# Mitigating the Scintillation Effect on GNSS Signals Using MP and ROTI
## 3 Results
### Statistical Results
#### 3.2.2 Observation Removal Strategy  
The improvement of height and 3D positioning errors after removing scintillation-affected observations based on the MT and ET of permutations and combinations of MP1, MP2, ROTI, S4 and \(\sigma_{\phi}\) on 14 days at 3 stations are summarized in Table 4. Due to the large number of combinations (see Section 3.1), results of the observation removal strategy are summarized in the main article and the detailed results are presented in Tables S1-S28 in the supporting material. Two criteria were used to evaluate the effectiveness of this strategy: proportion of days with improvement and the best improvement rate. As S4 was low at the SNA0P station, S4 was only used on 7 days at the other two stations in this strategy. When S4 was not considered for comparison, the highest proportions of days showing improvement in height and 3D errors were 8/14 and 11/14, respectively. The largest best improvement rate in height and 3D errors were 91.7% and 87.9%, respectively, both obtained with standard parameters. The largest proportion of days (8/14) with improvement in height errors was obtained by both standard and scintillation parameters. For 3D errors, the largest proportion of days (11/14) with improvement was obtained with the scintillation parameters. These results indicate that scintillation parameters could lead to a higher possibility of improvement and standard parameters could result in a higher degree of improvement. When MP1 and MP2 were used alone or the combination of MP1 and MP2 was used, the possibility and degree of improvement were relatively low. For example, when MP2 was used alone and ET was applied, the proportion of days with improvement and the best improvement in height errors were 3/14 and 16.3%, respectively, substantially lower than the others. However, when MP was combined with ROTI, the improvement was comparable or even higher than when ROTI was used alone. For instance, when MP1 was combined with ROTI and MT was used, the proportions of improved days and the best improvement in 3D errors slightly exceeded when ROTI was used alone. Moreover, \(\sigma_{\phi}\) was more effective than S4 according to the best improvement though it is largely because S4 was not high on 7 days at the Antarctica station SNA0P and can only be applied on the other 7 days. In terms of the proportion of days with improvement, S4 was comparable to \(\sigma_{\phi}\) when only considering the 7 days' data. Hence, \(\sigma_{\phi}\) was more effective than S4 in scintillation mitigation. MT was generally more effective than ET according to both proportion of days with improvement and also the best improvement. The proportion of days with improved 3D errors was generally higher than that of height errors and the case was contrary for best improvement rate. Furthermore, when a single reference parameter was applied, the effectiveness of ROTI and scintillation parameters were comparable. When combinations were applied, the improvement in effectiveness of scintillation parameters was not substantial due to low S4 at SNA0P. However, combinations of standard parameters, such as the combination of MP1 and ROTI were able to further improve the results. For standard parameters, the combination of MP1 and ROTI was more robust than the others, in the sense that was able to acquire higher possibility and level of improvement. Thus, it was possible that the combination of MP and ROTI was able to cover and mitigate more errors than a single parameter.