## 4 Discussion
### Ionospheric Impacts on GNSS Positioning Errors
For example, in the Greenland region, the ionospheric TEC depletion was significant until \(\sim\)14 UT, and the recovery also could be observed in the rapid decrease from 28% to 11% of stations that exceeded the threshold of maximum 3D positioning error \(\sim\)14 UT, where the persistence of the positioning errors provoked by the 10 June 2021 annular eclipse lasted \(\sim\)6 h. Although the TEC depletion in sectors of South America could be observed until\(\sim\)19-21 UT, a ionospheric TEC enhancement was observed around 16-17 UT, similar to the behavior of the GNSS stations with a maximum 3D positioning error greater than the threshold of 10 cm (from 28% to 22% between 16 and 17 UT). Therefore, the persistence of the positioning errors provoked by the 10 June 2021 annular eclipse lasted \(\sim\)10 h.  
The annular eclipse in Greenland caused significant TEC changes (\(\sim\)\(-60\%\)), although with low ROTI activity. However, the GNSS positioning errors are similar to those caused during a weak geomagnetic storm with high auroral activity. From Table 1, Figures 8 and 9, we see that the stations (PIFL, TRO1, GLS2, KUAQ, SENU) presented maximum 3D position errors >60%, also had A[%] \(\leqslant\)\(-49\%\), but without ROTI activity (<0.25 TECu/min). PIFL station was the only one with ROTI activity over the 5-day period under consideration. Additionally, not all the stations that had A[%] \(\leqslant\)\(-49\%\) got maximum 3D errors >60% (BLAS, LEFN, IQAL, SVTL, LMMF, and CN57 stations). The LMMF station presented A[%] = \(-61\%\), but maximum 3D position errors = \(-8\%\), and ROTI = 0.2 TECu/min. Although the BLAS and LEFN stations had strong ROTI activity and the IQAL station had weak ROTI activity, the percentage of maximum 3D positioning error in these stations was between 24% and 31%. Thus, the results suggest that when maximum 3D errors >60%, with respect to the maximum of the reference days, we can find A[%] \(\leqslant\)\(-49\%\), but not the opposite. The results also reinforce the idea that ROTI activity is not a necessary condition to affect GNSS accuracy. We were not able to estimate the ionospheric effects on GNSS positioning in the magnetic conjugate region of MPO of the solar eclipse, due to the lack of GNSS stations in this region. Our study showed that the ionospheric TEC disturbances due to the solar eclipse in the polar regions can produce disturbances in low and medium latitudes. Ionospheric changes can cause GNSS positioning errors. The estimation of these errors is critical in teleoperated and autonomous (ground, maritime, and aerial) applications and other high-precision activities. For example, mining, agriculture, and fishing are all key economic activities in Chile that are considering the use of more teleoperated or autonomous systems. If the positioning error in the GNSS receivers spikes in vehicles in these industries, it could impose a serious risk to people and infrastructure. For open-pit mines, a high error can generate a failure in the estimation of the terrace on which a vehicle is located, with the consequent risk of falling. Halting autonomous operations during some events such as eclipses can reduce potential risks, but they can be complex for these industries. Stopping the operation for even a short period of time, such as an hour, could be prohibitively expensive. Therefore, forecasting the impact should be precise in location and duration.