Orbital analysis of LAGEOS and LAGEOS II laser ranged satellites: relativistic effects and geophysical issues

We present here the results of a recent analysis of LAGEOS and LAGEOS II laser range data. The higher accuracy in determining the orbits of these satellites makes it possible to see very tiny relativistic effects like frame-dragging and a wide variety of other phenomena at work. In particular, it is apparent the need of better understanding some effects of non-gravitational origin. The importance of these orbital fits as a geophysical probe is also stressed with a particular example. The analysis is carried out with GEODYN II Software, whose broad structure and use is described