Grs 77 Attitude, Heading, And Reference Unit (Ahrs); Gmu 44 Magnetometer; Grs 77 Ahrs Unit - Garmin G1000 Maintenance Manual

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The GIA 63W is the central 'Integrated Avionics Unit' (IAU) in the G1000 system. It functions
as the main communication hub, linking all LRUs (except GIA #2) with the on-side PFD. Each
GIA 63W contains a GPS WAAS receiver, VHF COM/NAV/GS receivers, a flight director (FD)
and system integration microprocessors. Each GIA 63W is paired with a CDU via HSDB
connection. The GIA 63Ws are not paired together and do not communicate with each other
directly.
3.4

GRS 77 ATTITUDE, HEADING, AND REFERENCE UNIT (AHRS)

The GRS 77 provides aircraft attitude and heading information via ARINC 429 to both the on-
side GDU and the on-side GIA 63W. The GRS 77 contains advanced sensors (including
accelerometers and rate sensors) and interfaces with the on-side GMU 44 to obtain magnetic
field information, with the GDC 74B to obtain air data, and with both GIA 63Ws to obtain GPS
information.
3.5

GMU 44 MAGNETOMETER

The GMU 44 measures local magnetic field. Data is sent to the GRS 77 for processing to
determine aircraft magnetic heading. This LRU receives power directly from the GRS 77 and
communicates with the GRS 77 using an RS-485 digital interface.
Page 3-4
Rev. A
Figure 3-6. GRS 77 AHRS Unit
Figure 3-7. GMU 44 Magnetometer
G1000 System Maintenance Manual
190-00903-00