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Control Theory and Technology 2024年第1期22卷 81-91页

作者： Luodi zhao long zhao School of Automation Science and Electrical Engineering Beihang UniversityBeijing100191China Digital Navigation Center Beihang UniversityBeijing100191China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing100191China

This paper proposes an automatic algorithm to determine the properties of stochastic processes and their parameters for inertial error. The proposed approach is based on a recently developed method called the generalized method of wavelet moments (GMWM), whose estimator was proven to be consistent and asymptotically normally distributed. This algorithm is suitable mainly (but not only) for the combination of several stochastic processes, where the model identification and parameter estimation are quite difficult for the traditional methods, such as the Allan variance and the power spectral density analysis. This algorithm further explores the complete stochastic error models and the candidate model ranking criterion to realize automatic model identification and determination. The best model is selected by making the trade-off between the model accuracy and the model complexity. The validation of this approach is verified by practical examples of model selection for MEMS-IMUs (micro-electro-mechanical system inertial measurement units) in varying dynamic conditions.

关键词： GMWM Stochastic process Inertial sensor Sensor calibration Error model Allan variance

A two-step robust adaptive filtering algorithm for GNSS kinematic precise point positioning

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Chinese Journal of Aeronautics 2021年第10期34卷 210-219页

作者： Qieqie ZHANG Luodi zhao long zhao School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China

In kinematic navigation and positioning,abnormal observations and kinematic model disturbances are one of the key factors affecting the stability and reliability of positioning ***,robust adaptive filtering algorithm is used to reduce the influence of them on positioning ***,it is difficult to accurately identify and separate the influence of abnormal observations and kinematic model disturbances on positioning results,especially in the application of kinematic Precise Point Positioning(PPP).This has always been a key factor limiting the performance of conventional robust adaptive filtering *** address this problem,this paper proposes a two-step robust adaptive filtering algorithm,which includes two filtering steps:without considering the kinematic model information,the first step of filtering only detects the abnormal *** on the filtering results of the first step,the second step makes further detection on the kinematic model disturbances and conducts adaptive *** analysis and experiment results indicate that the two-step robust adaptive filtering algorithm can further enhance the robustness of the filtering against the influence of abnormal observations and kinematic model disturbances on the positioning ***,improvement of the stability and reliability of kinematic PPP is significant.

关键词： Classification factor adaptive filtering Global positioning system Precise position holding Robust filtering Two-step filtering

An algorithm for terrain-aided inertial navigation based on nonlinear optimal filtering

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Science China(Physics,Mechanics & Astronomy) 2011年第6期54卷 1083-1088页

作者： zhao long Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100191China

When the initial position error or the altimeter measurement noise is large,the BUAA Inertial Terrain-Aided Navigation (BITAN) algorithm based on extended Kalman filtering can not be located *** solve this problem,we propose a modified BITAN algorithm based on nonlinear optimal *** posterior probability density correction is obtained by using the prior probability density of the system's state transition model and the most recent ***,the local unobservable system caused by the measurement equation through terrain linearization is *** algorithm is tested by using the digital elevation model and flight data,and is compared with *** show that the accuracy of the proposed algorithm is higher than BITAN,and the robustness of the system is improved.

关键词： navigation inertial navigation terrain-aided navigation robust adaptive filtering

Multi‑level autonomous integrity monitoring method for multi‑source PNT resilient fusion navigation

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Satellite Navigation 2023年第3期4卷 210-226页

作者： Rui Chen long zhao School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

For the integrity monitoring of a multi-source PNT(Positioning,Navigation,and Timing)resilient fusion navigation system,a theoretical framework of multi-level autonomous integrity monitoring is *** to the mode of multi-source fusion navigation,the framework adopts the top-down logic structure and establishes the navigation source fault detection model based on the multi-combination separation residual method to detect and isolate the fault source at the system level and subsystem *** isolated non-redundant navigation sources,the system level recovery verification model is *** the isolated multi-redundant navigation sources,the sensor fault detection model optimized with the dimension-expanding matrix is used to detect and isolate the fault sensors,and the isolated fault sensors are verified in ***,according to the fault detection and verification results at each level,the observed information in the fusion navigation solution is dynamically *** this basis,the integrity risk dynamic monitoring tree is established to calculate the Protection Level(PL)and evaluate the integrity of the multi-source integrated navigation *** autonomous integrity monitoring method proposed in this paper is tested using a multi-source navigation system integrated with Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),long Baseline Location(LBL),and Ultra Short Baseline Location(USBL).The test results show that the proposed method can effectively isolate the fault source within 5 s,and can quickly detect multiple faulty sensors,ensuring that the positioning accuracy of the fusion navigation system is within 5 m,effectively improving the resilience and reliability of the multi-source fusion navigation system.

关键词： Autonomous integrity monitoring Fault detection and isolation Multi-source PNT resilient fusion navigation Protection level

Adaptive cancellation of Es layer interference using auxiliary horizontal antennas

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Journal of Systems Engineering and Electronics 2006年第2期17卷 313-315页

作者： zhao long Zhang Ning Inst. of Electronic Engineering Harbin Inst. of Technology Harbin 150001 P. R. China

Based on a dual-polarization high-frequency wave radar system, an adaptive system using horizontal antennas for the suppression of the Es layer interference （ELI） is deseribech The data received from the horizontal antennas were correlated with the data received from the Vertically Polarized Antennas （VPAs） to estimate and cancel the interference adaptively in the VPAs. Suppressing the interference after each coherent integration time interval, about 25 dB signal-to-interference ratio is expected with the experimentally derived data.

关键词： dual-polarization auxiliary horizontal antennas adaptive cancellation signal-to-interference ratio.

Energy efficient power allocation strategy for downlink MU-MIMO with massive antennas

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The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 1-7页

作者： zhao long zhao Hui ZHENG Kan Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications School of Information and Communication Engineering Beijing University of Posts and Telecommunications

With the increasing energy consumption, energy efficiency （EE） has been considered as an important metric for wireless communication networks as spectrum efficiency （SE）. In this paper, EE optimization problem for downlink multi-user multiple-input multiple-output （MU-MIMO） system with massive antennas is investigated. According to the convex optimization theory, there exists a unique globally optimal power allocation achieving the optimal EE, and the closed-form of the optimal EE only related to channel state information is derived analytically. Then both the approximate and accurate power allocation algorithms with different complexity are proposed to achieve the optimal EE. Simulation results show that the optimal EE obtained by the approximate algorithm coincides to that achieved by the accurate algorithm within the controllable error limitation, and these proposed algorithms perform better than the existing equal power allocation algorithm. The optimal EE and corresponding SE increase with the number of antennas at base station, which is promising for the next generation wireless communication networks.

关键词： green communications SE EE MU-MIMO zero-forcing

Dynamic Response of 6MW Spar Type Floating Offshore Wind Turbine by Experiment and Numerical Analyses

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China Ocean Engineering 2020年第5期34卷 608-620页

作者： MENG long HE Yan-ping zhao Yong-sheng YANG Jie YANGHe HAN zhao-long YU long MAO Wen-gang DU Wei-kang a State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China b Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE) Shanghai Jiao Tong UniversityShanghai 200240China c School of Naval Architecture Ocean&Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China d China Aerodynamics Research and Development Center Mianyang621000China e Ocean Engineering Department Texas A&M UniversityCollege StationTX 77843USA f Department of mechanics and Maritime Sciences Chalmers University of Technology41296GothenburgSweden g Ocean Engineering Group Department of CivilArchitecture and Environmental EngineeringUniversity of Texas at AustinTexasTX 78712USA

The floating offshore wind turbine(FOWT) is widely used for harvesting marine wind energy. Its dynamic responses under offshore wind and wave environment provide essential reference for the design and installation. In this study,the dynamic responses of a 6 MW Spar type FOWT designed for the water depth of 100 m are investigated by means of the wave tank experiment and numerical analysis. A scaled model is manufactured for the experiment at a ratio of65.3, while the numerical model is constructed on the open-source platform FAST(Fatigue, Aerodynamics,Structures, and Turbulence). Still water tests, wind-induced only tests, wave-induced only tests and combined windwave-current tests are all conducted experimentally and numerically. The accuracy of the experimental set-up as well as the loading generation has been verified. Surge, pitch and heave motions are selected to analyze and the numerical results agree well with the experimental values. Even though results obtained by using the FOWT calculation model established in FAST software show some deviations from the test results, the trends are always consistent. Both experimental and numerical studies demonstrate that they are reliable for the designed 6 MW Spar type FOWT.

关键词： floating offshore wind turbine dynamic responses Spar type platform FAST model test

Preparation of entangledW states based on the cavity QED system

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Chinese Physics B 2024年第9期33卷 290-296页

作者： Ke Li Jun-long zhao Department of Physics Shanghai Second Polytechnic UniversityShanghai 201209China Quantum Information Research Center Shangrao Normal UniversityShangrao 334001China

We present a qubit-loss-free(QLF)fusion scheme for generating large-scale atom W states in cavity quantum electrodynamics(QED)*** to the most current fusion schemes which are conditioned on the case where one particle can be extracted from each initial W state to the fusion process,our scheme will access one or two particles from each W *** on the atom–cavity-field detuned interaction,three jWin+m+t states can be generated from the jWin,jWim,and jWit states with the help of two auxiliary atoms,and three jWin+m+t+q states can be generated from jWin,jWim,jWit,and a jWiq state with the help of three auxiliary *** the numerical simulations of the resource cost of fusing three small-size W states based on the previous schemes,our fusion scheme seems to be more *** QLF fusion scheme can be generalized to the case of fusing k different or identical particle W ***,with no qubit loss,it greatly reduces the number of fusion steps and prepares W states with larger particle numbers.

关键词： W state detuned interaction state fusion cavity quantum electrodynamics

A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1243-1260页

作者： long zhao Zeqi LU Hu DING Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China School of Microelectronics Shanghai UniversityShanghai201800China

Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant *** has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic *** paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration *** viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy *** nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction *** dynamic equations of viscoelastic metamaterials under transverse excitation are established,and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are *** results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band *** the same time,the elastic waves are limited in the nonlinear resonator with an energy harvesting function,which improves the energy ***,an experimental platform of viscoelastic metamaterial vibration is established for validation purposes.

关键词： viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting