Attitude and heading reference system

These are sometimes referred to as MARG (Magnetic, Angular Rate, and Gravity)[1] sensors and consist of either solid-state or microelectromechanical systems (MEMS) gyroscopes, accelerometers and magnetometers.

This is in contrast to an IMU, which delivers sensor data to an additional device that computes attitude and heading.

With sensor fusion, drift from the gyroscopes integration is compensated for by reference vectors, namely gravity, and the Earth's magnetic field.

In addition to attitude determination an AHRS may also form part of an inertial navigation system.

A form of non-linear estimation such as an Extended Kalman filter is typically used to compute the solution from these multiple sources.

Garmin G1000 Primary Flight Display.
Garmin G1000 Primary Flight Display.