## 4 Discussion
### Ionospheric Impacts on GNSS Positioning Errors  
The manner in which we present the positioning errors in this work was through the statistics of perturbed stations around the world and, in particular, in the Greenland and South American sectors. On the eclipse day, we could see a slight increase in the percentage of GNSS stations around the world that exceeded both positioning thresholds compared to previous days. The main increment suffered by the maximum 3D positioning error goes from \(\sim\)8% to \(\sim\)14%. Then, Greenland and the southern sector of America were within the regions that presented GNSS stations with the highest positioning errors during the eclipse time window. This positioning behavior in both regions was consistent with the global ionospheric TEC changes. Contrary to what happens with the activity of electrons, the percentage of stations that exceed both positioning-error thresholds was greater on DoY 161 compared to DoYs 159, 160, and 163 (see Figures 6 and 7 (upper panels)). We could see similar behavior in both cases of the 3D-RMS and ROTI activity relationships (RMS&ROTI). The eclipse day was the second DoY with the highest percentage of stations that exceeded the positioning-error thresholds. The effects of the eclipse day were only exceeded by DoY 162 due to weak geomagnetic activity (AE-index \(>\)500 nT) in the polar regions from 5 UT to 15 UT. In South America, the behavior of maximum 3D positioning error \(\geqslant\)10 cm (34%) and 3D-RMS \(\geqslant\)3 cm (22%) on day 161 was similar to day 162. In Greenland, these parameters were also similar on days 161 and 162, where maximum 3D positioning error \(\geqslant\)10 cm was \(>\)55% and 3D-RMS \(\geqslant\) 3 cm was \(\sim\)17%. However, the effects on positioning on DoY 162 were slightly higher (see Figures 6 and 7 (bottom panels)). Our RMS position values for the quiet days were in accordance with those from previous results [29; 30]. They showed that the precision of the post-processing kinematic PPP-AR method was \(\leqslant\)0.8 and \(\leqslant\)2 cm for the horizontal and vertical components, respectively. Moreover, our 3D-RMS results in percentage (\(\leqslant\)3 cm = \(-\)4 to 225%) are consistent with the \(-\)4 to 324% presented by [PERSON] et al. [26]. Unlike previous studies [61; 62; 63; 64], the results presented by [PERSON] et al. [29], suggested that positioning errors also occur, regardless of whether the ROTI has rapid variations, with or without ROTI activity, in this type of DF-GNSS stations with the use of PPP-AR. Moreover, our results confirm that ionospheric disturbance sources can cause degradation of the GNSS accuracy (maximum 3D positioning error \(\geqslant\) 10 cm and 3D-RMS \(\geqslant\) 3 cm) when ROTI \(\geqslant\) 0.25 TECu/min, ROTI \(\geqslant\) 0.5 TECu/min, and without ROTI activity (see Table 1, and Figures 6-9). In addition, not all GNSS stations that had ROTI activity presented position errors. Further, the ROTI activity-positioning variation relationship would have been met if two necessary conditions had been observed on each day in Figure 7. First, the positioning bars (RMS and MAX) had to be greater than or equal to the ROTI activity bar. This condition ensures that any ROTI activity causes variations in GNSS positioning. Second, the positioning ROTI bars (RMS&ROTI and MAX&ROTI) had to be the same or similar to the ROTI activity bar. In most GNSS stations, we can observe the positioning errors were around the beginning of the TEC reduction (\(\sim\)P1 time), the TEC peak (\(\sim\)MOT and GE time), and/or in the final phase of the TEC recovery (see Figure 8). Then, we can see from one to more than three time slots with positioning errors. In general, after P1 time, the behavior of the stations with maximum 3D positioning error \(\geqslant\)10 cm is similar to the DVTEC [%] of the stations located in Greenland (see Figure 8 (left, center left panels), Figure 5 (left panels)) and South America (see Figure 8 (center right panels), Figure 5 (right panel)).