Constant false alarm rate (CFAR) is a desired property for target detection in unknown and nonstationary sea clutter. Analysis of the experimental data shows that gamma distribution promising model A robust CFAR method proposed nonhomogeneous gamma-distributed clutter, using weighted amplitude iteration samples reference window as adaptive threshold. By combining advantages cell-averaging (CA-CFAR), greatest selection (GO-CFAR), ordered statistic (OS-CFAR), similar performance CA-CFAR...

In this paper, a heterogeneous clutter model named £ distribution is introduced into the level set method for segmentation of high-resolution polarimetric synthetic aperture radar (PolSAR) images. Level methods are robust and effective techniques segmentation. However, traditional PolSAR data based on complex Wishart distribution, which not an applicable to images regions such as forest urban areas. The proved be highly flexible multilook data, product with generalized-gamma-distributed...

In this paper, we propose an improved attributed scattering model to mathematically unify the models of several canonical primitives. These primitives include not only point- and line-segment-scatterers, such as trihedral, cylinder, dihedral, rectangular plane, but also arc scatterers, sphere top-hat. The estimation parameters can be posed ill-posed linear inverse problem. To overcome ill-posedness, employ incremental sparse Bayesian learning method realize sparsity-driven continuous...

In this paper, a flexible directional monopole antenna for wearable head imaging system stroke detection is presented. To ensure better flexibility applications, very thin PET substrate, Melinex 339 with thickness of 75μm utilized. The size the 70mm × 30mm. An array 8 antennae are arranged in elliptical configuration to follow human contour. operate at frequency 1.3GHz 3.5GHz which would provide sufficient penetration and resolution. These were designed optimized work close proximity head....

Constant false alarm rate (CFAR) is the desired property for automatic target detection in an unknown and non‐stationary background. Here, a modified cell averaging CFAR (CA‐CFAR) detector based on Grubbs criterion (CAG‐CFAR) proposed non‐homogeneous The of CAG‐CFAR with respect to distribution parameter exponential‐distributed background verified via Monte Carlo simulations. performances method scenarios multiple targets clutter edges are investigated different significance levels sizes...

Targets with uniform rotational motion may cause migration through cross-range cells during the imaging time, which makes inverse synthetic aperture radar image smeared. Traditional compensation methods hardly work well because it is difficult to estimate quadratic phase error (QPE) caused by efficiently. To solve this problem, a novel QPE estimation method based on cancellation (PC) proposed in letter. In method, PC used eliminate linear term of phase, disadvantage estimation. By employing...

This letter presents a multiscale edge detection method for multilook polarimetric synthetic aperture radar (PolSAR) images based on the nonsubsampled contourlet transform (NSCT). The NSCT can provide flexible and directional decomposition. In decomposition, coefficients of pyramid in are calculated via maximizing contrast between adjacent subband levels, instead using difference subbands as used additive noise model. By this way, we make applicable to PolSAR data multiband data. Then, edges...

In inverse synthetic aperture radar (ISAR) imaging, the echoes from rotating parts on a target may contaminate ISAR image of main body. The performance autofocus algorithms also be degraded when interference is too strong, for commonly used rigid‐body motion assumption not satisfied. this study, novel method based robust principal component analysis proposed imaging targets with parts. low rank property body returns and sparse components in certain range cell are utilised to separate them...

In the high-resolution inverse synthetic aperture radar (ISAR) imaging of low-earth-orbit space targets, received signal from one range bin can be modeled as a multicomponent cubic phase (CPS) after motion compensation. The chirp rates and quadratic CPS need to estimated with parameter estimation algorithms obtain focused ISAR image. this article, new parametric range-instantaneous-Doppler method is proposed, which introduces algorithm for CPSs. cross terms generalized function (GCPF) are...

Constant false alarm rate (CFAR) is the desired property for automatic target detection in unknown and nonstationary background. In this letter, an analysis of experimental data shows that gamma (GM) distribution a promising model sea clutter. Furthermore, modified cell-averaging (CA) detector GM-distributed clutter proposed by using maximum likelihood estimation method. Theoretical demonstrates maintains CFAR with respect to scale parameter The verified be optimal homogenous known shape...

Recent years, a new SAR concept based on Multi-Input Multi-Output (MIMO) conflguration has demonstrated the potential advantages to simultaneously improve performance of Synthetic Aperture Radar (SAR) imaging and ground moving target detection by utilizing multiple antennas both at transmission reception. However, precise signal model, as well efiect in image domain approaches for indication MIMO system are rarely investigated. Our paper three main contributions. Firstly, we present detailed...

Inverse synthetic aperture radar (ISAR) cross-range scaling is used to obtain the actual size of target, which essential for space surveillance and automatic target recognition. In this letter, a novel two-step ISAR method earth-orbit targets proposed, improves computational efficiency through use prior information achieves high estimation accuracy. An initial rotation velocity (RV) calculated first using open two-line element data satellite orbit coarsely achieve image with efficiency....

A novel single-feed design of a patch antenna with polarization reconfigurability is proposed in this paper. Four identical notches parasitic elements are embedded into the design. The can switch between linear (LP), left hand circular (LHCP) and right (RHCP). results show that demonstrates an impedance bandwidth 50 MHz (S11 <;-10 dB), 44.3 (axial ratio <; 3 dB). Also, axial obtained broad angular range when LHCP RHCP mode. structure simple suitable for array applications require diversity...

In this letter, a constant false-alarm rate line detector for polarimetric synthetic aperture radar (Pol-SAR) images is presented based on Wilks' test statistic, which can be used to the equality of two covariance matrices following complex Wishart distribution. Due two-tailed nature, statistic detect both bright and dark features. The probability distribution proposed derived verified using simulated Pol-SAR images. Experimental results measured data show effectiveness its superiority over...

The hyperbolic frequency-modulated (HFM) waveform has an inherent Doppler-invariant property. It is more conducive than the conventional linear (LFM) to high speed moving target imaging. In order apply HFM existing inverse synthetic aperture radar (ISAR) imaging systems, a new pulse compression algorithm proposed. First, received echoes are demodulated with transmitted signal, which called “decurve” in this paper. By operation, bandwidth of effectively reduced and can be processed by...

Bistatic multiple-input multiple-output (MIMO) radar can improve the system performance for obtaining waveform diversity and larger degrees of freedom (DoF), efiectively counteract stealthy target its transmit antennas receive separated placement. Similarly with conventional bistatic radar, geometry conflgurations MIMO also play an important role in system's performance. Aimed at considering these efiects on this paper extended ambiguity function is deflned as coherent cumulation matching...

To analyze the characteristic and space-time distribution of first-order sea clutter in shipborne high-frequency surface wave radar (HFSWR) with six degree-of-freedom (DOF) motion, a time-varying array steering vector pulse domain is presented. The spectrum model can be derived by classical cascaded processing received echo signal. Simulations are carried out under given motion parameters. Results show that both forward movement DOF have important influences on clutter, which may bring...

The effect of antenna rotation on the angle measurement accuracy in onshore or shipborne Inverse Synthetic Aperture Radar (ISAR) is investigated this paper. main monopulse ratio after coherent integration approximately amplitude and phase weighted sum all instantaneous ratios, which may affect azimuth estimation. In order to reduce impact, a non-coherent model established. Furthermore, based experimental data, method using calculate error its polarity respectively proposed, verified for...

This paper presents a novel bidirectional planar monopole antenna array, with its feeding network, to apply for WiFi/Bluetooth and LTE mobile standards. The array is comprised of elements that utilise Archimedean spiral slots, inspired as resonance paths, in order generate multi-band performance. Contrary conventional structures, the network composed three Wilkinson power dividers, purpose providing synchronised output signals over required frequency range, miniaturising dissipation losses...