CL_mod_precessionMatrix — Precession matrix and rotation vectors (IERS 1996)
[PREC[,OM[,OMP]]] = CL_mod_precessionMatrix(K,KP,KPP[,flag])
if P0 is the pole of J2000 equator, and P is the pole of the equator at date t; if G0 is the equinox of J2000 and G is the equinox at date t:
zetaa : angle between the meridians (pole P0) P0-P and P0-G0
thetaa: angle between the equateur J2000 and the equateur t
za : angle between the meridians (pole P) P-P0 and P-G
[zetaa;tetaa;za] (3xN)
[zetaap;tetaap;zap] (3xN)
[zetaapp;tetaapp;zapp] (3xN)
(optional) "n" -> matrix only; "p" -> matrix and rotation vector; "s" -> matrix, rotation vector and its time derivatives (defatul depends on number of outputs)
precession matrix (3x3xN)
(optional) rotation vectors (3xN)
(optional) first time derivative of OM (3xN)