A new formulation is discussed for the rigorous calculation of radiation pattern a bow-tie antenna finite length and infinitesimal thickness, placed on lossless dielectric substrate. The analysis based representation current density metal surface as sum an imposed (quasistatic) term set modes with unknown amplitudes. Free-space fields that are expressed in terms continuous spectra symmetrized plane waves matched to using method moments. resulting equations solved calculations show increasing...

Long-read sequencing has the capacity to interrogate difficult genomic regions and phase variants; however, short-read is more commonly implemented for clinical testing. Given advances in long-read HiFi chemistry variant calling, we analytically validated this technology small detection (single nucleotide variants, insertions/deletions; SNVs/indels; <50bp). genome was performed on DNA from reference materials specimen types, accuracy results were compared data. recall precision across...

A 20-channel far-infrared imaging interferometer system has been used to obtain single-shot density profiles in the UCLA Microtor tokamak. This differs from conventional multichannel interferometers that phase distribution produced by plasma is imaged onto a single, monolithic, integrated microbolometer linear detector array and provides significantly more channels than previous interferometers. The demonstrated provide diffraction-limited images of dielectric targets.

Interrupted sampling repeater jamming(ISRJ) is an effective coherent jamming type for wideband chirp radar. Different parameter settings correspond to different strategies, and the generated false target can achieve effects of both deception suppression. In this paper, a estimation method ISRJ with intra-pulse modulation proposed by analyzing characteristics. The time-frequency(TF) distribution result be used determine strategy. duration repeat interval are estimated Hilbert transform peak...

This paper is concerned with the problem of ℓ2-ℓ∞ filtering for discrete-time Takagi-Sugeno (T-S) fuzzy systems stochastic perturbation. Firstly, a basis-dependent existence condition desirable filters proposed. Then by means convex linearisation technique, derived transformed into some strict linear matrix inequality (LMI) constraints, which both full- and reduced-order can be designed. Moreover, filter design, novel analysis design method projection lemma also provided. Finally, numerical...

With the development of electronic jamming technology, more and active is applied in warfare. Because there are many kinds complex electromagnetic environment, it difficult for radar to recognize all effectively. In order solve this problem, seven typical suppression deception modeled simulated paper. Then, a set highly separable features extracted from time domain, frequency domain time-frequency which sent into decision tree support vector machine (SVM) recognition their accuracy compared....

High-frequency (HF) radar systems exploit refractive and diffractive properties of HF waves to sense targets beyond the line sight. skywave radars use ionosphere medium reflect signals thus illuminate thousands kilometers away, but they suffer from close-distance blind zone severe decorrelation effect. surface wave diffraction vertically polarized detect within hundreds offshore. But diffracted is highly attenuated, has vertical incidence ionospheric clutter problems. hybrid sky-surface...

Abstract:

In high‐frequency hybrid sky‐surface wave radars, the spread‐Doppler clutter (SDC) compromise low‐velocity target detection performance. Generally, adaptive filter methods achieve suppression by estimating a clutter‐plus‐noise covariance matrix from target‐free training data, which are typically obtained neighbouring range bins. Under certain circumstances, statistics change significantly across adjacent To deal with this problem, single dataset algorithm is proposed to suppress SDC without...

The nonstandard dynamic characteristics of flexible air-breathing hypersonic vehicles along with the aerodynamic effects flight cause control such highly challenging. Additionally, wide range speed and varied parameters make problem more difficult. In this article, sampled-data switched output tracking design is addressed for vehicles. First, nonlinear longitudinal model linearized respect to different regions, guaranteed cost controller discussed. Using an input delay approach, system...

Motivated by target tracking of HF Hybrid Sky-Surface (HF-HSSW) Radar which is a new radar system presented in recent years, this paper formulates modelling and filtering problem. Based on the dynamic geometry relationship between carrier, we derive planar measurement model HF-HSSW apply augment method to UKF . The joint estimation state carrier improves accuracy postion. performance comparison AUKF discussed for single scenario, simulation experimental results show that has better Radar's tracking.

Abstract High frequency (HF) radio waves propagating through regions of ionospheric plasma irregularities exhibit random fluctuations in both amplitude and phase referred to as scintillations, which heavily influences the detection performance HF sky‐wave radar hybrid sky‐surface wave systems. In this paper, a numerical multiple screen model for propagation is developed, can simulate field scintillations caused by inhomogeneous media. model, changes due diffraction effect mixing are...

In this paper, the aperture synthesis processing techniques for distributed shipborne high frequency hybrid sky-surface wave radar (HFHSSWR) are proposed to improve azimuth resolution and obtain velocity vector estimation of moving target. First, system geometry signal model target HFHSSWR formulated, then improvement principle is derived. Second, based on developed model, we propose an algorithm, which can synthetic bandwidth improved using sub-band combination. Finally, a parameters...

The performance of high‐frequency hybrid sky‐surface wave radar (HFSSWR) is known to suffer from the spread Doppler clutter (SDC). As a major source SDC, ionospheric generally possesses high directivity within main detection range. Classical coherent sidelobe cancellation method provides an efficient way suppress highly directional clutter. However, it performs poorly when directions target and are both in lobe. To address this problem, novel suppression using oblique projection proposed,...

Nonstationary spread-Doppler clutter (SDC) within a coherent processing interval often precludes target detection. Across range bins, nonstationarity severely limits the amount of training data available to estimate covariance matrix required for adaptive Such difficult conditions are not uncommon in High Frequency (HF) hybrid sky-surface wave radar which utilizes ionosphere as propagation media. This paper applies amplitude and phase estimator (APES) based space-time (STAP), operates only...

An integrated-circuit antenna array has been developed that images both polarization and intensity. The consists of a row antennas lean alternately left right, creating two interlaced sub-arrays respond to different polarizations. arrays the bismuth bolometer detectors are made by photoresist shadowing technique requires only one photolithographic mask. measured at wavelength 800 µm with an absolute accuracy 0.8° relative precision 7 arc min. demonstrated nearly diffraction-Iimited...

A two-dimensional monolithic array has been developed that gives the elevation and azimuth of point source targets. The is an arrangement rows columns antennas bismuth bolometer detectors on a fused quartz substrate. Energy focused onto through lens placed back side At 1.38 mm with 50 diameter objective lens, demonstrated positioning accuracy 26 arcmin. In differential mode this precision improves to 9 arcsec, limited by mechanics rotating stage. This tracking could be automated fast...

It transpires that the irregularity in structure of ionospheric plasma plays a significant role on ionospherically-propagated HF signals. In this paper, special attention has been paid to derive simulator can explicate perturbed phase influence imposed by ionosphere irregularities. This achieved studying space-time correlation as well statistics phases so problem simulation is recast generating particular time series satisfying specific power spectrum and statistical distribution....

Shipborne HF hybrid sky-surface wave radar (HFHSSWR) system contains skywave transmit channel and surface channel. The ionosphere is delaminated highly uncertain, which causes the sky to be results in multiple measurements for one target leads track loss. In addition, due size of shipborne receiving platform, measurement accuracy low, decrease filtering more serious tack this paper, we establish a model radar. Based on ionospheric height as Gaussian distribution introduce error into...

To investigate the inhibitory mechanisms of ginsenoside F1 on hydrogen peroxide induced cholesterol metabolism disorder and oxidative stress in HepG2 cells.