Abstract-An effective sparse array extension method for maximizing the number of consecutive lags in the fourth-order difference co-array is proposed, leading to a novel enhanced sparse array structure based on co-prime arrays with significantly increased number of degrees of freedom (DOFs). One method to exploit the increased DOFs based on non-stationary signals is also proposed, with simulation results provided to demonstrate the effectiveness of the proposed structure.

No abstract

No abstract

A wideband off-grid model is proposed to represent dictionary mismatch under the compressive sensing framework exploiting difference co-arrays. A group sparsity based off-grid method is proposed for underdetermined wideband direction of arrival (DOA) estimation which provides improved performance over the existing group sparsity based method with a same search grid. A two-step approach is then proposed which achieves an even better performance with significantly reduced computational complexity.

Abstract-It is well known that the motion of a ground moving target may induce the range cell migration, spectrum spread and velocity ambiguity during the imaging time, which makes the image smeared. To eliminate the influence of these factors on image focusing, a novel method for parameter estimation of ground moving targets, known as SKT-DLVT, is proposed in this paper. In this method, the segmental keystone transform (SKT) is used to correct the range walk of targets simultaneously, and a new transform, namely, Doppler Lv's transform (LVT) is applied on the azimuth signal to estimate the parameters. Theoretical analysis confirms that no interpolation is needed for the proposed method and the targets can be well focused within limited searching range of the ambiguity number.The proposed method is capable of obtaining the accurate parameter estimates efficiently in the low signal-to-noise ratio (SNR) scenario with low computational burden and memory cost, making it suitable to be applied in memory-limited and real-time processing systems. The effectiveness of the proposed method is demonstrated by both simulated and real data.Index Terms-ground moving target, segmental keystone transform (SKT), Doppler Lv's transform (LVT), parameter estimation.

This is a repository copy of Simplified and enhanced multiple level nested arrays exploiting high order difference co-arrays.

To reach a higher number of degrees of freedom by exploiting the fourth-order difference co-array concept, an effective structure extension based on two-level nested arrays is proposed. It increases the number of consecutive lags in the fourth-order difference coarray, and a virtual uniform linear array (ULA) with more sensors and a larger aperture is then generated from the proposed structure, leading to a much higher number of distinguishable sources with a higher accuracy. Compressive sensing based approach is applied for direction-of-arrival (DOA) estimation by vectorizing the fourthorder cumulant matrix of the array, assuming non-Gaussian impinging signals.

A novel wideband direction-of-arrival (DOA) estimation method is proposed for co-prime arrays. After decomposing the wideband signals into different frequencies/subbands through a discrete Fourier transform or, more generally, a filter bank system, the increased degrees of freedom provided by co-prime arrays are fully exploited with a group sparsity based signal reconstruction method. Simulation results show that this novel method can distinguish much more sources than the number of physical sensors. Compared with the existing narrowband DOA estimation method for co-prime arrays, the proposed wideband method achieves a significant performance improvement.