OK.

So I am working on a little project.

I have this thing that periodically gives me the coordinates of an object in three dimensional space.

[x, y, z]

This is an object following a ballistic path and is affected by air resistance. I actually do not know the factor of resistance though... I would have to look that up.

Does anyone know how to calculate a trajectory for it from this data?

I would need a fairly robust algorithm, to be able to take samples at any point on the accession.

So you are trying to calculate velocity based on a set of coordinates and air resistance, or what?

quote:

Originally posted by MrJiveBoJingles So you are trying to calculate velocity based on a set of coordinates and air resistance, or what?

well velocity is fairly easy, i just need to poll a certain number of samples and shift that polling across new data as it comes in to get the average velocity for a certain period of time... I would assume that at least.


What I want to figure out is where this object came from and where its going to land. Not exactly, but approximately.

Where's Winston?

He's a scientist you know.

quote:

Originally posted by enydo Where's Winston? He's a scientist you know.

what makes u say that?

quote:

Originally posted by Joss Weatherby well velocity is fairly easy, i just need to poll a certain number of samples and shift that polling across new data as it comes in to get the average velocity for a certain period of time... I would assume that at least. What I want to figure out is where this object came from and where its going to land. Not exactly, but approximately.

Im thinking you dont need a complicated algorithm to do that. As ,ong as you have your starting directional vector you can do all of the speed and/or distance calculations in 2d space (im assuming here that the only two variables we are dealing here are hight and speed) and then just apply the end result to the directional vector and you have your approximate landing place.

It could also be that im talking rubbish here, its beeen years since ive deal with this stuff, and once again its past 4am and i am unable to fall asleep despite being dead tired. Fucking insomnia...

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You could use a software that compiles the data for X, Y, Z and models it through chronographs, the same way you would use a pendulum, No need to worry about time, simply Mass & Distance (and the uncertainty principle)

quote:

Originally posted by winston You could use a software that compiles the data for X, Y, Z and models it through chronographs, the same way you would use a pendulum, No need to worry about time, simply Mass & Distance (and the uncertainty principle)

and this...

http://jbrwww.che.wisc.edu/tech-rep...mcc-2001-01.pdf

I could be wrong, but you're dealing with 'disturbances in velocity/disturbances in acceleration', The link above would give you an idea of a similar algorithm. I never said I was right or smart.

Last edited by winston on Aug-21-2009 at 03:16

ax^2 + by + z

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http://en.wikipedia.org/wiki/Drag_(physics)

You could translate it to a 2-d plane and figure out the quadratic function which describes a parabola that would best fit the flight path?


.. just an attempt. Haven't formally studied any physics or maths beyond high school.

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quote:

Originally posted by Krypton ax^2 + by + z

You mean ax^2 + bx + c?
or ax + by + cz + d = 0

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