AUTHOR=Ma Chunyong , Wang Xuan , Gao Zhanwen , Li Zheng , Zhao Chaofang , Chen Ge TITLE=Overlapping-calibration of wide-swath altimeter baseline errors using two satellites formation flying design JOURNAL=Frontiers in Marine Science VOLUME=9 YEAR=2022 URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1027654 DOI=10.3389/fmars.2022.1027654 ISSN=2296-7745 ABSTRACT=

The sea surface height (SSH) measured by future wide-swath altimetry satellites contains observation error due to baseline measurement, which is called SSH_Error_Baseline. It is a huge challenge for satellite engineering to maintain such high accuracies of the baseline roll and length in orbit to ensure that the SSH_Error_Baseline can be maintained below 1 cm. Therefore, how to effectively reduce the SSH_Error_Baseline is extremely important. In order to solve the existing problem, an innovative overlapping-calibration method is proposed based on two-satellite formation flight design with overlapping swath. In this study, the differences of SSH data observed by these two satellites in the overlapping area is so small that it can be ignored, and the SSH_Error_Baseline dominates the difference. Then, the baseline parameters of the two satellites can be well estimated by adopting an optimal inverse method. A total of 9 groups of observing system simulation experiments (OSSEs) have been carried out, and they respectively indicate different pessimistic theoretical scenarios of baseline measurement systems. According to the results, this design can effectively reduce the SSH_Error_Baseline in most scenarios. Regarding the advantage of this method, it can be applied to all along-track observation data without requiring the application of additional auxiliary data (i.e. model data, SSH derived from nadir altimetry). Therefore, when two wide-swath altimetry satellites are simultaneously designed, the formation flight scheme proposed in this paper is recommended, especially when the measurements of the baseline cannot meet the expected accuracies.