Abstract
For high resolution imaging of a non-cooperative moving target, this paper proposes a sparse fusion imaging method. The imaging system contains two radar stations, which are separated by a certain bistatic angle and configured in a transmitter/receiver-receiver (T/R-R) manner. Consequently, two synthetic apertures are obtained at the same time from different aspect angles. By coherently fusing the echoes of the two radars, a virtual aperture spanned by these two sub-apertures can be constructed, which is larger than either of the sub-apertures; thus, the cross-range resolution of the image is enhanced. Moreover, the fusion of the echoes is realized by exploiting the sparse scattering property of the target. Then, based on the maximum a posteriori (MAP) criterion, the T/R-R fusion imaging problem is converted into a sparse signal recovery problem with unknown parameters. Finally, it is solved in an iterative manner, which contains two steps, i.e., sparse imaging and parameter estimation. Simulation results show that the proposed sparse fusion imaging method can improve the cross-range resolution significantly compared to inverse synthetic aperture radar (ISAR) within the same coherent processing interval (CPI).
Highlights
Microwave radar imaging is one of the major techniques for non-cooperative moving target recognition (NCTR)
In Inverse synthetic aperture radar (ISAR) imaging, the target is mapped onto a slant range and cross-range plane, where the slant range resolution is determined by the bandwidth of the transmitted signal and the cross-range resolution is obtained by exploiting the motion of the target
For the purpose of high resolution imaging with short coherent processing interval (CPI) time, this paper proposes a sparse fusion imaging method by combining the monostatic ISAR and bistatic ISAR (B-ISAR) together
Summary
Microwave radar imaging is one of the major techniques for non-cooperative moving target recognition (NCTR). Compared to optical or infrared imaging, it has the ability to work under all weather, all time and long-range conditions. It plays an important role in both defense and civilian applications [1,2,3,4]. Inverse synthetic aperture radar (ISAR) is the traditional microwave imaging method for a moving target [5,6,7,8]. After the translational motion is compensated, the rotational motion forms a synthetic aperture with size being ∆θ = ωT , where ω is the rotational angular speed and
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