## 4 Results and Discussion
Figure 9 indicates that there is not a high difference between the GAN and LSTM ROC performance. However, our proposed GAN-BLT shows a higher value for the area under the ROC, which confirms the superiority of this method in the correct recognition of inbound and outbound trajectories. The well-trained GAN and its optimized Discriminator allowed the model to accurately predict the forthcoming trajectories of the UAV-S4. Table 2 gives the GAN model accuracy-based performances describing the details of the ROC curves. In accordance with the results in Table 2, among the three models analyzed, the GAN model obtained the best trajectory prediction accuracy for both training (96.5%) and testing (92.1%) phases. The Long Short-Term Memory (LSTM) gave a 97.2% precision, and it outperformed GAN-based methodologies in terms of precision. Using the Blockchain Ledger Technology, the GAN sensitivity was improved, up to 94.3%; this was higher than that of the LSTM. The F1 score performance index confirmed the superiority of the GAN-BLT over the two other trajectory prediction methodologies. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Method**} & **Training Accuracy** & **Testing Accuracy** & **Precision** & **Sensitivity** & **F1 Score** \\  & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline LSTM & 94.9 & 90.6 & **97.2 & 93.6 & 93.7 \\ GAN & **96.5** & **92.1** & 95.6 & 91.2 & 94.1 \\ GAN-BLT & 95.7 & 91.6 & 94.1 & **94.3** & **96.4** \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Performance of the LASM, GAN, and GAN-BLT at trajectory prediction. Figure 8: GAN Discriminator’s output. Figure 9: Receiver operating characteristic (ROC) performance for the LSTM, GAN, and GAN-BLT. Blockchain Ledger Technology (BLT) was designed to safely store trajectory data in an untrusted environment, even when new agents were approached. Therefore, a sufficient delay was needed for confirmation in order to generate a new on-chain block for trajectory data storage. Figure 10 shows the agents' (UAVs) agreement confirmation probability. Figure 10 shows the cumulative probability versus the block number. Hence, a percentile analysis can estimate the percentile of executed confirmations up to the generation of a particular block. This metric is used by ground satiation to evaluate the risk from confirmation failures. According to Figure 10, the cumulative probability of a successful confirmation is 64.7% after the first block generation. After generating four blocks, this value settles on 97.2%, and exceeds 99.1% when the sixth block is generated. Consequently, the generation of six blocks was considered essential for the storage of future trajectory data. The blockchain used in this study was also evaluated in terms of reliability [55], and its error rates were considered as the performance index. Error rates arising from failures in block execution were measured while various consensus mechanisms were experiencing adversarial attacks. Concretely, Leader-based, Leader-free, and Deterministic consensus methodologies were utilized. Table 3 shows that the leader-free consensus methodologies caused 0.63% block execution error rates, while deterministic and leader-based approaches caused 2.03% and 1.86% block execution error rates, respectively. In accordance with the error rate values, it can be inferred the leader-free blockchain is more reliable than deterministic and leader-based consensus protocols in terms of adversarial attacks resiliency. For a comparative analysis, a Long Short-Term Memory model (LSTM) [30] was employed. Adversarial attacks based on Adapted Fast Gradient Sign Method (AFGSM) were imposed in order to attack resiliency evaluation. Excluding adversarial attacks, the prediction accuracy stood at 99.51% for LSTM and 99.1% for GAN. These findings imply that both methods can effectively predict future trajectories as they are not facing adversarial samples. To further scrutinize the efficacy of the LSTM and GAN models, another analysis was carried out when adversarial attacks were considered.