Autonomous orbit control procedure, using a simplified GPS navigator and a new longitude phase drift prediction method, applied to the CBERS satellite

摘要

This paper presents a performance analysis of an autonomous orbit control procedure using a simplified GPS navigator (Galski et al., 2001), where the ground track drift of the satellite is estimated on-board with help of a recently developed approach (Orlando et al., 2009) that directly calculates the acceleration of the orbit ground track as a function of the solar and geomagnetic activity. The simplified navigation procedure improves the coarse geometric navigation solution provided by GPS receivers. This is done by using the GPS solutions as inputs (observations) for a real time Kalman filtering process. The orbital state vector is extended and includes the systematic error imposed to the GPS geometric solution by the changes in the set of satellites which are visible to the receiver. The simplified navigator has reduced computational cost, allowing it to be carried and executed on-board of spacecrafts. The improved outputs of this process are used in the computational implementation of an autonomous control system for the ground track drift of the spacecraft orbit. The behavior of the system is evaluated by means of orbit simulations using a CBERS-like phased remote sensing satellite. The aim of the paper is to verify if the coupled system is able to correctly calculate and perform variable size semi-major axis orbit increment maneuvers in order to keep the satellite ground track within its allowed limits (\ub14km).