Doppler Synthetic Aperture Hitchhiker imaging

Abstract

We consider passive airborne receivers that use backscattered signals from sources of opportunity transmitting fixed-frequency waveforms, which we refer to as Doppler Synthetic Aperture Hitchhiker (DSAH). We present a novel image formation method for DSAH. Our method first correlates the windowed signal obtained from one receiver with the windowed, filtered, scaled and translated version of the received signal from another receiver, and then uses the microlocal analysis to reconstruct the scene radiance by the weighted-backprojection of the correlated signal. This imaging algorithm can put the visible edges of the scene radiance at the correct location, and under appropriate conditions, with correct strength. We show that the resolution of the image is directly related to the length of the support of the windowing function and the frequency of the transmitted waveform. We present numerical experiments to demonstrate the performance of the proposed method.

Passive radar imaging of moving targets using distributed apertures

“…Note that γ y,v,ij is the Doppler-hitchhiker-scale-factor defined in. 27 Due to the static nature of the receivers in the present work, we refer to γ y,v,ij as the passive-Dopplerscale-factor.…”

Passive radar imaging of moving targets with sparsely distributed receivers

“…Note that if we multiply both sides by ω, the left-hand side of (42) becomes the hitchhiker-Doppler defined in [11] and for a fixed frequency it becomes the DSAH-Doppler defined in [12]. In this regard, we refer to the four-dimensional manifold formed by {(y, v) ∈ R 2 × R 2 : γ y,v,ij = C} in (y, v) space, for some constant C ∈ R + , as a passive-iso-Doppler manifold.…”

Passive synthetic aperture radar imaging of ground moving targets

“…Passive radar systems provide many important advantages over active monostatic or bistatic imaging modalities. [11][12][13][14][15][16] A passive radar system does not employ a dedicated transmitter by relying on illuminators of opportunity such as radio, cell phone, and television transmission towers. The absence of active signal propagation from the system provides key advantages such as cost, simplicity of implementation, and stealth.…”

“…Literature on passive SAR imaging can be found in. 15,16 In, 15 an image reconstruction method is developed using filtered backprojection (FBP) on data correlated between the receivers to image a stationary scene. Similarly, 16 also presents a method for passive SAR imaging of a stationary scene, but uses ultra-narrowband waveforms of opportunity.…”