An extended algorithm for the ocean tide term in the force model of the computer programs CELEST and TERRA

A revised and extended version if presented of a computer algorithm specifying the gravitational action by which the ocean tides perturb satellite motion. The current ocean tide term in the CELEST and TERRA equations of motion is based entirely on the semidiurnal (M2) tide mode. Also, the corresponding solid earth tide term neglects ocean loading. The present algorithm for the perturbing acceleration caused by the ocean tide re-formulates the M2 tide and introduces ten additional spectral components (S2, N2, K2, K1, O1, P1, Q1, Mf, Mm, Ssa). In addition, the effect on the solid earth of hydrostatic loading by the ocean tide is now included.