Since most solid state, so called gyros, if not all use a capacitor
 bridge circuit to sense acceleration and this is how they work.

 The mass is seeing the one G acceleration force due to gavity
 and is deflected downward. That means the spacing between the plates
 of C1 gets larger and the spacing of C2 gets smaller.

 As the spacing of the plates of a capacitor get larger
 the capacitance is reduced. When the spacing gets smaller
 the capacitance is increased.

 Think of a capacitor as a variable resisters for waves.

 There is an oscillator that supplies a constant amplitude  sine wave to the
device.

 The amplitude of the wave coming out of this circuit will
 then be proportional to the number of G's the mechanical circuit is
subjected
 too.

 Very high frequencies are used as these capacitors are tiny to say the
least.
 The basic capacitance is on the order of only one pico farad.

 The wave amplitude coming out can be rectified or converted to DC and
 then fed to an A to D for computer input. Use four of them
 mounted equally spaced in a circle and you have a angular rate sensor.

 This is an extremely simple idea and it is easy to make.
 One can make their own, in any shop, using nothing but hand tools,
 vastly scaled up from what one finds in a MEMS chip.

 Paul Lamar


 It seems that you are discounting the sensors based on vibrating beam and
the Coriolis effect.  Not sure why..  These are the sensors that actually
act like gyroscopes.

 http://m.sensorsmag.com/sensors/acceleration-vibration/an-overview-mems-inertial-sensing-technology-970


 Regards,

 Matt-

 Again they are misusing the term "gyroscope" for marketing purposes IMHO. A
real gyroscope is a 3D device. A change
 in the Z axis of the real gyroscope results in a force in the X or Y axis.
You get both roll and
 pitch information from one device.

 "As a result, the gyroscope[???] provides accurate angular rate sensing for
rate changes from very small
 to very large, with minimal errors from short- or long-term drift."

 These are plainer devices hence they are angular rate sensors. It takes two
and computer
 integration to get roll and pitch information. The beam deflection they are
talking about
 here can be sensed by the same bridge capacitor electronics.

 http://en.wikipedia.org/wiki/Coriolis_effect

"In physics, the Coriolis effect is a deflection of moving objects when they
are viewed in a rotating reference frame. In a reference frame with
clockwise rotation, the deflection is to the left of the motion of the
object; in one with counter-clockwise rotation, the deflection is to the
right."

 Note: no mention is made of a 3D system.

 Also they are not telling you how they sense the deflection of the sensing
beam.


 Paul Lamar

 http://en.wikipedia.org/wiki/Vibrating_structure_gyroscope


 Matt-

And: http://en.wikipedia.org/wiki/Halteres


Matt-

Agree that a vibrating structure gyro is not an accelerometer. It
should measure absolute change in heading. It's closer to this:

http://en.wikipedia.org/wiki/Foucault_pendulum

-Chris

No I don't agree.
It is not a gyro!!!!!

A pendulum senses the vertical. Is it a gyro. Hell no!!!!


Paul Lamar