High resolution inverse synthetic aperture radar imaging of three-axis-stabilized space target by exploiting orbital and sparse priors

Abstract

The development of inverse synthetic aperture radar (ISAR) imaging techniques is of notable significance for monitoring, tracking and identifying space targets in orbit. Usually, a well-focused ISAR image of a space target can be obtained in a deliberately selected imaging segment in which the target moves with only uniform planar rotation. However, in some imaging segments, the nonlinear range migration through resolution cells (MTRCs) and time-varying Doppler caused by the three-dimensional rotation of the target would degrade the ISAR imaging performance, and it is troublesome to realize accurate motion compensation with conventional methods. Especially in the case of low signal-to-noise ratio (SNR), the estimation of motion parameters is more difficult. In this paper, a novel algorithm for high-resolution ISAR imaging of a space target by using its precise ephemeris and orbital motion model is proposed. The innovative contributions are as follows. 1) The change of a scatterer projection position is described with the spatial-variant angles of imaging plane calculated based on the orbital motion model of the three-axis-stabilized space target. 2) A correction method of MTRC in slant-and cross-range dimensions for arbitrarily imaging segment is proposed. 3) Coarse compensation for translational motion using the precise ephemeris and the fine compensation for residual phase errors by using sparsity-driven autofocus method are introduced to achieve a high-resolution ISAR image. Simulation results confirm the effectiveness of the proposed method.

Bi‐ISAR sparse imaging algorithm with complex Gaussian scale mixture prior

“…Due to the sparse apertures, traditional phase correction methods cannot satisfy the requirement. Residual phase errors still exist after the conventional phase correction methods [34]. Assuming that is the fusion data of valid apertures and the valid pulse number is K ().…”

Bistatic-ISAR Linear Geometry Distortion Alleviation of Space Targets

“…R , R and L can be calculated according to the geometry shown in Two positions of the transmitting station and receiving station are known previously in the bistatic-ISAR system. Positions of the space targets can be calculated by combining the orbital motion model with precise ephemeris, as we mentioned in [10]. The precise ephemeris can be calculated from the telemetry data.…”

“…The bistatic configuration is capable of obtaining complementary information of the target and providing better anti-jamming ability [6]. Hence, the bistatic-ISAR system has been an effective solution for space targets surveillance [7][8][9][10][11][12]. The bistatic-ISAR research, with respect to application and algorithm, has been studied in recent years [6,[13][14][15][16][17][18][19].…”

High-Resolution Bistatic ISAR Imaging of a Space Target with Sparse Aperture

“…A high-resolution image of Bi-ISAR provides more target details, which is beneficial to further target classification and recognition [3][4][5][6][7][8]. Hence, high-resolution Bi-ISAR systems have been an important technique of space target surveillance [9][10][11][12][13][14].…”