Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) is very important for battlefield awareness. For SAR systems mounted on a UAV, the motion errors can be considerably high due to atmospheric turbulence and aircraft properties, such as its small size, which makes compensation (MOCO) in UAV more urgent than other systems. In this paper, based 3-D error analysis, novel MOCO method proposed. The main idea extract necessary parameters, i.e., forward velocity displacement line-of-sight...

In recent years, ground moving target imaging in synthetic aperture radar (SAR) has attracted the attention of many researchers all over world. A novel approach is proposed for and motion parameter estimation using single channel SAR. First, a second-order generalised keystone formatting method used to compensate range curvature. Secondly, estimated slope echo's envelope walk compensation. Thirdly, Doppler parameters targets obtained via spectral analysis are positioning targets. Finally,...

Range-Doppler (RD) processing is widely used in conventional inverse synthetic aperture radar (ISAR) imaging. The unwanted translational motion of moving targets compensated by envelope alignment and autofocus. For existing ISAR imaging algorithms, the scatterers' migration through resolution cells (MTRC) caused rotational usually ignored. With improvement or increase target size, MTRC cannot be neglected. In this letter, keystone formatting algorithm developed SAR for compensation ISAR....

Synthetic aperture radar (SAR) has found wide applications in many areas, e.g., battlefield awareness. However, SAR is vulnerable to various kinds of interference, among which narrow-band interference (NBI) commonly used. In this letter, an eigensubspace-based filtering approach proposed for NBI suppression without using passive-sniff data as the reference signal. Moreover, method can deal with smart or interrupted NBI. Both simulation and experimental results are provided illustrate performance

Range–Doppler (RD) algorithms are widely used in inverse synthetic aperture radar (ISAR) imaging. In the standard RD algorithm, envelope alignment and autofocus first applied to transform original data into equivalent turntable target data, then FFT is for image formation. Usually, migration through resolution cells (MTRCs) due rotation ignored. With improvement of or increase size, MTRCs cannot be ignored must mitigated. For high speed moving targets, most 'stop-and-go' model violated. this...

Inverse synthetic aperture radar (ISAR) imaging of air, space or ship targets with complex motion has attracted the attention many researchers in past decade. Complex induce cross-range scatterer-variant quadratic phase terms, which will degrade resolution and affect focusing quality. A new algorithm is proposed for ISAR moving targets. First, conventional range alignment, compensation compression are performed over raw history data such that each bin can be modelled as sum several linear...

Detection of subsurface defects is important for maintaining runway structural health and reliability. A potential solution to employ a robot equipped with Ground Penetrating Radar (GPR) perform scanning. To automate the inspection process, we develop defect detection algorithm which deep learning that fuses 2D planar features in each panel GPR B-scans 3D voxel-wise C-scan robustly detect regions even presence significant noises. Named as GPR-RCNN, have tested our real airport data collected...

High-resolution inverse synthetic aperture radar (ISAR) imaging and recognition of ship target is very important for many applications. Although the principle ISAR on sea same as that flying in sky, former usually has more complex motion (fluctuation with oceanic waves) than latter, which makes compensation difficult. However, change phase chirp rate caused by ships will deteriorate azimuth focusing quality. In this paper, we first model cubic terms (parameterised its rate), then a new...

Infrared (IR) image small target detection and identification is a massive challenge with vast applications in essential places such as military industries airports. Homoplastically, the unclear outline of IR images, complex background, tiny percentage targets images make it challenging to accurately acquire targets' features other characteristics, all which research significantly challenging. In this article, we first contribute an open dataset single-frame dubbed CAUC-SIRST. After that,...

The combination of a multihop relay system and orthogonal frequency-division multiplexing (OFDM) modulation is promising way to increase the capacity coverage area. For OFDM two-hop with separate power constraints, joint subcarrier matching allocation considered in this paper, which uses ldquodecode-and-forwardrdquo strategy. aforementioned problem can be formulated as mixed binary integer programming problem, prohibitive when trying find global optimum. By separating allocation, optimal...

Hiding capacity is very important for efficient covert communications. For JPEG2000 compressed images, it necessary to enlarge the hiding because available redundancy limited. In addition, bitstream truncation makes difficult hide information. this paper, a high-capacity steganography scheme proposed baseline system, which uses bit-plane encoding procedure twice solve problem due truncation. Moreover, embedding points and their intensity are determined in well defined quantitative manner via...

DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy have been recognized as kind novel algorithm. However, the success these limited by RIP (Restricted Isometry Property) condition or mutual coherence measurement matrix. In problem, columns matrix are steering vectors corresponding to different DOAs. Thus, it violates condition. The situation gets worse...

A two-stage blind adaptive anti-jamming algorithm for global positioning systems (GPS) is proposed in this study. The new cancels interferences by projecting the array received signals on orthogonal complement space of interferences. Then utilises CLEAN method to estimate direction arrivals GPS according period repetitive feature coarse/acquisition (C/A) code and form multi-beam, where each beam can point one signal. Test data simulation results show effectiveness algorithm.

The automatic dependent surveillance-broadcast (ADS-B) is a surveillance system for air traffic management where aircrafts asynchronously broadcast the position and other information on same frequency band. However, this simple transmission protocol will result in inevitable overlapping among multiple ADS-B signals. In paper, with inherent characteristics of signal, an algorithm proposed to separate First, nonconvex blind adaptive beamforming problem formulated constraints are different from...

In this paper, Adaboost and SVM are applied to SAR ATR (synthetic aperture radar automatic target recognition) respectively. The performance of these two classifiers is analyzed compared in aspect window with different size. First, PCA (principal component analysis) features selected as feature, then Adaboost.Ml used classify, Experimental results based on MSTAR data sets show that classifier has better robustness than

Direction-of-arrival estimation in the presence of gain and phase errors is investigated from retrieval (PR) perspective. In order to remove influence errors, they are isolated by taking absolute values elements compensated covariance matrix. Finally, formulated nonconvex PR optimization problem solved utilizing feasible point pursuit algorithm. Simulation results demonstrate effectiveness proposed

Identifying small objects is essential in airport clearances, such as UAVs and bird flocks affecting the safety of entire airport. Due to complex backgrounds, it a formidable task learn iconic representations from images. Convolution neural networks (CNNs) dominant framework past few years. Although CNNs can effectively mitigate local redundancy with convolutional kernels, also extremely challenging for kernels obtain more feature information about object. Alternatively, prediction box loss...

High range resolution (HRR) moving target indicator (MTI) is becoming increasingly important for many military and civilian applications such as the detection classification of targets in strong clutter background. We consider problem extracting HRR features with very closely spaced scatterers presence stationary clutter, where migration Doppler frequency are taken into account. A relaxation-based algorithm, which robust computationally simple, proposed to deal above problem. Numerical...

In sonar and many other applications, time-delay estimation is an important problem. When bandpass probe signals are used, the correlation function between received known transmitted oscillates near carrier frequency of signal. this case, existing algorithms perform poorly due to converging local optimum points. paper, two efficient algorithms, Hybrid-WRELAX EXIP-WRELAX, proposed deal with above They relaxation-based global minimizers a highly oscillatory nonlinear least-squares cost...

Adaptive beamforming techniques are now widely used to reject interference (jammer/clutter) signals in radar, communication, and sonar applications. In adaptive arrays using the sample matrix inversion (SMI) algorithm, inadequate estimation of covariance results antenna patterns with high sidelobes distorted mainbeams. this paper, a method is proposed precisely control peak (rather than average) sidelobe level array patterns. The also generalized antennas moderate bandwidth large random...

Recently, iris recognition has been paid more attention due to its high reliability in personal identification. But feature extraction is easily affected by some practical factors, such as inaccurate localization, occlusion, nonlinear elastic deformation and so on. In order solve the problem, this paper presents an efficient algorithm of based on scale invariant transform (SIFT). Experimental results show that proposed can reduce preprocessing, describe local properties effectively have...