What principle does the attitude indicator in the G1000 use?
G1000 is a multi-unit system. The attitude information comes from a specialised unit called AHRS (Attitude and Heading Reference System), typically GRS 77. AHRS uses two solid-state gyros (vertical and directional), plus a magnetometer, to obtain a complete attitude information.

In addition, AHRS does employ accelerometers and rate gyros. Their data is used for stabilisation, filtering, and as an input for autopilot and other systems.