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Range Ambiguous Clutter Suppression for Forward-Looking Airborne Radar Based on frequency coding and Phase Waveforms Modulation in Slow-Time

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2024年第6期60卷 8470-8482页

作者： Qiu, Zizhou Duan, Keqing Liao, Zhipeng Sun Yat Sen Univ Sch Elect & Commun Engn Shenzhen 518107 Peoples R China

Airborne radars tasked with detecting low-altitude or ground targets frequently face the challenge posed by ground and sea clutter interference, which can drastically reduce target detection capabilities. To counteract this, airborne radars are necessitated to implement clutter suppression strategies, among which space-time adaptive processing (STAP) stands out as a key technique. Nevertheless, in forward-looking mode, the Doppler frequency of clutter varies with distance due to range dependency. Furthermore, operational modes with medium-to-high pulse-repetition frequencies introduce range ambiguity into radar signals. The combination of clutter range dependency and range ambiguity severely diminishes the clutter suppression efficacy of STAP. In response to these challenges, this article proposes a strategy for suppressing range ambiguous clutter, using slow-time frequency coding and phase waveforms modulation radar. This approach involves utilizing distinct phase waveforms and carrier frequency modulations for different pulses at the transmitter. At the receiver, the method employs joint filtering within the Doppler and waveform domains, exploiting the unique characteristics of the transmitted signal to resolve range ambiguity. In addition, Doppler compensation is deployed to address the issue of clutter range dependency. Ultimately, STAP is utilized to process clutter from each range region individually, thus achieving efficient suppression of range ambiguity clutter. Theoretical analysis and simulation experiments are included, demonstrating the efficacy of the proposed method.

关键词： Clutter Radar Airborne radar Radar clutter Doppler effect Encoding Radar detection frequency coding phase waveform modulation range ambiguous clutter space-time adaptive processing (STAP)

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Intra-Pulse frequency coding Design for a High-Resolution Radar against Smart Noise Jamming

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REMOTE SENSING 2022年第20期14卷 5149-5149页

作者： Xi, Rongyan Ma, Dingyou Liu, Xiang Wang, Lei Liu, Yimin Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Key Lab Universal Wireless Commun Minist Educ Beijing 100876 Peoples R China China Acad Engn Phys Inst Elect Engn Mianyang 621900 Sichuan Peoples R China

Smart noise jamming forms active jamming by intercepting, modulating, and forwarding radar signals into the radar receiver, which seriously affects the radar range recovery performance. In this paper, we propose a novel waveform design approach and an efficient range recovery method for high-resolution radar in the jamming scenario. Firstly, we propose an intra-pulse frequency-coded frequency-modulated continuous waveform (IPFC-FMCW), which contains multiple FMCW chips with different widths and frequencies, to combat the smart noise jamming. After the jamming suppression, the proposed waveform has a low sidelobe level, which is different from traditional FMCW signals for which the observations are periodically missing, resulting in high sidelobe levels. Then, to improve the range recovery performance of the waveform after jamming suppression, we optimize the range profile by designing the transmit waveform and then solve it by a simulated annealing algorithm. Next, based on the designed waveform, we derive the echo model after jamming suppression and propose a gridless compressed sensing (CS) method to recover the range of the targets. Compared with the existing waveforms and methods, the proposed waveform and the processing method achieve better range recovery performance in the jamming scenario. Numerical simulations are utilized to demonstrate the range recovery effectiveness of the proposed waveform and method in smart noise jamming.

关键词： high-resolution radar frequency coding smart noise jamming waveform design

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The Application of the Joint Range and Speed Estimation Method in Short-Range Radars Using Ultra-Wideband Signals with a Pseudo-Random frequency coding

The Application of the Joint Range and Speed Estimation Meth...

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Systems of Signals Generating and Processing in the Field of on Board Communications

作者： D. I. Sapronov I. V. Kamenskiy Moscow Aviation Institute (National Research University) Moscow Russia

ISBN: (数字)9781728147727

ISBN: (纸本)9781728147734

This article uses the previously presented method [1] of joint estimation of range and radial velocity in short-range radars using one ultra-wideband signal with discrete frequency coded waveform (DFCW). The core of the method is the use of the expression of the two-dimensional digital compression function of the output of the radar receiver ADC. The results of the practical implementation of this method are presented in a radar with a generation circuit using a phase-locked loop (PLL) generator, direct digital synthesis generator (DDS) and a quadrature modulator (IQ modulator). The results of the method are compared for signals with linear and pseudo-random frequency codes. The results of the method after using the calibration algorithm are presented.

关键词： Ultra-wideband signals discrete frequency coded waveform linear DFCW pseudo-random DFCW Ultra wideband technologies radar Pseudorandom frequency coding Height finding radar signals joint estimation direct digital synthesis CORING METHODS Speed Estimation RADIAL VELOCITY Phase locked loops

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Prestin derived OHC surface area reduction underlies age-related rescaling of frequency place coding

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HEARING RESEARCH 2022年 423卷 108406页

作者： Zhang, Yu Lin, Guotong Wang, Yi Xue, Na Lin, Xin Du, Tingting Xiong, Wei Song, Lei Shanghai Jiao Tong Univ Shanghai Peoples Hosp 9 Dept Otolaryngol Head & Neck Surg Sch Med Shanghai Peoples R China Shanghai Jiao Tong Univ Ear Inst Sch Med Shanghai Peoples R China Shanghai Key Lab Translat Med Ear & Nose Dis Shanghai Peoples R China Tsinghua Univ Sch Life Sci Beijing Peoples R China Tsinghua Univ McGovern Inst Brain Res Tsinghua Univ IDG Beijing Peoples R China Fudan Univ Shanghai Zhongshang Hosp Dept Otolaryngol Head & Neck Surg Sch Med Shanghai Peoples R China

Outer hair cells (OHC) are key to the mammalian cochlear amplifier, powered by the lateral membrane protein Prestin. In this study, we explored age-related OHC changes and how the changes affected hearing in mouse. OHC nonlinear membrane capacitance measurements revealed that, starting upon completion of postnatal auditory development, a continuous reduction of total Prestin in OHCs accompanied by a sig-nificant reduction in their cell surface area. Prestin's density is unaffected by Prestin level drop over the whole age range tested, suggesting that the OHC size reduction is Prestin-dependent. Stereocilia length in aged OHCs remained unchanged but the first row stereocilia on the aged inner hair cells (IHCs) were elongated. Distortion product otoacoustic emission (DPOAE) group delays became longer with aging, sug-gesting an apical shift in vibration on basilar membrane. Acoustic lesion experiments revealed an apical shift in damage place in old cochleae accompanied by a shallower progression in synaptic damage over a wider frequency range that was indicative of a broader frequency filter. Overall, these findings suggest that in aging cochlea, a shift in frequency place coding could occur due to the changes in cochlear active and passive *** article is part of the Special Issue Outer hair cell Edited by Joseph Santos-Sacchi and Kumar Navaratnam.(c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://***/licenses/by-nc-nd/4.0/ )

关键词： Aging Prestin Outer hair cell DPOAE group delay Cochlear mechanics frequency coding

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frequency coding quantum key distribution channel based on serial photons amplitude modulation and phase commutation 15

Frequency coding quantum key distribution channel based on s...

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15th International Conference on Optical Technologies for Telecommunications

作者： Gabdulkhakov, Ildaris M. Morozov, Oleg G. Morozov, Gennady A. Zastela, Mikhail Yu. Tyajelova, Alina A. Sarvarova, Lucia M. PJSC Tattelecom 57 N Ershov St Kazan 420061 Russia Kazan Natl Res Tech Univ 10 K Marx St Kazan 420111 Russia

ISBN: (数字)9781510621206

ISBN: (纸本)9781510621206;9781510621190

The technology of frequency coding in channels of quantum key distribution allows to determine the ground state of photons through the value of the amplitude of its carrier, frequency modulated in phase (PM) or amplitude (AM) by a radio- frequency signal, and the resulting side components. Over the past twenty years, it has been substantially modified and improved. At the same time, in recent works, an expanded understanding of the frequency coding principle is used, in which each photon state is associated not with the phase of the modulating signal at a certain frequency, but with one or more sideband frequencies or the carrier frequency of the photon itself. In this paper, we present the results of constructing a frequency coding system of quantum key distribution (QKD) based on the serial electro- optical photon amplitude modulation and phase commutation. The possibility of reducing the probability of achieving a positive result in PNS attacks by Eva is shown by eliminating the carrier of the signal transmitted via the quantum channel from the structure of the key distribution. It was early noted, that the smallest value of QBER is achieved in schemes with a passive definition of one or two basic states of a photon, i.e. without the use of remodulation processes, that is realized in considering. Additionally it is not necessary to form a notch filter system, which is usually carried out using fiber Bragg gratings (FBG) or arrayed waveguide gratings (AWG) for discrimination the photon carrier and its sideband components.

关键词： quantum cryptography quantum key distribution frequency coding electro-optical photon amplitude modulation electro-optical photon phase commutation PNS attack remodulation process notch filter

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Two-step quantum secure direct communication scheme with frequency coding

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Chinese Physics B 2017年第3期26卷 231-235页

作者：赵学亮李俊林牛鹏皓马鸿洋阮东 Department of Physics Tsinghua University School of Science Qingdao University of Technology

Quantum secure direct communication （QSDC） is an important branch of quantum cryptography. It can transmit secret information directly without establishing a key first, unlike quantum key distribution which requires this precursory event. Here we propose a QSDC scheme by applying the frequency coding technique to the two-step QSDC protocol, which enables the two-step QSDC protocol to work in a noisy environment. We have numerically simulated the performance of the protocol in a noisy channel, and the results show that the scheme is indeed robust against channel noise and loss. We also give an estimate of the channel noise upper bound.

关键词： quantum cryptography quantum secure direct communication frequency coding

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Controlling Energy Radiations of Electromagnetic Waves via frequency coding Metamaterials

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ADVANCED SCIENCE 2017年第9期4卷 1700098页

作者： Wu, Haotian Liu, Shuo Wan, Xiang Zhang, Lei Wang, Dan Li, Lianlin Cui, Tie Jun Southeast Univ State Key Lab Millimeter Waves Nanjing 210096 Jiangsu Peoples R China Peking Univ Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China

Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits "0" and "1" to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency-spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.

关键词： energy radiations frequency coding metamaterials multiple controls phase sensitivity

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Quantum secure direct communication with frequency coding scheme 4

Quantum secure direct communication with frequency coding sc...

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Conference on Quantum and Nonlinear Optics IV

作者： Zhao, Xue-Liang Ruan, Dong Tsinghua Univ Dept Phys Beijing Peoples R China

ISBN: (数字)9781510604780

ISBN: (纸本)9781510604773;9781510604780

Quantum secure direct communication (QSDC) is an important branch of quantum cryptography. It can transmit secret information directly without establishing a key first, unlike quantum key distribution which requires this precursive event. One of the most highlighted QSDC protocol is the Two-step protocol. This paper will focus on proposing a frequency coding scheme in the Two-step protocol, while retaining other contents of the QSDC protocol. This new coding scheme will significantly increase the protocol's ability against channel noise and loss, and provides an efficient protocol for secure direct quantum communication in a noisy environment. Besides, the frequency coding technology is also easy to understand and highly practical. After numerically simulating the performance of the protocol in a noisy channel, the results showed that the scheme was robust against channel noise and loss.

关键词： Quantum cryptography QSDC Noise channel frequency coding

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Metamaterials: Controlling Energy Radiations of Electromagnetic Waves via frequency coding Metamaterials (Adv. Sci. 9/2017)

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Advanced Science 2017年第9期4卷 n/a-n/a页

作者： Haotian Wu Shuo Liu Xiang Wan Lei Zhang Dan Wang Lianlin Li Tie Jun Cui State Key Laboratory of Millimeter Waves Southeast University Nanjing 210096 China School of Electronic Engineering and Computer Sciences Peking University Beijing 100871 China

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An Angle Insensitive Chipless Tag Using frequency Domain And Polarization coding 10

An Angle Insensitive Chipless Tag Using Frequency Domain And...

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IEEE 10th Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Li, Sen Tian, Yijia Zhuang, Lu Ouyang, Jun Univ Elect Sci & Technol China Chengdu 611730 Peoples R China

ISBN: (纸本)9781665489546

In this paper, a ring chipless tag insensitive to the incident wave angle is proposed. The tag adopts the patch type frequency selective surface structure, the surface of the dielectric substrate is composed of three groups of rings. By designing the coding frequency band as the staggered arcs, designing the radius and radian of them, in addition extracting and processing the dual polarization Radar Cross Section(RCS), the frequency domain and polarization coding are realized. Changing the incident angle of the plane wave to the tag, due to the good symmetry of the tag, the shift of the RCS absorption extreme frequency point of the tag is small, which improves the feasibility of tag coding.

关键词： chipless tag angle insensitive frequency coding polarization coding

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