Garmin G1000:Socata Pilot's Manual page 28

SYSTEM OVERVIEW
In addition to using internal sensors, the GRS 77 AHRS uses GPS information, magnetic field data and air
data to assist in attitude/heading calculations. In normal mode, the AHRS relies upon GPS and magnetic
field measurements. If either of these external measurements is unavailable or invalid, the AHRS uses air
data information for attitude determination. Four AHRS modes of operation are available (see Figure 1-
13 and 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 message advisory alerts.
AHRS Modes
Normal
Reversionary:
No GPS
Reversionary:
No Magnetometer
Reversionary:
No Magnetometer
No Air Data
GPS INPUT FAILURE
The G1000 system provides two sources of GPS information. If a single GPS receiver fails, or if the
information provided from one of the GPS receivers is unreliable, the AHRS seamlessly transitions to using the
other GPS receiver. An alert message informs the pilot of the use of the backup GPS path. If both GPS inputs
fail, the AHRS continues to operate in reversionary No-GPS mode so long as the air data and magnetometer
inputs are available and valid.
1-18
GPS Data
Magnetometer Data
Air Data
AHRS no- AHRS no-Mag/
AHRS Normal
Mag Mode no-Air Mode
Operation
Heading Invalid
Figure 1-13 AHRS Operation
Available AHRS Functions
Pitch Roll Heading
  
  
–
 
–
 
Table 1-1 AHRS Operation Modes
Garmin G1000 Pilot's Guide for the Socata TBM 850
Magnetometer Data
Air Data
AHRS
no-GPS
Mode Attitude/Heading Invalid
Available Sensor Inputs
GPS Input GMU 44
(At least one) Magnetometer
 
–

–

–

GDC 74B
Air Data Computer



–
190-00709-00 Rev. A