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Groups > sci.physics.relativity > #358787 > unrolled thread
| Started by | Lofty Goat <rlwatkins@gmail.com> |
|---|---|
| First post | 2015-07-26 23:44 -0500 |
| Last post | 2015-07-28 22:01 +0000 |
| Articles | 20 on this page of 97 — 16 participants |
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Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Lofty Goat <rlwatkins@gmail.com> - 2015-07-26 23:44 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-07-27 22:52 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-07-28 16:41 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-01 12:32 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-02 15:51 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-02 20:29 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-03 01:12 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-03 00:07 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-02 19:32 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-03 12:17 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-03 19:00 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Bohuš Matuška <bohu@paranetnet.net> - 2015-08-03 18:01 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-03 20:31 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Bohuš Matuška <bohu@paranetnet.net> - 2015-08-03 19:28 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-03 18:01 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-03 19:47 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-03 14:52 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-03 23:00 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Ignorant Raving Crackpot <ignorantravingcrackpot@gmail.com> - 2015-08-03 14:32 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-06 10:36 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-07 07:58 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-07 08:35 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-07 10:13 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-08 00:26 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-07 22:25 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-08 07:14 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-08 05:44 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Emmerich Schultheiß <emme@noemail.thx> - 2015-08-08 13:23 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-08 10:16 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-08 10:34 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-09 10:47 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-09 17:09 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Emmerich Schultheiß <emme@noemail.thx> - 2015-08-09 17:24 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-09 17:56 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-09 20:05 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-09 18:44 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Emmerich Schultheiß <emme@noemail.thx> - 2015-08-09 19:08 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-10 10:49 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-09 19:53 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-09 18:47 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-09 17:52 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-10 00:07 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-09 22:33 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-09 22:55 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-09 22:58 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-10 10:54 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-10 17:38 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-10 18:07 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-11 01:11 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-10 23:28 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-09 20:43 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-10 10:55 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-10 11:01 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-10 09:32 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-10 17:42 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-11 11:38 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-11 23:00 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-11 22:27 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-11 22:12 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-11 20:05 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Tom Roberts <tjroberts137@sbcglobal.net> - 2015-08-12 23:32 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-13 07:32 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Odd Bodkin <bodkinodd@gmail.com> - 2015-08-13 07:30 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-13 13:11 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Odd Bodkin <bodkinodd@gmail.com> - 2015-08-13 08:23 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-13 13:28 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-13 15:20 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-13 13:22 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Odd Bodkin <bodkinodd@gmail.com> - 2015-08-13 07:24 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-13 15:10 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-13 13:15 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <Poutnik4NNTP@gmail.com> - 2015-08-13 15:21 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System paparios <paparios@gmail.com> - 2015-08-13 06:24 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Felipe Delgado <fd@spreadspectrum.org> - 2015-08-13 13:31 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-13 19:02 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-13 19:07 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-13 16:26 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Ignorant Raving Crackpot <ignorantravingcrackpot@gmail.com> - 2015-08-13 14:13 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Odd Bodkin <bodkinodd@gmail.com> - 2015-08-13 16:35 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-13 21:52 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Ignorant Raving Crackpot <ignorantravingcrackpot@gmail.com> - 2015-08-13 21:46 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Odd Bodkin <bodkinodd@gmail.com> - 2015-08-14 07:42 -0500
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-14 14:04 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System paparios <paparios@gmail.com> - 2015-08-13 16:02 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System John Gogo <jfgogo22@yahoo.com> - 2015-08-13 18:57 -0700
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System dsr@mail.lns.cornell.edu (Daniel S. Riley) - 2015-08-13 12:27 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-11 22:20 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-09 11:39 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-09 12:42 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-11 14:40 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Poutnik <poutnik4nntp@gmail.com> - 2015-08-11 22:35 +0200
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Jackpol11@hotmail.com - 2015-08-12 21:56 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-03 17:57 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2015-07-30 11:03 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2015-08-04 03:10 -0400
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System jimp@specsol.spam.sux.com - 2015-08-04 17:24 +0000
Re: Sensors in Motion Launches MEMS-Based Inertial Nav System wobbly <wobbly@dont-email.me> - 2015-07-28 22:01 +0000
Page 1 of 5 [1] 2 3 4 5 Next page →
| From | Lofty Goat <rlwatkins@gmail.com> |
|---|---|
| Date | 2015-07-26 23:44 -0500 |
| Subject | Re: Sensors in Motion Launches MEMS-Based Inertial Nav System |
| Message-ID | <ZJWdnZAbVqLcKijInZ2dnUU7-a-dnZ2d@giganews.com> |
On Sun, 26 Jul 2015 13:33:20 +0000, Fritz Köhler wrote: > jimp wrote: > >> Sam Wormley <swormley1@gmail.com> wrote: >>> Sensors in Motion Launches MEMS-Based Inertial Nav System >> >> It still needs calibration by something like GPS shit head. > > MEMS does not need GPS calibration, asshat. That's the whole idea with > inertial MEMS, they calibrate by completely other means. What an idiot, > lol, to calibrate MEMS by GPS. Given your great willingness to speak up, I wish you knew what you were talking about. Pennino may blather some, but at least he knows things: "MEMS" doesn't necessarily "require calibration" or "not require calibration". It's an acronym for micro-electro-mechanical-system. MEMS-based *inertial guidance systems* do require calibration. They drift. Some of them drift less than others, but they all drift. -- Goat
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| From | jimp@specsol.spam.sux.com |
|---|---|
| Date | 2015-07-27 22:52 +0000 |
| Message-ID | <kapi8c-7vg.ln1@mail.specsol.com> |
| In reply to | #358787 |
In sci.physics Yousuf Khan <bbbl67@spammenot.yahoo.com> wrote: > On 27/07/2015 3:08 AM, Fabian Russell wrote: >> Yes, of course, they do drift. >> >> But the point is that for certain military applications they can >> adequately replace GPS. Cruise missiles, for example, will only >> be in flight for a few hours, at most, and thus the drift will >> be negligible. The same for smart bombs. The advantage is that >> MEMS INS cannot be jammed. > > It would extremely useful in consumer electronics to integrate a MEMS > chip into a traditional GPS system. The GPS could still keep going even > when you're in a long tunnel, or inside an underground garage, or > something like that. It would supplement the GPS signal, and keep the > car on track even while the GPS signal was nowhere to be found. It > wouldn't have to be as accurate as military MEMS, of course. > > Yousuf Khan As there is usually only one way in or out of a tunnel or underground garage, I hardly see where GPS is needed there at all. Perhaps some people don't know what those signs with an arrow and the word "exit" mean. Also, MEMS is a type of component, not a system. https://en.wikipedia.org/wiki/Microelectromechanical_systems -- Jim Pennino
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| From | Jackpol11@hotmail.com |
|---|---|
| Date | 2015-07-28 16:41 -0400 |
| Message-ID | <82qfra9pj2cl00sna26pa7v01j9s5s317q@4ax.com> |
| In reply to | #358842 |
On Mon, 27 Jul 2015 22:52:36 -0000, jimp@specsol.spam.sux.com wrote: >In sci.physics Yousuf Khan <bbbl67@spammenot.yahoo.com> wrote: >> On 27/07/2015 3:08 AM, Fabian Russell wrote: >>> Yes, of course, they do drift. >>> >>> But the point is that for certain military applications they can >>> adequately replace GPS. Cruise missiles, for example, will only >>> bShould Jesuse in flight for a few hours, at most, and thus the drift will >>> be negligible. The same for smart bombs. The advantage is that >>> MEMS INS cannot be jammed. >> >> It would extremely useful in consumer electronics to integrate a MEMS >> chip into a traditional GPS system. The GPS could still keep going even >> when you're in a long tunnel, or inside an underground garage, or >> something like that. It would supplement the GPS signal, and keep the >> car on track even while the GPS signal was nowhere to be found. It >> wouldn't have to be as accurate as military MEMS, of course. >> >> Yousuf Khan > >As there is usually only one way in or out of a tunnel or underground >garage, I hardly see where GPS is needed there at all. Perhaps some >people don't know what those signs with an arrow and the word "exit" >mean. > >Also, MEMS is a type of component, not a system. > >https://en.wikipedia.org/wiki/Microelectromechanical_systems It might clarify things to see how an inertial guidance system really works. There is a stable platform containing several accelerometers. Their outputs are integrated to give velocity and again for distance. The function of the 3 gyroscopes is to keep the stable platform exactly horizontal locally, so the gravity vector can never get into the accelerometers. There's no way to accomplish this except for dependence on gyroscopes. Gyros do drift and so you do get gravity input to the accelerometers. Notice that as the distance is accumulated by the accelerometers, the vertical axis will have changed by angle x/R, and a computed current must be supplied to the torque motors to replicate the local vertical Of course the gyros need to keep directional stability also, not allowing the platform to rotate about the vertical axis. They work best in a freefalling ballistic missile.. The inertial system could work for a short period of time to augment a GPS that was out of service, but there's no way that the GPS would be able to correct the gyroscopes for their drift. After one hour's flight the platform could be badly off the horizontal leading to some misdirection. I spent a number of years in inertial guidance, and the gyros were always of the most concern, promise exceeding performance! John Polasek
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| From | Poutnik <poutnik4nntp@gmail.com> |
|---|---|
| Date | 2015-08-01 12:32 +0200 |
| Message-ID | <mpi75b$f81$1@dont-email.me> |
| In reply to | #358910 |
Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): > I didn't hear you say anything helpful, sure they are a different kind > of gyroscope that hopefully can compete in accuracy with the > conventional ones. If their function is not to keep a local vertical, > and keep gravity out of the accelerometers,then what is it? Classical meaning of gyroscope as measure against to be rotated misses the etymology of the word. Freely translated it is "noticing the rotation", and this is followed by MEMS gyroscopes . https://www.google.cz/search?q=MEMS+gyroscope http://www.quora.com/How-does-a-MEMS-gyroscope-work https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope https://www.youtube.com/watch?v=A03AENwOVNY ( MEMS gyroscopes - A revolutionary way to interface with the real world (ePresentation) ) http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ -- Poutnik ( the Czech word for a wanderer )
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| From | Jackpol11@hotmail.com |
|---|---|
| Date | 2015-08-02 15:51 -0400 |
| Message-ID | <k5ssratdurv88agr91mppf95v83u7hclao@4ax.com> |
| In reply to | #359309 |
On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> wrote: >Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): > >> I didn't hear you say anything helpful, sure they are a different kind >> of gyroscope that hopefully can compete in accuracy with the >> conventional ones. If their function is not to keep a local vertical, >> and keep gravity out of the accelerometers,then what is it? > >Classical meaning of gyroscope >as measure against to be rotated >misses the etymology of the word. > >Freely translated it is "noticing the rotation", >and this is followed by MEMS gyroscopes . > >https://www.google.cz/search?q=MEMS+gyroscope > >http://www.quora.com/How-does-a-MEMS-gyroscope-work > >https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope > >https://www.youtube.com/watch?v=A03AENwOVNY >( MEMS gyroscopes - A revolutionary way to interface with the real world >(ePresentation) ) > >http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ I've read one of the articles by the manufacturer, and I see these gyroscopes are nothing more than rate gyroscopes which are not really gyroscopes, but sensors of angular rate. They are of great use in steering missiles etc. by feeding back the rate of turn. They are useless for inertial navigation because I notice their lowest rate of detection is something like 30° per second. Inertial guidance needs to detect rates like .01° or .001°per hour! John Polasek
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| From | jimp@specsol.spam.sux.com |
|---|---|
| Date | 2015-08-02 20:29 +0000 |
| Message-ID | <e6b29c-tks.ln1@mail.specsol.com> |
| In reply to | #359398 |
In sci.physics Jackpol11@hotmail.com wrote: > On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> > wrote: > >>Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): >> >>> I didn't hear you say anything helpful, sure they are a different kind >>> of gyroscope that hopefully can compete in accuracy with the >>> conventional ones. If their function is not to keep a local vertical, >>> and keep gravity out of the accelerometers,then what is it? >> >>Classical meaning of gyroscope >>as measure against to be rotated >>misses the etymology of the word. >> >>Freely translated it is "noticing the rotation", >>and this is followed by MEMS gyroscopes . >> >>https://www.google.cz/search?q=MEMS+gyroscope >> >>http://www.quora.com/How-does-a-MEMS-gyroscope-work >> >>https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope >> >>https://www.youtube.com/watch?v=A03AENwOVNY >>( MEMS gyroscopes - A revolutionary way to interface with the real world >>(ePresentation) ) >> >>http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ > I've read one of the articles by the manufacturer, and I see these > gyroscopes are nothing more than rate gyroscopes which are not really > gyroscopes, but sensors of angular rate. They are of great use in > steering missiles etc. by feeding back the rate of turn. > They are useless for inertial navigation because I notice their lowest > rate of detection is something like 30° per second. Inertial guidance > needs to detect rates like .01° or .001°per hour! > John Polasek There you go; letting reality get in the way of arm waving bafflegab from breathless press releases. -- Jim Pennino
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| From | Poutnik <poutnik4nntp@gmail.com> |
|---|---|
| Date | 2015-08-03 01:12 +0200 |
| Message-ID | <mpm82k$ub3$1@dont-email.me> |
| In reply to | #359398 |
Dne 02/08/2015 v 21:51 Jackpol11@hotmail.com napsal(a): > On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> > wrote: > >> Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): >> >>> I didn't hear you say anything helpful, sure they are a different kind >>> of gyroscope that hopefully can compete in accuracy with the >>> conventional ones. If their function is not to keep a local vertical, >>> and keep gravity out of the accelerometers,then what is it? >> >> Classical meaning of gyroscope >> as measure against to be rotated >> misses the etymology of the word. >> >> Freely translated it is "noticing the rotation", >> and this is followed by MEMS gyroscopes . >> >> https://www.google.cz/search?q=MEMS+gyroscope >> >> http://www.quora.com/How-does-a-MEMS-gyroscope-work >> >> https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope >> >> https://www.youtube.com/watch?v=A03AENwOVNY >> ( MEMS gyroscopes - A revolutionary way to interface with the real world >> (ePresentation) ) >> >> http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ > I've read one of the articles by the manufacturer, and I see these > gyroscopes are nothing more than rate gyroscopes which are not really > gyroscopes, but sensors of angular rate. They are of great use in Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope (n.1)), because the device demonstrates that the earth rotates. Gyroscope IS a sensor of angular rate. > steering missiles etc. by feeding back the rate of turn. > They are useless for inertial navigation because I notice their lowest > rate of detection is something like 30° per second. Inertial guidance > needs to detect rates like .01° or .001°per hour! > John Polasek > I remember 30 deg/s was full scale limit, not sensitivity, as seen on the video at 4:56. "The person who says it cannot be done should not interrupt the person doing it." --Chinese proverb -- Poutnik ( the Czech word for a wanderer )
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| From | jimp@specsol.spam.sux.com |
|---|---|
| Date | 2015-08-03 00:07 +0000 |
| Message-ID | <svn29c-2i.ln1@mail.specsol.com> |
| In reply to | #359469 |
In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: > Dne 02/08/2015 v 21:51 Jackpol11@hotmail.com napsal(a): >> On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> >> wrote: >> >>> Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): >>> >>>> I didn't hear you say anything helpful, sure they are a different kind >>>> of gyroscope that hopefully can compete in accuracy with the >>>> conventional ones. If their function is not to keep a local vertical, >>>> and keep gravity out of the accelerometers,then what is it? >>> >>> Classical meaning of gyroscope >>> as measure against to be rotated >>> misses the etymology of the word. >>> >>> Freely translated it is "noticing the rotation", >>> and this is followed by MEMS gyroscopes . >>> >>> https://www.google.cz/search?q=MEMS+gyroscope >>> >>> http://www.quora.com/How-does-a-MEMS-gyroscope-work >>> >>> https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope >>> >>> https://www.youtube.com/watch?v=A03AENwOVNY >>> ( MEMS gyroscopes - A revolutionary way to interface with the real world >>> (ePresentation) ) >>> >>> http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ >> I've read one of the articles by the manufacturer, and I see these >> gyroscopes are nothing more than rate gyroscopes which are not really >> gyroscopes, but sensors of angular rate. They are of great use in > > Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope > (n.1)), because the device demonstrates that the earth rotates. > > Gyroscope IS a sensor of angular rate. A gyroscope CAN BE a sensor of angular rate, and several other things including just a toy. -- Jim Pennino
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| From | John Gogo <jfgogo22@yahoo.com> |
|---|---|
| Date | 2015-08-02 19:32 -0700 |
| Message-ID | <7a064228-3c70-4088-a8e5-937da872b418@googlegroups.com> |
| In reply to | #359471 |
On Sunday, August 2, 2015 at 7:16:04 PM UTC-5, ji...@specsol.spam.sux.com wrote: > In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: > > Dne 02/08/2015 v 21:51 Jackpol11@hotmail.com napsal(a): > >> On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> > >> wrote: > >> > >>> Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): > >>> > >>>> I didn't hear you say anything helpful, sure they are a different kind > >>>> of gyroscope that hopefully can compete in accuracy with the > >>>> conventional ones. If their function is not to keep a local vertical, > >>>> and keep gravity out of the accelerometers,then what is it? > >>> > >>> Classical meaning of gyroscope > >>> as measure against to be rotated > >>> misses the etymology of the word. > >>> > >>> Freely translated it is "noticing the rotation", > >>> and this is followed by MEMS gyroscopes . > >>> > >>> https://www.google.cz/search?q=MEMS+gyroscope > >>> > >>> http://www.quora.com/How-does-a-MEMS-gyroscope-work > >>> > >>> https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope > >>> > >>> https://www.youtube.com/watch?v=A03AENwOVNY > >>> ( MEMS gyroscopes - A revolutionary way to interface with the real world > >>> (ePresentation) ) > >>> > >>> http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ > >> I've read one of the articles by the manufacturer, and I see these > >> gyroscopes are nothing more than rate gyroscopes which are not really > >> gyroscopes, but sensors of angular rate. They are of great use in > > > > Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope > > (n.1)), because the device demonstrates that the earth rotates. > > > > Gyroscope IS a sensor of angular rate. > > A gyroscope CAN BE a sensor of angular rate, and several other things > including just a toy. > > > -- > Jim Pennino The gyroscope is a wonderful toy.
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| From | Jackpol11@hotmail.com |
|---|---|
| Date | 2015-08-03 12:17 -0400 |
| Message-ID | <g94vraliadmh0rv4gml02avf66riutvv43@4ax.com> |
| In reply to | #359471 |
On Mon, 3 Aug 2015 00:07:56 -0000, jimp@specsol.spam.sux.com wrote: >In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: >> Dne 02/08/2015 v 21:51 Jackpol11@hotmail.com napsal(a): >>> On Sat, 1 Aug 2015 12:32:41 +0200, Poutnik <poutnik4nntp@gmail.com> >>> wrote: >>> >>>> Dne 31/07/2015 v 22:58 Jackpol11@hotmail.com napsal(a): >>>> >>>>> I didn't hear you say anything helpful, sure they are a different kind >>>>> of gyroscope that hopefully can compete in accuracy with the >>>>> conventional ones. If their function is not to keep a local vertical, >>>>> and keep gravity out of the accelerometers,then what is it? >>>> >>>> Classical meaning of gyroscope >>>> as measure against to be rotated >>>> misses the etymology of the word. >>>> >>>> Freely translated it is "noticing the rotation", >>>> and this is followed by MEMS gyroscopes . >>>> >>>> https://www.google.cz/search?q=MEMS+gyroscope >>>> >>>> http://www.quora.com/How-does-a-MEMS-gyroscope-work >>>> >>>> https://en.wikipedia.org/wiki/Vibrating_structure_gyroscope >>>> >>>> https://www.youtube.com/watch?v=A03AENwOVNY >>>> ( MEMS gyroscopes - A revolutionary way to interface with the real world >>>> (ePresentation) ) >>>> >>>> http://electroiq.com/blog/2010/11/introduction-to-mems-gyroscopes/ >>> I've read one of the articles by the manufacturer, and I see these >>> gyroscopes are nothing more than rate gyroscopes which are not really >>> gyroscopes, but sensors of angular rate. They are of great use in >> >> Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope >> (n.1)), because the device demonstrates that the earth rotates. >> >> Gyroscope IS a sensor of angular rate. > >A gyroscope CAN BE a sensor of angular rate, and several other things >including just a toy. A rate gyroscope is elastically restrained with a spring. A true gyroscope as used in an inertial guidance system is insulated against the angular rates by virtue of being mounted in gimbals, from which the angles can be read for navigation computation. It tries to maintain a rigid orientation in an inertial space. Deviation sensed by gyroscopes produce correction torques at the gimbals. John Polasek
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| From | Poutnik <Poutnik4NNTP@gmail.com> |
|---|---|
| Date | 2015-08-03 19:00 +0200 |
| Message-ID | <mpo6l8$5mq$1@dont-email.me> |
| In reply to | #359528 |
On 08/03/2015 06:17 PM, Jackpol11@hotmail.com wrote: > On Mon, 3 Aug 2015 00:07:56 -0000, jimp@specsol.spam.sux.com wrote: > >> In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: >>> Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope >>> (n.1)), because the device demonstrates that the earth rotates. >>> >>> Gyroscope IS a sensor of angular rate. >> >> A gyroscope CAN BE a sensor of angular rate, and several other things >> including just a toy. Is. Even those rotating masses in gimbals sense the angular rate. > A rate gyroscope is elastically restrained with a spring. Can, but need not to be. Vibrating ones based on Coriolis force are not. > A true gyroscope as used in an inertial guidance system is insulated > against the angular rates by virtue of being mounted in gimbals, from > which the angles can be read for navigation computation. It tries to > maintain a rigid orientation in an inertial space. Deviation sensed by > gyroscopes produce correction torques at the gimbals. In fact, "untrue" gyroscopes are more true gyroscopes than "true" gyroscopes. "True" gyroscopes are not not well suited for "watching the circle", they just try to keep the platform free from any rotation. There are 2 possible approaches for inertial systems, wrt rotation: 1/ to keep the orientation 2/ to know how orientation changed In fact, systems based on MEMS are reaching quality of classical gyroscopes, with advantage of price, mass, volums and durability. -- Poutnik ( the Czech word for a wanderer )
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| From | Bohuš Matuška <bohu@paranetnet.net> |
|---|---|
| Date | 2015-08-03 18:01 +0000 |
| Message-ID | <mpoa91$3iu$1@speranza.aioe.org> |
| In reply to | #359532 |
Poutnik wrote: > In fact, "untrue" gyroscopes are more true gyroscopes than "true" > gyroscopes. "True" gyroscopes are not not well suited for "watching the > circle", > they just try to keep the platform free from any rotation. no > There are 2 possible approaches for inertial systems, wrt rotation: > 1/ to keep the orientation 2/ to know how orientation changed no gyro can't do that. Orientation is about a higher level, signal processing including a microcontroller unit. > In fact, systems based on MEMS are reaching quality of classical > gyroscopes, with advantage of price, mass, volums and durability. no
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| From | Poutnik <Poutnik4NNTP@gmail.com> |
|---|---|
| Date | 2015-08-03 20:31 +0200 |
| Message-ID | <mpobvq$se0$1@dont-email.me> |
| In reply to | #359538 |
On 08/03/2015 08:01 PM, Bohuš Matuška wrote: > Poutnik wrote: > >> In fact, "untrue" gyroscopes are more true gyroscopes than "true" >> gyroscopes. "True" gyroscopes are not not well suited for "watching the >> circle", >> they just try to keep the platform free from any rotation. > > no My 3 year old nephew was used to say it very often. > >> There are 2 possible approaches for inertial systems, wrt rotation: >> 1/ to keep the orientation 2/ to know how orientation changed > > no gyro can't do that. Orientation is about a higher level, signal > processing including a microcontroller unit. Did I say othwerwise ? > >> In fact, systems based on MEMS are reaching quality of classical >> gyroscopes, with advantage of price, mass, volums and durability. > > no > And I bet my nephew was better in that. -- Poutnik ( the Czech word for a wanderer )
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| From | Bohuš Matuška <bohu@paranetnet.net> |
|---|---|
| Date | 2015-08-03 19:28 +0000 |
| Message-ID | <mpofde$ef6$2@speranza.aioe.org> |
| In reply to | #359542 |
Poutnik wrote: > On 08/03/2015 08:01 PM, Bohuš Matuška wrote: >> Poutnik wrote: >> >>> In fact, "untrue" gyroscopes are more true gyroscopes than "true" >>> gyroscopes. "True" gyroscopes are not not well suited for "watching >>> the circle", >>> they just try to keep the platform free from any rotation. >> >> no > > My 3 year old nephew was used to say it very often. > >>> There are 2 possible approaches for inertial systems, wrt rotation: >>> 1/ to keep the orientation 2/ to know how orientation changed >> >> no gyro can't do that. Orientation is about a higher level, signal >> processing including a microcontroller unit. > > Did I say othwerwise ? >> >>> In fact, systems based on MEMS are reaching quality of classical >>> gyroscopes, with advantage of price, mass, volums and durability. >> >> no >> > And I bet my nephew was better in that. A giro won't show you orientation, angle, position and such, Poutink. They are not capable to do that. They only output signal when change/rotation occurs. Otherwise they output nothing (except avoidable drift). Makes sure you know what you are talking about.
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| From | jimp@specsol.spam.sux.com |
|---|---|
| Date | 2015-08-03 18:01 +0000 |
| Message-ID | <6sm49c-fgj.ln1@mail.specsol.com> |
| In reply to | #359532 |
In sci.physics Poutnik <Poutnik4NNTP@gmail.com> wrote: > On 08/03/2015 06:17 PM, Jackpol11@hotmail.com wrote: >> On Mon, 3 Aug 2015 00:07:56 -0000, jimp@specsol.spam.sux.com wrote: >> >>> In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: > >>>> Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope >>>> (n.1)), because the device demonstrates that the earth rotates. >>>> >>>> Gyroscope IS a sensor of angular rate. >>> >>> A gyroscope CAN BE a sensor of angular rate, and several other things >>> including just a toy. > > Is. Even those rotating masses in gimbals sense the angular rate. How does this gyroscope sense anything given it has no sensors of anything? http://www.thinkgeek.com/product/eafc/ -- Jim Pennino
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| From | John Gogo <jfgogo22@yahoo.com> |
|---|---|
| Date | 2015-08-03 19:47 -0700 |
| Message-ID | <96c17973-7cbc-4e71-88d3-fa2839710689@googlegroups.com> |
| In reply to | #359539 |
On Monday, August 3, 2015 at 1:01:27 PM UTC-5, ji...@specsol.spam.sux.com wrote: > In sci.physics Poutnik <Poutnik4NNTP@gmail.com> wrote: > > On 08/03/2015 06:17 PM, Jackpol11@hotmail.com wrote: > >> On Mon, 3 Aug 2015 00:07:56 -0000, jimp@specsol.spam.sux.com wrote: > >> > >>> In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: > > > >>>> Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope > >>>> (n.1)), because the device demonstrates that the earth rotates. > >>>> > >>>> Gyroscope IS a sensor of angular rate. > >>> > >>> A gyroscope CAN BE a sensor of angular rate, and several other things > >>> including just a toy. > > > > Is. Even those rotating masses in gimbals sense the angular rate. > > How does this gyroscope sense anything given it has no sensors of anything? > > http://www.thinkgeek.com/product/eafc/ > > > > -- > Jim Pennino A toy gyroscope. If I pulled too hard and spun it too fast and set it on the ground the gyroscope would flitter along chaotically not wanting to stand up. It was too wound up. If you wanted to get the best life out of one pull of the string- you would pull it just so... set it down and it was still unstable until it reached a stability that would go on for awhile... and then would slow to the point of another kind of chaos... and then fall to a standstill.
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| From | Jackpol11@hotmail.com |
|---|---|
| Date | 2015-08-03 14:52 -0400 |
| Message-ID | <1scvra5cp2tqmp55klrrc9m6v8iq3a2sqp@4ax.com> |
| In reply to | #359532 |
On Mon, 03 Aug 2015 19:00:56 +0200, Poutnik <Poutnik4NNTP@gmail.com> wrote: >On 08/03/2015 06:17 PM, Jackpol11@hotmail.com wrote: >> On Mon, 3 Aug 2015 00:07:56 -0000, jimp@specsol.spam.sux.com wrote: >> >>> In sci.physics Poutnik <poutnik4nntp@gmail.com> wrote: > >>>> Greek gyros "a circle" (see gyre (n.)) + skopos "watcher" (see scope >>>> (n.1)), because the device demonstrates that the earth rotates. >>>> >>>> Gyroscope IS a sensor of angular rate. >>> >>> A gyroscope CAN BE a sensor of angular rate, and several other things >>> including just a toy. > >Is. Even those rotating masses in gimbals sense the angular rate. > >> A rate gyroscope is elastically restrained with a spring. > >Can, but need not to be. >Vibrating ones based on Coriolis force are not. > >> A true gyroscope as used in an inertial guidance system is insulated >> against the angular rates by virtue of being mounted in gimbals, from >> which the angles can be read for navigation computation. It tries to >> maintain a rigid orientation in an inertial space. Deviation sensed by >> gyroscopes produce correction torques at the gimbals. > >In fact, "untrue" gyroscopes are more true gyroscopes than "true" >gyroscopes. "True" gyroscopes are not not well suited >for "watching the circle", >they just try to keep the platform free from any rotation. > >There are 2 possible approaches for inertial systems, wrt rotation: >1/ to keep the orientation >2/ to know how orientation changed > >In fact, systems based on MEMS are reaching quality of classical >gyroscopes, with advantage of price, mass, volums and durability. You are imagining what is called a "strapped-down" inertial system. I believe that calls for Euler's equations which cannot be solved in closed form. This vehicle will be assuming all kinds of different orientations and it would be sheer folly to think that you could subtract gravity out of the real accelerations. The inertial platform is actually set in a roll gimbal inside a pitch gimbal inside a yaw gimbal fully retaining its inertial position throughout while the gimbal angles change as aircraft maneuvers. The gyroscope error signals are sent through resolvers that perform matrix transformations, apportioning the torques to the correct gimbals. The general idea as I said in the 1st place is preserve and protect the accelerometers so they measure only navigational accelerations. The error signals from the gyroscope provide the rigidity required to resist torques from the gimbal angles as they change. I also mentioned that the accuracy needs to be at least .01° per hour which translates to 0.000002778° per second and the resolution of the mems might be 0.03, and therefore nowhere qualified for navigation purposes. Ti si hloupak! John Polasek
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| From | Poutnik <poutnik4nntp@gmail.com> |
|---|---|
| Date | 2015-08-03 23:00 +0200 |
| Message-ID | <mpokm2$2m6$1@dont-email.me> |
| In reply to | #359544 |
Dne 03/08/2015 v 20:52 Jackpol11@hotmail.com napsal(a): >> >> In fact, "untrue" gyroscopes are more true gyroscopes than "true" >> gyroscopes. "True" gyroscopes are not not well suited >> for "watching the circle", >> they just try to keep the platform free from any rotation. >> >> There are 2 possible approaches for inertial systems, wrt rotation: >> 1/ to keep the orientation >> 2/ to know how orientation changed >> >> In fact, systems based on MEMS are reaching quality of classical >> gyroscopes, with advantage of price, mass, volums and durability. > You are imagining what is called a "strapped-down" inertial system. I > believe that calls for Euler's equations which cannot be solved in > closed form. This vehicle will be assuming all kinds of different > orientations and it would be sheer folly to think that you could > subtract gravity out of the real accelerations. "Strapdown systems are nowadays commonly used in commercial and tactical applications (aircraft, ships, ROV's missiles, etc.) and are starting to become more widespread in applications where superb accuracy is required (like submarine navigation or strategic ICBM guidance) and FOG based strapdown inertial navigation systems have been selected by the UK Royal Navy for the Astute class submarine and the Queen Elizabeth class aircraft carriers." https://en.wikipedia.org/wiki/Inertial_navigation_system#Strapdown_systems > The inertial platform is actually set in a roll gimbal inside a pitch > gimbal inside a yaw gimbal fully retaining its inertial position > throughout while the gimbal angles change as aircraft maneuvers. The > gyroscope error signals are sent through resolvers that perform > matrix transformations, apportioning the torques to the correct > gimbals. I am aware of that. But truth is, not limited to gyroscopes and navigation systems, people experienced in past technology often ignore advances of incoming technologies. What was true 2 years ago need not to be true now. > The general idea as I said in the 1st place is preserve and protect > the accelerometers so they measure only navigational accelerations. > The error signals from the gyroscope provide the rigidity required to > resist torques from the gimbal angles as they change. > I also mentioned that the accuracy needs to be at least .01° per hour > which translates to 0.000002778° per second and the resolution of the > mems might be 0.03, and therefore nowhere qualified for navigation > purposes. Peiple saying it is not possible should not interupt those doing it. ( chinese proverb ) All depends on purpose of the navigation. For some applications 0.01 deg / hour is far from needed. To have the platform leveled is equivalent to knowledge how it is tilted. > Ti si hloupak! Correct form would be "Ty jsi hlupák !" But such a calling would say more about its author... -- Poutnik ( the Czech word for a wanderer )
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| From | Ignorant Raving Crackpot <ignorantravingcrackpot@gmail.com> |
|---|---|
| Date | 2015-08-03 14:32 -0700 |
| Message-ID | <fb45b828-2884-49e6-8b3f-98ae5f22f595@googlegroups.com> |
| In reply to | #359562 |
On Monday, August 3, 2015 at 4:00:20 PM UTC-5, Poutnik wrote: > Dne 03/08/2015 v 20:52 Jackpol11@hotmail.com napsal(a): > > The general idea as I said in the 1st place is preserve and protect > > the accelerometers so they measure only navigational accelerations. > > The error signals from the gyroscope provide the rigidity required to > > resist torques from the gimbal angles as they change. > > I also mentioned that the accuracy needs to be at least .01° per hour > > which translates to 0.000002778° per second and the resolution of the > > mems might be 0.03, and therefore nowhere qualified for navigation > > purposes. > > Peiple saying it is not possible > should not interupt those doing it. ( chinese proverb ) > > All depends on purpose of the navigation. > For some applications 0.01 deg / hour is far from needed. > > To have the platform leveled is equivalent > to knowledge how it is tilted. A primitive system would have been immensely helpful today. I took my wife to see the ENT specialist today. Parking was in a big, poorly marked parking garage. I tried to find level/section signs, but there weren't any that I could see. No GPS signal in the garage, of course. I took photos of where the car was parked with my phone, but there were few landmarks. After seeing the specialist, we had to find the car based on our memory of its layout. Our memory was off. Don't need all that much accuracy for an inertial guidance system that will help us find the car in a parking structure with the help of GPS.
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| From | Jackpol11@hotmail.com |
|---|---|
| Date | 2015-08-06 10:36 -0400 |
| Message-ID | <mqq6sadm7a2lnl4p627hia8mjfonvnhffb@4ax.com> |
| In reply to | #359562 |
On Mon, 3 Aug 2015 23:00:17 +0200, Poutnik <poutnik4nntp@gmail.com> wrote: >Dne 03/08/2015 v 20:52 Jackpol11@hotmail.com napsal(a): >>> >>> In fact, "untrue" gyroscopes are more true gyroscopes than "true" >>> gyroscopes. "True" gyroscopes are not not well suited >>> for "watching the circle", >>> they just try to keep the platform free from any rotation. >>> >>> There are 2 possible approaches for inertial systems, wrt rotation: >>> 1/ to keep the orientation >>> 2/ to know how orientation changed >>> >>> In fact, systems based on MEMS are reaching quality of classical >>> gyroscopes, with advantage of price, mass, volums and durability. > >> You are imagining what is called a "strapped-down" inertial system. I >> believe that calls for Euler's equations which cannot be solved in >> closed form. This vehicle will be assuming all kinds of different >> orientations and it would be sheer folly to think that you could >> subtract gravity out of the real accelerations. > > >"Strapdown systems are nowadays commonly used in commercial and tactical >applications (aircraft, ships, ROV's missiles, etc.) and are starting to >become more widespread in applications where superb accuracy is required >(like submarine navigation or strategic ICBM guidance) and FOG based >strapdown inertial navigation systems have been selected by the UK Royal >Navy for the Astute class submarine and the Queen Elizabeth class >aircraft carriers." > >https://en.wikipedia.org/wiki/Inertial_navigation_system#Strapdown_systems > >> The inertial platform is actually set in a roll gimbal inside a pitch >> gimbal inside a yaw gimbal fully retaining its inertial position >> throughout while the gimbal angles change as aircraft maneuvers. The >> gyroscope error signals are sent through resolvers that perform >> matrix transformations, apportioning the torques to the correct >> gimbals. > >I am aware of that. >But truth is, not limited to gyroscopes and navigation systems, >people experienced in past technology >often ignore advances of incoming technologies. >What was true 2 years ago need not to be true now. > >> The general idea as I said in the 1st place is preserve and protect >> the accelerometers so they measure only navigational accelerations. >> The error signals from the gyroscope provide the rigidity required to >> resist torques from the gimbal angles as they change. >> I also mentioned that the accuracy needs to be at least .01° per hour >> which translates to 0.000002778° per second and the resolution of the >> mems might be 0.03, and therefore nowhere qualified for navigation >> purposes. > >Peiple saying it is not possible >should not interupt those doing it. ( chinese proverb ) > >All depends on purpose of the navigation. >For some applications 0.01 deg / hour is far from needed. > >To have the platform leveled is equivalent >to knowledge how it is tilted. > > >> Ti si hloupak! > >Correct form would be "Ty jsi hlupák !" >But such a calling would say more about its author...him Enough of the fun! They may or may not be using strapped down systems, which are fraught with hazards. I'm referring to the gimbaled systems discussion. For that I looked up https://en.wikipedia.org/wiki/Gimbal#Inertial_navigation which fills in more detail about the function of gimbals. The article has a number of errors, since it is apparently written by someone with no actual knowledge because he says that gimbal angles are measured to provide the 9 direction cosines needed for navigation. instead, the 3 resolvers (transformers) automatically parcel out all the gyro signals to the proper axes. Therefore I edited it, which was apparently effective immediately. (See inertial navigation section). John Polasek
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