## 4 Discussion  
In order to estimate the changes in the average PDOP value between individual positioning solutions for both measurement campaigns, it was proposed to adopt the relative percentage change in the average PDOP value, which is presented in Figures 14 and 15 based on the relationships [52]:  
\[\Delta PDOP_{GPS/GLONASS}=\frac{PDOP_{GPS/GLONASS_{c},n,k}-PDOP_{GPS/GLONASS_{c}, n,k}}{PDOP_{GPS/GLONASS_{c},n,k}}\cdot 100\%, \tag{4}\]  
where:  
\(PDOP_{GPS/GLONASS_{c},n,k}\)--the average value of the PDOP for the continuous GPS/GLONASS variant during the implementation of the n-th measurement campaign on the k-th route (-), \(PDOP_{GPS/GLONASS_{c},n,k}\)--the average value of the PDOP for the optimum GPS/GLONASS variant during the implementation of the n-th measurement campaign on the k-th route (-), \(n\)--measurement campaign number (-),  
\(k\)--measurement route number (-),  
and:  
\[\Delta PDOP_{GPS-GPS/GLONASS}=\frac{PDOP_{GPS_{c},n,k}-PDOP_{GPS/GLONASS_{c}, n,k}}{PDOP_{GPS/GLONASS_{c},n,k}}\cdot 100\%, \tag{5}\]  
where: \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Area**} & \multicolumn{2}{c}{**Continuous GPS Variant**} & \multicolumn{2}{c}{**Continuous GPS/GLONASS Variant**} & \multicolumn{2}{c}{**Optimal GPS/GLONASS Variant**} \\  & **Mean PDOP** & **Availability** & **Mean PDOP** & **Availability** & **Mean PDOP** & **Availability** \\ \hline Entire route & 2.768 & 89.81\% & 2.065 & 96.60\% & 1.989 & 96.70\% \\ Area A & 2.212 & 97.32\% & 1.636 & 99.11\% & 1.741 & 99.11\% \\ Area B & 2.781 & 92.41\% & 1.949 & 97.77\% & 1.885 & 95.24\% \\ Area C & 3.837 & 76.71\% & 2.891 & 91.78\% & 2.500 & 95.89\% \\ \hline \end{tabular}
\end{table} 
Table 4: The average values of the PDOP, obtained during simulation tests for the second measurement campaign. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Area**} & \multicolumn{2}{c}{**Continuous GPS Variant**} & \multicolumn{2}{c}{**Continuous GPS/GLONASS Variant**} & \multicolumn{2}{c}{**Optimal GPS/GLONASS Variant**} \\  & **Mean PDOP** & **Availability** & **Mean PDOP** & **Availability** & **Mean PDOP** & **Availability** \\ \hline Entire route & 2.978 & 87.88\% & 2.408 & 95.85\% & 1.971 & 95.85\% \\ Area A & 2.585 & 94.64\% & 2.018 & 98.21\% & 1.700 & 97.32\% \\ Area B & 2.987 & 90.41\% & 2.325 & 96.43\% & 2.010 & 95.72\% \\ Area C & 3.718 & 75.34\% & 3.137 & 91.78\% & 2.505 & 93.1 The average value of the PDOP for the continuous GPS variant during the implementation of the n-th measurement campaign on the k-th route (-). Analysis of the obtained simulation test results indicates that the campaign implementation in accordance with the pre-determined schedule significantly improves the quality of recorded GNSS data. This is particularly noticeable during the first measurement campaign. For example, the average PDOP value for the GPS/GLONASS solution decreased by 22.17% when software for the planning of a linear object GNSS measurement campaign was used (Figure 14). The greatest drop in the geometric coefficient was noted for area C, characterised by a very large number of field obstacles. In this case, the parameter value decreased by approx. 25%. In areas A and B, which are characterised by a small number of field obstacles, the changes in the DOP value were slightly smaller and amounted to several percent. As regards the second measurement campaign, a slight decrease of 3.82% in the average PDOP value was noted. The changes in the geometric coefficient between the continuous and the optimal variant are minor, which undoubtedly results from the good geometry of satellite constellations during the implementation of the second measurement campaign in the continuous variant. Noteworthy is the fact that the average PDOP  
Figure 14: The relative percentage change in the average PDOP values between the continuous variant and the optimal variant for the GPS/GLONASS solution. Figure 15: The relative percentage change in the average PDOP values between the continuous variant for the GPS and GPS/GLONASS solutions.