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Helicopter Attitude, Heading and Reference System (AHRS)

Attitude, Heading and Reference Systems, AHRS in short, are 3-axis sensor systems which provide real-time 3D data concerning the attitude and positioning of helicopter by calculating pitch, roll and heading.
AHRS are used in navigation to assess the orientation and direction of a chopper, in the control and stabilization of antennas mounted on helicopter platforms and in measurement and correction applications such as the collection of accurate data via imaging systems.

In many cases, AHRS sensors experience gyro bias drifts, which can lead to a misreading of the aircraft’s true trajectory. In order to counter that, AHRS require a filter structure and independent measurements from accelerometers so that they might provide the initial attitude reference and on-flight corrections required to correct the bias drifts.

The MEMS sensors

Designed to replace traditional gyro-based instruments, MEMS-based AHRS provide superior reliability and accuracy due to having 3-axis magnetic, 3-axis acceleration and 3-axis gyroscopic sensors. In order for the AHRS to work properly, all these sensors combine with a built-in processor to create an inertial sensor system able to measure the attitude of objects in 3D space.

MEMS accelerometers provide exceptional levels of performance in terms of long-term stability, temperature stability and accuracy and are able to function successfully under harsh conditions.

Colibrys MEMS accelerometer

Our MS9000 sensor is available in various range from ±2g to ±200g and is part of the exclusive group of MEMS used in EASA, FAA and DAL A certified systems. The MS9000 is a single-axis analog accelerometer based on bulk micro-machined silicon elements.

It is specifically designed for high bias stability over temperature in harsh environments. The MS9000 embeds a low-power ASIC (0.5 mA) and a temperature sensor. It comes fully calibrated from the get-go in a robust, hermetically-sealed LCC20 ceramic package, guaranteeing long-term stability and durability.

Recommended sensor

MS9100 Sensor

Colibrys strongly recommends the MS9000 for AHRS applications. The sensor features long term stability and high repeatability bias after shock.

AHRS sensor