A SIMULATION FOR GRAVITY FINE STRUCTURE RECOVERY FROM LOW-LOW GRAVSAT SST DATA

摘要

Covariance error analysis techniques were applied to investigate estimation strategies for the 1OH-1OW SST mission for accurate local recovery of gravitational fine structure, considering the aliasing effects of unsolved for parameters. A 3° x 5° surface density block representation of the high order geopotential was utilized with the drag-free "low-low" GRAVSAT configuration in a circular polar orbit ac 250 km altitude. Recovery of local sets of density blocks from long data arcs was found not to be feasible due to strong aliasing effects. The error analysis for the recovery of local sets of density blocks using independent short data arcs demonstrated that the estimation strategy of simultaneously estimating a local;set of blocks covered by data and two "buffer layers" of blocks not covered by data greatly reduced aliasing errors. However, for the low-low configura?tion the SST data type exhibits strong satellite state recovery abili?ty only for the along track component of velocity, the normal matrix being poorly conditioned for the recovery of radial and cross track components. This requires satellite orbital accuracies from other tracking weans to a minimum of 10 meters in position and 01 meters/ sec in radial and cross track velocity components.