# Designation of the Quality of EGNOS+SDCM Satellite Positioning in the Approach to Landing Procedure
## 4 Results
The spread of the results of the vector of the shift in the position of the aerial vehicle from the multi-system Multi-SBAS solution ranged from 1.19 m to 3.55 m with a mean value of 2.39 m. It is worth noting that the factor that has the strongest influence on the results of the \(dr\) parameter are position errors, in particular the position errors for the h component. The lower the accuracy of the vertical component h becomes, the higher is the value of the shift vector \(dr\). Obviously, the application of the square root function in Equation (6) reduces the increase in the \(dr\) parameter, but it is still noticeable, as shown in the results in Figure 8. As a result, it is necessary to continue solving and improving the algorithms for determining the position of an aerial vehicle, in particular for the vertical component h.  
Equation (7) was used to calculate the availability of Multi-SBAS positioning for the analysed stage of flight of the aerial vehicle. In the conducted experiment, the availability of Multi-SBAS positioning was 100% through the entire procedure of landing approach and landing itself. Table 3 presents the results of the availability of positioning of the aerial vehicle from the Multi-SBAS solution. Availability is expressed in percent. Apart from that, Table 3 presents the results of calculating the continuity parameter from the Multi-SBAS solution. In this case, calculations were performed with use of Formula (8). \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value [m]** \\ \hline \(RMS_{AB}\) & 0.72 \\ \(RMS_{AL}\) & 0.63 \\ \(RMS_{dh}\) & 2.23 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The results of RMS error. Figure 8: The values of parameter \(dr\). The continuity parameter takes into account the number of occurring outages in the functioning of SBAS supporting systems. Due to the fact that the subject of this study is the determination of the quality of Multi-SBAS positioning in the landing approach procedure, the conducted calculations were based on the probability of continuity for SBAS APV approach for the GNSS satellite technique in compliance with the requirements of ICAO, where the values \(\frac{P_{E}}{\Delta t_{E}}=\frac{P_{S}}{\Delta t_{S}}\) are the same and equal, respectively, from \(\frac{1\cdot 10^{-6}}{15\;s}\) to \(\frac{8\cdot 10^{-6}}{15\;s}\)[2]. The final continuity valuers from the Multi-SBAS solution ranged from 0.0000699 to 0.0005595. Figure 9 presents the results of positioning integrity according to Formula (9). The integrity values were presented in form of the HPL and VPL security parameters. The HPL values in the landing approach procedure ranged from 0.02 m to 2.01 m, with the mean value of HPL of 0.51 m, while the VPL values ranged from 0.15 m to 3.29 m, with the mean value of 1.74 m. Thus, one may state that the proposed Multi-SBAS solution allowed for a significant increase in the value of the integrity parameter, so that the maximum value did not exceed 3.3 m. This is particularly important for the improvement of the safety of performing aviation operations, as integrity is a measure of trust in the obtained navigation solution of the position of the aerial vehicle obtained from the Multi-SBAS positioning solution. Analysing the obtained HPL/VPL integrity parameters presented in Figure 9, it is worth to refer to the results of the positioning accuracy shown in Figure 7. The determination of the HPL/VPL values is mainly influenced by the standard deviations of the calculated aircraft coordinates [77]. The smaller the values of standard deviations, the smaller the HPL/VPL values are. Positioning accuracy, on the other hand, will mean by how much the determined aircraft coordinates are offset from the flight reference position. The smaller the difference of the compared coordinates from the SBAS and RTK-OTF solution, the higher the positioning accuracy. research method was verified, and then the influence of the obtained research results was highlighted in the context of the analysis of the state of knowledge.