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[old thread] Trajectories : atmospheric predictions

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@Kobymaru would you have any interest in developing a glide cardioid display? Useful for shuttle like gliding re-entries. I could help you with the algorithm. See page 62 of pdf (38 in document)  http://www.sinphi.com/aerospace/thesis.html page 35 of the pdf (11 in document) for derivation.

Basically you would get something like:

glide.png

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4 hours ago, Kobymaru said:

Hey guys, could we get a little bit of stock precision testing with this one?

Trajectories.dll

Testing in bone stock rn. Will edit and report findings.

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39 minutes ago, TheRagingIrishman said:

Testing in bone stock rn. Will edit and report findings.

Well it doesn't have to be bone stock, I just meant Stock Aero and not FAR :wink:

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3 hours ago, Sin_Phi said:

@Kobymaru would you have any interest in developing a glide cardioid display?

TBH, right now I can't quite imagine what this has to do with Trajectories, what to do with that data. Is it related to that "landing ellipse" thing that people have been asking about in the past?

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It is useful in terminal glide of space planes to tell you your maximum glide performance envelope. So if you reenter off the runway inclination you will know you can no power glide to the runway. You can do powered flight with the algorithm, but it significantly complicates things.

Most stuff glides really well and has more control authority in Kerbal, so may not be necessary/wanted.

I didn't see stuff about a landing ellipse searching back through the thread. There aren't atmospheric uncertainties in Kerbal, so you aren't really going to get a Gaussian of possible landings in a pure drag situation.

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8 hours ago, Sin_Phi said:

It is useful in terminal glide of space planes to tell you your maximum glide performance envelope.

Cool. I mean that does sound interesting, but I'm afraid I won't have time to implement it.

If there are more interested people, you could join forces and implement it yourself! I take pull requests if the code quality is OK and it doesn't bog down performance too much.

 

Quote

I didn't see stuff about a landing ellipse searching back through the thread. There aren't atmospheric uncertainties in Kerbal, so you aren't really going to get a Gaussian of possible landings in a pure drag situation.

It's discussed on GitHub: https://github.com/neuoy/KSPTrajectories/issues/37

But it's not really related to your feature, and a totally different topic :wink:

Edited by Kobymaru

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7 hours ago, TheRagingIrishman said:

@Kobymaru unfortunately I'm having some major deviations (10-100km off target) using the newest dll. 

Well that's probably because I uploaded an old version :rolleyes:

Sorry guys. Download again from the same link: https://github.com/neuoy/KSPTrajectories/releases/download/v1.6.9-rc1/Trajectories.dll

If the file size is 95 232 Bytes, then it should be the right file.

Also, for testing please state the situation that you tested (which planet, which Periapsis/Apoapsis, AoA, what kind of craft, wings, control surfaces?)

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8 hours ago, Kobymaru said:

It's discussed on GitHub: https://github.com/neuoy/KSPTrajectories/issues/37

But it's not really related to your feature, and a totally different topic :wink:

What they are asking for is actually what I do for my work. It is not trivial and will take far more than 3 points to do right. You either need a 10,000 point Monte Carlo (or less if you don't want to be accurate to 3 sigma) or a propagation of the covariance like the Julier-Uhlmann method. They are also asking not for just unguided stable reentry, but guided predictions which would require a 3+3 or 6 DOF model.

The last comment is actually describing what I have proposed. Glide performance is described as a cardioid, not an ellipse however. You generally do not consider stall performance in glide, but you can close the rear of the cardiod to account for that.

I may take a crack at it in a few months, still learning how to mod Kerbal.

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1 minute ago, Sin_Phi said:

I may take a crack at it in a few months, still learning how to mod Kerbal.

Looking forward to it :)

I'm also relatively fresh, by the way. If you want, I can give you some pointers.

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This thread has moved here:

Please only respond in the new thread. Thanks.

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Locked as requested. Please report this post if you would like it reopened, @Youen.

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