Ahrs Operation - Garmin G900X Pilot's Manual

SYSTEM OVERVIEW

AHRS OPERATION

Aggressive maneuvering while AHRS is not operating normally may degrade AHRS accuracy.
NOTE:
The Attitude and Heading Reference System (AHRS) performs attitude, heading, and vertical acceleration
calculations for the G900X System, utilizing GPS, magnetometer, and air data in addition to information from
its internal sensors. Attitude and heading information are updated on the PFD(s) while the AHRS receives
appropriate combinations of information from the external sensor inputs.
The AHRS (GRS 77) corrects for shifts and variations in the Earth' s magnetic field by applying the Magnetic
Field Variation Database. The Magnetic Field Variation Database is derived from the International Geomagnetic
Reference Field (IGRF). The IGRF is a mathematical model that describes the Earth' s main magnetic field and its
annual rate of change. The database is updated approximately every 5 years. See the Appendices for information
on updating the Magnetic Field Variation Database. The system will prompt you on startup when an update is
available. Failure to update this database could lead to erroneous heading information being displayed to the
pilot.
Magnetometer Data
AHRS Normal
Operation
16
GPS Data
Air Data
AHRS no- AHRS no-Mag/
Mag Mode no-Air Mode
Heading Invalid
Figure 1-12 AHRS Operation
Garmin G900X Pilot's Guide
Magnetometer Data
Air Data
AHRS
no-GPS
Mode Attitude/Heading Invalid
190-00726-00 Rev. J