Novel phased array antennas suitable for X-band satellite communication are introduced and investigated right-handed circular polarization (RHCP) in a multi-layered fabrication. The primary function of the proposed is to transmit high quality data obtained from satellites ground station systems with lowest amount loss. For accurate transmission, important parameters regarding antenna specifications electrical performance gain high-purity polarization. Hence, this paper describes novel...

A structural modification of S-band turnstile antenna with cylindrical parasitic elements around a main radiator is introduced and investigated respect to its gain, axial-ratio (AR) beamwidth, radiation pattern. The overall structure composed two crossed bowtie-shaped dipole antennas feeding network using Wilkinson power divider phase differences between parts. final optimization the parameter values for enhancement AR beamwidth carried out from parametric studies. proposed has not only...

This paper presents the design of a dual-polarized frequency-modulated continuous wave (FMCW) radar system with coupler-integrated lens antenna for automotive synthetic aperture (SAR) applications. High-resolution imaging is imperative use, SAR providing robust support in achieving this objective. However, exploration FMCW systems has been limited. The outlines aforementioned system, emphasizing its suitability It details requisite parameters and considerations antenna. Additionally, it...

Drone-based synthetic aperture radar (SAR) systems have increasingly gained attention due to their potential for rapid surveillance in localized areas. This paper presents a novel approach SAR processing subsurface target detection from lightweight drone platform. The limited capacity and memory resources of small platforms demand efficient recovery performance high-resolution imaging. Compressed sensing (CS) algorithms are widely used mitigate data storage requirements, yet they often...

Synthetic aperture radar (SAR), which can generate images of regions or objects, is an important research area radar. The chirp scaling algorithm (CSA) a representative SAR imaging algorithm. CSA has simple structure comprising phase compensation and fast Fourier transform (FFT) operations by replacing interpolation for range cell migration correction (RCMC) with compensation. However, real-time processing still requires many computations long execution time. Therefore, it necessary to...

In this paper, we propose a method for reconstructing synthetic aperture radar (SAR) images by applying compressive sensing (CS) technique to sparsely acquired sensor data. general, SAR image reconstruction algorithms require data at regular spatial intervals. However, when the speed of radar-equipped platform is not constant, it difficult consistently perform acquisitions. Therefore, used CS-based signal recovery efficiently reconstruct even acquisition was performed. proposed method,...

This paper presents a polar-format algorithm (PFA)-based synthetic-aperture radar (SAR) processor that can be mounted on small drone to support video SAR (ViSAR) imaging. For mounting, it requires miniaturization, low power consumption, and high-speed performance. Therefore, meet these requirements, the design was based field-programmable gate array (FPGA), implementation results are presented. The proposed PFA-based consists of both an interpolation unit fast Fourier transform (FFT) unit....

Purpose The purpose of this paper is to classify body shapes using angular defects instead sizes. Design/methodology/approach A large amount dimensional data from a national anthropometry survey was analysed, and basic pattern its polyhedron were also used create three‐dimensional shape three Using method, the sizes converted into nine defects. Findings authors could define factors explaining characteristics four groups. groups be characterised by two making difficulties upper lower parts as...

Intelligent video surveillance systems detect pre-configured events through background modeling, foreground and object extraction, tracking, event detection. Shadow regions inside frames sometimes appear as objects, interfere with ensuing processes, finally degrade the detection performance of systems. Conventional studies have mostly used intensity, color, texture, geometric information to perform shadow in daytime video, but these methods lack capability removing shadows nighttime video....

In this paper, we propose a range-Doppler algorithm (RDA)-based synthetic aperture radar (SAR) processor for real-time SAR imaging and present FPGA-based implementation results. The processing steps the RDA include range compression, cell migration correction (RCMC), azimuth compression. A matched filtering unit (MFU) an RCMC (RPU) are required processing. Therefore, proposed RDA-based contains MFU that uses mixed-radix multi-path delay commutator (MRMDC) FFT RPU. reduces memory requirements...

In this paper, we attempt to generate high resolution profile of flying drone targets. To purpose, multi-bands radar signals are adopted carry out inverse synthetic aperture (ISAR) imaging moving drones. After theoretical analysis is performed, experimental results acquired through field tests. demonstrate that ISAR provide effective measures detect and classify the class multiple target

A novel pulse compression technique is developed that produces an optimal uniform range sidelobe of the ideal Barker code level. The newly obtained pattern provides compromise between resolution and peak level (PSL), regardless signal length, also retains merit strong resistance to Doppler shift effect. Very low regions appear around mainlobe peak, which useful in target tracking recognition. processing proposed reduce ISL energy. canceller generated directly from incoming combined together...

In this paper, we propose an effective waveform diversity scheme that can be applicable to synthetic aperture radar (SAR) operations affected by interfering signals. A novel approach is taken achieve fully adaptive SAR generates sufficient number of orthogonal signals with modest performance trade-off. To purpose, multiple phased-code waveforms are arbitrarily generated mutually low cross-correlations. They exhibit a highly flexible characteristic as their code lengths not limited and...

We show that an L-branch maximal ratio combining (MRC) receiver with average signal-to-noise (SNR) γ̅ in Nakagami-m fading channels is equivalent to mL-branch MRC SNR γ̅/m Rayleigh terms of symbol error probability (SEP) when mL integer. Moreover, the orthogonal space-time block code (OSTBC) employing M <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> transmit antennas and xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> receive shown...

Sequences with low autocorrelation levels are highly desirable in digital communication. Conventional sidelobe reduction techniques have suffered from performance degradations range resolutions and signal-to-noise ratio (SNR) gains. In this paper we propose a way to synthesize amplitude weight correlators for polyphase codes. These weighted codes generate sidelobes that lower than those found Barker The level is kept uniformly flat over all time delays while the resolution loss prevented....

Nowadays, remote sensing missions and their analysis are carried out by multiple satellites or airborne images. Naturally, techniques for image fusion have attracted increased attentions become a topic of major research. The images from the optical SAR sensors enables an effective complementing weakness each other. However, unlike image, geometrical distortions commonly occur during acquisition due to characteristics target ground. Thus, use data obtained different techniques, preprocessing...

This paper explores novel architectures for fast backprojection based video synthetic aperture radar (BP-VISAR) with multiple GPUs. The SAR frame rate is analyzed non-overlapped and overlapped modes. For the parallelization of process, a processing data unit defined as phase history or range profile from partial synthetic-apertures divided full resolution target data. Considering whether full-aperture performed compression are parallelized on GPU basis, we propose six distinct architectures,...

최근 무인기 탑재를 위한 소형 SAR 시스템 관련연구가 활발하게 진행되고 있으나, 드론과 같은 비행 플랫폼에 대한 적용 사례는 매우 드물다. 드론의 경우, 고정익 무인항공기에 비해 기상, 조종환경 등에 취약하므로 고품질의 영상을 획득하기 위해서는 정밀한 요동 분석 및 오차 보상 알고리즘이 요구된다. 특히 드론에서는 탑재체 무게 전력의 제약으로 자세 제어 센서 장착이 어려워 영상 품질 보장이 어려워진다. 본 연구에서는 드론에 SAR를 탑재하여 획득하는 가능성을 제시한다. 이를 위해 실제 레이다가 탑재된 드론을 사용하여 획득하고, 그 품질을 분석하였다. 드론 기하 구조 분석을 통해 요동에 의해 발생될 수 있는 위상오차를 분석하고, 불규칙한 이동에 의한 왜곡을 보상함으로써 SAR의 운용 검증하였다. The use of small drone platform has become a popular topic in these days but its application for...

전자전(Electronic Warfare) 상황에서 레이다는 재머에 의해 전파교란공격(ECM: Electronic Counter Measures)을 받게 된다. Linear-FM 신호는 도플러 특성이 우수하고, 신호의 구현이 용이하여 레이다에서 주로 사용되어 왔지만, 반복된 패턴에 피탐 확률이 높고, 신호 특성변수 추정이 가능하여 기만재밍에 취약하다. 최근 제안된 APCN(Advanced Pulse Compression Noise) 랜덤 진폭과 위상코드로 이루어진 신호로서, 저피탐 성능이 우수한 신호이다. 하지만, APCN 신호를 비롯한 일반적인 위상코드 좋지 않으므로, 주파수 천이에 신호수신 저하될 수 있다. 따라서 본 논문에서는 특성을 개선하기 위한 방안으로 위상천이 및 부호율 천이(RPCR: Random Phase and Code Rate transition) 레이다 파형을 제안하고, 성능과 성능을 분석하였다. Ambiguity 함수를 이용하여 의한 특성 개선을...

A high resolution inverse synthetic aperture radar (ISAR) technique is presented using modified Doppler history based motion compensation. To this purpose, a novel wideband ISAR system developed that accommodates parametric processing over extended length. The proposed method derived from an ISAR-to-SAR approach makes use of spotlight SAR and sub-aperture recombination. It dedicated to wide imaging exhibits robust performance against unstable targets having non-linear motions. We demonstrate...

In this paper, an adaptive block compressive sensing (BCS) method is proposed for compression of synthetic aperture radar (SAR) images. The enhances the efficiency by dividing magnitude entire SAR image into multiple blocks and subsampling individual with different ratios depending on sparsity coefficients in discrete wavelet transform domain. Especially, a new algorithm devised that selects best measurement matrix from predetermined codebook to reduce side information about matrices...