jimi
Well-known member
A large friend of mine is considering using this on his Nicholson to aid him in his mud slithering. Will it help?
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Inertial Navigation
- Thread starter jimi
- Start date
longjohnsilver
Well-known member
Come on then Jimi tell us all about inertial navigation, I believe you're an expert!
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Ships_Cat
New member
I am sure that it will be an aid and would be very interested in hearing more about it.
We here at Ship Hydrodynamic Investigations and Technologies have been recently working on Natural Navigation and will soon be publishing our findings - perhaps there is something in common if birds are involved?
John
<hr width=100% size=1>I am the cat but I am only 6.
We here at Ship Hydrodynamic Investigations and Technologies have been recently working on Natural Navigation and will soon be publishing our findings - perhaps there is something in common if birds are involved?
John
<hr width=100% size=1>I am the cat but I am only 6.
jfm
Well-known member
It's standard on BMWs (cos the GPS signal is lost in tunnels, so the inertial takes over)
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Cutter
Active member
Is this where you hit a container and tell everyone else its at the other side of the IoW?
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jimi
Well-known member
Well it works like this
there are vertical and horizonral motion sensors and it works by knowing where you've started from and how you've moved from there.
I feel there are several fundamental flaws in my friends plan
1) He often does'nt know where he's started from
2) There is very little vertical or indeed horizontal motion whilst at sea.
3) The mud often moves whilst his craft dont
perhaps inertial navigational systems attached to mud particles could provide a real time chart of the East Coast
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there are vertical and horizonral motion sensors and it works by knowing where you've started from and how you've moved from there.
I feel there are several fundamental flaws in my friends plan
1) He often does'nt know where he's started from
2) There is very little vertical or indeed horizontal motion whilst at sea.
3) The mud often moves whilst his craft dont
perhaps inertial navigational systems attached to mud particles could provide a real time chart of the East Coast
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longjohnsilver
Well-known member
Well maybe he'd be better off with a long piece of string, let it out on the way out and reel it back in when coming home.
Problem solved!
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Problem solved!
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PaulJ
Member
I can't for the life of me see why anybody would want to use Intertial Nav on a boat when GPS is so cheap, accurate and available.
Inertial was originally developed for the Space programme because it needs no external reference other than a gyro's tendancy to maintain it's position with reference to Space rather than Earth. However the Earth is moving in relation to "Space" so when an inertial system is used with reference to the Earth it has to be continuously updated to compensate for the fact that the Earth itself is moving.
In aircraft, the gyro's "precession" was (and often still is) updated with reference to Radio aids where they are within range. On long hauls where there are no radio aids, over the ocean for instance, an inertial platform would be a few miles out by the time it came within range of the radio aids on the other side.
Initially the Aviation industry was reluctant to use GPS because it was principally used by the military and there was always the fear that it could be switched off. Nowadays confidence in GPS has grown and it is increasingly used to update the still widely used inertial systems.
I believe some large vessels do use Inertial but I really can't imagine why.... Inertial is a fine system in some applications but for every application I can think of on the water..... except perhaps Submarines.... GPS is cheaper, easier to use and more accurate.
Hope this helps.
Paul.
<hr width=100% size=1>I used to have an open mind but my brains kept falling out.....
Inertial was originally developed for the Space programme because it needs no external reference other than a gyro's tendancy to maintain it's position with reference to Space rather than Earth. However the Earth is moving in relation to "Space" so when an inertial system is used with reference to the Earth it has to be continuously updated to compensate for the fact that the Earth itself is moving.
In aircraft, the gyro's "precession" was (and often still is) updated with reference to Radio aids where they are within range. On long hauls where there are no radio aids, over the ocean for instance, an inertial platform would be a few miles out by the time it came within range of the radio aids on the other side.
Initially the Aviation industry was reluctant to use GPS because it was principally used by the military and there was always the fear that it could be switched off. Nowadays confidence in GPS has grown and it is increasingly used to update the still widely used inertial systems.
I believe some large vessels do use Inertial but I really can't imagine why.... Inertial is a fine system in some applications but for every application I can think of on the water..... except perhaps Submarines.... GPS is cheaper, easier to use and more accurate.
Hope this helps.
Paul.
<hr width=100% size=1>I used to have an open mind but my brains kept falling out.....
tome
New member
IN was originally developed for aircraft and used conventional gyros on gimballed platforms. It is undetectable and unjammable. Later systems use various forms of strapdown rate gyro (now mostly laser) which don't need the gimballed mechanics. IN is very good at short-term accuracy but subject to long term drifts, some predictable.
IN will continue to be used on aircraft for the foreseeable future, slaved to GPS. It also provides attitude and heading references (AHRS) to other avionics. GPS for critical applications has some perceived weaknesses which are being addressed, but integrity is also an issue. It can take 6 seconds to detect and flag a GPS error, which is a long time in terms of flight.
AHRS is also used in tanks and fighting vehicles where there is a need to stabilise eg gun platforms.
For East Coast adventures, I think the ball of string is the correct approach.
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IN will continue to be used on aircraft for the foreseeable future, slaved to GPS. It also provides attitude and heading references (AHRS) to other avionics. GPS for critical applications has some perceived weaknesses which are being addressed, but integrity is also an issue. It can take 6 seconds to detect and flag a GPS error, which is a long time in terms of flight.
AHRS is also used in tanks and fighting vehicles where there is a need to stabilise eg gun platforms.
For East Coast adventures, I think the ball of string is the correct approach.
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jimi
Well-known member
Not a trail of butt ends?
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ChrisE
Active member
Ah, we at Buttmaster HQ, sniff an opportunity here.
Now that you won't be able to smoke in public, we will be offering a service for people to smoke in private and keep the butts for sale as navving aids to poor mud slitherers. Should be a money spinner, methinks.
BM HQ
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Now that you won't be able to smoke in public, we will be offering a service for people to smoke in private and keep the butts for sale as navving aids to poor mud slitherers. Should be a money spinner, methinks.
BM HQ
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Graham_Wright
Well-known member
Er.........no.
Our system on a sub found a hole in the Artic ice cap rather well.
Are there any other literalists out there?!
<hr width=100% size=1>GBW
Our system on a sub found a hole in the Artic ice cap rather well.
Are there any other literalists out there?!
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MarkJohnson
New member
jfm
Well-known member
BMW Inertial Navigation
Ah well some tunnels have junctions innem. The old mersey tunnel frexample had a left fork, and the little tunnel leaving Monte Carlo has a bit of a T junction. So the gyro and IN is all very necessary gear. Also if you go into the set up screen by holding menu for 10secs or summink you can get a direct acceleration readout from the gyro. Useful when cornering hard, becuase when it approaches 1g you know to take extra care
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Ah well some tunnels have junctions innem. The old mersey tunnel frexample had a left fork, and the little tunnel leaving Monte Carlo has a bit of a T junction. So the gyro and IN is all very necessary gear. Also if you go into the set up screen by holding menu for 10secs or summink you can get a direct acceleration readout from the gyro. Useful when cornering hard, becuase when it approaches 1g you know to take extra care
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sailorman
Well-known member
a friend of mine wus trained ( @ great expence to the taxpayer) in this system, that involved many Gyros & wus accurate to within yards after 1000s of miles some, 20 yrs ago.
he wus a clean shaven little ossifer & jollied south to see the pinguins with Georgia on his mind.
Left soon after for some reason
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he wus a clean shaven little ossifer & jollied south to see the pinguins with Georgia on his mind.
Left soon after for some reason
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tome
New member
Re: BMW Inertial Navigation
John
I think the term IN is used rather loosely nach Muenchen! It's basically a compass and an odometer connection AFAIK.
Tom
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by tome on 16/11/2004 20:51 (server time).</FONT></P>
John
I think the term IN is used rather loosely nach Muenchen! It's basically a compass and an odometer connection AFAIK.
Tom
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by tome on 16/11/2004 20:51 (server time).</FONT></P>
jfm
Well-known member
Re: BMW Inertial Navigation
Nope Tom, it definitely has gyro to measure cornering acceleration, plus a speedo link to get road speed. It can compute the car's track around a bend. In one of the set up screens you can get a direct read out of the gyro data
I'm refering to the VDO satnav unit with the widescreen TV, as fitted to 5 series, X-5 and RangeRovers for the last few years
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Nope Tom, it definitely has gyro to measure cornering acceleration, plus a speedo link to get road speed. It can compute the car's track around a bend. In one of the set up screens you can get a direct read out of the gyro data
I'm refering to the VDO satnav unit with the widescreen TV, as fitted to 5 series, X-5 and RangeRovers for the last few years
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tome
New member
Re: BMW Inertial Navigation
Blimey John, I stand well corrected, sorry.
Such a system may have prevented me from rolling my new beemer back in '80 as I'd have had widescreen warnings and surround-sound steering commands. In them days it was the personal gyro what got you round the bend. Or not, in my case.
I had an early computer, but it annoyed me with its constant nagging at my fuel economy and I frequently over-rode it with predictable consequences. No-one to sue in them days, had to take the insurance hit on the chin.
Happy days!
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Blimey John, I stand well corrected, sorry.
Such a system may have prevented me from rolling my new beemer back in '80 as I'd have had widescreen warnings and surround-sound steering commands. In them days it was the personal gyro what got you round the bend. Or not, in my case.
I had an early computer, but it annoyed me with its constant nagging at my fuel economy and I frequently over-rode it with predictable consequences. No-one to sue in them days, had to take the insurance hit on the chin.
Happy days!
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Peppermint
New member
Re:That would
have tumbled the gyro. So not only would you have been upside down but you'd be lost as well.
Anyway this solves Jimi's friends problem. If he just straps a BMW to his foredeck he's away. Bound to be cheaper than buying a yottie system anyway.
How many yachts get lost in tunnels????
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by Peppermint on 16/11/2004 21:26 (server time).</FONT></P>
have tumbled the gyro. So not only would you have been upside down but you'd be lost as well.
Anyway this solves Jimi's friends problem. If he just straps a BMW to his foredeck he's away. Bound to be cheaper than buying a yottie system anyway.
How many yachts get lost in tunnels????
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by Peppermint on 16/11/2004 21:26 (server time).</FONT></P>
tome
New member
Re:That would
Aha!
Now we come to the need for the 4th gimbal, a difficult concept to grasp with IN.
Imagine you are at 90 degs left roll and 90 deg downward pitch. Your heading axis is now pointing at the ditch, and you can hear sirens approaching. You foolishly accepted the bet that you couldn't neck a pint of creme de menthe in under a minute just before launch. Time's running out, and Q's let you down with the fountain pen.
The 4th gimbal gets you out of trouble by banking to the right to compensate, returning your heading to its normal axis thus allowing you to leg it down the road. Unfortunately, mine was an early beemer.
This 99 Rioja Crianza has a lot to answer for
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Aha!
Now we come to the need for the 4th gimbal, a difficult concept to grasp with IN.
Imagine you are at 90 degs left roll and 90 deg downward pitch. Your heading axis is now pointing at the ditch, and you can hear sirens approaching. You foolishly accepted the bet that you couldn't neck a pint of creme de menthe in under a minute just before launch. Time's running out, and Q's let you down with the fountain pen.
The 4th gimbal gets you out of trouble by banking to the right to compensate, returning your heading to its normal axis thus allowing you to leg it down the road. Unfortunately, mine was an early beemer.
This 99 Rioja Crianza has a lot to answer for
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