检索结果-南通市图书馆

Dual-assisted high-precision tracking technique for wideband multiplexed signals in new generation GNSS

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2024年第1期5卷 52-73页

作者： Yunhan Qi Zheng Yao mingquan lu Department of Electronic Engineering Tsinghua UniversityBeijing100084China Beijing National Research Center for Information Science and Technology Beijing100084China

With the evolution of Global Navigation Satellite System(GNSS),new generation GNSS signals have adopted the dual-frequency multiplexing modulation techniques,which jointly modulate multiple signals located on multiple sub-frequencies into a Wideband Multiplexed Signal(WMS).Although WMSs were proposed initially to reduce the complexity of satellite transmitters and improve the transmission efficiency of signals,their multi-component structures and wide root mean square bandwidths introduced by high-frequency subcarriers also provide the possibility to improve the GNSS ranging ***,this paper proposes a Dual-assisted Multi-component Tracking(DMT)technique,which can not only fully use high-frequency subcarriers in WMSs,but also effectively track carrier,subcarrier,and code by jointly utilizing all components in *** this paper,the tracking and ranging performances of DMT are comprehensively analyzed theoretically and by simulation and real *** results show that compared with existing WMS tracking methods,DMT can achieve tracking results with lower tracking jitters and ranging results with higher precision,providing a highly advantageous solution for new generation GNSS signal processing.

关键词： Wideband multiplexed signal Dual-assisted Multi-component High precision tracking

Effects of Power Inversion Spatial Only Adaptive Array on GNSS Receiver Measurements

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2018年第2期23卷 172-183页

作者： Hailong Xu Xiaowei Cui mingquan lu Department of Electronic Engineering Tsinghua University Beijing 100084 China.

The Spatial Only Processing Power Inversion(SOP-PI) algorithm is frequently used in Global Navigation Satellite System(GNSS) adaptive array receivers for interference mitigation because of its simplicity of implementation. This study investigates the effects of SOP-PI on receiver measurements for high-precision applications. Mathematical deductions show that if an array with a centro-symmetrical geometry is used, ideally,SOP-PI is naturally bias-free; however, this no longer stands when non-ideal factors, including array perturbations and finite-sample effect, are added. Simulations are performed herein to investigate how exactly the array perturbations affect the carrier phase biases, while diagonal loading and forward-backward averaging are proposed to counter the finite-sample effect. In conclusion, whether SOP-PI with a centro-symmetrical array geometry will satisfy the high precision demands mainly depends on the array perturbation degree of the element amplitude and the phase center.

关键词： Global Navigation Satellite System(GNSS) receiver adaptive array high-precision application power inversion measurement bias array perturbation diagonal loading forward-backward averaging

A Robust Graph Optimization Realization of Tightly Coupled GNSS/INS Integrated Navigation System for Urban Vehicles

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2018年第6期23卷 724-732页

作者： Wei Li Xiaowei Cui mingquan lu Department of Electronic Engineering Tsinghua University Beijing 100084 China

This paper describes a robust integrated positioning method to provide ground vehicles in urban environments with accurate and reliable localization results. The localization problem is formulated as a maximum a posteriori probability estimation and solved using graph optimization instead of Bayesian filter. Graph optimization exploits the inherent sparsity of the observation process to satisfy the real-time requirement and only updates the incremental portion of the variables with each new incoming measurement. Unlike the Extended Kalman Filter （EKF） in a typical tightly coupled Global Navigation Satellite System/Inertial Navigation System （GNSS/INS） integrated system, optimization iterates the solution for the entire trajectory. Thus, previous INS measurements may provide redundant motion constraints for satellite fault detection. With the help of data redundancy, we add a new variable that presents reliability of GNSS measurement to the original state vector for adjusting the weight of corresponding pseudorange residual and exclude faulty measurements. The proposed method is demonstrated on datasets with artificial noise, simulating a moving vehicle equipped with GNSS receiver and inertial measurement unit. Compared with the solutions obtained by the EKF with innovation filtering, the new reliability factor can indicate the satellite faults effectively and provide successful positioning despite contaminated observations.

关键词： Global Navigation Satellite System (GNSS) sensor fusion Inertial Navigation System (INS) optimization factor graph tightly coupled integration

GNSS Spoofing Detection Based on Consistency Check of Velocities

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2019年第2期28卷 437-444页

作者： TAO Huiqi WU Hailing LI Hong lu mingquan Department of Electronic Engineering Tsinghua University China Satellite Navigation Project Center

Spoofing attacks for Global navigation satellite system(GNSS) would cause the abnormal changes of receiver measurements. Monitoring the abnormal changes is the main pattern of anti-spoofing *** of Doppler shifts are important for GNSS spoofing detection. Most researchers focus on the consistency of Doppler such as the consistency of carrier Doppler and code rate. But the method is powerless in some *** shift measurement is proportional to change rate of pseudorange, and the relationship would be broken in the case of spoofing attack. As both Doppler measurements and pseudoranges are related to velocity of receiver,two approaches of computing velocity can be used to check the consistency of Doppler shifts and pseudoranges measurements. An efficient spoofing detection method based on the consistency check of velocities is proposed in the paper. Principle of the method is given in detail and its performance evaluations are provided as well. Simulation results demonstrate the effectiveness of the solution.

关键词： GNSS Anti-spoofing Pseudoranges Doppler Velocity Consistency

Optimizing the Gabor Bandwidth of satellite navigation signals by MCS signal expression

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第6期54卷 1077-1082页

作者： ZHANG XiaoMing YAO Zheng lu mingquan Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing Global Information Center Beijing 100094China

Satellite navigation is playing an important role in social *** performances of the services a navigation system provides are the concern of the builders and *** signal structure determines the inherent ability of a satellite navigation system to provide these ***,it is necessary and reasonable to optimize the signal in the initial *** waveforms of signals in satellite navigation chips are an important aspect of the signal's structure,which impact the characteristics of the autocorrelation function and power spectrum in the time domain and frequency *** range accuracy of a navigation system is usually described by its Gabor *** Gabor Bandwidth of the Binary Offset Carrier (BOC) modulation in next-generation GNSS signal systems is not *** paper presents a signal expression based on Multilevel Coded Symbol (MCS) signals,which can describe the fine structure of navigation *** this expression,we can optimize the Gabor Bandwidth of the signal,and find out the corresponding MCS vector and chip waveform,so as to get higher range *** method in this paper,in theory,is of great value in the design of next-generation navigation signals.

关键词： satellite navigation MCS signal Gabor Bandwidth bound

A GNSS Acquisition Method with the Capability of Spoofing Detection and Mitigation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2018年第1期27卷 213-222页

作者： YUAN Dingbo LI Hong WANG Fei lu mingquan Department of Electronic Engineering Tsinghua University

For Global navigation satellite system(GNSS), spoofing attack is extremely dangerous and destructive since it can lead GNSS receivers to generate misleading time and position information. Thus, reliable and timely spoofing detection and mitigation methods are of great importance. A new GNSS acquisition method with the capability of spoofing detection and mitigation is proposed in the paper. The proposed method can not only perform acquisition, but also detect and mitigate spoofing signals based on joint consistency detection of code and carrier Dopplers. We provide performance analysis and numerical simulation results to demonstrate the validity of the proposed method when there are one or even more spoofing signals. Successful acquisition probability of the authentic signal is compared to that achieved by traditional acquisition method. The proposed method can be easily implemented with only a little modification of current receiver acquisition module.

关键词： Global navigation satellite system(GNSS) Spoofing mitigation Acquisition Doppler Joint detection

Vector tracking loops in GNSS receivers for dynamic weak signals

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2013年第3期24卷 349-364页

作者： Jing Liu Xiaowei Cui mingquan lu Zhenming Feng Department of Electronic Engineering Tsinghua University

Vehicle positioning with the global navigation satellite system （GNSS） in urban environments faces two problems which are attenuation and dynamic. For traditional GNSS receivers hardly able to track dynamic weak signals, the coupling between all visible satellite signals is ignored in the absence of navigation state feedback, and thermal noise error and dynamic stress threshold are contradictory due to non-coherent discriminators. The vector delay/frequency locked loop （VDFLL） with navigation state feedback and the joint vector tracking loop （JVTL） with coherent discriminator which is a synchronization parameter tracking loop based on maximum likelihood estimation （MLE） are proposed to improve the tracking sensitivity of GNSS receiver in dynamic weak signal environments. A joint vector position tracking loop （JVPTL） directly tracking user position and velocity is proposed to further improve tracking sensitivity. The coherent navigation parameter discriminator of JVPTL, being able to ease the contradiction between thermal noise error and dynamic stress threshold, is based on MLE according to the navigation parameter based linear model of received baseband signals. Simulation results show that JVPTL, which combines the advantages of both VDFLL and JVTL, performs better than both VDFLL and JVTL in dynamic weak signal environments.

关键词： dynamic weak signal maximum likelihood estimation (MLE) linear model navigation state feedback coherent discriminator

Low-complexity method for DOA estimation based on ESPRIT

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第5期21卷 729-733页

作者： Xuebin Zhuang Xiaowei Cui mingquan lu Zhenming Feng Department of Electronic Engineering Tsinghua University Beijing 100084 R R. China

A low-complexity method for direction of arrival（DOA） estimation based on estimation signal parameters via rotational invariance technique（ESPRIT） is *** of using the cross-correlation vectors in multistage Wiener filter（MSWF）,the orthogonal residual vectors obtained in conjugate gradient（CG） method span the signal subspace used by *** computational complexity of the proposed method is significantly reduced,since the signal subspace estimation mainly needs two matrixvector complex multiplications at the iteration of data ***,the prior training data are not needed in the proposed *** overcome performance degradation at low signal to noise ratio（SNR）,the expanded signal subspace spanned by more basis vectors is used and simultaneously renders ESPRIT yield redundant DOAs,which can be excluded by performing ESPRIT once more using the unexpanded signal *** with the traditional ESPRIT methods by MSWF and eigenvalue decomposition（EVD）,numerical results demonstrate the satisfactory performance of the proposed method.

关键词： direction of arrival(DOA) multistage Wiener filter(MSWF) conjugate gradient(CG) estimation signal parameters via rotational invariance technique(ESPRIT) eigenvalue decomposition(EVD).

Efficient Signal Separation Method Based on Antenna Arrays for GNSS Meaconing

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2019年第2期24卷 216-225页

作者： Jiaqi Zhang Xiaowei Cui Hailong Xu Sihao Zhao mingquan lu Department of Electronic Engineering Tsinghua University

As an effective deceptive interference technique for military navigation signals, meaconing can be divided into two main types: those that replay directly and those that replay after signal separation. The latter can add different delays to each satellite signal and mislead the victim receiver with respect to any designated position,thus has better controllability and concealment capability. A previous study showed there to be two main spatial processing techniques for separating military signals, whereby either multiple large-caliber antennas or antenna arrays are used to form multiple beams that align with all visible satellites. To ensure sufficient spatial resolution,the main lobe width of the antenna or beam must be sufficiently narrow, which requires the use of a large antenna aperture or a large number of array elements. In this paper, we propose a convenient and effective signal separation method, which is based on an antenna array with fewer elements. While the beam of the array is pointing to a specified satellite, the other satellite signals are regarded as interference and their power is suppressed to a level below the receiver's sensitivity. With this method, the number of array elements depends only on the number of visible satellites, thus greatly reducing the hardware cost and required processing capacity.

关键词： GNSS meaconing antenna array beamforming signal separation