Precise absolute and relative orbit determination for distributed InSAR satellite system

Abstract

Precise orbit and baseline determination of formation-flying low Earth orbiters are prerequisites for the success of distributed InSAR satellite system mission. GNSS-based reduced-dynamic absolute and relative orbit determination method is the main method to obtain high-precision orbit and baseline products. The absolute and relative orbit determination for TH-2 satellite system is researched using the space-borne GPS data. The results show that the signal tracking abilities and data qualities of the receivers equipped on satellite A and satellite B are almost the same. By modeling orbital maneuvers with constant empirical accelerations, the influences of orbital maneuvers on absolute and relative orbit determination for TH-2 satellite formation can be effectively eliminated. For single-satellite absolute orbit determination, the three-dimensional (3D) RMS of 6 h overlapping orbit differences is less than 1.2 cm. The RMS values of satellite laser ranging data validation residuals for satellite A and satellite B are 2.76 cm and 2.33 cm, respectively. For dual-satellite relative orbit determination, the 3D RMS of 6 h overlapping baseline differences is about 0.66 mm. Baseline comparison RMS with the products of Xi'an Research Institute of Surveying and Mapping are 0.73 mm, 1.11 mm, 0.51 mm and 1.43 mm in radial, tangential, normal and 3D direction, respectively