# Motion Compensation for Long Integration Times and DoA Processing in Passive Radars
## 8 Conclusions  
This article tackles the problem of target detection and tracking with a passive radar signal exploiting DVB-S signals. Geostationary satellites IoOs involve high availability but also high propagation losses. The use of the surveillance high-directivity antenna could reduce the azimuth illuminated area, so long integration times for achieving high coherent processing gain are proposed to improve both azimuth and range coverage. However, target dynamics can produce range and Doppler migration (when the target movement during \(T_{int}\) exceeds the range or Doppler resolution). To control the corresponding processing gain reduction and to improve DVB-S based PR systems, a multistage target motion compensation technique is proposed. In the proposed scheme, the detection and tracking techniques are applied at different processing stages to estimate velocities and accelerations and to apply range and Doppler migration compensation adapted to each target. In the first stage without any compensation algorithm, the bistatic tracker results are used to define a set of discrete possible bistatic accelerations. The corresponding Doppler Shift rates are used to design a Doppler migration compensation filter bank that is performed to the IDFT of the CAF generated by each  
Figure 19: Study of SIR improvement versus integration time. Figure 20: Estimated target trajectory with \(T_{int}=500\) ms versus GPS data in geographical coordinates. element of the surveillance antenna array. As SIR improvement is expected, new target trajectories are estimated using the outputs associated with each filter. Tracks provided by the filters corresponding to the same target are combined using a weighted centroid of target detections and their SIR in each CPI. Then, a final trajectory with more accuracy is obtained for each target to estimate the mean bistatic acceleration during the acquisition time and to reduce the complexity of the Doppler walk correction filter bank. As \(f_{Dr}\) can vary during \(T_{acq}\), only outputs provided by the filter of the filter bank constrained version with the highest SIR in each CPI are selected. Then, range migration compensation is carried out and SIR is outperformed again. New SIR values lead to an improvement of the detection and tracking capabilities estimating the target direction of arrival with more accuracy. The proposed scheme is used with data acquired in a semi-urban scenario by IDEPAR, a DVB-S based PR demonstrator developed in the University of Alcala. As reference and surveillance antenna systems, a commercial parabolic antenna and a 7-element planar array of commercial horn antennas are considered, respectively. The selected IoO signal, provided by _Hispast 30W-5_, was centered at 11.315 GHz with an acquisition bandwidth of 100 MHz covering 4 DVB-S channels. For the coherent processing signal, a \(T_{int}=500\) ms was considered. The corresponding Doppler Shift and bistatic range resolutions of 2 Hz and 12 m, respectively, were obtained. During the acquisition time, a collaborative target with a GPS device is used for validation purposes. After the proposed multistage target motion compensation is performed, the results confirm an improvement of SIR and detection capabilities. This trend could lead to an enhancement of the range coverage, which is restricted in satellite PR systems. The target ranges and azimuths estimated in each CPI were depicted in geographical coordinates, and the target trajectory fits very well with the GPS data. This document has been prepared thanks to the collaboration of the different members of the Acoustic and Electromagnetic Smart Sensor Networks and Signal Processing research team of the University of Alcala, who have actively collaborated in the study, development, and validation of the proposed methodology. Within this margin, [PERSON] and [PERSON] have been in charge of conceptualizing the main milestones of the work carried out.