Determination of Mean Orbital Elements Using GPS Data for LAPAN Satellite Daily Operation

In their operation, LAPAN-A2/ORARI and LAPAN-A3/IPB satellites use SGP4 propagator to predict their position and velocity vectors. The SGP4 propagator needs mean orbital elements which are updated by NORAD in the form of two-line elements (TLE). Because NORAD TLE sometimes is not regularly updated which can lead to a huge error when it is propagated, a new way to create mean elements is needed for the satellite's daily operation. This paper discusses the method to determine the mean orbital elements using GPS data for satellite daily operation. The position and velocity vectors measured by the GPS receiver on the satellite are used to find the osculating elements. Then, these osculating elements are converted to mean orbital elements. Only one set of position and velocity vector is used to calculate the mean orbital elements. Then, It is found that even though only one set of position and velocity vector is used, that the determined means orbital elements are comparable to mean orbital elements produced by North American Aerospace Defense Command (NORAD). Then, by setting the BSTAR drag term is equals to zero, it is concluded that this method that only uses one set of position and velocity vector data is sufficient for the daily operation of LAPAN-A2 and LAPAN-A3 satellites that the orbit is about 630 km and 505 above the sea level respectively.