# How can I convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates (ECI)?

I need to convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates relative to earth center (ECI) -- i.e., position x,y,z and velocity x,y,z.

Standard Anaconda Python 3.7 is preferred, but I'm open to other solutions.

• This is the second question about a Walker constellation in two days: Special Case Constellation Analysis Approach: Walker Constellation with Circular (e = 0) orbit in LEO I think you need to show some effort first and explain what you have tried and where you've become stuck. Right now this looks like "please do my task for me". The i: t/p/f notation seems straightforward, what part is giving you trouble? – uhoh Jun 25 '19 at 10:28
• No idea what that other question on Walker Constellations is, that's probably a coincidence. You mention "showing some effort" -- I spent 3 hours Googling and reading academic papers about Walker constellations, but I couldn't find anywhere how to translate those into a geocentric coordinate frame. I'm sure I'm not the first to need to do this, but I haven't had any luck finding info on how to do it. I don't need someone to do my conversions for me, I'm trying to learn how to do it. Isn't that the point of StackExchange? – user254657 Jun 25 '19 at 16:05
• I don't mean to be critical of your googling, but there isn't enough information in the question to understand what kind of answer you need. Do you want someone to write a whole python program for you? Or do you need some help understanding the math involved? Imagine someone takes some time to write up an answer for you and then you comment "Oh, I already understand how to do that, it's the xxx that I haven't been able to get to work yet". Without some guidance as to what it is you already do know how to do, it's possible that people are not ready to invest the time in answering. – uhoh Jun 25 '19 at 23:40