5 of 6 added 125 characters in body

Earth geopotential effect on orbit propagation

I'm trying to take into account the Earth geopotential effect on the orbit. The only term I could consider, is J2.

  1. Are the terms (J2, etc.) change with time?
  2. I found other terms coefficients here. How to add them also to differential equation, taken from here?

    enter image description here

    3.Why does the shown equation give 1 km error in 1 day in comparison with GMAT (configuration is below)? The coefficients for Eq radius and J2 are the same. The integrator is 9th order Runge-Kutta with tol=10e-13.

enter image description here

enter image description here