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Delco Carousel IV-A INS For Microsoft Flight Simulator >> Delco Carousel IV-A INS For Microsoft Flight Simulator >> local velocity transformations
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Message started by Naruto-kun on Dec 4^th, 2012, 7:09am

Title: local velocity transformations
Post by Naruto-kun on Dec 4^th, 2012, 7:09am

Hi guys

So...Im working on a Litton LN-94 INS...And Im having a devil of a time trying to find/figure out the math to convert local velocities into world velocities to get my position in the inertial reference frame. Is there anyone here who can help me out?

Thanks
JB
P.S. Marco or Gianfranco if one of you two would be willing to help me out I will happily donate my time to any other INS projects you may have...since i have several aircraft that require various INS systems in the works.

Title: Re: local velocity transformations
Post by Marco Ravanello on Dec 13^th, 2012, 2:48pm

> convert local velocities into world velocities

Sorry but I don't understand what you really meant.

A really GREAT starting point is this -> http://williams.best.vwh.net/avform.htm

I'm sure you'll find there the solution of most of your INS-development-related problems or, at least, I hope so.

And if you have more questions feel free to ask! :)

Title: Re: local velocity transformations
Post by Naruto-kun on Dec 16^th, 2012, 9:27pm

Well that does help when you know your current position (even if it is flawed due to lag) and want to get bearings/distances to a steerpoint or make an offset from a steerpoint but im finding it a bit hard to apply when it comes to determining my position using XYZ velocities in conjuction with attitude and heading....Im trying to figure out the inputs and outputs of directional cosine matrices but so far to no avail.

Title: Re: local velocity transformations
Post by Gianfranco Corrias on Dec 16^th, 2012, 10:22pm

are you speaking about an INS(INERTIAL NAVIGATION SYSTEM)???
Regards Gianfranco

Title: Re: local velocity transformations
Post by Naruto-kun on Dec 17^th, 2012, 8:48am

Yep

Title: Re: local velocity transformations
Post by Marco Ravanello on Dec 17^th, 2012, 4:32pm

> determining my position using XYZ velocities in conjuction with attitude and heading

This cannot be done in FS, basically because it's not a real time software (nor Windows is) and consequently the very precise calculations you would like to perform would bring you to very wrong results.

I initially tried your approach while developing CIVA but I soon reverted to a much easier method which offers almost the same realistic result