Talk:Inertial guidance system

message: I have added a comment on Dr. Robert Goddard's early works with gyroscopically stabilized guidance systems here - I hope all find it appropriate.
Also, since inertial guidance does not necessarily require "digital computers", I shortened the referenced phrase to simply "computers" (allowing the inferred inclusion of highly-tuned analog systems).
:allowing the inferred inclusion of highly-tuned analog systems
:Oh you Luddite! :-)  Seriously, good change! There were lots of computers in the world before digital computers, and many systems still depend upon fine mechanisms.
:Atlant 11:29, 27 Apr 2005 (UTC)
thread_title:  General edits 

message: This work seems to be copyrighted! See http://www.answers.com/topic/inertial-guidance-system-1 , the explanation of Inertial Guidance System is equal!
:Did you notice that that page is crediting Wikipedia for this text? We appear to be the source and not the destination. Wikipedia is "open content"; you'll find lots of sites out on the web that "repackage" this content as their own (but credit Wikipedia).
:Atlant 11:29, 27 Apr 2005 (UTC)
thread_title: Copyrighted content?

message: What is the difference between INS and IMU (Inertial Measurement Unit)?
As far as I can tell a INS is effectively a IMU but has
more functionality? IMUs should at least be mentioned in the article.
:An INS gives position, and is generally dynamic. An IMU gives orientation and maybe tracking capability, and may or may not be dynamic - data could be collected and analyzed later.
:An INS includes an IMU. An IMU is an assembly of at least 3 gyros and 3 accelerometers. INS is a system. It must have a computer or processor to calculate position and velocity using IMU outputs.
:An INS produces a full position/attitude solution: XYZ position and yaw,pitch and roll in some frame of reference. An IMU merely outputs inertial data: rates of acceleration and/or rates of rotation about predefined local axes. A typical modern INS is usually composed of a 6-DOF IMU, GPS, compass, and some sort of a computer that runs an estimation algorithm to combine all of the available data into a (hopefully) optimal state (position,attitude) estimate. Vectra14 11:47, 28 January 2007 (UTC)
thread_title:  IMU vs. INS 

message: Alas, the shaker is the most accurate, because both light beams use exactly the same path. Thus laser gyros retain moving parts, but they do not move as far.
I'm guessing that a more qualitative difference is that with mechnical gyros the friction can have a significant effect on the accuracy of the system, whereas the anti-phase-locking mechanism in the optical gyro is merely required to prevent the phase-lock.  The computer simply integrates out the jitter provided.  This would mean that the 'shaker' only has to happen rather than have to happen precisely. njh 08:28, 2 January 2006 (UTC)
thread_title:  ring inferometers 

message: I happen to work with IMU's/INS's and i've never heard of such a thing. Furthermore, I can't seem to find anything about it on Google or in IEEE. Could someone provide a citation? Vectra14 03:00, 1 December 2006 (UTC)
replies: text: Well, I'm guessing that he meant 4 multi-axis accelerometers, which would produce a total of 12 measurements. Still, unless the tetrahedron is REALLY big (and the accelerometers REALLY good), this isn't really practical. And why use accelerometers to measure rates of rotation when you can get a MEMS gyro to do the same thing (though the principle is actually the same). I have to add that furthermore, especially in small missiles, there's no reason to not simply use MEMS rate gyros for rotation (supposedly with low-rate absolute attitude coming in either from gps or from low-passed accelerometers). Anyway, that section should be deleted unless someone provides a reference for an IMU that uses this "TIP" setup. Everyone (that deals with robotics-type stuff) goes through a phase where they try to figure out how to use just accelerometers to build a full IMU... it'd be a shame if they decided that it's somehow practical based on this article. Vectra14 11:40, 28 January 2007 (UTC)
replies: text: removed "Accelerometer-only systems" section. If anyone can provide a link/reference to an actualy INS that uses this "tetrahedral" accelerometer-only arrangement, feel free to revert. Vectra14 06:32, 12 March 2007 (UTC)
thread_title:  tetrahedral inertial platforms?