Timeline for How to obtain UTC of the epoch time in a satellite TLE (two line element)?
Current License: CC BY-SA 4.0
11 events
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| Oct 3, 2023 at 18:00 | history | edited | Ryan C | CC BY-SA 4.0 |
fixed acronym SPG4 => SGP4
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| Sep 27, 2022 at 22:30 | history | edited | CommunityBot |
replaced https://www.celestrak.com with https://celestrak.org
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| Feb 7, 2018 at 15:19 | comment | added | uhoh | You should also make the comment under the other post, not just here. If you look more carefully at what I wrote there, and think about the mathematics, a negative sign in the mean motion would do the trick, at least for hyperbolic flyby's. I believe there is even a blank space for it; column 52. I'm not sure it's such an open and closed case yet. | |
| Feb 7, 2018 at 14:54 | comment | added | Jim De Camp | For an object not bound to earth mean motion would be 0.0. TLE can only model keplerian (elliptical) orbits. Humanity Star (cruel misnomer!) passes overhead everywhere on earth several times a day. You can only see it near twilight, when the satellite is illuminated by the sun, and the sun is below the horizon. Go here: n2yo.com/?s=43166 | |
| Feb 5, 2018 at 22:46 | comment | added | uhoh | Also Has a TLE ever been issued for a spacecraft trajectory not bound to Earth orbit? as well as It's been over two weeks now, will the real Humanity Star please stand up? may be of interest. | |
| Feb 5, 2018 at 22:46 | comment | added | uhoh | OK thanks! Yes "Day of Year" is certainly clearer/less ambiguous for me. fyi What would be a “big picture” understanding of how the orbits of Earth satellites are monitored? still needs an answer, as does “Deep space” corrections in SGP4; how does it account for the Sun's and Moon's gravity?. | |
| Feb 5, 2018 at 17:16 | comment | added | Jim De Camp | I think the use of the term "Julian Day" in descriptions of TLE is confusing and unnecessary. 1.) Stick with the term "Day of Year", where December 31, 2017 00:00 HR is day 0.0 of 2018. 2.) See original post for treatment of leap seconds. TLE and SPG4 ignore leap seconds. Only use them for translation for epoch in DoY to UT1 and translation of prediction in UT1 to UTC for your application. FWIW, I did analysis of radar data resulting from the collision of a Kosmos satellite with an Iridium, and my "post diction" for point of closest approach was 70 meters, using my approach. | |
| Feb 4, 2018 at 16:17 | comment | added | uhoh | Thanks! Is your answer in any way inconsistent with this answer? | |
| Feb 4, 2018 at 14:42 | review | Late answers | |||
| Feb 4, 2018 at 15:22 | |||||
| Feb 4, 2018 at 14:27 | review | First posts | |||
| Feb 4, 2018 at 19:06 | |||||
| Feb 4, 2018 at 14:22 | history | answered | Jim De Camp | CC BY-SA 3.0 |