Passive imaging of moving targets exploiting multiple scattering using sparse distributed apertures

Abstract

We present a new passive imaging method for moving targets using a sparse array of receivers and illumination sources of opportunity operating in multiplescattering environments. We assume that the receivers are spatially distributed in an arbitrary fashion and the illumination sources of opportunity are noncooperative where the locations of the transmitters and transmitted waveforms are unknown. Our method is capable of exploiting the multiple scattering in the environment. We use a physics-based and statistical approach to develop a model under Born approximation that relates the measurements at a given receiver to measurements at other receivers in terms of a hypothetical target in position and velocity spaces, the Green function of the background environment, as well as the statistics of the target, clutter and noise. Next, we use this model to formulate the imaging problem as a test of binary hypotheses for unknown target position and velocity, and address it by maximizing the signal-to-noise ratio of the test statistic. We use the resulting test statistic to form an image in position and velocity spaces. We illustrate our imaging method and analyze its resolution using a first-order specular reflection-based model of the Green function suitable for urban environments throughout the paper. We present numerical experiments to verify our theory and to demonstrate the performance of our method using practical waveforms of opportunity. While our primary interest is in radar imaging, our method can also be applied to passive acoustic and geophysical imaging.

Moving Target Artifacts in Bistatic Synthetic Aperture Radar Images

“…The theoretical framework developed in this paper can be used to analyze moving target positioning errors in other SAR modalities, such as Doppler SAR [3], [4], [7] and passive SAR [1], [2], [5], [9], [11], [40], [41].…”

“…(iv) The analysis is based on microlocal analysis [16]. Therefore, the underlying methodology is general and can be used to analyze moving target positioning errors in other SAR modalities [1]- [4], [8]- [11], [40].…”

Passive polarimetrie multistatic radar for ground moving target

“…In recent years, interest in passive radar systems has been growing due to ubiquity of sources of opportunities such as digital television stations, wideband cell-phone towers, radio transmissions, satellites, etc [1]- [6]. In contrast to traditional active radar systems, passive systems do not include any dedicated transmitters under direct control.…”

Passive synthetic aperture radar imaging based on low-rank matrix recovery

“…Additionally, it requires a "reference receiver" with a direct line-of-sight to the transmitter of opportunity to estimate transmitted waveforms. The second approach is based on correlation of measurements [5], [8]- [11]. Both approaches form backrojection images based on delay: The first approach uses time-of-flight and the second approach uses time-difference-of-arrival (TDOA).…”