An Image Focusing Method for Sparsity-Driven Radar Imaging of Rotating Targets

Ngoc Hung Nguyen; Kutluyıl Doğançay; Hai-Tan Tran; Paul Berry

doi:10.3390/s18061840

An Image Focusing Method for Sparsity-Driven Radar Imaging of Rotating Targets

Sensors (Basel). 2018 Jun 5;18(6):1840. doi: 10.3390/s18061840.

Authors

Ngoc Hung Nguyen¹, Kutluyıl Doğançay², Hai-Tan Tran³, Paul Berry⁴

Affiliations

¹ School of Engineering, University of South Australia, Mawson Lakes, SA 5095, Australia. ngoc.nguyen@mymail.unisa.edu.au.
² School of Engineering, University of South Australia, Mawson Lakes, SA 5095, Australia. kutluyil.dogancay@unisa.edu.au.
³ National Security and ISR Division, Defence Science and Technology Group, Edinburgh, SA 5111, Australia. haitan.tran@dst.defence.gov.au.
⁴ National Security and ISR Division, Defence Science and Technology Group, Edinburgh, SA 5111, Australia. paul.berry@dst.defence.gov.au.

Abstract

This paper presents a new image focusing algorithm for sparsity-driven radar imaging of rotating targets. In the general formulation of off-grid scatterers, the sparse reconstruction algorithms may result in blurred and low-contrast images due to dictionary mismatch. Motivated by the natural clustering of atoms in the sparsity-based reconstructed images, the proposed algorithm first partitions the atoms into separate clusters, and then the true off-grid scatterers associated with each cluster are estimated. Being a post-processing technique, the proposed algorithm is computationally simple, while at the same time being capable of producing a sharp and correct-contrast image, and attaining a scatterer parameter estimation performance close to the Cramér⁻Rao lower bound. Numerical simulations are presented to corroborate the effectiveness of the proposed algorithm.

Keywords: compressive sensing; high-resolution ISAR; image focusing; micro-Doppler; micro-motion; radar imaging; rotating target; sparse reconstruction; sparsity.