# Motion Compensation for Long Integration Times and DoA Processing in Passive Radars
## 7 Experimental Results  
A semi-urban scenario located in the external campus of the University of Alcala was selected for validating the array architecture. Figure 10 shows the Area of Interest (AoI) for the experiments. The radar scenario was next to Nursing School, with its surveillance area covering a straight road of about 350 m length from the PR, which is surrounded by medium-height buildings, some trees, and a metallic fence that surrounds the sports facilities, where a cooperative vehicle described almost radial movements (Figure 11c). Figure 10: Semi-urban scenario for trials located in the external campus of University of Alcala. Figure 9: Range and Doppler migration compensation scheme. For the experiment, the DVB-S version of IDEPAR was used to acquire real data. In Figure 11a,b, the reference and surveillance antenna systems are depicted: for the reference channel, a commercial parabolic antenna was used with a 40 cm reflector to generate a \(5^{\circ}\) beamwidth; for the surveillance channel, a 7-element planar array of commercial horn antennas detailed in Section 5. The selected IoO is the _Hispast 30W-5_ satellite, which transmits DVB-S signals with an EIRP of 54 dBW. The satellite is seen from the considered scenario at an elevation of \(35^{\circ}\) and azimuth of \(217^{\circ}\)N. The scenario geometry shows a quasi mono-static configuration with the PR located between the IoO and the AoI. The selected central frequency is 11.315 GHz, with an acquisition bandwidth of 100 MHz covering 4 horizontally polarized DVB-S channels detailed in Table 1 and presented in Figure 12. \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multicolumn{5}{c}{**Hispast 30W-5 (1E) Channels**} \\ \hline
**Central Frequency** & 11,276 MHz & 11,302 MHz & 11,330 MHz & 11,347 MHz \\ \hline
**Polarization** & H & H & H & H \\ \hline
**Modulation** & DVB-S2 QPSK & DVB-S2 8 PSK & DVB-S2 8 PSK & DVB-S2 8 PSK \\ \hline
**IF** & 1526 MHz & 1552 MHz & 1580 MHz & 1597 MHz \\ \hline
**Bandwidth** & 7.140 MHz & 30 MHz & 9.140 MHz & 20.858 MHz \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Adquires DVB-S channels. Figure 11: DVB-S IDEPAR antennas systems and collaborative vehicle in the considered scenario. (**a**) Reference antenna. (**b**) Surveillance antenna array. (**c**) Collaborative vehicle. Figure 12: Spectrum of acquired data showing the available DVB-S channels. For each acquisition chain of the surveillance channel, 80 overlapping CPIs were generated using \(T_{int}=500\) ms and \(PRI=250\) ms. Doppler Shift and bistatic range resolutions of 2 Hz and 12 m, respectively, were obtained. Surveillance signals were pre-filtered for DVB-S channels selection and noise reduction. To reject DPI and stationary clutter contributions, whose maxima are concentrated along the zero Doppler line of the CAF, the extensive cancellation (ECA) filter was applied. For each CPI and surveillance element, a CAF was generated to apply the proposed processing stages. Due to waveform characteristics, the ECA filter not only removes the peaks of stationary clutter but also reduces the CAFs pedestal throughout the range-Doppler domain. As a result, DPI contribution will be rejected. In the DVB-S based passive radar, the DPI contribution level is very low for the high propagation losses associated with satellite illuminators, so the implementation of Zero Doppler interference rejection is not a critical stage. For example, Figure 12(a),b shows the CAF at a single radiating element level with and without the ECA filter, respectively. The stationary contributions maxima extend along the zero Doppler line up to 200 th range bin. The pedestal level reduction is around 4.5 dB. For the considered scenario, car traffic can be modelled with a mean speed of \(v_{tg}=10\) m/s (\(v_{bis}<20\) m/s) and an acceleration of \(a_{tg}=1\) m/s\({}^{2}\), assuming a variation from 0 to 10 m/s in 10 s (\(a_{bis}<2\) m/s\({}^{2}\)).