Orbit maintenance for calibration of KOMPSAT-5

The first Korean SAR mission satellite, KOMPSAT-5 will be launched atop of Russian Dnepr rocket. The satellite is injected into Sun-synchronous dawn-dusk orbit at the mean altitude of 550 km. The satellite orbit has a characteristic of exact repeat ground track for 28 days. There are total 421 reference longitude points around the Earth equator to maintain the ground path of the satellite within ± 2 km longitude band. The ground track maintenance requirement is specified for obtaining interferometry radar image from KOMPSAT-5. After releasing from the launch vehicle, the satellite should acquire a nominal ground track within 2 months for SAR calibration and validation. In order to calibrate the SAR payload, total of 52 corner reflectors are constructed in Mongolia. The satellite should pass over the corner reflectors with three imaging mode and two looking mode during 4 months of calibration and validation period. The satellite orbit should be carefully maintained to follow the exact repeat ground track at that time. In this paper, the acquisition and maintenance of the KOMPSAT-5 satellite reference ground track will be presented. The ground track acquisition after separation from Dnepr launch vehicle is analyzed using simulated spacecraft orbit data. A series of orbit maintenance maneuvers to keep the satellite following the reference ground track are presented.