Radar observations in Find_Orb

Bill J Gray Apr 23, 2012

I've read a bit more on this subject, and it appears there
is good news and bad news.

The good news is that the "physics" end of handling radar
astrometry isn't so tough. The precision of radar data is much
greater than that of optical astrometry, but isn't so great that
I need to consider currently ignored effects; Find_Orb's current
physical model is already up to the job. (With some exceptions.
Occasionally, the radar data is good to .1 microsecond,
corresponding to a round-trip sigma of 30 meters, meaning the
asteroid was ranged to within 15 meters! At that point, I'd
have to consider all the small variations in the earth' orientation.
And possibly some smaller effects of general relativity that I
was able to ignore until now. And maybe Yarkovsky and YORP
effects.)

The bad news is that the actual programming effort involved
would be pretty high. The current orientation of the program is
entirely aimed at optical astrometry; at almost every point where
observations are processed, I'd have to add code to say "if it's
an optical observation, do A; if it's radar, do B." None of
that is rocket surgery. In fact, it's quite straightforward.
But there would be a lot of small changes, requiring lots of
testing to catch unexpected side effects. So I don't expect to
add radar observations to Find_Orb very soon.

-- Bill