# Relative Positioning in Remote Areas Using a GNSS Dual Frequency Smartphone
## 4 Results
### Test 1  
Figure 10 above presents the RMS for all Galileo+GPS solutions calculated in Test 1, using observations from the two smartphones with each of the reference stations.  
From Table 7, we see RMS values between 20 and 22 cm in the three components for the more distant station CEUT (645 km), which is very interesting and promising for this level of equipment used in the rapid survey (10 min of observation). The other two long baselines VIGO (121 km) and CASC (277 km) have practically all values below 20 cm, with components E and N tending to have values around 15 cm. As expected, the best results were obtained using GAIA, a very small baseline, with the N component below 10 cm and the other two components between 12 and 13 cm. In fact, it was expected that even better values could be achieved with this GAIA station, but previous work experience with a fast survey (\(<\)10 min) has shown values of this level. This seems to be a usual accuracy for a quick survey using a smartphone, with the results being close to those obtained in the other tests (Figures 14-18).  
When looking at the impact of flight mode on or off, we notice that in the case of flight mode off, the results are slightly better, with RMS values mostly below 15 cm. When in flight mode, the results are worse, with values reaching 26 cm. Apparently, WIFI or GSM signals turned on (flight mode off), do not interfere in a way that can degrade the quality of the solutions, presenting even better performance in this mode, which allows us to say that smartphones can be used to collect raw GNSS observations in their normal operating mode.  
Figure 12 shows the comparisons of the RMS for Galileo + GPS solutions calculated for each one of the smartphones A and the B. In Table 9, we can see the statistics obtained.  
When comparing the two smartphones, we found no significant differences, although smartphones A and B do not track the same satellites (see Figure 5). The results are similar, with maximums below 26 cm and with most values below 20 cm.  
In this Test 1, we also compared the positional performance between the Galileo-only and GPS-only solutions. Figure 13 shows the RMS errors obtained for each GNSS system using observations from two pillars (3 and 5). Due to the smaller number of Galileo satellites available (this constellation is not yet finalized), as seen above in Table 2 and Figure 5, most of the time, there were not enough Galileo satellites to process differential solutions at all points, only these results were presented.  
We see a positional performance of Galileo similar to GPS, with most errors below 15 cm, even surpassing GPS in some cases, as in the Up component, which has smaller errors than GPS, except for the VIGO station. In general, the positioning results with both GNSS systems alone are also interesting, being similar to the solution obtained with the combination of both. The best results were for the horizontal components from the Galileo solutions relative to the GAIA station, respectively, 6 cm in the East and 2 cm in the North, while the altitude component Up had an error of 1 cm with the CASC station. Looking at the biggest errors, we found 26 cm for the E component in the Galileo solutions using the VIGO station and 25 cm for the Up component of the GPS using the CEUT station. Bearing in mind that the current limitation on the number of satellites in the Galileo constellation will no longer exist in the future, the positioning performance with this system in itself is quite promising.