This package provides models that simulate certain physical phenomena of Earth and the near-Earth environment.

Currently the following models are included:

  • Tropospheric Delay
  • Ionospheric Delay
  • Global weather
  • Geomagnetic Field
  • Geoid
  • Atmospheric refraction
  • Displacement of ground points
  • Tessellation of zones of interest as tiles
  • Sampling of zones of interest as grids of points


A Geoid is an equipotential surface of Earth's gravity field. This package provides the means to compute a Geoid from the gravity field harmonic coefficients, as in the following example. See the comment for Geoid for some important caveats.

 ReferenceEllipsoid ellipsoid
         = new ReferenceEllilpsoid(a, f, bodyFrame, GM, spin);
 Geoid geoid = new Geoid(
         GravityFieldFactory.getNormalizedProvider(degree, order),
 double undulation = geoid.getUndulation(lat, lon, date);
T. Neidhart, E. Ward