Year-end Sale % OFF 
Abstract
When jammers move rapidly or an antenna platform travels at high speed, interference signals may move out of the null width in the array beampattern. Consequently, the interference suppression performance can be significantly degraded. To solve this problem, both the null broadening technique and robust adaptive beamforming are considered in this paper. A novel null broadening beamforming method based on reconstruction of the interference-plus-noise covariance (INC) matrix is proposed, in order to broaden the null width and offset the motion of the interfering signals. In the moving case, a single interference signal can have multiple directions of arrival, which is equivalent to the existence of multiple interference sources. In the reconstruction of the INC matrix, several virtual interference sources are set up around each of the actual jammers, such that the nulls can be broadened. Based on the reconstructed INC and signal-plus-noise covariance (SNC) matrices, the steering vector of the desired signal can be obtained by solving a new convex optimization problem. Simulation results show that the proposed beamformer can effectively broaden the null width and deepen the null depth, and its performance in interference cancellation is robust against fast-moving jammers or array platform motion. Furthermore, the null depth can be controlled by adjusting the power parameters in the reconstruction process and, if the direction of interference motion is known, the virtual interference sources can be set to achieve better performance.
Highlights
As antenna arrays have been applied to radar, sonar, radio astronomy, medical imaging, and in other areas, beamforming is widely used for interference suppression, target detection, and direction of arrival (DOA) estimation [1,2]
It should be noted that the relative motion between the interference sources and the antenna array is known, which usually could be obtained in advance by DOA estimated techniques and the inertial measurement system, the virtual interference sources can be set up according to the incoming direction of the interference signals to achieve better performance in interference suppression
The proposed algorithm was compared with the following methods: (i) the robust adaptive beamformer (Rec-ISVPE) of Reference [5], (ii) the Laplace-based null broadening algorithm of Reference [10], (iii) the Mailloux-based null broadening algorithm of Reference [11], (iv) the improved null broadening beamforming based on covariance matrix reconstruction (Rec-minimum variance distortionless response (MVDR)) of Reference [23], and (v) the analytical approach to null broadening (AANB) of Reference [15]
Summary
As antenna arrays have been applied to radar, sonar, radio astronomy, medical imaging, and in other areas, beamforming is widely used for interference suppression, target detection, and direction of arrival (DOA) estimation [1,2]. In References [10,11,12,13,14], these approaches were based on the covariance matrix tapering and effectively broadened the null width This technique decreases the array gain and the depth may become shallower [15]. In References [22,23], an adaptive null broadening technique based on reconstruction of the covariance matrix was proposed These approaches have poor robustness against various mismatches in the antenna array. The main contributions of this paper can be summarized as follows: 1) Compared with other existing null broadening beamforming techniques, we propose an algorithm based on INC matrix reconstruction by setting up several virtual interference sources around the actual jammers directly in the Capon spatial spectrum, which can simultaneously broaden the nulls and eliminate the self-null phenomenon of the desired signal.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
