[time-nuts] Slightly OT - GPS-Based Accurate Direction Finding

Jim Cotton jim.cotton at wmich.edu
Fri Aug 27 14:16:07 UTC 2010


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

bg at lysator.liu.se 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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