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Robust Adaptive pulse compression Method Based on Two-Stage Phase Compensation

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2022年 60卷 1页

作者： Pei, Jiazheng Huang, Yong Guan, Jian Cai, Mi Chen, Baoxin Chen, Xiaolong Naval Aviat Univ Radar Target Detect Res Grp Yantai 264001 Peoples R China Naval Aviat Univ Res Inst Informat Fus Yantai 264001 Peoples R China PLA 92337 Troop Dalian 116000 Peoples R China

The conventional pulse compression method [i.e., matched filter (MF)] and adaptive pulse compression (APC) methods are based on the assumption that the echo sampling point is located in the target point which is in a range cell. If the echo sampling point is not located in the target point, it will result in sampling mismatch problem and the performance of MF and APC methods will be significantly reduced when using the continuous-time phase-modulated waveforms, such as linear frequency modulation (LFM) signal. Aiming at solving the sampling mismatch problem, an APC based on two-stage phase compensation (TPC-APC) and its dimensionality-reduced version-contiguous fast APC based on two-stage phase compensation (TPC-CFAPC) are proposed in this article. In TPC-APC/TPC-CFAPC method, the mismatch phase caused by the sampling mismatch is first compensated through the first-stage phase compensation, which suppresses the sampling-mismatch-induced range sidelobes;then the mismatch phase caused by the target's Doppler frequency is compensated through the second-stage phase compensation to suppress the Doppler-mismatch-induced range sidelobes;finally, the APC is applied to suppress the range sidelobe. To further compensate the mismatch phases of different targets, this article proposes a reiterative TPC-APC method and its dimensionality-reduced version, which iteratively use TPC-APC or TPC-CFAPC to suppress the range sidelobes caused by the mismatch phases of different targets. The results of the experiments have shown that the proposed methods are more robust compared with MF and APC methods.

关键词： White noise Doppler shift Signal to noise ratio Scattering pulse compression methods Chirp modulation Bandwidth Adaptive pulse compression (APC) Doppler mismatch linear frequency modulation (LFM) signal phase compensation sampling mismatch

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Photonics Generation of pulsed Arbitrary-Phase-Coded Microwave Signals Based on the Conversion Between Intensity Modulation and Phase Modulation

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2020年第6期38卷 1243-1249页

作者： Song, Chunqi Zheng, Zhennan Lei, Mingzheng Qian, Jinwang Gao, Xinlu Huang, Shanguo Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China

This article proposes a pulsed arbitrary-phase-coded microwave signals (APCMSs) photonics generation system. The key to this scheme is to achieve the single-sideband modulated (SSBM) optical signal with the conversion capability between intensity modulation and phase modulation by utilizing dual-parallel Mach-Zehnder modulator (DPMZM) and optical bandpass filter (OBPF). Through heterodyne detection of the SSBM optical signal, pulsed APCMSs can be generated. Unlike previous continuous-wave (CW) APCMSs and pulsed binary phase-coded microwave signals (PCMSs) photonics generation schemes, our scheme provides a pulsed APCMSs generation scheme. The scheme realizes the generation of APCMSs without CW background signals, and the scheme is not only suitable for binary phase codes but also suitable for arbitrary phase codes. The useless CW background signals are effectively suppressed without cascading an intensity modulator for gating operation and the coded phases are linear with the input pre-encoding signals amplitudes, leading to great improvement of practical application values. A theory analysis, a system simulation, and a proof-of-concept experiment are provided. Simulation demonstrates the generations of 2-Gbps 14-GHz and 1-Gbps 16-GHz pulsed APCMSs. The generations of 2-Gbps 14-GHz and 1-Gbps 16-GHz pulsed PCMSs with a 13-bit binary Barker-code and a 16-bit quaternary Frank-code are verified in experiment.

关键词： Microwave photonics phase modulation pulse compression methods

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Numerical Studies for Magneto-Acousto-Electrical Tomography with Magnetic Field Measurement Using Linear Frequency Modulated Excitation

Numerical Studies for Magneto-Acousto-Electrical Tomography ...

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Medical Technologies National Conference (TIPTEKNO)

作者： Mehmet Soner Gözü Ahmet Önder Tetik Nevzat Güneri Gençer Elektrik - Elektronik Mühendisliği Bölümü Orta Doğu Teknik Üniversitesi Ankara Türkiye

ISBN: (数字)9781665454322

ISBN: (纸本)9781665454339

Magneto-acousto-electrical tomography (MAET) is an imaging method based on measurements of the electric current induced by the Lorentz force. This current is generated when an acoustic wave propagates through a conducting body in the presence of a static magnetic field. The resulting current generates an electric potential and magnetic field distribution on the body surface. The surface potential measured by electrodes placed on the body or the magnetic fields measured by receiver coils placed near the body are used to reconstruct the electrical properties of tissues. In this study, the feasibility of the pulse compression method to the MAET with magnetic field measurement is investigated through numerical studies. A numerical breast model with a tumor inhomogeneity is formed. In order to apply the pulse compression method, a linear frequency modulated (LFM) excitation signal is applied to the ultrasound transducer. Additive white Gaussian noise is added to the MAET signal detected by the coils. In this case, the signal-to-noise ratio is increased by using a matched filter of pulse compression method and it is shown that MAET signals of a 2 mm x 2 mm tumor can be obtained. Moreover, the axial resolution that can be obtained with a conventional single pulse excitation can be achieved with the bandwidth selected in the applied LFM excitation signal.

关键词： Magnetic field measurement Tomography Magnetic fields Chirp modulation Tumors Surface reconstruction pulse compression methods

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pulse compression for Moving Target Echo in the First-order Approximate Model

Pulse Compression for Moving Target Echo in the First-order ...

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IEEE International Conference on Signal and Image Processing (ICSIP)

作者： Wenchao Yu Weimin Su Hong Gu Jianchao Yang Xingyu Lu School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing China

ISBN: (纸本)9781665446006

Compared with the conventional stop-and-go model in the pulse-Doppler (PD) radar, the first-order approximate model can describe the echo model of moving target more accurately due to its consideration of the target’s motion during intrapulse, whereas the conventional pulse compression process is not suitable for this model. In order to solve the problem, this paper presents a modified pulse compression method for the radar echo pulse in the first-order approximate model, which can avoid performance loss induced by the conventional method. In addition to the theoretical analysis, some simulation results are given to show the effectiveness of the proposed method.

关键词： pulse compression methods Image coding Simulation Conferences Radar

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Nonlinear Correction Approach for FMCW Radar based on Spectrum Recovery

Nonlinear Correction Approach for FMCW Radar based on Spectr...

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IEEE International Conference on Signal and Image Processing (ICSIP)

作者： Yanqi Liu Lili Gao Tianyue Shi Xinhua Mao Key Laboratory of Radar Imaging and Microwave Photonics Ministry of Education Nanjing University of Aeronautics and Astronautics Nanjing China R&D Center for Artificial Intelligence and Detection Technology Beijing institute of control and electronic technology Beijing China

ISBN: (纸本)9781665446006

There are two basic approaches for LFM (linear frequency modulation) signal pulse compression – matched filtering and Dechrip. For high-resolution imaging of small scenes, Dechirp is much more popular because it requires a lower sampling rate. However, the transmission signal of demodulation needs to be an ideal chirped signal for Dechirp. When linear modulation cannot be guaranteed accurately, the compression result will be spatially defocused, which causes the compensation complicated. This paper first derives the equivalence of matched filtering and Dechirp processing. Then, for the Dechirp received signal, this paper proposes a pulse compression method for nonlinear FM signals based on matched filtering without upsampling. Finally, the feasibility of the method was verified through experiments.

关键词： pulse compression methods Image coding Frequency modulation Filtering Imaging High-resolution imaging Radar

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A new shift pulse compression method for multiple targets' detection

A new shift pulse compression method for multiple targets' d...

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IEEE International Conference on Radar

作者： Pengfei Shi Yao Wei Wenying Wang Ming Hao Nanjing Research Institute of Electronics Technology Nanjing China

ISBN: (数字)9781665498142

ISBN: (纸本)9781665468893

The detection of multiple targets is always a difficult problem in radar. The core point is that the multiple targets cover each other, which makes it difficult to detect small targets. In order to solve above problem, a new detection method for multiple targets based on shift pulse compression (shift PC) is proposed in this paper. The idea of sum-difference amplitude ratio is used to suppress mutual masking problem caused by main broadening of multiple targets, where the difference channel is constructed by shift PC of left and right with each half range cell. The experimental results for the detection of multiple targets show that the proposed method can improve 20% the detection probability of small targets among multiple targets when the false alarm rate is 10 −5 .

关键词： pulse compression methods Radar clutter Radar detection Object detection Clutter

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Resistance against spot jamming by using pulse compression based on quadru-phase and frequency codes in radar systems

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DIGITAL SIGNAL PROCESSING 2020年第0期99卷 102679-000页

作者： Azadegan, Behnam Soleimani, Hossein Soleimani, Mohammad IUST Dept Elect Engn Tehran Iran

In electronic warfare, enemies apply many attacks to the radar systems, and try to obtain their signal information. In one type of spot jamming, the jammer accesses the structure of radar's signal. This information increases the success rate of attacks. In this paper, we propose a pulse compression method that uses the output of a block cipher as phase and frequency codes. The proposed method resists against spot jamming as the codes generated by the cipher blocks are confidential. We also use quadru-phase codes, instead of binary codes. Thus, a required level of confidentiality can be satisfied by codes with a shorter length. We investigate the probability of false alarms, autocorrelation and integrated side-lobes ratio by mathematical equations and verify them by simulation results. Results show that the proposed method provides a high level secure system with ultra-low side lobes and false alarm probability. (C) 2020 Elsevier Inc. All rights reserved.

关键词： pulse compression methods Security Cryptography Autocorrelation False alarm

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Stable Low-Repetition-Rate Time-Lens Picosecond Seed Source

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IEEE PHOTONICS TECHNOLOGY LETTERS 2018年第21期30卷 1854-1857页

作者： Dorrer, C. Brown, R. J. Univ Rochester Lab Laser Energet Rochester NY 14623 USA

The design and performance of a sub-10-picosecond source based on temporal focusing implemented with a lithium niobate phase modulator and a grating compressor are presented. The source is optimized taking into account spectral gain narrowing in subsequent amplifiers. It advantageously delivers low-repetition-rate pulses with tunable pulse duration, and its short-term jitter and long-term drift over extended periods of time are of the order of a few picoseconds.

关键词： Chromatic dispersion optical pulse generation phase modulation pulse compression methods

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The pulse compression with Doppler shift in synthetic aperture sonar

The pulse compression with Doppler shift in synthetic apertu...

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International Conference on Systems and Informatics (ICSAI)

作者： Mengbo Ma Jinsong Tang Heping Zhong Naval Institute of Underwater Acoustic Technology Naval University of Engineering Wuhan China

ISBN: (数字)9781728152561

ISBN: (纸本)9781728152578

In low-frequency, high-speed synthetic aperture sonar (SAS), the range pulse compression is affected by the time-scale factor and Doppler shift. This paper starts with the one- dimensional model, and analyzes the pulse compression of the large time-bandwidth linear chirp signal with Doppler shift. The three pulse compression methods are compared and analyzed. According to the peak offset, the main lobe broadening and the phase errors, the scopes of application of different pulse compression methods are given, which lays a theoretical foundation for the low-frequency and high-speed SAS imaging algorithm research.

关键词： Doppler shift Synthetic aperture sonar Brain modeling Frequency-domain analysis Synthetic aperture radar pulse compression methods

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Sampling the Multiple Facets of Light

Sampling the Multiple Facets of Light

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作者： Gilles BAECHLER ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE

学位级别：博士

The theme of this thesis revolves around three important manifestations of light, namely its corpuscular, wave and electromagnetic nature. Our goal is to exploit these principles to analyze, design and build imaging modalities by developing new signal processing and algorithmic tools, based in particular on sampling and sparsity concepts. First, we introduce a new sampling scheme called variable pulse width, which is based on the finite rate of innovation (FRI) sampling paradigm. This new framework enables us to sample and perfectly reconstruct weighted sums of Lorentzians; perfect reconstruction from sampled signals is guaranteed by a set of theorems. Weighted sums of Lorentzians provide an interesting parametric model to describe signals that can be naturally represented by a sum of pulses. For instance, extensive experiments have shown that it is a particularly suitable model to tackle the problem of electrocardiogram compression. Second, we return to the context of light and study its reflection, which is based on the corpuscular model of light. More precisely, we propose to use our FRI-based model to repre- sent bidirectional reflectance distribution functions. Such functions are naturally defined on the sphere, which is also a motivation to generalize our sampling framework to the spherical domain. We develop dedicated light domes to acquire reflectance functions and use the measurements ob- tained to demonstrate the usefulness and versatility of our model. In particular, we concentrate on the representation of specularities, which are sharp and bright components generated by the direct reflection of light on surfaces. Third, we explore the wave nature of light through Lippmann photography, a century-old photography technique that acquires the entire spectrum of visible light via the phenomenon of interference. This fascinating process captures interferences patterns created by the exposed scene inside the depth of a photosensitive plate. Following development

关键词： Color electrocardiogram finite rate of innovation Hilbert transform hyperspectral imaging interference inverse problem Lippmann phase retrieval photography polarizing filter pulse compression methods reflectance function sampling signal denoising sparsity spectral analysis specularity spherical harmonics standing wave variable width X-ray crystallography

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