## 2 Materials and Methods
### DVB-S Passive FSR Experimental Campaign for Drone Detection
The high gain of the LNA amplified the signal power, and the Measat3 signal waveform was acquired by using a high-definition ADC. In total, 22 transponders by the Measat3 satellite were received. Although multiple transponders can be received at the same time, the transponder having the highest power received was assumed to be utilized in the detection of the target, with little or no Doppler contribution from other channels. The multiple-frequency channels received can also be used to improve the SNR of the received signal, as suggested by [33]. The actual Measat3 signal spectrum of the transponder with the highest power was illustrated in Figure 6. One of the channels received 11.104 GHz and it was the highest power received with \(-\)10.26 dBm. Table 5 illustrates all signals received in the order of their power. As indicated in Table 4, the other two channels, 12 and 12.749 GHz, are still within our operating frequencies with \(-\)26.88 and \(-\)26.79 dBm, respectively. Figure 7 shows the experimental setup of the receiver including the parabolic dish antenna. A parabolic dish antenna was placed to point towards the satellite direction and was located at the end of the futsal court to enable the drone to have enough flying space. Our best efforts were made to decide the baseline between the satellite and the parabolic dish antenna, despite the transmission nature of the DVB-S signal which is circularly polarized. The receiving system parameters are depicted in Table 6. A commercial quadcopter drone was used during the experiment as a target of interest. \begin{table}
\begin{tabular}{c c} \hline \hline
**Absolute Frequency (GHz)** & **Absolute Amplitude (dBm)** \\ \hline
11.104 & \(-\)10.26 \\
12.000 & \(-\)26.88 \\
12.749 & \(-\)26.79 \\
13.501 & \(-\)24.47 \\
14.250 & \(-\)32.62 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Receiver transponders and their power level. Figure 6: Snapshot of actual Measat3 signal (**a**) measured on Digital Satellite meter and (**b**) signal spectrum. The detection procedure is described in Figure 8, which includes target detection from a disrupted continuous time domain signal; then, the micro-Doppler will be extracted from the signal before drone detection. The sampling frequency of ADC was set to 50 kHz and is sufficient for the expected maximum Doppler value of the rotating blades. Additionally, the FS receiver just needs to capture the modulation caused by the moving target and does not need to reconstruct the signal from the satellite. The received signal is represented in the joint time-frequency domain by STFT with a hamming window. The drone was set to fly horizontally crossing the FS satellite receiver ground station. To analyze the effectiveness of the system, two signals acquired at a different time (namely Signals 1 and 2) are analyzed in detail. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Receiver Location**} \\ \hline Latitude & 3.0083\({}^{\circ}\) \\ Longitude & 101.7219\({}^{\circ}\) \\ \hline \hline \multicolumn{2}{c}{**Satellite Data**} \\ \hline Name & 91.5\({}^{\circ}\)E \\ Measat3a/33b \\ Distance & 35,921 km \\ \hline \multicolumn{2}{c}{**Dish Setup Data**} \\ \hline Elevation angle & 77.5\({}^{\circ}\) \\ Azimuth (true) & 253.8\({}^{\circ}\) \\ Azimuth & 254.3\({}^{\circ}\) \\ (magnitude) & 73.5\({}^{\circ}\) \\ LNB skew & 73.5\({}^{\circ}\) \\ \hline \multicolumn{2}{c}{**Dish Parameters**} \\ \hline Dish size & 65 cm \\ Minimum gain & 36 dBi \\ Beam width at 3 dB & 2.6\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Receiver system parameters. Figure 7: Experimental site (**a**) receiving systems experimental setup (**b**) parabolic dish antenna.