# Mitigating the Scintillation Effect on GNSS Signals Using MP and ROTI
## 5 Conclusions  
In this paper, the experiment on mitigating scintillation effects on PPP has been conducted based on three strategies: satellite removal, observation removal and weighting the measurement noise matrix. The satellite removal strategy led to the smallest improvement, the observation removal strategy resulted in the most consistent improvement and the weight strategy generated the largest improvement. In the observation removal strategy, the effectiveness of standard parameters was comparable to that of scintillation parameters, especially with the combination of MP1 and ROTI. Though the observation removal strategy resulted in the most consistent improvement, the GDOP variation due to excessive removals led to the instability of this strategy. Using data from multiple constellations is a possible way to address the drawback of the observation removal strategy. In contrast, the weight strategy improved the height error by 93.1% at most. The standard parameters were also comparable to scintillation parameters in the observation removal and weight strategy. Thus, the primary novelty of the method in this paper was that parameters from 30 s data could also be used to effectively mitigate the scintillation effects on PPP. In addition, the observation removal strategy was proposed for the first time. Though there were some shortcomings with this strategy, it was easier-to-use than the weight strategy and could improve the errors more consistently. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/rs14236089/s1](https://www.mdpi.com/article/10.3390/rs14236089/s1)]([https://www.mdpi.com/article/10.3390/rs14236089/s1](https://www.mdpi.com/article/10.3390/rs14236089/s1)), Tables S1-S28: Change of the height and 3D positioning errors through the observation removal strategy based on MT/ET at SAOOP/SJCU/SNAOP on 4 September 2017/7 September 2017/13 September 2017/18 February 2016/13 April 2016/9 May 2016/6 June 2016/28 July 2016/13 October 2016. Improved RMSEs (m) are highlighted in bold [44]. **Author Contributions:** Conceptualization, C.L., N.A.S.H. and C.M.H. ; methodology, C.L., D.Z. and N.A.S.H. ; software, C.L. and D.Z. ; validation, C.L., C.M.H., S.V.V. and N.A.S.H. ; formal analysis, C.L. ; investigation, C.L. ; resources, C.M.H. and N.A.S.H. ; data curation, C.L. ; writing--original draft preparation, C.L. ; writing--review and editing, C.L., C.M.H., S.V.V. and N.A.S.H. ; visualization, C.L. ; supervision, C.M.H., S.V.V. and N.A.S.H. ; project administration, N.A.S.H. ; funding acquisition, N.A.S.H., C.M.H. and D.Z. All authors have read and agreed to the published version of the manuscript. **Funding:** We acknowledge the University of Nottingham Ningbo China Faculty of Science and Engineering for provision of a PhD scholarship to [PERSON]. (17053 FOSE) as well as further support through a new researcher's grant to N.A.S.H. and C.M.H. This project was further supported by the Natural Science Foundation of Jiangsu Province (No. BK20200664) and Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University (No. 20-01-09). The APC was funded by a waiver to C.M.H. **Data Availability Statement:** The GNSS data at the SJCU station was provided by Projects CIGALA and CALIBRA which can be accessed from [[https://ismrquerytool.fct.unesp.br/is/ismrtool/retrieval/download_ismr.php?lan=en](https://ismrquerytool.fct.unesp.br/is/ismrtool/retrieval/download_ismr.php?lan=en)]([https://ismrquerytool.fct.unesp.br/is/ismrtool/retrieval/download_ismr.php?lan=en](https://ismrquerytool.fct.unesp.br/is/ismrtool/retrieval/download_ismr.php?lan=en)) (accessed 28 November 2022). The GNSS data at the SAOOP station were provided by INGV which can be accessed from [[http://www.eswua.ingv.it/](http://www.eswua.ingv.it/)]([http://www.eswua.ingv.it/](http://www.eswua.ingv.it/)) (accessed 28 November 2022).