Adahrs Operation - Garmin G1000 NXi Pilot's Manual

SYSTEM OVERVIEW

ADAHRS OPERATION

In addition to using internal sensors, the GSU 75 ADAHRS uses GPS information, magnetic field data and
air data to assist in attitude/heading calculations. In normal mode, the ADAHRS relies upon GPS and magnetic
field measurements. If either of these external measurements is unavailable or invalid, the ADAHRS uses air
data information for attitude determination. Eight ADAHRS modes of operation are available (see Table 1-1)
and depend upon the combination of available sensor inputs. Loss of air data, GPS, or magnetometer sensor
inputs is communicated to the pilot by system messages.
Refer to the Appendices for specific AHRS and ADC system message information.
NOTE:
Aggressive maneuvering while the ADAHRS is not operating normally can degrade ADAHRS accuracy.
NOTE:
ADAHRS Mode
ADAHRS Normal
ADAHRS no-Air
Data
ADAHRS no-GPS
ADAHRS no-GPS/
no-Mag
ADAHRS no-Mag
Data
ADAHRS no-Mag/
no-Air Data
ADAHRS coast-
on-gyros until
invalid
ADAHRS no-Mag/
coast-on-gyros
until invalid
14
GPS Data Magnetometer
Available Data Available
Yes Yes
Yes Yes
No Yes
No No
Yes No
Yes No
No Yes
No No
Table 1-2 ADAHRS Operation
Garmin G1000 NXi Pilot's Guide for Cessna Nav III
Air Data Condition
Available
Yes
Valid Pitch/Roll/
No Heading.
Yes
Valid Pitch/Roll.
Heading will coast-
Yes
on-gyros until it
becomes invalid.
Yes
Valid Pitch/Roll.
Invalid Heading.
No
No
Invalid Pitch/Roll/
Heading.
No
Attitude
Indicator
190-02177-00 Rev. A