Function lupnt::RotSideralMotionDot

• Defined in File frame_conversions.h

Function Documentation

Mat3 lupnt::RotSideralMotionDot(Real t_tdb)

Returns the exact time derivative dR_s/dt of the sidereal-motion rotation matrix (see RotSideralMotion) at epoch t_tdb, evaluated using the Earth rotation rate w_E (from the EOP length-of-day, or the analytic derivative of the SPICE-fitted UT1-UTC if InitFrameConversionFromSpice has fitted a model covering t_tdb).

Used internally by GcrfToItrf/ItrfToGcrf to compute the velocity-transformation term R_GcrfToItrf_dot = R_po * R_s_dot * R_pn, which accounts for the Earth-fixed frame’s rotation rate when converting velocities between GCRF and ITRF.

Parameters:

t_tdb – Epoch [s, TDB since J2000]

Returns:

3x3 matrix dR_s/dt [1/s] (time derivative of the sidereal-motion rotation matrix)