Timeline for How to programmatically calculate orbital elements using position/velocity vectors?
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Apr 15, 2019 at 4:39 | comment | added | Aaron Franke | @MattJessick How would you do this using Atan2? | |
| Apr 15, 2019 at 3:03 | comment | added | Aaron Franke |
What is h_K and n_I?
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| Apr 14, 2019 at 7:29 | comment | added | Aaron Franke |
What is the node vector n^? What is K^? What is μ? What is r and how is it different from r⃗? What about v and v⃗? What is p?
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| Apr 14, 2019 at 6:01 | comment | added | Aaron Franke |
What is a? I'm looking at this reference image.
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| Dec 4, 2018 at 21:24 | comment | added | jimlux | One problem is that this is taking a point r and v and turning it into elements at that instant, which will not be the usual mean values in a two line element set. What people do to generate a TLE from vectors is propagate the vector forward using numerical integration, then fit the TLE terms to match it. If you're reasonably high, then you can probably ignore the drag term. If you don't need super high precision, you can model earth as a point mass. | |
| Sep 15, 2016 at 7:15 | comment | added | Ben Lu | What khat in the second line? I see in the sample code it's [0 0 1] is that the normal vector of the earth equatorial plane? | |
| Feb 4, 2016 at 0:39 | comment | added | Matt Jessick | For programming, I would prefer equivalent relations using the atan2 function, because that will perform quadrant resolutions automatically and protects you from needing to check the range before most of the uses of acos above. (Sometimes, numerical precision will cause the argument to an acos function to be very slightly autside the valid range of -1.00000 to +1.00000. When that happens, the program as shown will crash.) It is also possible for h to be zero, allowing a divide by zero error. | |
| Nov 24, 2014 at 12:44 | comment | added | 9a3eedi | Is there any difference between nhat and n? I'm not sure what n is (assuming nhat is the node vector) but it's been used for calculating the argument of periapsis. I assume n is the same as nhat and n was used by mistake? | |
| Aug 25, 2014 at 20:32 | vote | accept | Stu | ||
| Jun 11, 2014 at 10:06 | comment | added | grom | What about calculating the mean anomaly? | |
| May 1, 2014 at 17:47 | comment | added | CogitoErgoCogitoSum | I would love to see the proof for these equations as well as their application in a real problem deriving a set of orbital elements. Are orbital elements even necessary if you have these position and velocity vectors to begin with? It seems vector calculus can handle this simply enough. Also, Im confused by the fact that you didnt define little mu. Also the v-vector is the first time derivative of the r-vector. The n-hat is a unit vector but you didnt show the math for unit-izing it. What are the n and h subscripted values? Also, you failed to show how to derive mean anomaly and mean motion | |
| Mar 24, 2014 at 14:27 | comment | added | Stu | Finally recreated in Python. Thanks for the help! It was pretty easy and now I understand the math much better. | |
| Sep 12, 2013 at 14:02 | history | answered | user29 | CC BY-SA 3.0 |
