumer electronics due to size and cost, while high-precision applications use optical or quantum-based gyros. In practice, IMUs combine multiple sensors and rely on data fusion algorithms, such as Kalman filters or complementary filters, to estimate position, velocity, and attitude. In navigation, the inertial measurements can be integrated over time, but exhibit drift without external references such as GPS or visual measurements.

Performance is described by bias stability, scale factor, noise density, and dynamic range. Accelerometers measure proper acceleration; gravity is not a separate input and will appear in readings. Calibration, temperature compensation, and bias estimation are important for accuracy. Inertial sensors are widely used in aerospace, automotive, robotics, mobile devices, and virtual reality.