Refinement of the solar radiation pressure model for the BDS-3 satellites with considering illuminated antennas

Solar Radiation Pressure (SRP), which plays a crucial role in satellite Precision Orbit Determination (POD), is associated with the satellite’s optical properties and surface structure. The BDS-3 satellites offer a wide range of featured services, which result in complex satellite structures. Significant systematic errors related to solar elevation angles (up to 30 cm) are observed in precision orbit products. To address this issue, we compared the theoretical trend and actual values of acceleration in the Sun-satellite direction, revealing that the satellite antennas may introduce additional SRP perturbations. Consequently, an a priori model that includes antenna illumination was established based on the adjustable box-wing model. The employment of the a priori model shows a notable enhancement in orbit accuracy for the BDS-3 satellites. The mean offset and standard deviation of SLR residuals for C45/C46 are reduced to a level consistent with satellites from the same manufacture. The systematic errors in the residuals are notably reduced, achieving the RMS of 3.85 cm, which represents a 74% improvement over the results obtained using only ECOM1. For IGSO satellites, the 3D OBD is reduced to 18.5 cm, reflecting improvements of 55% and 25% over ECOM1 and ECOM2, respectively. Moreover, the 3-day-arc POD has been demonstrated to markedly enhance the orbit internal consistency of the IGSO satellite, with a 3D OBD reduction to 3.1 cm.