Dear all,

I want to find satellites with repetitive ground tracks, so find the inclination and semi-major axis that would create the correct drift of the ascending node.

Analytically, it can be computed using the orbital period and the RAAN drift due to J2, as explained here: Ground track - Wikipedia.

However, when I use BrouwerLyddanePropagator (with mean elements), I do not find the same relation between inclination and semi-major axis. As a positive point, I find the same with BrouwerLyddanePropagator than with STK J2 propagator.

Why is there a difference between a simple analytical computation and BrouwerLyddanePropagator taking into account J2?

Thank you !