Hi:
An interesting fact about gyros, independent of how they work, is that
their Long Term Drift Rate is proportional to some power of the inverse
of their volume. As the sensor gets smaller the LTDR goes up as 10 ^ 4
http://www.prc68.com/I/Sensors.shtml#Gyroscopic
Ring Laser Gyros at 7E-4 deg/hour to MEMS at 1000 deg/hr.
I find the AG8 North Finding Gyro theodolite system very interesting,
but have heard that's it's very easy to break the gyro suspension and so
buying one used is very risky if you want to actually use it. It uses
a classical spinning mass gyro to find True North. I expect it's still
being used in places where GPS is not available, like in caves.
An old web page on North Finding:
http://www.prc68.com/I/North.shtml
Have Fun,
Brooke Clarke
http://www.PRC68.com
Jim Cotton wrote:
Back in the early 1980's when attending college I worked on a single
axis multi-mode fiber optic
rate gyro project that used GRIN fiber. Back then a military three
axis unit based on single mode
fiber was alleged to be a little larger than a one inch cube and cost
slightly less than a million dollars.
We used a three inch spool for the fiber and put everything in a six
inch cube for a housing.
The NASA contract was part of the NASP program.
The company that we worked with wanted to produce a product for the
commercial "private
pilot" aviation market. I will have to ask what happened...
I think the patent issue may have had something to do with it since
the company had a
relationship with Litton.
Jim Cotton
n8qoh
[email protected] wrote:
Does anyone know how laser gyroscopes are developing?
Laser gyroscopes - as in Ring Laser Gyroscopes or as in Fiber Optic
Gyroscopes?
RLGs are a standard commercial product. Several years back I was
walking through the Honeywell plant in St Paul, MN, and they had a
display case of at least a dozen RLGs that they've made over the past
few decades.
Commercial?
US RLGs are all ITAR.
"All types of gyros usable in the systems in Item 1, with a rated drift
rate stability of less than 0.5 degree (1 sigma or rms) per hour"
http://www.fas.org/spp/starwars/offdocs/itar/p121.htm
Honeywell has about 2 different RLGs. Only one (gg1320) of which you can
make a north sensing out of. Litton (now NGC) used to do RLGs (their
"zero
lock gyros") but I think they were on the loosing side of a patent war
with Honeywell.
French Sagem do some for high end military systems. Have I missed a RLG
manufacturer? Almost as few vendors as in the Cesium oscillator
market...
No new RLG sensors has been announced during the last decade or two.
--
Björn
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--
Have Fun,
Brooke Clarke
http://www.PRC68.com
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