Localization and tracking of electronic devices with their unintended emissions

The precise localization and tracking of electronic devices via their unintended emissions has a broad range of commercial and security applications. Active stimulation of the receivers of such devices with a known signal generates very low power unintended emissions. This dissertation presents localization and tracking of multiple devices using both simulation and experimental data in the form of five papers. First the localization of multiple emitting devices through active stimulation under multipath fading with a Smooth MUSIC based scheme in the near field region is presented. Spatial smoothing helps to separate the correlated sources and the multipath fading and results confirm improved accuracy. A cost effective near-field localization method is proposed next to locate multiple correlated unintended emitting devices under colored noise conditions using two well separated antenna arrays since colored noise in the environment degrades the subspace-based localization techniques. Subsequently, in order to track moving sources, a near-field scheme by using array output is introduced to monitor direction of arrival (DOA) and the distance between the antenna array and the moving source. The array output, which is a nonlinear function of DOA and distance information, is employed in the Extended Kalman Filter (EKF). In order to show the near- and far-field effect on estimation accuracy, computer simulation results are included for localization and tracking techniques. Finally, an L-shaped array is constructed and a suite of schemes are introduced for localization and tracking of such devices in the three-dimensional environment. Experimental results for localization and tracking of unintended emissions from single and multiple devices in the near-field environment of an antenna array are demonstrated --Abstract, page iv

Localization of Near-Field Sources in Spatially Colored Noise

This paper presents near-field localization of unintended emitting radio-controlled (RC) sources in a colored noise environment using a uniform linear array antenna. Existing localization methods for RC devices perform satisfactorily under white noise, but they ignore multipath fading or correlation among the sources. Therefore, a suite of novel schemes, referred to as 2-D multiple signal classification (MUSIC)-smooth sparse arrays and 2-D MUSIC-whitened noise, is proposed to bring correlation together among the sources, multipath fading, and color noise effects during near-field location estimation. Experimental evaluation of the proposed methods and the original smooth 2-D MUSIC compares both schemes while demonstrating their effectiveness

Analysis of Localization Methods for Unintended Emitting Sources

This paper presents an analysis of localization and tracking of unintended emissions from electronic devices using computer simulations. The available localization and tracking methods assume that the device is in the far-field region of the array. However, the received power of unintended emissions is very low and, therefore, requires near-field techniques. In the near-field, the performance of far-field schemes degrades since they ignore the effect of range on phase characteristics. Computer simulation results for localization and tracking methods developed by the authors are summarized to analyze the effects of near and far-field regions