GYROSCOPE

Today's gyros can be categorized into three types:
Spinning-mass gyro , vibrating gyro , and laser gyro.
Other types (e.g. gas rate gyro) do exist but are not common.

SPINNING MASS GYROSCOPE
Probably the most commonly implied gyro that has a top
suspended with two perpendicular free moving brackets.
Due to gyroscopic effect the spinning mass tries to stay
with the fixed frame, hence the moving frame would know
how much it has moved. Prices vary from $50 to $10000
range depending on accuracy and precision. Demerit is
that because it is a precision mechanical device the life is
short compared to other types.
Used for: RC Heli, Stabilised Camera, Short-range Missiles

VIBRATING GYROSCOPE
A self-vibrating mass, when applied rotation produces
another vibration to a different direction by Corioli's
effect. �@Costs $10 to $1000. Small and long life, it is
suited for mass-produced products. There's a tendency
to output erroneous signals when external shock or
vibration exists. This tendency, however, has supposedly
been eliminated with recent developments.
Used for: Home Video Camera, Car Navigation,
Automotive (ABS), Stabilised platforms

LASER GYROSCOPE
A set of prisms, or optical fiber coil making the laser
go around many times inside a box, produces laser
ray to interfare when rotating. Costs at least a few
hundred dollars up to over $10000? Bulkiness and
expensive balances with high precision. Deterioration
of laser transmitter and fiber to consider.
Used for: Aircrafts, Cruising missiles