A Multi-Antenna GNSS-Over-Fiber System for High Accuracy Three-Dimensional Baseline Measurement

AbstractIn this paper, we introduce the multi-variate spectral quasi-linearization method which is an extension of the previously reported bivariate spectral quasi-linearization method. The method is a combination of quasi-linearization techniques and the spectral collocation method to solve three-dimensional partial differential equations. We test its applicability on the (2 + 1) dimensional Burgers’ equations. We apply the spectral collocation method to discretize both space variables as well as the time variable. This results in high accuracy in both space and time. Numerical results are compared with known exact solutions as well as results from other papers to confirm the accuracy and efficiency of the method. The results show that the method produces highly accurate solutions and is very efficient for (2 + 1) dimensional PDEs. The efficiency is due to the fact that only few grid points are required to archive high accuracy. The results are portrayed in tables and graphs.

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An Acoustic System for Pipeline Profile Measurement

Journal of Energy Resources Technology ◽

10.1115/1.3230956 ◽

1983 ◽

Vol 105 (4) ◽

pp. 475-479

Author(s):

H. Van Calcar

Keyword(s):

Measurement Technique ◽

Measurement System ◽

Performance Enhancement ◽

Three Dimensional ◽

Profile Measurement ◽

Baseline Measurement ◽

Acoustic System ◽

Position Measurement ◽

Long Baseline ◽

Hardware Configuration

This paper presents an acoustic position measurement system used for precise three-dimensional flowline profile measurement. The system measures several points along the flowline using the long-baseline measurement technique and augments this measurement with depth telemetry repeaters to maintain elevation accuracy throughout the changing installation geometry. The paper discusses both the measurement system and the performance enhancement features. The paper concludes with a discussion of the hardware configuration and the accuracy that can be expected when the technique is extended into deeper operating areas.

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A High-Accuracy Mechanical Quadrature Method for Solving the Axisymmetric Poisson's Equation

Advances in Applied Mathematics and Mechanics ◽

10.4208/aamm.2015.m1287 ◽

2017 ◽

Vol 9 (2) ◽

pp. 393-406 ◽

Cited By ~ 4

Author(s):

Hu Li ◽

Jin Huang

Keyword(s):

Three Dimensional ◽

High Accuracy ◽

Poisson’S Equation ◽

Two Dimensional ◽

Quadrature Method ◽

Poisson's Equation ◽

Mechanical Quadrature ◽

Asymptotic Error ◽

Accuracy Order ◽

Mechanical Quadrature Method

AbstractIn this article, we consider the numerical solution for Poisson's equation in axisymmetric geometry. When the boundary condition and source term are axisymmetric, the problem reduces to solving Poisson's equation in cylindrical coordinates in the two-dimensional (r,z) region of the original three-dimensional domain S. Hence, the original boundary value problem is reduced to a two-dimensional one. To make use of the Mechanical quadrature method (MQM), it is necessary to calculate a particular solution, which can be subtracted off, so that MQM can be used to solve the resulting Laplace problem, which possesses high accuracy order and low computing complexities. Moreover, the multivariate asymptotic error expansion of MQM accompanied with for all mesh widths hi is got. Hence, once discrete equations with coarse meshes are solved in parallel, the higher accuracy order of numerical approximations can be at least by the splitting extrapolation algorithm (SEA). Meanwhile, a posteriori asymptotic error estimate is derived, which can be used to construct self-adaptive algorithms. The numerical examples support our theoretical analysis.

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USING MOBILE LASER SCANNING DATA FOR FEATURES EXTRACTION OF HIGH ACCURACY DRIVING MAPS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b3-433-2016 ◽

2016 ◽

Vol XLI-B3 ◽

pp. 433-439 ◽

Cited By ~ 4

Author(s):

Bisheng Yang ◽

Yuan Liu ◽

Fuxun Liang ◽

Zhen Dong

Keyword(s):

Laser Scanning ◽

Human Error ◽

Traffic Accidents ◽

Three Dimensional ◽

Point Clouds ◽

High Accuracy ◽

3D Point Clouds ◽

Assistant Systems ◽

Novel Method ◽

High Flexibility

High Accuracy Driving Maps (HADMs) are the core component of Intelligent Drive Assistant Systems (IDAS), which can effectively reduce the traffic accidents due to human error and provide more comfortable driving experiences. Vehicle-based mobile laser scanning (MLS) systems provide an efficient solution to rapidly capture three-dimensional (3D) point clouds of road environments with high flexibility and precision. This paper proposes a novel method to extract road features (e.g., road surfaces, road boundaries, road markings, buildings, guardrails, street lamps, traffic signs, roadside-trees, power lines, vehicles and so on) for HADMs in highway environment. Quantitative evaluations show that the proposed algorithm attains an average precision and recall in terms of 90.6% and 91.2% in extracting road features. Results demonstrate the efficiencies and feasibilities of the proposed method for extraction of road features for HADMs.

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