Attitude Heading Reference System

Background:

An attitude heading reference system consists of sensors on three axis that provide heading, attitude, and yaw information for aircraft. They are designed to replace traditional mechanical gyroscopic flight instruments and provide superior reliability and accuracy.

AHRS consists of either solid-state or MEMS gyroscopes, accelerometers, and magnetometers on all three axis. The key difference between an IMU and an AHRS is the addition of an on-board processing system in an AHRS, which provides estimation of attitude and heading, versus an IMU which only provides the measured (and calibrated) sensors data. A form of non-linear estimation, such as a Kalman filter, is typically used estimate the atitude and heading angles. AHRS differs from Inertial Navigation Systems by attempting to estimate only attitude (i.e., roll, pitch, yaw, a.k.a. attitude) states rather than heading, position, and velocity vector.

Development:

It started in 2004 as a private R&D and educational project for a few weekends.

It was my first attempt to work with MEMS Gyros & accelerometers.

In 2006, I used it to perform some inertial measurements on a airplane we planed using for aerial photography. I needed to measure the vibrations, forces, and rotation rates during maneuvers and straight flight.

In 2009, as a private R&D, I developed the AHRS algorithm for it.

On 2013 I 3D-Printed the nice enclosure and gave it to a young and talented student as a gift.