I am a new member so this message may be irrelevant, outdated, out of place, or all the above. If so, please advise me by email. I would like to begin to share some ideas with those among the group who write programs pertaining to satellite tracking and orbit determination, unless all the software that needs to be written has already been written. I was thinking that I needed a program to determine satellite orbits from visual observations with no prior knowledge of the satellite. So I wrote one that calculates an orbit from two or three observations on a single pass. I call it Elfind. Does something like this already exist or is it unnecessary? Then I thought it would be nice to improve the new orbit from subsequent observations by the differential correction process. The differential correction programs that already exist correct the mean elements. This process seems inherently unstable, requiring lots of user input. Almost an art form. I was looking for something more automatic. Maybe we could try correcting the components of the state vectors, or correcting the osculating elements. But both of these approaches would require the capability to determine mean elements from state vectors as the SGP4/SDP4 models would still be used to propagate the orbits. The capability to calculate mean elements from state vectors (or osculating elements) already exists in the program vec2tle, but a general algorithm was not available (at least I couldn't find it). So I got to work and discovered it. I call it rv2el. Work is now progressing slowly on the two differential correction approaches just mentioned, but perhaps other, more experienced programmers could arrive at a solution sooner. With rv2el we can also advance a tle to any epoch and compare elsets to obtain satellite identification. Just throwing out some ideas here. Is anyone interested in working on this stuff, or am I way out of touch? What programs are currently being used to do these chores? Who are the analysts among the group? Can we improve the process? Respectfully submitted, Scott Campbell ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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