A class of low-complexity compressive sensing-based direction-of-arrival (DOA) estimation methods for wideband co-prime arrays is proposed. It based on a recently proposed narrowband method, where virtual array model generated by directly vectorizing the covariance matrix and then using sparse signal recovery method to obtain result. As there are large number redundant entries in both auto-correlation cross-correlation matrices two sub-arrays, they can be combined together form with...

This letter proposes a novel parameter estimation method based on keystone transform (KT) and Radon-Fourier (RFT) for space moving targets with high-speed maneuvering performance. In this method, second-order KT is used to correct the range curvature part of walk all simultaneously. Then, fractional Fourier employed estimate targets' radial acceleration, followed by quadric phase term compensation. Finally, RFT Clean technique are carried out residual walk, initial velocity further obtained....

Based on the high-order difference co-array concept, an enhanced four-level nested array (E-FL-NA) is first proposed, which optimizes consecutive lags at fourth-order stage. To simplify sensor location formulations for comprehensive illustration and also convenient structure construction, a simplified (SE-FL-NA) then whose performance compromised but still better than (FL-NA). This further extended to higher order case with multiple sub-arrays, referred as level arrays (SE-ML-NAs), where...

It is well known that the motion of a ground moving target may induce range cell migration, spectrum spread, and velocity ambiguity during imaging time, which makes image smeared. To eliminate influence these factors on focusing, novel parameter estimation algorithm for targets, namely SKT-DLVT, proposed in this paper. In method, segmented keystone transform (SKT) used to correct walks targets simultaneously, new transform, namely, Doppler Lv's (DLVT) applied azimuth signal estimate...

Array structures based on the high-order difference co-array concept provide a large number of degrees freedom, but are typically difficult to design under multiple optimality criteria. In this paper, we present joint across-order (across different cumulant order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$q$</tex-math></inline-formula> ) and inner-order (within same fractal framework form array...

A longstanding concern in plant essential oil extraction is how to optimize efficiency with limited materials. Supercritical CO2 has been proven effective enhancing the yield and of extracting oils. However, impact temperature, pressure, co-solvent content on Hetian rose remains unclear. There a lack research influence pretreatment methods. This study focuses investigating supercritical oils from Xinjiang Hetian. The analyzes effects pressure temperature rate validates by calculating...

The hardware-in-the-loop (HIL)-based virtual calibration technology for power machinery significantly enhances the efficiency and flexibility of electronic controller calibration, reducing dependency on physical experiments lowering development costs. This paper presents an independently developed modular platform, designed based ISO/IEC 42010 architecture approach V-Model process. platform adopts a layered comprising layer, communication model software application layer. Each layer is...

Under the compressive sensing (CS) framework, a novel focusing based direction of arrival (DOA) estimation method is first proposed for wideband off-grid sources, and by avoiding application group sparsity (GS) across frequencies interest, significant complexity reduction achieved with its computational close to that solving single frequency finding problem. To further improve performance alleviating both approximation errors which are even worse case, dynamic dictionary re-focused DOA...

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

Group-sparsity-based method is applied to the 2qth-order difference coarray for underdetermined wideband direction of arrival (DOA) estimation. For complexity reduction, a focused compressive-sensing-based approach proposed, without sacrificing its performance. Different from conventional focusing approach, in proposed one, virtual arrays and no preliminary DOA estimation required. Simulation results are provided demonstrate effectiveness methods.

To deal with the problems of range cell migration (RCM) and spectrum spread during integration time induced by motion a target, this paper proposes new coherent method based on Radon nonuniform fractional Fourier transform (NUFrFT) for random pulse repetition interval radar. In method, RCM is eliminated via searching in parameter space resolved NUFrFT along trajectory. Simulation results demonstrate effectiveness proposed algorithm.

Array robustness and mutual coupling are two important factors affecting the direction finding performance of various array structures. These properties not typically analyzed in DOA estimation based on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2q$</tex-math></inline-formula> th-order difference co-arrays. In first part this work, we proposed fractal arrays for exploiting co-array ( th-O-Fractal)....

This paper proposes a novel low scattering tightly coupled dipole array (TCDA), aiming to reduce the radar cross section (RCS) of phased antenna arrays under certain oblique incident wave. First, we build three types elements that exhibit similar radiation characteristics but diverse reflection phase differences based on proposed theoretical analysis. The required difference is achieved by using different dielectric super-strates for each element. Then, arranging subarrays next other, TCDA...

This paper proposes a new motion parameter estimation algorithm, namely subband dual-frequency conjugate-Lv's transform, for fast moving targets. algorithm first constructs two signals with different central frequencies. Then, the are shifted by values and signal is constructed multiplying one complex conjugate of other. Finally, Keystone transform LVT performed to obtain estimates. method does not need any prior-knowledge targets can resolve Doppler ambiguity problem when work, especially...

Based on an experimental system involving a pulsating airflow burner and gliding arc generator, the characteristics of plasma at different flow rates its control effect static instability swirl flame have been studied. The current, voltage, power wave forms, as well simultaneous evolution topology, were measured to reveal discharge arc. A bandpass filter was used capture chemiluminescence CH in flame, pressure outlet acquired investigate instability. Experimental results showed that there...

This article studies the problem of reconstructing spectrally sparse signals from a small random subset time domain samples via low-rank Hankel matrix completion with aid prior information. By leveraging structure in lifting and similarity between their information, we propose convex method to recover undersampled signals. The proposed approach integrates inner product desired signal its information lift into vanilla completion, which maximizes correlation Theoretical analysis indicates that...

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

Nanoparticles, including Al2O3 and SiO2, ultrasound were adopted to improve the solidification properties of water. The effects nanoparticle concentration, contact angle, ultrasonic intensity on supercooling degree water investigated, as well dispersion stability nanoparticles in during solidification. Experimental results show that is reduced under combined effect nanoparticles. Consequently, reduction increases with increase concentration decrease angle Moreover, caused by together do not...