Long are orbit determination solutions using Encke's method

The long term tracking of geodetic satellites using laser ranging has provi ded an opportunity to conduct various geophysical studies by solving for co ntinuous, dynamically consistent trajectories that span up to tens of thous ands of orbital revolutions. The process of computing these long are soluti ons require a reliable technique that numerically integrates the equations of motion. Previous studies have demonstrated that Encke's method can be us ed to reduce numerical integration errors and improve filter convergence fo r long are solutions. However, current forms used to represent the referenc e orbit in Encke's method are not capable of maintaining the reference traj ectory close to the true trajectory for the extended trajectories involved in the long are solutions. To improve on the previous Encke reference orbit models, an expanded model has been developed and successfully applied to a 15 yr LAGEOS long are solution. (C) 2000 Elsevier Science Inc. All rights reserved.