Open AccessSpace‐time matched filter design for interference suppression in coherent frequency diverse array
Author(s) -
Wang Huake,
Liao Guisheng,
Xu Jingwei,
Zhu Shengqi
Publication year - 2020
Publication title -
iet signal processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.384
H-Index - 42
eISSN - 1751-9683
pISSN - 1751-9675
DOI - 10.1049/iet-spr.2019.0227
Subject(s) - beamforming , adaptive beamformer , matched filter , filter (signal processing) , computer science , algorithm , filter design , quadratic programming , convex optimization , control theory (sociology) , quadratic equation , mathematics , mathematical optimization , regular polygon , telecommunications , artificial intelligence , geometry , control (management) , computer vision
By transmitting a single frequency‐shifted waveform, coherent frequency diverse array (FDA) can provide a simple way to realize full spatial coverages with stable gains. Owing to the range‐angle dependency in coherent FDA, the authors implement a two‐dimensional angle‐time matched filter to perform equivalent transmit beamforming and matched filtering simultaneously. However, such filter structures merely control main‐lobes of equivalent transmit beams towards target directions. It fails to form nulls at interference directions. Moreover, traditional adaptive beamforming by designing adaptive weight vectors are no longer applicable. Additionally, they find that the range resolution scales linearly with the element number. To tackle these issues, a space‐time matched filter (STMF) in combination with the hybrid coding technique is proposed. Aiming at mitigating interferences, the STMF is designed with a formulation of quadratically constrained quadratic programing. By relaxation of quadratic constraints, the hard non‐convex problem can be turned into the second‐order cone programing to obtain optimal filter parameters. Furthermore, the hybrid coding technique is devised to jointly improve the range resolution. Numerical experiments of both two‐dimensional range‐angle outputs and one‐dimensional range profiles via filtering are provided, which demonstrate that the STMF with hybrid coding can effectively suppress sidelobe interferences with a range resolution enhancement.