@article{YI2022, 
author = {Bin YI and Defeng GU and Bing JU and Kai SHAO and Houzhe ZHANG},
title = {Enhanced baseline determination for formation flying LEOs by relative corrections of phase center and code residual variations},
year = {2022},
journal = {Chinese Journal of Aeronautics},
volume = {35},
number = {2},
pages = {185-194},
keywords = {Ambiguity resolution, Formation flying, Precise baseline determination (PBD), Relative phase centre variations (RPCVs) estimation, SD MW combination residuals variations (SD MWVs) estimation},
url = {https://www.sciopen.com/article/10.1016/j.cja.2021.03.016},
doi = {10.1016/j.cja.2021.03.016},
abstract = {Formation flying Low Earth Orbiters (LEOs) are important for implementing new and advanced concepts in Earth observation missions. Precise Baseline Determination (PBD) is a prerequisite for LEOs to complete specified mission targets. PBD is usually performed based on space-borne GNSS data, the relative corrections of phase center and code residual variations play crucial roles in achieving the best relative orbit accuracy. Herein, the influences of antenna Relative Phase Centre Variations (RPCVs) and Single-Difference (SD) Melbourne-Wübbena (MW) Combination Residuals Variations (SD MWVs) on PBD are studied. The methods were tested using flight data from Gravity Recovery And Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO). Results showed that the maximum values for RPCVs and SD MWVs were 14 mm and 0.32 cycles, respectively. Then, the RPCVs correction significantly enhanced the baseline accuracy; the K-Band Ranging (KBR) measurement consistency improved by 30.1% and 37.5% for GRACE and GRACE-FO, respectively. The application of SD MWVs further improved the accuracy and reliability of PBD results. For GRACE, the ambiguities fixing success rate increased from 85.1% to 97.9% and a baseline consistency of 0.57 mm was achieved for the KBR measurements. It was found that the correction of both RPCVs and SD MWVs reduced the carrier phase observation minus computation residuals from double-difference ionosphere-free combination. In addition, in-flight data processing demonstrated that RPCVs and SD MWVs estimations for the current period could be used for the previous and subsequent periods.}
}