[Server-sky] sanity check, please: orbit intersections

[Tony Rick]

On Sat, Mar 28, 2009 at 12:30 PM, Keith Lofstrom <keithl at kl-ic.com> wrote:

> Tony, good work!
>
>
Ubuntu Hardy (8.04) seems to handle unicode OK.  I stayed away from Greek
and
other special characters, not being ready to assume that everyone would be
able to
read them.  The true anomaly I referenced is υ in the diagram, and argument
of periapsis is ω, as you indicated.  I also thought about using OO for
documentation, for better formula rendering.

Since I'm still skeptical about my code, there needs to be some independent
verification path, maybe an existing orbit simulator.   The TLE data is snap
shot,
but a TLE history for a particular object might give a rough gauge. I don't
know
yet how well a set ot TLE's populates an orbit.

I have access to the TLE data, and am playing with download options.  One
class of
prepackaged data sets is a twice daily collection of all TLEs for objects
with updates in the last 30 days.  I've been using those sets (three-line to
get the object name).  The
first one I used had ~38k lines or ~13k entries.  Of those, ~1k showed m288
intersection.

I'm using the c++ SGP4/SDP4 algorithm library that I modified to support my
development.  It provides an orbit object that translates TLE to orbit
description
including apogee, perigee, semi-major/semi-minor axes, useful angles and
other
stuff (added an entry on the wiki, and uploaded a set of source/build
files).

- tony
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