KOMPSAT-2 Precise Orbit Determination Using GPS Data

Abstract

A Precise Orbit Determination (POD) has been developed for Korea multipurpose satellite-2 (KOMPSAT-2) to fulfill the requirement for 1 m positioning accuracy. The POD is resolved using single-frequency Global Positioning System (GPS) data in a dynamic filter. To compensate for the ionospheric delay by single-frequency GPS receiver, we use following techniques such as the group and phase ionosphere calibration (GRAPHIC) and scale factor estimate for international reference ionosphere-2000 (IRI-2000). Also, time drifting error of GPS receiver is estimated during the data preprocessing. The POD produced 4-hour overlapping arc position error approximately 1 m Root-Sum-Square (RMS) for 30-hour data arc, which satisfies the design requirement for KOMSAT-2. The implemented method and achieved results for the KOMPSAT-2 POD are presented. Nomenclature N = integer ambiguity 1 P = pseudorange observable on GPS L1 frequency 1 Φ = carrier phase range observable on GPS L1 frequency 0 ,t t k = tagging time of measurement for arbitrary epoch, k and minimum range epoch, 0 during the phase lock, respectively, sec ion ρ Δ = ionospheric range delay, m S R ρ = geometric range from GPS satellite transmitter to the LEO satellite receiver antenna, m ph gr e e , = measurement error for group delay and pseudorange except ionosphere error, respectively α = scale factor