Sammo
New member
Same as you Ken. They follow the ferrys.
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How do submarines navigate?
- Thread starter Twister_Ken
- Start date
Piers
Well-known member
When I used to use Inertial, it did indeed drift. But, by inputting a precise position during use, it would understand it had made an error and teach itself not to do it again! In other words, the more the set was used, the more accurate it became.
tome
New member
Sadly, IN cannot repair it's own drift so is often coupled to another nav system which can kick out the error from time to time to keep it on the beaten track. An occasional GPS position via periscope will do very nicely
Have never navigated a sub, but was offered a job by Barr & Stroud in Glasgow who make the periscopes. Subs have 2 of these - a small attack model with a low surface footprint, and the big mother which can track panty hose on a line 2 miles away from the factory and has built-in sextant etc
One big consideration is not giving away the sub position, so limited pinging. Also, though I'm probably giving away more than should, there are sea bed cables which can detect the transit of a sub ahem, some around northern Norway etc
It's a black art down there
Have never navigated a sub, but was offered a job by Barr & Stroud in Glasgow who make the periscopes. Subs have 2 of these - a small attack model with a low surface footprint, and the big mother which can track panty hose on a line 2 miles away from the factory and has built-in sextant etc
One big consideration is not giving away the sub position, so limited pinging. Also, though I'm probably giving away more than should, there are sea bed cables which can detect the transit of a sub ahem, some around northern Norway etc
It's a black art down there
Piers
Well-known member
Hi Tome, the INS on the Boeing 707 I used to fly was able to refine its drfit by inputting position as I said. This was further refined (after I left the airline) by automatic position updating using radio beacon bearings & distance. Again, this would teach the INS accordingly.
But no cables in the sky to determine where we were....
But no cables in the sky to determine where we were....
Twister_Ken
Well-known member
Re: How did submarines navigate?
"In WW2 they had problems"
But at least in WW2 they had to surface frequently to charge batteries, so they had a chance of getting a sight, or some electronic bearing lines, before nipping down again for the next bout of underwater DR.
"In WW2 they had problems"
But at least in WW2 they had to surface frequently to charge batteries, so they had a chance of getting a sight, or some electronic bearing lines, before nipping down again for the next bout of underwater DR.
tome
New member
Yes, it could refine its position but sadly could never 'learn' though it sounds neat
woody001
New member
they use SINS.
tome
New member
Don't you think you've enough on your plate Si?
tome
New member
Piers
On your 707 you'd have had 3 IN systems, and could monitor the error between them. Reason for 3 was that if there were 2, you could never be sure which one had gone tits up
On your 707 you'd have had 3 IN systems, and could monitor the error between them. Reason for 3 was that if there were 2, you could never be sure which one had gone tits up
woody001
New member
Ships Inertial Navigation System - yes devloped by the us navy, just to wind a few up on here! Made by boeing, must new subs have 2 sims systems, go on a Trident sub.
Yea things have been a bit mad, but iam only trying to make a go with my life.
Yea things have been a bit mad, but iam only trying to make a go with my life.
woody001
New member
oh hang on, someones already talking about sims...opps, should read these threads.
mikejames
New member
Apart from R4 with the story which I didnt hear,
I think somewhere in a GPS journal is a description of the voyage of the USS Nautilus to the North Pole, in which they describe recalibrating the gyros in the inertial navigation system so that the North Pole was placed somewhere on the equator. That was to prevent errors in maths stopping them reaching the pole as the latitude hit 90 degrees.
The whole idea of that submarine is that it knew where it was accurately enough to hit a city with a missile reckoning its position from the submarine, and the stars. Without GPS or Loran or Decca. On receipt of the slow transmissions on 10kHz giving the ultimate command...
I think somewhere in a GPS journal is a description of the voyage of the USS Nautilus to the North Pole, in which they describe recalibrating the gyros in the inertial navigation system so that the North Pole was placed somewhere on the equator. That was to prevent errors in maths stopping them reaching the pole as the latitude hit 90 degrees.
The whole idea of that submarine is that it knew where it was accurately enough to hit a city with a missile reckoning its position from the submarine, and the stars. Without GPS or Loran or Decca. On receipt of the slow transmissions on 10kHz giving the ultimate command...
capt_courageous
New member
Oh yes it could.
bilbobaggins
N/A
One of the residual reasons for the continued production of the Nautical Almanac, jointly, by ourselves and the US is that the 'boomers' still have a requirement to be able to fix really accurately by astro. They can get their star fixes down to about 0.1 nm, reliably, if left undisturbed.
I leave it to others to consider in what circumstances MilSpec GPS ( a handful of centimetres ) would no longer be available to them.....
The Royal Air Force no longer have that requirement, but when they did, their Air Almanacs permitted a notional accuracy of 0.25 nm. However, with some specialised tweaking, the better Vulcan guys could regularly drop 'practice bombs' ( RBS ) to within 150 metres CEP.
That's close enough for Government work.... especially with a 5-megaton shape!
/forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
I leave it to others to consider in what circumstances MilSpec GPS ( a handful of centimetres ) would no longer be available to them.....
The Royal Air Force no longer have that requirement, but when they did, their Air Almanacs permitted a notional accuracy of 0.25 nm. However, with some specialised tweaking, the better Vulcan guys could regularly drop 'practice bombs' ( RBS ) to within 150 metres CEP.
That's close enough for Government work.... especially with a 5-megaton shape!
/forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
tome
New member
And if IN had the ability to self-train, the almanacs wouldn't need to be published and nor indeed would there be any need for the expense of putting up a gps constellation in the first place
jprstoney
New member
My father used to work on subs carrying ICBMs. He tested the telemetry systems for the missiles (which were programmed on BBC micros in the 80's). It turned out that during 10 year tests that 70% of the mock launches either didn't work or couldn't locate their target as they didn't have a start point.......comforting isn't it.
Cruiser2B
Active member
Nautilus predates INS. See again "expanding pool of errors." INS now use ring laser gyro's and ultra-sophiticated accelerometers. GPS fixing is still done to calibrate the systems, but they are now so accurate that the drift is next to nothing. The GPS is still required for the cruise missiles that they launch though...
Kevin
Kevin
Evadne
Active member
Our little one uses PHINS and an ADCP when underwater, GPS on the surface. So now you know.
Twister_Ken
Well-known member
"PHINS and an ADCP "
PHINS - Pretty Horrible Inertial Navigation System?
ADCP - Advanced Depth Charge Program?
PHINS - Pretty Horrible Inertial Navigation System?
ADCP - Advanced Depth Charge Program?
