Moving target indication

About: Moving target indication is a research topic. Over the lifetime, 2653 publications have been published within this topic receiving 32435 citations.

Bistatic GMTI experiment for airborne platforms

Abstract: The concept of bistatic ground moving target indicator BGMTI is presented here. Monostatic GMTI radars use separate modes for ground movers whose Doppler does and does not allow separation of the target return from ground clutter using frequency processing. Bistatic flight scenarios that minimize Doppler spreading in the vicinity of a designated target area are presented as candidate flight test plans. Flight scenarios supporting a sustained broadside spot mode and an oblique spot mode are presented.

Bistatic SAR Clutter-Ridge Matched STAP Method for Nonstationary Clutter Suppression

Abstract: Clutter suppression is a challenging task in synthetic aperture radar-ground moving target indication (SAR-GMTI). In general, sufficient secondary samples are not easily acquired due to the nonstationary and nonhomogeneous characteristics of bistatic SAR (BiSAR) clutter, resulting in worse clutter suppression results. Recently, space–time adaptive processing based on sparse recovery (SR-STAP) has been developed since its better clutter suppression performance with less samples. However, since the off-grid problem in space–time domain caused by BiSAR’s separate configuration, existing SR-STAP would suffer from severe performance degradation. To address this problem, a clutter-ridge matched STAP (CRM-STAP) method for BiSAR nonstationary clutter suppression is proposed. First, clutter distribution modeling with arbitrary BiSAR configuration is applied to accurately obtain the clutter ridge in space–time domain. Then, keystone transform and time-division processing are applied to correct range cell migration and eliminate Doppler frequency migration, respectively. Next, to solve the off-grid problem, the CRM dictionary is reconstructed via adaptive gradient method, which is established along the direction of clutter ridge and its orthogonal direction. Then, with the constructed CRM dictionary, the clutter covariance matrix (CCM) estimation process is transformed to a multimeasured vector optimization problem, and it can be directly solved by the sparse Bayesian learning algorithm. Finally, based on the estimated CCM, the CRM-STAP filter is built to suppress the nonstationary clutter effectively. Compared with the existing STAP and SR-STAP methods, this method can avoid the performance degradation in clutter suppression caused by the off-grid problem and overcomes the strong nonstationary problem of BiSAR clutter in heterogeneous environments. In October 2020, we have successfully carried out the world’s first airborne BiSAR-GMTI experiment, and the experimental results are given to verify the effectiveness of this method.

A signal processing method for airborne three-channel SAR-GMTI

Abstract: Aiming at airborne three-channel SAR-GMTI system, a signal processing method based on Clutter Suppression Interferometry(CSI) is presented including the processing diagram and the principle of clutter suppression Channel calibration is proposed to correct the magnitude and phase imbalance between inner channels utilizing the test signal, SAR imaging and clutter cancellation are done successively, finally the accurate target parameters (location and velocity) are obtained The signal processing approach which has been applied in real data proved its good performance and turned out to be efficient

Coverage area analysis for decentralized detection in Weibull clutter

Abstract: The performance of a decentralized constant false-alarm rate (CFAR) detection system with data fusion in homogeneous non-Gaussian background is analyzed in terms of ground area covered. The advantages of using a distributed radar system and the differences between the system behavior in Rayleigh clutter and in Weibull clutter are stressed. Notably, the increasing benefit of cooperative decision making when clutter becomes spikier is pointed out.

Challenges and potentials using multi aspect coverage of urban scenes by airborne sar on circular trajectories

Abstract: . Airborne SAR on small and flexible platforms guarantees the evaluation of local damages after natural disasters and is both weather and daylight independent. The processing of circular flight trajectories can further improve the reconstruction of target scenes especially in complex urban scenarios as shadowing and foreshortening effects can be reduced by multiple views from different aspect angles (hyper- or full- aspect). A dataset collected with the Miranda 35 GHz radar system with 1 GHz bandwidth on a small ultralight aircraft on a circular trajectory over an urban scene was processed using a time domain approach. The SAR processing chain and the effects of the navigational data for such highly nonlinear trajectories and unstable platforms are described. The generated SAR image stack over the entire trajectory consists of 240 individual SAR images, each image visualizing the scene from a slightly different aspect angle. First results for the fusion of multiple aspect views to create one resulting image with reduced shadow areas and the possibility to find hidden targets are demonstrated. Further potentials of such particular datasets like moving target indication are discussed.