Residuals of a 1000-day estimation of initial state. A coupled model was used for observations and an uncoupled model for estimation. Panel a: differences between the coupled and uncoupled trajectories when the same initial state is used and when the best-fit estimated initial state is used for the uncoupled model. Panel b: time history of the RSW components of residuals. Panel c: frequency content of residual components. Vertical lines indicate (integer multiples/divisors of) the mean motion (solid) and the three normal modes: longitudinal (dotted), latitudinal (dashed), and wobble (dash-dot-dot). Panel d: differences in inclination between observed and estimated trajectories.