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An Improved Method of Ambiguity Resolution in GNSS Positioning

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Chinese Journal of Electronics 2019年第1期28卷 215-222页

作者： GU Xiaoying zhu bocheng School of Electronics Engineering and Computer Science Peking University

High precision navigation with positioning accuracy of decimeter or even centimeter is becoming more and more important in many fields. Accurate carrier phase observations are the prerequisites for this requirement. Because they have much lower measurement noises than the code observations which are primarily used nowadays. However, the existence of integer ambiguity when counting cycles of carrier phases prohibits the straightforward application of the measurements. Once the integer ambiguity has been resolved, the application of carrier phase measurement is almost equivalent to pseudorange however with much higher precision. Therefore ambiguity resolution is key for fast and high precision positioning. The success rate of ambiguity resolution is affected by the ionospheric delay and observation noise. In previous methods, ionospheric errors are simply ignored. To resolve ambiguity reliably and quickly, we propose a modified method for precise point positioning.We analyze the characteristics of the dual-frequency combinations of original observations and the ones with longer wavelengths and lower noises are preferable. The wide-lane and sub-wide-lane combinations with higher success rates are chosen for ambiguity resolution. Extra pseudoranges are included to eliminate the ionospheric delay which hampers ambiguity resolution seriously. After the combined ambiguities have been resolved, the original ambiguities of each frequency can be calculated from the linearly independent equations. Based on real Global positioning system(GPS) navigation data, performances of the modified method are tested and compared with that of the traditional method. The results show that the modified method is less affected by ionospheric delay and can obtain more accurate ambiguity resolution.

关键词： Global navigation satellite system Integer ambiguity resolution Precise point positioning High precision positioning

Research of Fast Satellite Selection Algorithm for Multi-constellation

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Chinese Journal of Electronics 2016年第6期25卷 1172-1178页

作者： MENG Fanchen WANG Shan zhu bocheng School of Electronics Engineering and Computer Science Peking University

We propose a fast satellite selection algorithm for multi-constellation, which is based on both Newton’s identities for Geometric dilution of precision(GDOP)fast computation and optimal satellite geometric distribution for less cycle participation. An effective closed-form formula is proposed for GDOP approximation, avoiding conventional matrix inversion and complexity. We reduce computational cycles with auxiliary optimal satellite geometric distribution, which improves the efficiency of realtime positioning under the combined action of both. Simulation results indicate that we can save more than 44% and99% computational complexity when selecting 7 satellites from 10 and 30 visible satellites respectively. The GDOP of proposed method is very close to optimal result, better than that of Quasi-Optimal algorithm.

关键词： Global navigation satellite system(GNSS) Geometric dilution of precision(GDOP) Newton’s identities Fast satellite selection

A Convolutional Network Coding Oriented Four-Stage Contention Protocol for All-to-All Broadcasting Networks

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Chinese Journal of Electronics 2016年第1期25卷 192-198页

作者： LIU Yun WANG Shan zhu bocheng School of Electronics Engineering and Computer Science Peking University

Most practical networks are cyclic and demand Convolutional network coding(CNC). Researches on application of CNC in practical networks are still insufficient. Conventional graph theories cannot model the multicast channel properly. This paper introduces a multicast graph with multicast edges to model the multicast networks, and proposes a Multicast edge generation and max-flow detection(MEGAMAD) algorithm to approach the lower bound of necessary multicast edge number for a multicast network. Based on the algorithm we designed a new Media access control(MAC) protocol, the CNC oriented four-stage contention protocol(NC-FSCP) for the all-to-all broadcasting networks. The protocol runs a four stage reservation procedure to reserve time slots for encoded data transmission. Simulation proves that the reserved slot number approaches the lower bound for data dispersion in an all-to-all broadcasting network.

关键词： Convolutional network coding(CNC) MAC Multicast networks Max-flow min-cut

A Probability Driven Quadri-Stage Contention Protocol for Mobile Ad Hoc Networks

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Chinese Journal of Electronics 2014年第3期23卷 591-597页

作者： LIU Yun MA Yongqiang zhu bocheng School of Electronics Engineering and Computer Science Peking University

The paper proposes a new contention based Time division multiple access(TDMA) Medium access control(MAC) protocol in wireless ad hoc networks,which can be termed Quadri-stage contention protocol(QSCP). The QSCP protocol is free of both the "hidden terminal" and the "exposed terminal" problems. It is distributive and arbitrarily scalable. In the dedicated contention stage, nodes exchange their "Normalized accumulation and dissipation rate of payload(NADROP)" messages in 2-hop neighborhood, and then run a contention probability calculation algorithm to decide the probability of sending a contention frame. The algorithm guarantees that the number of time slot reserved by a node is proportional to its NADROP value, which can remarkably improve the end-to-end throughput when network load is heavy, and is more efficient in energy consumption. The simulation results demonstrate that QSCP performs better than the existing protocols.

关键词： Mobile ad hoc network TDMA MAC Contention probability Data payload QSCP

Reduced-order H∞ filtering for navigation with carrier phase

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Science China(Information Sciences) 2014年第2期57卷 27-36页

作者： LU ChenXi TAN YunHua zhu bocheng ZHOU Lezhu School of Electronics Engineering and Computer Science Peking University

A reduced-order H∞filtering algorithm for navigation with carrier phase is presented.By taking advantage of decoupling between filtering states in a navigation solution,this algorithm reduces computational cost and is robust in colored noise.Furthermore,the estimation precision is also improved by taking ambiguities as nuisance states when the filtering process converges.Applications to kinetic simulations under diferent noise are presented to demonstrate robustness and efciency of the algorithm.

关键词： navigation reduced-order H∞ filtering carrier phase

向未来要空间:论新质生产力的经济空间逻辑及实践旨向

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重庆大学学报（社会科学版） 2024年第2期30卷 98-109页

作者：胡博成朱千叶华东理工大学马克思主义学院上海200237 华东理工大学社会发展与公共管理学院上海200237 复旦大学哲学学院上海200433

人类生产力是一个从低级向高级形态发展演进的过程,同时生产力的跃升发展离不开新技术变革的驱动。新质生产力是习近平总书记立足百年未有之大变局对马克思主义生产力理论的创新发展,它进一步凸显了科技创新在生产力质变过程中的地位和... 详细信息

人类生产力是一个从低级向高级形态发展演进的过程,同时生产力的跃升发展离不开新技术变革的驱动。新质生产力是习近平总书记立足百年未有之大变局对马克思主义生产力理论的创新发展,它进一步凸显了科技创新在生产力质变过程中的地位和作用,为新时代乡村振兴和中国式现代化指明了前进方向。作为依靠关键技术实现生产力质态跃升发展的范畴,新质生产力既实现了对生产力三要素的创新发展,也在经济高质量发展特别是新经济空间生产方面发挥了革命性作用。就理论基础来看,马克思借助资本主义生产方式深刻说明了生产力与创新的深层关联逻辑,为把握和理解新质生产力的经济空间逻辑澄清了理论前提。就现实层面来看,社会主义经济深化拓展了新质生产力的经济空间逻辑向度,为创新和发展21世纪马克思主义政治经济学作出了重要贡献。基于上述分析,新时代要进一步优化科创体制机制,以创新理论和体制机制为新质生产力创造新经济空间,同时要制定面向新技术革命的经济发展战略,以社会主义竞争优势和前瞻规划布局为新质生产力开掘新经济空间。

关键词：新质生产力政治经济学新产业革命创新发展经济空间

Low-Complexity LS Algorithm Using Coordinate Transformation

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Chinese Journal of Electronics 2017年第1期26卷 156-159页

作者： YAN Wen XIE Yizhuang zhu bocheng CHEN He MA Cuimei School of Information and Electronics Beijing Institute of Technology School of Electronics Engineering and Computer Science Peking University

To reduce the computational complexity, decrease hardware resource consumption, and make it practicable, we propose a novel coordinate transformation based low-complexity Least squares(LS) algorithm. The positive integral variable is set as a reference coordinate and coefficients are transformed to be constant. The fitting polynomial in the reference coordinate system can be easily realized with lower complexity. To achieve the fitting curve in the original coordinate system, coordinate transformation is needed. Compared with the conventional LS fitting, our implementation results show that the proposed LS fitting algorithm can greatly reduce hardware resources in the premise of meeting the precision requirements.

关键词： Least squares(LS) fitting Reference coordinate Coordinate transformation Low computational complexity

On Finite Word Length Computing Error of Fixed-Point SAR Imaging Processing

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Chinese Journal of Electronics 2014年第3期23卷 645-648页

作者： XIE Yizhuang zhu bocheng YAN Wen ZHANG Weijie School of Information and Electronics Beijing Institute of Technology School of Electronics Engineering and Computer Science Peking University

Synthetic aperture radar(SAR) imaging system is generally realized by fixed-point with the purpose of reducing system implementation scale and enhancing real-time performance. Finite word length computing error of fixed-point SAR imaging system is studied. The characteristic of computing error in SAR imaging system is analyzed. A finite word length computing error model of SAR imaging system is built, by means of which the empirical formula of system’s output noise-to-signal ratio is derived. Based on the empirical formula, SAR imaging system processing word length is presented according to different processing granularities. The validity of this proposed finite word length computing error model of SAR imaging system is verified by system level fixed-point simulation.

关键词： Synthetic aperture radar(SAR) imaging Finite word length Analysis of computing error

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力法原理在机器人碰撞点识别中的应用

组合机床与自动化加工技术 2024年第6期 86-92页

作者：朱博承王志军李占贤马文文华北理工大学机械工程学院唐山063210 华北理工大学河北省工业机器人产业技术研究院唐山063210

随着机器人技术、人机协同作业技术被广泛关注,如何实现一个人机共融的安全系统至关重要。想要实现真正的人机共融,保证安全性、做好碰撞点的识别工作是重点。针对皮肤传感器应用包覆性来感知外力的局限性,提出了一种人机协同作业时当... 详细信息

随着机器人技术、人机协同作业技术被广泛关注,如何实现一个人机共融的安全系统至关重要。想要实现真正的人机共融,保证安全性、做好碰撞点的识别工作是重点。针对皮肤传感器应用包覆性来感知外力的局限性,提出了一种人机协同作业时当碰撞连杆已知,引入一种新的求解碰撞点处外部接触力的方法。利用力法原理求解超静定结构的方式,只需借助机器人本体输出的部分参数信息,即可根据受力信息,得到碰撞点的位置信息。最后,搭载实验平台对所提出的算法进行仿真实验,实验结果表明通过受力信息锁定碰撞点位置时,其受力情况的误差范围在可接受的范围之内,满足机器人碰撞点识别算法的精度要求。

关键词：人机协作超静定结构力法求解碰撞点识别

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