AH gyro
Free to move in all three planes.
Earth gyro held by gravity and spin axis is aligned with centre of the earth therefore has a plane of rotation is horizontal
Rate gyro
In a turn co ordinator 2 planes of rotation including spin axis, third plane is measured by precession. Horizontal axis and spins away from you
Tied gyro
Free in three planes held in in place by an external force such as air suction in a DI. Horizontal axis and vertical plane of rotation
L1 frequency
Course acquisition 1575mhz
L2 frequency
Military Py 1220mhz