Space‐Doppler adaptive processing for radar imaging of moving targets masked by ground clutter

Abstract

Non-cooperative moving targets appear defocused within synthetic aperture radar (SAR) images and, in the case of ground targets, the blurring effect because of the uncompensated target motion decreases the radar's detection capabilities. Ground clutter, if sufficiently strong, may also obscure individual scatterers on moving targets resulting in a decreased ability to successfully classify the target. In this study, clutter suppression and inverse synthetic aperture radar (ISAR) imaging are combined to obtain high-resolution images of non-cooperative moving ground targets within SAR images. The clutter suppression technique proposed here is ISAR application oriented and is termed space-Doppler adaptive processing. Results obtained by processing a real dataset demonstrate the effectiveness of the proposed method.

Virtual multichannel SAR for ground moving target imaging

“…The model of the target contribution, S t,p (n, m ), can be derived as in [5] under the assumptions that the straight iso-range approximation holds true and the virtual array size is much smaller than the radar target distance. The received signal from the generic virtual channel p th relative to the k th scatterer can be expressed as…”

“…is the LoS relative to the p th virtual receiver expressed with respect to T y . As shown in [5] [23] for small values of T obs and, as a consequence, of a constant rotation vector during the observation time (Ω T (m) ≈ Ω T ), the inner product in Eq. (3) can be expressed as follows…”

“…The Multichannel Range Doppler (M-RD) image is obtained by summing the P complex images [5] and for α = 0 can be expressed as…”

SAR Ground Moving Target Indication Based on Relative Residue of DPCA Processing

“…Multifunctional SAR with large-area static scene imaging and ground moving target indication (SAR/GMTI) has drawn much more attentions in recent past decades [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32]. In the most of applications, not only the point moving targets but also the distributed moving targets are interested.…”

“…Therefore, many multichannel SAR methods have been proposed, such as displaced phase center antenna (DPCA) [1,9,10], along track interferometry (ATI) [11,12,13,14], space-time adaptive processing (STAP) [15,16,17,18] and velocity synthetic aperture radar (VSAR) [19,20,21,22]. Furthermore, a method combining SDAP and ISAR technique is proposed in [23] to improve the detection performance. In term of the dual-channel SAR system, ATI and DPCA are the two most popular techniques for GMTI.…”