Ted shared a gem with me off list as we chased USA 161 around during the summer of 2011 about planar searches. His elegantly simple paragraph has always stuck in my mind. "You asked about planar searching last night. Often we know most of the elements of an orbit fairly accurately, with the main uncertainty being the object's position in the orbit, i.e. mean anomaly. That being the case immediately after a new launch, before we have located the object, or due to the accumulation of perturbations after a long spell of invisibility, or after a manoeuvre of modest size." So vary the mean anomaly in some reasonable steps in a massaged generated TLE with the other more stable elements and follow the plane as you search. I used this knowledge to make up manual element sets and search for the missing USA 161. In the end it turned out USA 161 out smarted us and brute force was required to find it as it was making many maneuvers but the lesson about planar searches stuck. Cees' sattools automates this function when needed. Regards, Scott On 2/11/2016 2:07 PM, C. Bassa via Seesat-l wrote: > Hi Kevin, > > Ted explained it quite well in this post: > http://www.satobs.org/seesat/Dec-2003/0208.html > > This animated GIF visualizes the motion of the orbital plane of a sun > synchronous orbit at 450 km altitude. > https://dl.dropboxusercontent.com/u/52579487/sunsync.gif > > This is made from my implementation of a planar search in my skymap > software. I'd be happy to put the math into a document such that > others can implement it for their software. > > Regards, > Cees > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Thu Feb 11 2016 - 22:18:25 UTC
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