Horizontal displacement of control points using GNSS differential positioning and network adjustment

We compute the horizontal displacement in the first/second-order and Merowe Dam control points in a subset of a hybrid triangulation network in northern Sudan. The Global Navigation Satellite Systems (GNSS) and least-squares network adjustment are jointly used to determine the horizontal displacemen...

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Bibliographic Details
Published in:Measurement : journal of the International Measurement Confederation 2021-04, Vol.174, p.108965, Article 108965
Main Authors: Abdalla, Ahmed, Mustafa, Mubarak
Format: Article
Language:English
Subjects:
GNSS
Horizontal displacement
MCA
Merowe Dam
Relative positioning
Statistical indicators
Triangulation network
ZCA
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Summary:We compute the horizontal displacement in the first/second-order and Merowe Dam control points in a subset of a hybrid triangulation network in northern Sudan. The Global Navigation Satellite Systems (GNSS) and least-squares network adjustment are jointly used to determine the horizontal displacement in the control points. The GNSS observations collected by relative positioning are validated over the control points to create a corresponding subnetwork adjusted by the least-squares. The baselines and network loops show good quality through the statistical indicators that measure the ratio, root mean square (RMS), and reference variance. We apply minimum-constrained adjustment (MCA) and zero-constrained adjustment (ZCA) methods on the subnet. After adjustment. The horizontal displacement is determined as the Euclidean norm of the difference between the Easting/Northing components. The comparison shows large displacements in the first-order (0.6 m), second-order (2 m) points and small displacements (15 cm) in Merowe control points. •A subnetwork of first and second-order control points is selected for testing displacement.•The selected control points are reinforced by new control points established for the Merowe Dam project.•GNSS relative positioning and network adjustment are conducted over the selected control points to compute baselines and loop closures.•Statistical indicators are applied to validate the baseline solutions, and minimum and zero constrained adjustments are applied over the network.•Horizontal displacement is calculated as a euclidean distance between the adjusted coordinates’ locations and the original ones.
ISSN:0263-2241
1873-412X
DOI:10.1016/j.measurement.2021.108965