Aperiodic Magnetic Compass. Special compasses have been developed for airplanes. Gyroscopic systems are especially useful in such applications because, unlike magnetic compasses, their accuracy is not affected by rapid alterations of course
GSA-040 Directional Gyro Compass with Heading Bug - Flightillusion B.V.
Flight Instruments: The Heading Indicator and Magnetic Compass – Learn to Fly Blog - ASA (Aviation Supplies & Academics, Inc.)
What does it mean to slave a gyroscope in aircraft avionics components? - Quora