Analysis of FY‑3D Satellite Attitude and Orbit Accuracy and Its Influence on Geolocation

Objectives Satellite orbit and attitude errors are the key factors that affect the accuracy of image geolocation. The Fengyun-3D (FY‑3D) satellite medium resolution spectral imager (MERSI) is used as an example to analyze the measured data of orbit and attitude.

Methods In order to determine the source of the error, the calculation of the entire chain of on-board data is analyzed by using high-precision ephemeris of satellite-borne global navigation satellite system occultation sounder (GNOS), and it is determined that the attitude error comes from the error in the on-board algorithm. A revised and optimized scheme is proposed and the feasibility is analyzed. Then, the corrected attitude and orbit data are used for image geolocation and actual measurement data analysis.

Results It shows that the geolocation accuracy of MERSI's 1 ‍km image has increased by about 20% in both the along-track and cross-track directions, reach‍ing the sub-pixel level.

Conclusions The analysis show that it is effective to improve the accuracy of image geolocation by calibrating the error of attitude and orbit.