Spacecraft Orbit Determination from Code Informtation of Global Positioning System Signals

This paper presents the orbit determination of low- Earth orbit (LEO) spacecraft from code information of Global Position System (GPS) signals. An extended Kalman filter was implemented to estimate the position and velocity of the spacecraft. The effect of second harmonic, J2, of the Earth´s oblateness was included in the system model. The estimated results were evaluated by the reference solutions emulated from the developed GPS data-generator. The conventional least squares method was exploited to provide the initial guess.