War in Ukraine

#25,230
#25,230
NorthDallas40 said:
Anything that flys any real distance or navigates for a couple of hours has to have GPS position updates to augment the inertial free navigation system. That’s the way all the tactical stuff works now. The only systems that free navigate for extended periods are our subs and they even surface to get a positional fix and feed the error info into their navigator for it to correct. However subs use gyros so large they are literally laid into the keel when the sub is built.
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OT but how do gyros work?
 
#25,231
#25,231
NorthDallas40 said:
Anything that flys any real distance or navigates for a couple of hours has to have GPS position updates to augment the inertial free navigation system. That’s the way all the tactical stuff works now. The only systems that free navigate for extended periods are our subs and they even surface to get a positional fix and feed the error info into their navigator for it to correct. However subs use gyros so large they are literally laid into the keel when the sub is built.
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I get that is what is being used a lot no because of simplicity. As early as the 60's we could hit a target with a decent degree of accuracy on the other side of the world with the Titan II's. GPS came in to use about the late 1990's early 2,000 I believe. I was an Artillery FO in Vietnam and I had to use good map reading and dead reckoning along with the occasional air burst to figure out where we were. A GPS system would have been so sweet. Doesn't our cruise missiles use terrain recognition software. We were using those before GPS was ever around. IF they have went to only one system for guidance then we need to fire a bunch of people.
 
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#25,233
#25,233
Redleg68 said:
Well Hog, I was an Artillery FO Junior Officer in Vietnam and I haven't blown up myself or the wrong people yet. :) I was pretty darn good at reading a map. Helped a lot with my Bass Fishing when I got out. :)
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You’d find one every now and then that knew the difference between direction and deflection…. :)
 
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#25,239
#25,239
hog88 said:
OT but how do gyros work?
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Depends on the technology. Most all of the modern ones use light based technology either Fiber Optic Gyros or Ring Laser Gyros. Basically you literally measure the transit time of light thru a know path length. The variance from the nominal time to transit the path length is proportional to the rotational rate of the gyro spool.

The older electro mechanical gyros use the exact same principal as a toy gyroscope. You take a proof Mass momentum wheel and spin it at a known angular speed to set up a specific angular momentum. If you rotate the gyro momentum wheel about its input axis it generates a “precession torque” about its output axis which again is proportional to the input rate.

There are all kinds of other types like semiconductor MEMS (micro electronics mechanical system ) which use semiconductor proof masses on a monolithic silicon substrate, quartz rate sensors which generate a signal voltage proportional to the strain energy in a proof crystal which is again proportional to input rate, and there is a really cool emerging technology called hemispherical resonant gyro or HRG which is very similar to a wine glass resonance excitation.

So basically the device measurement package generally provides some kind of output generally proportional to the rotational rate of the device about its input axis. And then we get to how they all work in what is called the “inertial frame”. But generally they all have some sensing mechanism which applies specific physical properties, such conservation of momentum to the speed of light, which provides as output measurement proportional to the rotational input rate.

Sorry you asked yet or you want me to go on?😎
 
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#25,240
#25,240
NorthDallas40 said:
Depends on the technology. Most all of the modern ones use light based technology either Fiber Optic Gyros or Ring Laser Gyros. Basically you literally measure the transit time of light thru a know path length. The variance from the nominal time to transit the path length is proportional to the rotational rate of the gyro spool.

The older electro mechanical gyros use the exact same principal as a toy gyroscope. You take a proof Mass momentum wheel and spin it at a known angular speed to set up a specific angular momentum. If you rotate the gyro momentum wheel about its input axis it generates a “precession torque” about its output axis which again is proportional to the input rate.

There are all kinds of other types like semiconductor MEMS (micro electronics mechanical system ) which use semiconductor proof masses on a monolithic silicon substrate, quartz rate sensors which generate a signal voltage proportional to the strain energy in a proof crystal which is again proportional to input rate, and there is a really cool emerging technology called hemispherical resonant gyro or HRG which is very similar to a wine glass resonance excitation.

So basically the device measurement package generally provides some kind of output generally proportional to the rotational rate of the device about its input axis. And then we get to how they all work in what is called the “inertial frame”. But generally they all have some sensing mechanism which applies specific physical properties, such conservation of momentum to the speed of light, which provides as output measurement proportional to the rotational input rate.

Sorry you asked yet or you want me to go on?😎
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Ok..ND you just killed my posting to VN tonight as I have a headache. Good night.
 
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#25,241
#25,241
Redleg68 said:
I get that is what is being used a lot no because of simplicity. As early as the 60's we could hit a target with a decent degree of accuracy on the other side of the world with the Titan II's. GPS came in to use about the late 1990's early 2,000 I believe. I was an Artillery FO in Vietnam and I had to use good map reading and dead reckoning along with the occasional air burst to figure out where we were. A GPS system would have been so sweet. Doesn't our cruise missiles use terrain recognition software. We were using those before GPS was ever around. IF they have went to only one system for guidance then we need to fire a bunch of people.
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You have no idea just how bad the average service member is at understanding what an 8 or 10 digit grid coordinate is or how many can’t spell MGRS 😎

They all carry handheld units called Pluggrs or Dagrs now. It gives them the 10 digit coordinate and points where they go. They don’t have to actually KNOW where they are.

And don’t get me started on crossing service boundaries to convert to/from MGRS to LLA or ECEF

Edit: oh and those old school ICBMs used a really cool electro mechanical gyro. They were called gas bearing rate integrating gyroscopes or RIGs. Very accurate instruments even by todays standards but just not economical anymore.
 
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#25,243
#25,243
NorthDallas40 said:
You have no idea just how bad the average service member is at understanding what an 8 or 10 digit grid coordinate is or how many can’t spell MGRS 😎

They all carry handheld units called Pluggrs or Dagrs now. It gives them the 10 digit coordinate and points where they go. They don’t have to actually KNOW where they are.

And don’t get me started on crossing service boundaries to convert to/from MGRS to LLA or ECEF

Edit: oh and those old school ICBMs used a really cool electro mechanical gyro. They were called gas bearing rate integrating gyroscopes or RIGs. Very accurate instruments even by todays standards but just not economical anymore.
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So if a non-destructive EMB was set off they would not be able to find their way back home?:) I have often said that if no physical destruction EMB bombs were developed we would all be back in the stone ages.
 
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#25,245
#25,245
Redleg68 said:
I get that is what is being used a lot no because of simplicity. As early as the 60's we could hit a target with a decent degree of accuracy on the other side of the world with the Titan II's. GPS came in to use about the late 1990's early 2,000 I believe. I was an Artillery FO in Vietnam and I had to use good map reading and dead reckoning along with the occasional air burst to figure out where we were. A GPS system would have been so sweet. Doesn't our cruise missiles use terrain recognition software. We were using those before GPS was ever around. IF they have went to only one system for guidance then we need to fire a bunch of people.
Click to expand...
Oh yeah on the cruise missiles a lot of that is public domain now but yes they used terrain and feature mapping to their on board reference library for mid course corrections and for terminal homing. And yeah they did it without GPS. Amazing as hell.

It would amaze you what we call a miss in todays accuracy expectations. When this stuff works it works VERY well. We hit what we’re shooting at “dead center”. The CEPs we work to now would shock you based on the gun patterns you were used to working with 😬
 
#25,246
#25,246
NorthDallas40 said:
You have no idea just how bad the average service member is at understanding what an 8 or 10 digit grid coordinate is or how many can’t spell MGRS 😎

They all carry handheld units called Pluggrs or Dagrs now. It gives them the 10 digit coordinate and points where they go. They don’t have to actually KNOW where they are.

And don’t get me started on crossing service boundaries to convert to/from MGRS to LLA or ECEF

Edit: oh and those old school ICBMs used a really cool electro mechanical gyro. They were called gas bearing rate integrating gyroscopes or RIGs. Very accurate instruments even by todays standards but just not economical anymore.
Click to expand...
So if a non-destructive EMB was set off they would not be able to find their way back home?:) I have often said that if no physical destruction EMB bombs were developed we would all be back in the stone ages.
NorthDallas40 said:
You have no idea just how bad the average service member is at understanding what an 8 or 10 digit grid coordinate is or how many can’t spell MGRS 😎

They all carry handheld units called Pluggrs or Dagrs now. It gives them the 10 digit coordinate and points where they go. They don’t have to actually KNOW where they are.

And don’t get me started on crossing service boundaries to convert to/from MGRS to LLA or ECEF

Edit: oh and those old school ICBMs used a really cool electro mechanical gyro. They were called gas bearing rate integrating gyroscopes or RIGs. Very accurate instruments even by todays standards but just not economical anymore.
Click to expand...
You ever done any work down around Huntsville?
 
#25,247
#25,247
Redleg68 said:
So if a non-destructive EMB was set off they would not be able to find their way back home?:) I have often said that if no physical destruction EMB bombs were developed we would all be back in the stone ages.
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The day the balloon goes up the first thing everyone does is knock out the other guys satellites. Nav and ISR. Then we’re all equally blind and yes equally lost. Pretty damn scary and sad at the same time.
 
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#25,249
#25,249
NorthDallas40 said:
Oh yeah on the cruise missiles a lot of that is public domain now but yes they used terrain and feature mapping to their on board reference library for mid course corrections and for terminal homing. And yeah they did it without GPS. Amazing as hell.

It would amaze you what we call a miss in todays accuracy expectations. When this stuff works it works VERY well. We hit what we’re shooting at “dead center”. The CEPs we work to now would shock you based on the gun patterns you were used to working with 😬
Click to expand...
Would have loved to had that during the day. When you were walking 105's to within 25/50 meters of you position you just prayed that everyone was doing their job. I know that in todays world if you are going up against a modern army, you had better be pretty good at shoot and scoot.
 
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