Impact of solar radiation pressure models on earth rotation parameters derived from BDS

Earth rotation parameters (ERPs) are susceptible to absorbing the spurious effects from global navigation satellite system constellation characteristics and orbit modeling deficiencies, especially the deficiencies in the solar radiation pressure (SRP) models. This study investigates the impact of SRP modeling on the ERP estimation derived from BeiDou Navigation Satellite System (BDS). The adjusted optical properties are adopted in an a priori box-wing model and jointly used with the extended CODE orbit model (ECOM) for BDS ERP estimation. The BDS-derived ERPs are assessed by comparing them with International Earth Rotation and Reference Systems Service (IERS) 14C04 product. Our processing results of 3 years (2019–2021) show that the mean offsets of BDS-derived ERPs are nearly not affected by the a priori SRP model. However, the standard deviation (STD) is improved by approximately 20% for pole coordinates and their rates when considering an a priori box-wing model together with the ECOM1 (5 parameters). The a priori bow-wing model mitigates most spurious signals in the pole coordinate spectrum. It is noticeable that the BDS-derived ERPs are also affected by the system-specific spurious signals. The visible signals at the 3rd harmonics of draconitic year in the pole coordinates are related to the 3-plane constellations. The signal at the 2nd harmonics of the draconitic year for BDS-derived excess length of day (∆LOD) estimates is significantly larger than that of the GPS-derived. Additionally, the extension of the orbital arc in the BDS processing from 1 to 3 day is beneficial for the ERP quality. When switching to a 3-day arc length, the improvement of the ERP quality is about 28, 15 and 50 for X-pole, Y-pole coordinates and ∆ LOD, respectively. The STD is more than 3 times better than that of 1-day arc solutions for pole coordinate rates. The STD of the 3-day arc length BDS-derived ERPs with respect to the IERS 14C04 product reaches about 40 μas, 100 μas/day, 9 μs for pole coordinates, pole coordinate rates and ∆ LOD, respectively.