A METHOD TO IMPROVE THE PRECISION OF PREDICTED LEO SPACE OBJECTS EPHEMERIS

摘要

There are two major errors in predict ing Space Objectrn(SO) ephemeris (state vector): one is the error of thernInitial Orbital Element (IOE) sets, the other is that of thernDynamical Model (DM). In order to get a betterrnpredicted ephemeris, a better IOE or/and DM is needed.rnThis paper aims to seek a method of improving thernprecision of IOE and PM together. The basic idea is tornreduce the error of semi-major axis (a) together withrnthat of the Area-Mass ratio (A/M) by calibrat ion. Thernfundamental principle is that the error of a and A/Mrnwould propagate and augmented with time symmetricalrnin down-track component, the necessary condition isrnthat the precise ephemeris of the past must be obtained.