IMPROVEMENT OF ESTIMATED ORBIT BY USING SINGLE DIFFERENCED GPS OBSERVATION DATA

摘要

Previously, the development of a low budget precision orbit determination (LBPOD) program for use on-board, low-Earth-orbit (LEO) satellites and its application to a particular satellite and an improvement of a geopotential model in the LBPOD were described. To improve the Global positioning system (GPS) measurement model, the incorporation of single-differenced LEO-GPS pseudo range measurements is considered. A pairing method for the single differenced GPS measurements is discussed. Also, a true transmission time correction on GPS satellite position and velocity is introduced. A batch filter is used to provide statistical best state estimates. Results obtained for the LEO satellite, CHAMP (Challenging Mini-satellite Payload), are compared with those obtained with a current reference level precision orbit Determination (POD) program.