No abstract

No abstract

The practical feasibility of a WiFi transmissions based passive bistatic radar (PBR) is analyzed here. The required data processing steps are described including the adopted techniques for 1) the control of the signal autocorrelation function (ACF) usually yielding a high sidelobe level, and 2) the removal of the undesired signal contributions which strongly limit the useful dynamic range. The performance of the proposed techniques is firstly evaluated against simulated data generated according to the IEEE 802.11 Standards. Moreover the results are presented against a real data set collected by an experimental setup when using the conventional dual (reference and surveillance) channels PBR receiving scheme. This allows us to demonstrate the potentialities of a WiFi-based PBR for local area surveillance applications, where vehicles and people can be detected and tracked. Based on the digital nature of the exploited signals of opportunity, the attractive possibility is also investigated of avoiding the use of a dedicated receiving channel for the reference signal, by synthesizing it from the surveillance channel. This approach is shown to yield comparable performance with respect to the conventional PBR approach while yielding a remarkable saving in terms of system complexity

In this paper the exploitation of different linear polarimetric channels is considered as a way to mitigate the effect of interfering sources and to improve the target detection capability in a FM radio-based passive radar. The signals emitted on same/adjacent frequency channels by potential transmitters (other than the illuminator of opportunity) located in the surveillance area are shown to significantly affect the performance of the considered system in terms of both disturbance cancellation and target detection. Moreover, it is verified that the achievable performance is dependent on the adopted polarization at both the reference and surveillance channel since employing vertically or horizontally polarized antennas might yield very different results. Therefore effective approaches are introduced to jointly exploit the diversity of information conveyed by different polarizations at both the reference and surveillance channels. The results are shown against a real data set collected by an experimental multi-channel passive radar prototype developed and fielded at the DIET Dept. of the University of Rome “La Sapienza” (Italy). A significant performance improvement is achieved with the proposed processing schemes that always provide better results than the standard processing of the signals collected at the best polarimetric reference and surveillance channels. Besides the expected improvement due to non-coherent integration of target echoes received on multiple channels, the proposed multi-polarimetric operation is shown to yield a remarkable improvement when operating in a severe interference scenario so that it can be regarded as practical solution for robust and effective PCL

No abstract

No abstract

In this study the authors investigate the two-dimensional target localisation capabilities of a passive radar system based on WiFi transmissions. It is well known that the most straightforward way to achieve the target position estimation in the horizontal plane with a passive radar exploits the measurements either of a single bistatic range plus a direction of arrival (DoA) or of two bistatic ranges collected by two separate receivers. However, for a practical application it is interesting to clearly define which one of the two approaches provides the passive radar target localisation with a higher accuracy and whether combining both multiple bistatic range plus DoA measurements provides a further advantage. A multistatic configuration is considered which allows to collect a set of range/Doppler/angle measurements for a given target. Different target localisation strategies are devised and compared, based on subsets of the available measurements with the aim of understanding the localisation accuracies achievable using the different combinations of measurements. Experimental results are shown based on a passive radar prototype developed and fielded at the DIET Department - Sapienza University of Rome. This will contribute to demonstrate the fruitful application of the passive radar concept for short range surveillance

After summarizing the problems related with the variability of the characteristics of the waveforms received by PBR, especially when operating in the FM radio band, the concept of the MF integration has been introduced, aiming at (i) increasing the global SNR and (ii) making the detection performance robust w.r.t. the program content of the individual radio stations. © 1986-2012 IEEE