Orbit determination from three sets of observations (t, R.A., dec.) assuming heliocentric orbit and geocentric observer (i.e. requires R) and using Laplacian methods. See "Astrodynamics: Orbit Determination, Space Navigation, Celestial Mechanics, Volume 1" by Samuel Herrick, Van Nostrand Reinhold, 1971; esp. Ch. 10 and 12 (page numbers refer to the appropriate pages in this edition).
Requires an ASCII datafile, eight (8) lines:
comment
header
t(1) R.A.(1) dec(1) Rx(1) Ry(1) Rz(1)
t(1) R.A.(1) dec(1) Rx(2) Ry(2) Rz(2)
t(1) R.A.(1) dec(1) Rx(3) Ry(3) Rz(3)
k*
alpha
epsilon
where t is in JD and R.A., dec. are both in decimal degrees,
and k* = k = 1/(unit of canonical time) :
k = 0.017 202 09895 if canonical time in days
k = 0.001 239 444 if canonical time in seconds
note: tau = k*(t - to).
and alpha is the light-time constant:
alpha = 0.0057755 days/au or alpha = 0.021275 sec/gu
epsilon is the obliquity (inclination) of the ecliptic plane, in decimal degrees.
GSS, 12 Mar 1998, 3 Jun 1998, 7-9 Oct 1998