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| Member |
Nowadays, mechanical gyros are mostly used for stabilization. Which lets tanks like the abrahms fire accurately on the move. Navigation grade gyros are typically fiber optic (FOG) or Ring Laser (RLG). | |||
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His Royal Hiney |
This is interesting. No moving parts?? It's hard to wrap my mind on anything that would work in place of a stable static reference such as a gyroscope. The active sonar isn't a different type. It's the same sonar module except instead of receiving (changing a sound signal to an electrical signal), it's transmitting (changing an electrical signal to a sound signal). Just like plain headphones can be turned to microphones by plugging it into the microphone socket (I'm not talking about cell phone headphones with the microphone included). "It did not really matter what we expected from life, but rather what life expected from us. We needed to stop asking about the meaning of life, and instead to think of ourselves as those who were being questioned by life – daily and hourly. Our answer must consist not in talk and meditation, but in right action and in right conduct. Life ultimately means taking the responsibility to find the right answer to its problems and to fulfill the tasks which it constantly sets for each individual." Viktor Frankl, Man's Search for Meaning, 1946. | |||
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Glorious SPAM! |
Interesting. We still use mechanical gyros in all of our navigation systems also. At least the three types of navigation units we use in the tank do. I can see how the mechanical is used for sighting and fire control, it works. But unless us land based boys are behind the curve we still use the same for the INU. Instant on is something we look for. Going from power on to stabilized in an instant would be a benfit. A FOG (or an RLG) would be great. Going from unstab to stab right after power up would be nice. Not getting outside the box, the US Army runs an M1A1 with a certain type of INU, they have an M1A2 SEP with another type, and the USMC has a different M1A1 with yet a third type of navigation unit (the FEP tank). Because we need to be different. Ugg. And all still have spinning gyros. Who knows maybe someday we will upgrade (the USMC will be last trust me. If it isn't free or at least super cheap the USMC dosen't care. We are like the old neighborhood guy who still rolls his own cigarettes because he saves .03 cents a smoke...not that I am complining, and we still gets the job done, but...).  | |||
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| Run Silent Run Deep  |
On my boat, we had a large window in the front that was manned 24/7. There was also a wiper switch to keep the water off the window so the guy could see. For other ships and boats in the area, we used the Marco-Polo sonar. One button pushed issued a “Marco” signal...the other issued a “Polo” signal if you were hailed. _____________________________ Pledge allegiance or pack your bag! The problem with Socialism is that eventually you run out of other people's money. - Margaret Thatcher Spread my work ethic, not my wealth | |||
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fugitive from reality |
"Give me a ping, Vasili. One ping only." _____________________________ 'I'm pretty fly for a white guy'. | |||
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| california tumbles into the sea |
We're in the lane and approaching the first turn. Come left to course 195 in 30 seconds. Decrease depth to 200 meters. Maintain speed. Captain, we are approaching the first turn. Increase speed to 26 knots and recompute. Aye Captain. Navigator, recompute for 26 knots. Turn on my mark Five, four, three, two, one, mark. Diving control, come left to 195. Up on the bow planes. Course now 195 and maintaining speed 26 knots. | |||
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| Too soon old, too late smart |
Well, all this explains why submariners always win at “pin the tail on the donkey.” | |||
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Member |
Yep, no moving parts. A traditional mechanical gyrocompass works by using gyroscopic precession to align a gyroscope with the axis of the rotation of the earth (since things on the surface of the earth rotate with the earth). A fiber optic gyrocompass or ring laser gyrocompass just measures the rotation of the instrument itself with enough precision to detect the rotation of the earth directly (obviously it has to do this over some period of time, while subtracting out the local movement of the instrument).
I meant that it's different in use - listening to the sounds produced by other objects vs. generating sound that bounces off of other objects and listening for the echo. Also, I would be somewhat surprised if there weren't separate active and passive sonar transducers (and possibly separate transmitting and receiving transducers for active sonar) - I expect the range of frequencies of interest would be different, and I expect you could make a transducer more sensitive if it didn't have to pump out super high-power sound pulses. I was confused by your comment "Sonar is for passive listening. If you go active..." It sounded like you were saying active sonar isn't sonar. Obviously that isn't what you meant. | |||
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| His Royal Hiney |
Somehow, I fascinated with the no moving part. I'll try to find out more when I have the time. I can confirm it's only one type of sonar transducers. I've removed them myself from the submarine nose, standing on rebars and manually wrenching the rusted nuts loose. I've also worked on refurbishing them once off the sub. There wasn't no attempt to differentiate one transducer from another. If there is any differentiation which also makes sense to me as 1) you may not want to ping all around but just to a particular section away fro the sub and 2) you don't want to lag while switching from pinging to listening, the difference must be in the electronics in the sonar control equipment since you don't need all the modules to ping. But I'd think you'd want all to be able to listen also since you wouldn't want to waste the ability. "It did not really matter what we expected from life, but rather what life expected from us. We needed to stop asking about the meaning of life, and instead to think of ourselves as those who were being questioned by life – daily and hourly. Our answer must consist not in talk and meditation, but in right action and in right conduct. Life ultimately means taking the responsibility to find the right answer to its problems and to fulfill the tasks which it constantly sets for each individual." Viktor Frankl, Man's Search for Meaning, 1946. | |||
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