# Galileo: The Added Value for Integrity in
## 5 Experimental Results
### Positioning Results
The horizontal position errors are plotted as a function of time in Figure 8. In the upper box, the error of the configuration without RAIM application is shown. The presence of gross error in the position solution emerges from the figure: the inclusion of the Galileo measurements provides only a slight reduction of the error, and in a few cases, the inclusion of the measurements provided by Galileo satellites degrades the navigation solution. This is due to the additional blunders present in the measurement set. In the lower box, the horizontal position errors of the configurations with RAIM are shown. Furthermore, in this case, the benefits of the multi-constellation approach clearly emerge: the red line is lower than the blue one. In order to further analyze the performance of the configurations with RAIM, a short time interval of the test is considered in Figure 9, where the horizontal position errors are plotted as a function of time. The synergy between the GPS/Galileo multi-constellation solution and the implemented RAIM algorithm provides clear benefits. In particular, in the first grey box, the introduction of the Galileo measurements allows the proper identification of blunders within the GPS measurements improving the accuracy of the navigation solution. From the central grey box, improvements in terms of RA can be noted. Finally, in the grey box on the right, the navigation accuracy is improved and the solution passes from unreliable to reliable when Galileo measurements are included. In order to have a more clear representation of the performance in the horizontal channel, the CDFs of the horizontal errors are shown in Figure 10. In the upper box, the CDFs of the horizontal position errors are computed using all the epochs; the impact of the RAIM algorithm clearly emerges from the figure: the blue and green lines are higher than the other lines. The advantages are more evident in the central box, where the CDFs are computed using only the reliable epochs. Finally, in the lower box of Figure 10 the comparison between GPS and GPS/Galileo multi-constellation is performed using only the common epochs. The benefits of the introduction of the Galileo measurements clearly emerge from the figure: the blue line is higher than the green one. Figure 8: Horizontal error as a function of time. Upper box: horizontal position errors of the configuration without RAIM application; lower box: horizontal position errors of the configurations with RAIM. In Figure 11, the vertical position errors are plotted as a function of time. In the upper box of the figure, the vertical errors of the configurations without RAIM are plotted; the introduction of the Galileo measurements without quality control provides only a slight improvement, since the blue and red lines in Figure 11 are very close. In the lower box of Figure 11, the vertical position errors of the configurations with the RAIM application are shown. The inclusion of Galileo observables and the use of the RAIM technique have a clear impact on the system performance. GPS/Galileo multi-constellation solutions are characterized by significantly reduced errors. The CDFs of the vertical position errors of the four configurations considered are shown in Figure 12. In the upper box of the figure, the CDFs are computed using all available epochs: three of the four configurations, _i.e._, GPS noRAIM, GPS RAIM and GG noRAIM, have similar performance with only a slight improvement in the GPS RAIM case. However, the GPS/Galileo multi-constellation solution with RAIM application provides the best solution by far. A little improvement in the performance of the GPS RAIM configuration is obtained when the CDF is computed using only  
Figure 10: CDFs of the horizontal errors. Upper box: CDFs of the horizontal position errors computed using all epochs; central box: CDFs computed using only the reliable epochs; lower box: CDFs computed using only common epochs. Figure 9: Horizontal error as a function of time.