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| 1 | Orbit determination and time synchronization for BDS-3 satellites with raw inter-satellite link ranging observations显示文摘To provide competitive global positioning and timing services under the condition that monitoring stations are confined to Chinese territory,inter-satellite link(ISL)technology is used by the third-generation BeiDou Navigation Satellite System(BDS-3).The ISL,together with the dual one-way links between satellites and anchor stations,may enable autonomous navigation for BDS-3.In this paper,we propose a general observation model for orbit determination(OD)and time synchronization(TS)directly using non-simultaneous observations,such as raw ISL pseudoranges.With the proposed model,satellite orbits,clocks,and hardware delay biases of ISL equipment can be determined simultaneously by jointly processing inter-satellite one-way pseudorange data and observation data from ground monitoring stations.Moreover,autonomous OD and TS are also achievable with one-way pseudorange data from anchor stations and satellites.Data from eight BDS-3 satellites,two anchor stations,and seven monitoring stations located in China were collected to validate the proposed method.It is shown that by jointly processing data from the ISL and seven monitoring stations,the RMS of overlap orbit differences in radial direction is 0.019 m,the overlap clock difference(95%)is 0.185 ns,and the stability of the estimated hardware delay biases for each satellite is greater than 0.5 ns.Compared with the results obtained with the seven stations,the improvements of orbits in radial direction and clocks are 95.7%and 90.5%,respectively.When the hardware delay biases are fixed to predetermined values,the accuracies of orbits and clocks are further improved.By jointly processing pseudoranges from the satellites and the two anchor stations,the RMS of overlap orbit differences is 0.017 m in the radial direction,and the overlap clock difference(95%)is 0.037 ns.It has also been demonstrated that under the condition of one-way ranging links,the accuracies of orbits and clocks obtained by the above two modes are still significantly better than those obtained by using the data from the monitoring stations alone. | Rengui Ruan Xiaolin Jia Laiping Feng Jun Zhu Zongbo Huyan Jie Li Ziqing Wei | 2020 | Satellite Navigation2020，1，1： | 5 |
| 2 | Accuracy analysis of gradient reconstruction on isotropic unstructured meshes and its effects on inviscid flow simulation显示文摘The accuracy of gradient reconstruction methods on unstructured meshes is analyzed both mathematically and numerically.Mathematical derivations reveal that,for gradient reconstruction based on the Green-Gauss theorem(the GG methods),if the summation of first-and-lower-order terms does not counterbalance in the discretized integral process,which rarely occurs,second-order accurate approximation of face midpoint value is necessary to produce at least first-order accurate gradient.However,gradient reconstruction based on the least-squares approach(the LSQ methods)is at least first-order on arbitrary unstructured grids.Verifications are performed on typical isotropic grid stencils by analyzing the relationship between the discretization error of gradient reconstruction and the discretization error of the face midpoint value approximation of a given analytic function.Meanwhile,the numerical accuracy of gradient reconstruction methods is examined with grid convergence study on typical isotropic grids.Results verify the phenomenon of accuracy degradation for the GG methods when the face midpoint value condition is not satisfied.The LSQ methods are proved to be at least first-order on all tested isotropic grids.To study gradient accuracy effects on inviscid flow simulation,solution errors are quantified using the Method of Manufactured Solutions(MMS)which was validated before adoption by comparing with an exact solution case,i.e.,the 2-dimensional(2D)inviscid isentropic vortex.Numerical results demonstrate that the order of accuracy(OOA)of gradient reconstruction is crucial in determining the OOA of numerical solutions.Solution accuracy deteriorates seriously if gradient reconstruction does not reach first-order. | Nianhua Wang Ming Li Rong Ma Laiping Zhang | 2019 | Advances in Aerodynamics2019，1，1： | 1 |
| 3 | Real-Time Seam Tracking Technology of Welding Robot with Visual Sensing显示文摘 | Hongyuan Shen Tao Lin Shanben Chen Laiping Li | 2010 | Journal of Intelligent & Robotic Systems (-)2010，，3： | 1 |
| 4 | The relationship between slip behavior and dislocation arrangement for large-size Mo-3Nb single crystal at room temperature显示文摘The slip behavior and mechanism of large-size Mo-3Nb single crystal have been investigated and disclosed comprehensively at room temperature by quasi-static compression with various strains.With the increase of deformation,the slip traces change from shallow non-uniform slip lines to dense and uniform slip bands.Different slip traces in the same deformation condition were observed,suggesting that the slip traces in the single crystal are controlled by different types and arrangement mechanisms of mobile dislocation.To clarify the relationship between slip behavior and dislocation arrangement,TEM and AFM analyses were performed.Significant discrepancy between the mobility of screw segments and edge segments caused by double cross-slip multiplication mechanism is the reason why different slip features were witnessed.During the whole slip deformation process,screw dislocations play a dominant role and they are inclined to form wall-substructures by interaction and entanglement.With the development of dislocation accumulation,the entangled dislocation walls evolve into dislocation cells with higher stability. | Benqi Jiao Qinyang Zhao Yongqing Zhao Laiping Li Zhongwu Hu Xuanqiao Gao Wen Zhang Jianfeng Li | 2021 | Journal of Materials Science & Technology2021，，33： | 1 |
| 5 | Flexible service selection with user-specific QoS support in serv- ice-oriented architecture 显示文摘 | ZHAO Laiping REN Yizhi LI Mingchu | 2012 | Journal of Network Computer Applications2012，35，3： | 1 |
| 6 | Real- Time Seam Tracking Technology of Welding Robot with Visual Sensing显示文摘 | Hongyuan Shen Tao Lin Shanben Chen Laiping Li | 2010 | Journal of Intelligent and Robotic Systems2010，59，34： | 1 |
| 7 | Multi-functional stainless steel composite frames stabilize the sodium metal battery显示文摘The sodium(Na)metal battery has the prospect of promising high energy density and sustainable tech-nology for low-cost energy storage.However,the soft texture and high reactivity of Na cause it easy to structure collapse and produce side reactions with organic electrolytes.Inspired by ancient Chinese ar-chitecture,a structural engineering strategy is introduced to conquer the above issues.PVDF film-covered stainless steel mesh(SMPF)embedded in the obverse of Na metal to form a“self-limiting”Na/electrolyte interface and bare stainless steel mesh(SM)with high electronic conductivity embedded in the reverse of Na metal to form a uniformly electronic distributed Na/collector interface.Based on the electric field simulation and in-situ optical tests,the well-designed structure of the SM@Na@SMPF electrode can re-strict the dendrite growth and slow down the bubbles release.The above strategies provide important technical support for the large-scale application of flexible Na metal batteries. | Laiping Li Yusheng Luo Wenlu Yuan Peizhi Mou Qi Wu Lin Zhang Yong Chen Jie Shu Liyuan Zhang | 2023 | Journal of Materials Science & Technology2023，，18： | 0 |
| 8 | An Implicit Algorithm for High-Order DG/FV Schemes for Compressible Flows on 2D Arbitrary Grids显示文摘A Newton/LU-SGS(lower-upper symmetric Gauss-Seidel)iteration implicit method was developed to solve two-dimensional Euler and Navier-Stokes equations by the DG/FV hybrid schemes on arbitrary grids.The Newton iteration was employed to solve the nonlinear system,while the linear system was solved with LU-SGS iteration.The effect of several parameters in the implicit scheme,such as the CFL number,the Newton sub-iteration steps,and the update frequency of Jacobian matrix,was investigated to evaluate the performance of convergence history.Several typical test cases were simulated,and compared with the traditional explicit Runge-Kutta(RK)scheme.Firstly the Couette flow was tested to validate the order of accuracy of the present DG/FV hybrid schemes.Then a subsonic inviscid flow over a bump in a channel was simulated and the effect of parameters was investigated also.Finally,the implicit algorithm was applied to simulate a subsonic inviscid flow over a circular cylinder and the viscous flow in a square cavity.The numerical results demonstrated that the present implicit scheme can accelerate the convergence history efficiently.Choosing proper parameters would improve the efficiency of the implicit scheme.Moreover,in the same framework,the DG/FV hybrid schemes are more efficient than the same order DG schemes. | Laiping Zhang Ming Li Wei Liu Xin He | 2015 | Communications in Computational Physics2015，17，1： | 0 |
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