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A whole-net cooperative positioning method based on CDGNSS and inter-vehicle ranging

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Chinese Journal of Aeronautics 2024年第2期37卷 401-416页

作者： Shan HU Hongbo ZHAO Chen ZHUANG school of electronics and Information Engineering Beihang UniversityBeijing 100191China

Relative positioning is recognized as an important issue for vehicles in urban ***-vehicle Cooperative Positioning(CP)techniques which fuse the Global Navigation Satellite System(GNSS)and inter-vehicle ranging have attracted attention in improving the performance of baseline estimation between ***,current CP methods estimate the baselines separately and ignore the interactions among the positioning information of different *** interactions are called’information coupling’.In this work,we propose a new multivehicle precise CP framework using the coupled information in the network based on the Carrier Differential GNSS(CDGNSS)and inter-vehicle *** demonstrate the benefit of the coupled information by deriving the Cramer-Rao Lower Bound(CRLB)of the float estimation in *** fully use this coupled information,we propose a Whole-Net CP(WN-CP)method which consists of the Whole-Net Extended Kalman Filter(WN-EKF)as the float estimation filter,and the Partial Baseline Fixing(PBF)as the ambiguity resolution *** WN-EKF fuses the measurements of all baselines simultaneously to improve the performance of float estimation,and the PBF strategy fixes the ambiguities of the one baseline to be estimated,instead of full ambiguity resolution,to reduce the computation load of ambiguity *** tests involving four vehicles were conducted in urban *** results show that the proposed WN-CP method can achieve better performance and meanwhile maintain a low computation load compared to the existing methods.

关键词： GNSS Cooperative positioning Baseline Ambiguity resolution Information coupling

Client selection and resource scheduling in reliable federated learning for UA V-assisted vehicular networks

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Chinese Journal of Aeronautics 2024年第9期37卷 328-346页

作者： Hongbo ZHAO Liwei GENG Wenquan FENG ChangmingZHOU school of electronics and Information Engineering Beihang UniversityBeijing 100191China

Federated Learning(FL),a promising deep learning paradigm extensively deployed in Vehicular Edge Computing Networks(VECN),allows a distributed approach to train datasets of nodes locally,e.g.,for mobile vehicles,and exchanges model parameters to obtain an accurate model without raw data ***,the existence of malicious vehicular nodes as well as the inherent heterogeneity of the vehicles hinders the attainment of accurate ***,the local model training and model parameter transmission during FL exert a notable energy burden on vehicles constrained in *** view of this,we investigate FL client selection and resource management problems in FL-enabled UAV-assisted Vehicular Networks(FLVN).We first devise a novel reputation-based client selection mechanism by integrating both data quality and computation capability metrics to enlist reliable high-performance ***,to fortify the FL reliability,we adopt the consortium blockchain to oversee the reputation informa-tion,which boasts tamper-proof and interference-resistant ***,we formulate the resource scheduling problem by jointly optimizing the computation capability,the transmission power,and the number of local training rounds,aiming to minimize the cost of clients while guaranteeing *** this end,we propose a reinforcement learning algorithm employing an asynchronous parallel network structure to achieve an optimized scheduling *** results show that our proposed client selection mechanism and scheduling algorithm can realize reliable FL with an accuracy of 0.96 and consistently outperform the baselines in terms of delay and energy consumption.

关键词： Federated learning Vehicular edge computing Resource management Reinforcement learning Optimization techniques

A Fast Startup Crystal Oscillator with Digital SAR-AFC Based Two-Step Injection

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Chinese Journal of electronics 2024年第5期33卷 1147-1153页

作者： Bo ZHOU Yifan LI Zuhang WANG school of Integrated Circuits and electronics Beijing Institute of Technology

Crystal oscillators（XOs） provide a high-precision reference frequency but have a long startup time,which severely increases the average power consumption in duty-cycled *** paper proposes a fully-digital low-cost two-step injection technique,by using a successive approximation register（SAR） based auto frequency control（AFC） loop,to speed up the startup behavior of XOs.A theoretical analysis is carried out to determine the optimum injection time and design low-power *** in a 65 nm CMOS process,the proposed 12 MHz fast startup XO occupies an active area of 0.02 mm2and achieves a startup time less than 35 μ*** XO power consumption in the steady state is 40 μW from a 1.0-V supply,with a startup energy of 17.2 nJ.

关键词： Time-frequency analysis Power demand Power measurement Crystals Time measurement Steady-state Registers Crystal oscillator Two-step injection Successive approximation register Auto frequency control Fully-digital Fast startup ENERGY

Chipless textile electronics: human body-coupled fiber for wireless energy harvesting and signal transmission

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Science China Materials 2024年第7期67卷 2367-2368页

作者： Yixuan Wang Zuqing Yuan Guozhen Shen school of Integrated Circuits and electronics Beijing Institute of TechnologyBeijing 100081China

Wearable technology is rapidly advancing through the integration of electronic devices and textiles,enabling intelligent interaction between clothing and the surrounding *** electronics are specifically designed to provide functions such as sensing,computation,display,and ***,traditional wearable devices that rely on rigid von Neumann architectures and incorporate silicon chips face challenges in seamless integration,energy efficiency,and comfort[1–3].Difficulties arise when attempting to integrate complex circuits and electronic components,which are traditionally relied upon for signal modulation,into soft fibers[4,5].Recent reports have begun to explore alternative architectures for wearable devices that can incorporate electronics into a single fiber[6].However,this process presents challenges in simultaneously controlling energy capture and release within a single fiber.

关键词： fiber signal energy

An Extension of the Non-central Wishart Distribution with Integer Shape Vector

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2153-2168页

作者： Kaouthar KAMMOUN National school of electronics and Telecommunications of Sfax University of Sfax3018Tunisia

This research paper deals with an extension of the non-central Wishart introduced in 1944 by Anderson and Girshick,that is the non-central Riesz distribution when the scale parameter is derived from a discrete *** is related to the matrix of normal samples with monotonous missing *** characterize this distribution by means of its Laplace transform and we give an algorithm for generating *** we investigate,based on the method of the moment,the estimation of the parameters of the proposed *** performance of the proposed estimators is evaluated by a numerical study.

关键词： Cholesky decomposition Laplace transform method of moments non-central Wishart distribution Riesz distribution

CMOS-level mega-pixel organic camera chips made of photocrosslinked photovoltaic nanocells

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Science China Materials 2024年第9期67卷 3043-3045页

作者： Yegang Liang Zhuoran Wang Guozhen Shen school of Integrated Circuits and electronics Beijing Institute of TechnologyBeijing100081China

Organic and hybrid optoelectronics have been driving the frontiers in displays,sensing,and energy in recent decades due to their superior performance,low-cost high-yield manufacturing,and new form factor of mechanical flexibility that is promising for lightweight and wearable applications[1-3].However,the inherent vulnerability makes organic semiconductors incompatible with conventional semiconductor microfabrication,posing significant challenges in high density integration to compete with the resolution of conventional image sensors[4].

关键词： frontier driving lightweight

Intelligent secure near-field communication

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Science China(Information Sciences) 2024年第9期67卷 340-341页

作者： Nan ZHANG Jifa ZHANG Chengwen XING Na DENG Nan ZHAO school of Information and Communication Engineering Dalian University of Technology school of Information and electronics Beijing Institute of Technology

The research and development efforts for the sixth generation(6G) wireless communication are underway to fulfill the growing demands for wireless communications. 6G is expected to become the key enabler for diverse new applications and services [1]. To achieve the excellent performance, 6G will implement extremely large-scale antenna arrays(ELAAs), terahertz [2], and new types of antennas with metamaterials, leading to a paradigm shift for the electromagnetic characteristics.

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A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

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Journal of Beijing Institute of Technology 2024年第2期33卷 103-110页

作者： Liting Zhang Hao Huan Ran Tao Xiaogang Tang school of Information and electronics Beijing Institute of Technology school of Aerospace Information Space Engineering University

Recently, researchers have proposed an emitter localization method based on passive synthetic aperture. However, the unknown residual frequency offset(RFO) between the transmitter and the receiver causes the received Doppler signal to shift, which affects the localization accuracy. To solve this issue, this paper proposes a RFO estimation method based on range migration fitting. Due to the high frequency modulation slope of the linear frequency modulation(LFM)-modulation radar signal, it is not affected by RFO in range compression. Therefore, the azimuth time can be estimated by fitting the peak value position of the pulse compression in range ***, the matched filters are designed under different RFOs. When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time, the given RFO is the real RFO between the transceivers. The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s, the pulse repetition frequency(PRF) of the transmitter radar signal is not less than 1 k Hz, the range detection is not larger than 1 000 km, and the signal noise ratio(SNR) is not less than –5 d B.

关键词： range migration fitting (RMF) passive localization residual frequency offset (RFO)

Adjustable ion energy barrier for reliable memristive neuromorphic systems

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Science China Materials 2024年第11期67卷 3759-3760页

作者： Tianci Huang Zuqing Yuan school of Integrated Circuits and electronics Beijing Institute of Technology

With the rapid development of artificial intelligence and the processing of large-scale data, the demand for low-power and high-speed computing has become increasingly crucial [1].Neuromorphic computing, which mimics the neural structure of the human brain, offers a promising solution to overcome the limitations of traditional von Neumann architecture [2,3].

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