Parallel computation of satellite orbit acceleration

We present a formulation of parallel computation of the satellite orbit acceleration due to non-spherical gravitational field. The key techniques are the vector computation of associated Legendre functions and the do-loop folding. These are easily implemented by a slight modification of existing programs and by embedding a few OpenMP directives. The formulation significantly speeds up the orbit integrations of low-altitude satellites. For example, that of GRACE under the influence of EGM2008, a 2190×2159 geopotential model runs around 4 times faster than the serial computation if conducted at a PC with a quad-core 8-thread processor.

► We developed a parallel code to compute satellite orbit acceleration due to geopotential.
► A non-singular fixed-order recursion is adopted for vector computation of ALF derivatives.
► The parallelization is enhanced by folding the double do-loops.
► OpenMP is used for easy implementation of the Fortran programs.
► The speed-up factor at a quad-core PC amounts to around 4 when N>200N>200.