## 6 Conclusions  
In this work, the challenge of efficient, accurate, and reliable CP, incorporating low-cost GNSS receivers in various critical ITS scenarios, was addressed. The C-DGNSS framework was employed, which is the classical D-GNSS coupled with CP between a target vehicle and a number of surrounding candidate neighbors. By retaining the properties of D-GNSS, the cooperating vehicles disseminate their PVT data and GNSS corrections from the available satellites in view through radio links. The main hypothesis is that the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Criterion** & **1** & **2** & **3** & **4** & **5** & **6** \\ \hline \hline
**SAW** & **Number of Satellites** & **L1 RMS Double-Difference Phase Residuals** & **Hz std** & **V std** & **Amb Status** & **HDOP** \\
**SAW** & 0.996 & 0.969 & 0.995 & 0.994 & 0.995 & 0.988 \\
**CODAS** & 0.993 & 0.944 & 0.992 & 0.989 & 0.993 & 0.978 \\
**TOPL1** & 0.996 & 0.969 & 0.995 & 0.994 & 0.995 & 0.988 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Total Correlation Index (TCI) results using [PERSON]’s correlation method. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Criteria Ranking** & **I** & **II** & **III** & **IV** & **V** & **VI** \\ \hline
**SAW** & **2** & **6** & **3** & **4** & **1** & **5** \\
**CODAS** & 2 & 6 & 3 & 4 & 1 & 5 \\
**TOPL1** & 2 & 6 & 3 & 4 & 1 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 14: Criteria ranking from most to least sensitive using [PERSON]’s correlation method. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Criterion** & **1** & **2** & **3** & **4** & **5** & **6** \\ \hline \hline
**SAW** & **Number of Satellites** & **L1 RMS Double-Difference Phase Residuals** & **Hz std** & **V std** & **Amb Status** & **HDOP** \\
**SAW** & 0.937 & 0.731 & 0.869 & 0.920 & 0.971 & 0.811 \\
**CODAS** & 0.894 & 0.613 & 0.761 & 0.821 & 0.944 & 0.723 \\
**TOPL1** & 0.937 & 0.731 & 0.869 & 0.920 & 0.971 & 0.811 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Total Correlation Index (TCI) results using [PERSON]’s correlation method. target vehicle's low-cost receiver could improve both its relative and absolute positioning accuracy. The GNSS PVT information is comprised of NMEA messages, and the target vehicle parses the incoming NMEA sentences in a serial manner. With the aid of a MADM module, the target vehicle ranks and optimally decides in real-time which neighbors to select for retrieving GNSS corrections (RTCM data) to update its own PVT state. A set of thirteen MADM algorithms and several different normalization techniques were adopted for the simulation of scenarios involving various weightings and the criteria associated with positioning accuracy and ambiguities residual status. Real experimental criteria values derived from several low-cost GNSS receivers in complex driving environments were employed. A comparative analysis was then provided through an evaluation of the MADM algorithms in terms of ranking performance. A sensitivity analysis to determine the methods' robustness and the criticality of the criteria is also presented. It is concluded that L1 RMS, HDOP, and Hz std are the most critical, while the other criteria are less sensitive. Multi-purpose, generic applicability of the proposed scheme is suggested, not only for land vehicles, as it can be extended to drone positioning, swarm-of-entities guidance, drone-to-car communication, etc. Conceptualization, T.M., T.T.K., V.G. and A.D.P. ; methodology, T.M. and T.T.K. ; software, T.M. ; validation, T.M. and T.T.K. ; formal analysis, T.M. and T.T.K. ; investigation, T.M. and T.T.K. ; resources, T.M. and V.G. ; writing--original draft preparation, T.M. and T.T.K. ; writing--review and editing, A.D.P. and V.G. ; visualization, T.M. and T.T.K. ; supervision, A.D.P. and V.G. ; funding acquisition, T.M. and V.G. All authors have read and agreed to the published version of the manuscript. The research project was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the \"1 st Call for H.F.R.I.