RIHNOSAUR
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Question Regarding Navigational Gyroscopes

Sat Mar 29, 2008 10:14 pm

Hello,

A while ago I posted a similar question regarding Fiber optic Gyroscopes and got some good answers. But now I have further questions regarding these navigational aids.

To make the story short I am currently working on a project within my company that relates to the development of new navigational aids. Specifically In order to help my research I am entertaining the idea of purchasing (if allowable within my project budget) the best commercially available Fiber optic or optical gyroscope system, that can be used in commercial aircraft.

Mainly I am trying to get some tips of which compannies sell them and how i would go about buying something like this. I Understand I will not be able to buy the absolute state of the art because that kind of stuff is not available for purchase..but I would like to get the best possible inertial rotation sensor possible that I can get "off the shelf".....I and I guess it would be some sort of fiber optical gyro.

....Id figured this would be a good place to start my investigation on this matter,

Thanks in advance
particles and waves are the same thing, but who knows what that thing is...
 
BoeingOnFinal
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RE: Question Regarding Navigational Gyroscopes

Sat Mar 29, 2008 11:07 pm

Honeywell is a well known equipment, although I can't find any pricing on any of their IRS products. But my guess is they're not cheap.
norwegianpilot.blogspot.com
 
avioniker
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 2:20 am

80K will get you a repairable ADIRU but there's no optics involved. That's jurassic.
Collins makes very nice AHRS' for their ProLine 21 systems. No moving parts and no optics to burn out.
The only thing you need any type of gyro for now days is stabilzing the autopilot.
Bottom line is, if you don't own a plane you won't be sold a unit. The export restrictions and controls are virtually insurmountable. You might be able to talk them into some sort of arrangement if your project is well designed and thought out and commplies with all the current laws and whatever laws whoever you talk to thinks there are, but. . .
You can try Rockwell Collins at 319-295-1000 but don't say I didn't warn you.
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One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
RIHNOSAUR
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 4:12 am



Quoting Avioniker (Reply 2):
80K will get you a repairable ADIRU but there's no optics involved

is ADIRU a maker for these things?? if there is no optics it must mems based???
I am intrested in a fiber optic or a laser ring gyro....

but that is more expensive than I thought.. was kind of hoping for a 30-50K unit...nevertheless, if you say its ancient..why is it so expensive???

The other thing that I should clarify is that I guess I would not be needing the full capabilities of an 80k+ unit. I am sure this has much more than we need Eg. multi axis rotational sensing.. integration capabilities and all sorts of avionics related electronics all I would want is a single axis detector and if possible with everything striped off the except the required electronics to generate a signal for the rotation along one axis.

any how that gets me a rough order of magnitude idea

Quoting Avioniker (Reply 2):
The export restrictions and controls are virtually insurmountable.

exporting where ..to to the US...what do you mean??
particles and waves are the same thing, but who knows what that thing is...
 
RIHNOSAUR
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 4:44 am



Quoting Avioniker (Reply 2):
80K will get you a repairable ADIRU but there's no optics involved.

did a quick search and this thing is pretty much the navigational heart of a 777...altitude airspeed attitude....the hole 9 yards.....thats why its 80k...

when you say Jurassic how "Jurassic" are these optical based systems??? I Believe an old 747-100 uses gimbaled systems and that's like 30 -40 years old...how old are optical based systems 10 years old 20 ..or 5 years old..???


thanks
particles and waves are the same thing, but who knows what that thing is...
 
tdscanuck
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 5:18 am



Quoting RIHNOSAUR (Reply 3):
is ADIRU a maker for these things??

ADIRU is an acronym. Air Data Inertial Reference Unit. It's the name for the black box with the gyros, among other functions, not a brand name as far as I know.

Quoting RIHNOSAUR (Reply 3):
I am sure this has much more than we need Eg. multi axis rotational sensing.. integration capabilities and all sorts of avionics related electronics all I would want is a single axis detector and if possible with everything striped off the except the required electronics to generate a signal for the rotation along one axis.

What you're looking for is the bare sensor. In that case, you probably don't want to be working with the avionics supplier, since they're probably getting it from someone else. Scientific instrument suppliers might be more up the alley of what you're describing.

Quoting RIHNOSAUR (Reply 3):
Quoting Avioniker (Reply 2):
The export restrictions and controls are virtually insurmountable.

exporting where ..to to the US...what do you mean??

High precision gyros are an important part of military guidance systems. As a result, they're heavily regulated under either the EAR or ITAR (I can't remember which offhand) in the US. This controls who can have them, what they can do with them, and where they can send them.

Tom.
 
Tristarsteve
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 8:34 am



Quoting RIHNOSAUR (Reply 4):
when you say Jurassic how "Jurassic" are these optical based systems??? I Believe an old 747-100 uses gimbaled systems and that's like 30 -40 years old...how old are optical based systems 10 years old 20 ..or 5 years old..???

The first Laser gyro I met was on the B757/B767 which arrived in 1983. At that time all nav gyros were spinning tops with springs and accelerometers. You will still find these mechanical gyros in older aircraft.

Quoting RIHNOSAUR (Reply 4):
did a quick search and this thing is pretty much the navigational heart of a 777...altitude airspeed attitude....the hole 9 yards.....thats why its 80k...

The ADIRU on the B777 is a single box. It contains laser gyros and accelerometers all in one box. Definitely too complicated for you. The A320 has three ADIRU's. in separate boxes. But an ADIRU is still too complicated because it includes the AD part (air data). You don't need this. You need an IRU (Inertial sensing unit) which is just laser gyros and accelerometers. But the output from an IRU is digital data. You need something to digest this information.
Surely the best bet is to look for a Laser gyro based navigation set for a small business jet where everything is in one box including the computors and the display?
 
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zeke
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 10:04 am



Quoting RIHNOSAUR (Thread starter):

Have a look at http://www.pcflightsystems.com/ I have been thinking for some time about getting one for my nav bag.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
RIHNOSAUR
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RE: Question Regarding Navigational Gyroscopes

Sun Mar 30, 2008 5:43 pm



Quoting TristarSteve (Reply 6):
You need an IRU (Inertial sensing unit) which is just laser gyros and accelerometers. But the output from an IRU is digital data. You need something to digest this information.

Exactly, that is what I am looking for,.... just the bare laser gyro.
Now in my case there is nothing wrong with having a raw digital data output, Myself and our team know enough about electronics and signal processing that we can handle that. Or we could rig something up to read out the rotational rate info (which is what we are after)

Quoting TristarSteve (Reply 6):
It contains laser gyros and accelerometers all in one box.

OK, so sounds like the Laser Gyro is not that old after all, if they use it in the ADIRU of the triple seven.
particles and waves are the same thing, but who knows what that thing is...
 
avioniker
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RE: Question Regarding Navigational Gyroscopes

Mon Mar 31, 2008 1:34 am

I guess I don't understand why you are so stuck on laser gyro technology.
The first laser rings came out in the early 70's and like fiber optics, everyone jumped on the bandwagon and thought they were great.
The current technology uses a vibrating reed technology which replaces gyros, accelerometers, and lasers. The reed vibrates at a constant frequency dependant on the input voltage. It's impervious to frequency and temperature variations because it has extremely low mass. The current accuracy is better than 1/2 mm per 24 hours in a moving environment.
Hence my "lasers are jurassic" statement.
Call Rockwell Collins or Honeywell and maybe they'll turn you on to their suppliers. Sorry but I can't.
Lear Siegler used to make a pretty good AHRS that didn't cost an arm and a leg.
I didn't know the Honeywell or Thales ADIRU's used lasers. I thought they were more 80's technology.
Live and learn, eh?
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