单项选择题
A.follow-up system
B.transmitter
C.phantom element
D.azimuth motor
单项选择题 If the magnetic heading is greater than the compass heading，the deviation is（）.
单项选择题 If the gyrocompass error is east，what describes the error and the correction to be made to gyrocompass headings to obtain true headings?（）
单项选择题 If the compass heading and the magnetic heading are the same then（）.