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

Measurement ◽  
2021 ◽  
pp. 108965
Author(s):  
Ahmed Abdalla ◽  
Mubarak Mustafa
Keyword(s):  
Horizontal Displacement ◽  
Control Points ◽  
Network Adjustment ◽  
Differential Positioning

scholarly journals Design and Geodetic Adjustment of Levelling Network for Establishment of Unified Control Points in Korea

2021 ◽  
pp. 29-40
Author(s):  
H.K Lee ◽  
S.H. Yun ◽  
J.H. Kwon ◽  
J.S. Lee
Keyword(s):  
Pilot Study ◽  
Vertical Component ◽  
Reference Points ◽  
Spatial Density ◽  
Control Points ◽  
Network Adjustment ◽  
Technical Challenge ◽  
Adjustment Procedure ◽  
Geodetic Control ◽  
Horizontal Network

The unified control points (UCPs), the multi-dimensional geodetic reference points installed in the low elevated area, has been established in Korea for the combination of the horizontal and the vertical geodetic control. While the 1st-phase UCPs network was completed in 2011 with a spatial density of about 10km, its densification has been underway as the 2nd-phase project. The UCPs supersedes the legacy geodetic points, such as triangulation points and benchmarks (BMs) once the 2nd-phase implementation. Although the horizontal network of the UPCs can be readily realised by GNSS technology, a technical challenge of the vertical component remains to be settled due to characteristics of the geodetic levelling technique. To this end, a pilot study was conducted to design a new version of the UCPs-based levelling network and to demonstrate its effectiveness with a comparison of the legacy. In this paper, a concept of the UCPs-based levelling network is briefly addressed with some prominent examples, and details of a pilot network and its measurements is given with the network adjustment procedure. Finally, results of the adjustments are provided with an emphasis on the influence of the newly designed network in terms of accuracy, reliability and estimated heights.

scholarly journals Investigation of the Precision in Geodetic Reference-Point Positioning Because of Temperature-Induced Pillar Deflections

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3489 ◽  
Author(s):  
Robert Močnik ◽  
Božo Koler ◽  
Dejan Zupan ◽  
Tomaž Ambrožič
Keyword(s):  
Reinforced Concrete ◽  
Temperature Variation ◽  
Temperature Difference ◽  
Reference Point ◽  
Horizontal Displacement ◽  
Research Paper ◽  
Reference Points ◽  
Control Points ◽  
Temperature Changes ◽  
Influence Of Temperature

To perform geodetic measurements of displacements of the ground and manmade constructions, stabilised reference points are needed from which control points on the object or its surroundings could be measured. Reference points are most commonly stabilised with reinforced concrete pillars; however, they are not always constructed in an appropriate manner. The influence of temperature variation within a pillar on the position of the fixed screw for forced centring is not negligible and should be considered when performing precise measurements. In this research paper, the displacement of a pillar was calculated as a result of the temperature changes in the pillar, and then an experiment was performed in which the pillar was heated from one side, and the horizontal displacement of the fixed screw for forced centring was measured. Both, calculations and measurements, show that at a temperature difference of 16.2 °C, the fixed screw on a 1.5 m high pillar moves by approximately 1 mm, which is a displacement that should be taken into account in precise measurements.

scholarly journals Densification of (GNSS) Control Points for Cadastral and Mapping Purposes

2017 ◽  
Vol 1 (2) ◽  
pp. 287-298 ◽  
Author(s):  
M. O. Ehigiator ◽  
S. O. Oladosu ◽  
R. Ehigiator-Irughe
Keyword(s):  
Data Analysis ◽  
Real Time ◽  
Control Points ◽  
Network Adjustment ◽  
Static Mode ◽  
Continuous Exercise ◽  
Master Station

GNSS control densification is a continuous exercise in the field of Geomatics. This form the basis upon which other Geomatics and Engineering activities geared toward development are referenced. This paper employed the use of Hi-Target GPS to extend and establish controls at the confines of the study area in static mode while topographical survey was carried out using real-time kinematics method. Network adjustment, for the newly established control stations were carried out while the master station was held fixed. Data analysis and production of plans were done using softwares like Hi-Target V30, Carlson Civil Suite 2017 etc. The result of perimeter computation for the study area gave a total of 93.614 hectare

scholarly journals DIRECTIONS OF LINE CONSTRAINTS DILEMMA IN PARAMETRIC LINEAR REGRESSION

2021 ◽  
Vol 56 (5) ◽  
pp. 552-562
Author(s):  
Mohd Azwan Abbas ◽  
Norshahrizan Mohd Hashim ◽  
Mohamad Faiz Mohd Zaim ◽  
Muhammad Husaini Ya’cob ◽  
Ahmad Azmi Hashim ◽  
...  
Keyword(s):  
Linear Regression ◽  
Satellite System ◽  
Control Points ◽  
Process Data ◽  
Network Adjustment ◽  
Positional Accuracy ◽  
Rigorous Approach ◽  
Adjustment Procedure ◽  
Global Navigation Satellite

The demand for positional accuracy and multi-dimensional data have demonstrated drastic changes in the geomatics data adjustment approach. Furthermore, the capability of modern sensors to provide high accuracy data (i.e., global navigation satellite system) has caused the crucial requirement for a rigorous adjustment that can process data from multi-sensors. Geomatics practitioners have gradually transformed the adjustment procedure to the most rigorous approach (i.e., parametric linear regression) to adapt to current demand. However, legacy datasets that utilize independent line constraint in the traditional adjustment approach have caused significant uncertainties in parametric linear regression (LR) adjustment. To resolve this dilemma, this research has designed robust experiments using closed traverse types: single-line constraint, multi-line constraints, and sub-network line constraint. Through errors trend and network form deterioration analyses, the outcomes have visually and numerically verified the insignificant of independent line constraints in parametric LR. However, the establishment of control points at the beginning or end of lines could solve the limitation of the abovementioned issue. In both analyses, control points at initial lines have demonstrated the best solution for constrained adjustment. The obtained results have exemplified the appropriate implementation of network adjustment in the presence of line constraints. As positional accuracy becomes the main priority, it can be concluded that points-based constraints are more advisable in preserving the quality of cadastral network adjustment.

scholarly journals STUDY OF LARGE-SCALE BLOCK ADJUSTMENT WITH LASER ALTIMETRY DATA GLAS OF ZY3 IMAGES OVER SHANDONG

2020 ◽  
Vol V-2-2020 ◽  
pp. 87-94
Author(s):  
T. Wang ◽  
X. Li
Keyword(s):  
Large Scale ◽  
High Reliability ◽  
Stereo Image ◽  
Waveform Analysis ◽  
Control Points ◽  
Image Correction ◽  
Network Adjustment ◽  
Global Mapping ◽  
The Mean ◽  
Surveying And Mapping

Abstract. In the global mapping work, there will be no control points or uneven distribution of control points. The traditional method of single scene image correction based on ground control points is not suitable for modern surveying and mapping, which has no available control points in a large range. New control data is urgently needed to make up for the influence of traditional control points on surveying and mapping. In this paper, aiming at improving the elevation accuracy of ZY-3 uncontrolled point surveying, a filtering principle based on the analysis based on waveform analysis and the stereo image pair based on tie points is proposed for the screening of GLAS laser elevation points. A new method using high-reliability laser elevation control points as the height constraint and the regional network adjustment of ZY-3 images without control points is studied. Through the experiment in Shandong Province, it is proved that the elevation accuracy of the adjustment can be improved obviously by introducing the selected laser points. The mean error of adjustment elevation is increased from −2.297 to 0.216m and the mean square error of elevation is increased from 3.193m to 2.007m, significantly improving the elevation positioning accuracy of adjustment.

scholarly journals Application of statistical test on determining the unstable points in the basic network of horizontal displacement monitoring

2021 ◽  
Vol 62 (1) ◽  
pp. 35-41
Author(s):  
Khanh Quoc Pham ◽  
Keyword(s):  
Hydroelectric Plant ◽  
Hypothesis Test ◽  
Control Point ◽  
Horizontal Displacement ◽  
Test Method ◽  
Reference Network ◽  
Control Points ◽  
Displacement Monitoring ◽  
Local Statistics ◽  
Global Statistics

The paper represents the hypothesis test method that can determine the instability control points of the reference network in the displacement of construction. Regarding data processing in displacement monitoring, the detection and modification for instability points is an important task because this affects the computation of the displacement of monitoring points. This method has been applied in many countries over the world but not in Vietnam, and it is processed through two steps including the global statistics test and local statistics test. The global statistics test is to identify whether a control point is stable or not. The local statistics test based on the division of groups is to find the unstable control points exactly. Experimental computation is carried out in two monitoring cycles at Hoa Binh hydroelectric plant. In this experiment, this algorithm detected two unstable points among six control points. This result is in agreement with the result that is solved by Vietnam’s construction standard of TCVN 9399:2012. In conclusion, the hypothesis test method completely can apply in real geodetic production in Vietnam.

Practical Realization of a Reference System for Earth Dynamics by Satellite Methods

1975 ◽  
Vol 26 ◽  
pp. 341-380 ◽  
Author(s):  
R. J. Anderle ◽  
M. C. Tanenbaum
Keyword(s):  
Reference Frame ◽  
Polar Motion ◽  
Pole Position ◽  
Control Points ◽  
Significant Information ◽  
Crustal Motion ◽  
Average Reference ◽  
Future Data ◽  
Existing Data

AbstractObservations of artificial earth satellites provide a means of establishing an.origin, orientation, scale and control points for a coordinate system. Neither existing data nor future data are likely to provide significant information on the .001 angle between the axis of angular momentum and axis of rotation. Existing data have provided data to about .01 accuracy on the pole position and to possibly a meter on the origin of the system and for control points. The longitude origin is essentially arbitrary. While these accuracies permit acquisition of useful data on tides and polar motion through dynamio analyses, they are inadequate for determination of crustal motion or significant improvement in polar motion. The limitations arise from gravity, drag and radiation forces on the satellites as well as from instrument errors. Improvements in laser equipment and the launch of the dense LAGEOS satellite in an orbit high enough to suppress significant gravity and drag errors will permit determination of crustal motion and more accurate, higher frequency, polar motion. However, the reference frame for the results is likely to be an average reference frame defined by the observing stations, resulting in significant corrections to be determined for effects of changes in station configuration and data losses.

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1314-1315
Author(s):  
William P. Wergin ◽  
Eric F. Erbe
Keyword(s):  
Fold Increase ◽  
Horizontal Displacement ◽  
Three Dimensions ◽  
Stereo Image ◽  
Stereo Pair ◽  
Sem Micrograph ◽  
Left And Right ◽  
The Common ◽  
The Brain ◽  
Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

On-farm udder health monitoring

2011 ◽  
Vol 39 (02) ◽  
pp. 95-100
Author(s):  
J. C. van Veersen ◽  
O. Sampimon ◽  
R. G. Olde Riekerink ◽  
T. J. G. Lam
Keyword(s):  
Management Practices ◽  
Health Management ◽  
Action Plan ◽  
Real Life ◽  
Health Data ◽  
Control Points ◽  
Udder Health ◽  
Critical Control Points ◽  
On Farm ◽  
Clinical Problems

SummaryIn this article an on-farm monitoring approach on udder health is presented. Monitoring of udder health consists of regular collection and analysis of data and of the regular evaluation of management practices. The ultimate goal is to manage critical control points in udder health management, such as hygiene, body condition, teat ends and treatments, in such a way that results (udder health parameters) are always optimal. Mastitis, however, is a multifactorial disease, and in real life it is not possible to fully prevent all mastitis problems. Therefore udder health data are also monitored with the goal to pick up deviations before they lead to (clinical) problems. By quantifying udder health data and management, a farm is approached as a business, with much attention for efficiency, thought over processes, clear agreements and goals, and including evaluation of processes and results. The whole approach starts with setting SMART (Specific, Measurable, Acceptable, Realistic, Time-bound) goals, followed by an action plan to realize these goals.

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