scholarly journals Numerical and Experimental Evaluation of Error Estimation for Two-Way Ranging Methods

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 616 ◽  
Author(s):  
Cung Lian Sang ◽  
Michael Adams ◽  
Timm Hörmann ◽  
Marc Hesse ◽  
Mario Porrmann ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Error Estimation ◽  
Experimental Evaluation ◽  
Ieee 802.15.4 ◽  
Clock Synchronization ◽  
Estimation Model ◽  
Clock Drift ◽  
Wireless Transceiver ◽  
Accurate Performance

The Two-Way Ranging (TWR) method is commonly used for measuring the distance between two wireless transceiver nodes, especially when clock synchronization between the two nodes is not available. For modeling the time-of-flight (TOF) error between two wireless transceiver nodes in TWR, the existing error model, described in the IEEE 802.15.4-2011 standard, is solely based on clock drift. However, it is inadequate for in-depth comparative analysis between different TWR methods. In this paper, we propose a novel TOF Error Estimation Model (TEEM) for TWR methods. Using the proposed model, we evaluate the comparative analysis between different TWR methods. The analytical results were validated with both numerical simulation and experimental results. Moreover, we demonstrate the pitfalls of the symmetric double-sided TWR (SDS-TWR) method, which is the most highlighted TWR method in the literature because of its highly accurate performance on clock-drift error reduction when reply times are symmetric. We argue that alternative double-sided TWR (AltDS-TWR) outperforms SDS-TWR. The argument was verified with both numerical simulation and experimental evaluation results.

Numerical Simulation of Shock Wave in Air Based on FCT Method

2013 ◽  
Vol 397-400 ◽  
pp. 270-273
Author(s):  
Ying Li ◽  
Xiao Bin Li ◽  
Yu Wang ◽  
Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Comparative Analysis ◽  
Numerical Method ◽  
Blast Wave ◽  
Empirical Formula ◽  
Godunov Method ◽  
Numerical Accuracy

Blast wave is numerical simulated based on FCT method. According to the comparative analysis, taking Henrych empirical formula as a standard, FCT method is more accuracy than Godunov method. Moreover, it has been found that the numerical accuracy is insufficient when the distance is small, it is necessary to develop and modify the numerical method continuously.

Numerical Simulation on Deformation Features and Filling Efficiency of Channel Goaf Foundation

2013 ◽  
Vol 353-356 ◽  
pp. 3707-3712
Author(s):  
Zhi Dong Zhou ◽  
Hong Bo Zhang ◽  
Xiu Guang Song ◽  
Hong Ya Yue
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Comprehensive Analysis ◽  
Obvious Effect ◽  
Before And After ◽  
Check Gate ◽  
Deformation Features ◽  
Natural Foundation ◽  
The Stability

For analyzing and evaluating the deformation features of channel goaf foundation and its effect on superstructure, according to the foundation reinforcement engineering of Ji-Liang Channel Check Gate, the comparative analysis on the differential settlement between the unfavorable foundation and natural foundation was performed by numerical simulation with FLAC3D. The computer results showed that the present foundation had obvious effect on the stability and security of the superstructure, so the engineering treatment are needed. Based on technical-economic comprehensive analysis among three treatment methods for strengthening the channel golf foundation with different kinds of filling, the reasonable method is put forward in this paper. By comparing mechanical characteristic of flashboard in channel goaf before and after strengthening, we confirmed the foundation stability of channel goaf and the security of the ground building which can satisfy the long term usage requirements.

scholarly journals SAR Observation Error Estimation Based on Maximum Relative Projection Matching

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Y. Zhang ◽  
B. P. Wang ◽  
Y. Fang ◽  
Z. X. Song
Keyword(s):  
Error Estimation ◽  
Estimation Method ◽  
Estimation Methods ◽  
Estimation Accuracy ◽  
Reconstruction Method ◽  
Observation Error ◽  
Estimation Model ◽  
Reconstruction Process ◽  
Single Observation ◽  
Imaging Results

The existing sparse imaging observation error estimation methods are to usually estimate the error of each observation position by substituting the error parameters into the iterative reconstruction process, which has a huge calculation cost. In this paper, by analysing the relationship between imaging results of single-observation sampling data and error parameters, a SAR observation error estimation method based on maximum relative projection matching is proposed. First, the method estimates the precise position parameters of the reference position by the sparse reconstruction method of joint error parameters. Second, a relative error estimation model is constructed based on the maximum correlation of base-space projection. Finally, the accurate error parameters are estimated by the Broyden–Fletcher–Goldfarb–Shanno method. Simulation and measured data of microwave anechoic chambers show that, compared to the existing methods, the proposed method has higher estimation accuracy, lower noise sensitivity, and higher computational efficiency.

Study on the Capacity Increasing and Dam Heighten of Plain Reservoirs

2013 ◽  
Vol 353-356 ◽  
pp. 2531-2536
Author(s):  
Xiu Guang Song ◽  
Zhi Dong Zhou ◽  
Hong Bo Zhang ◽  
Hong Ya Yue
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Site Investigation ◽  
Seepage Flow ◽  
Differential Settlement ◽  
Construction Technology ◽  
Dam Stability ◽  
The Stability ◽  
Design Construction

In order to solve the problem of differential settlement, seepage flow and stability between the new and old dam boundary in capacity increasing of the plain reservoirs, the comparative analysis on the stability of the dam slope with different methods on dealing with the new and old dam boundary was performed by numerical simulation with FLAC3D. The result shows that combining the new and old dam by using geogrid indicates superiority for reducing differential settlement, improving the dam stability and safety, etc. In the meantime, on the basis of actual site investigation and theoretical analysis, combined with the requirements of design, construction and management in capacity increasing of the plain reservoirs, the key construction technology was put forward and widely applied foreground, which can improve the quality of the construction, reduce engineering disease and provide references for capacity increasing engineering of in plain reservoirs.

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