Method for determining the normal heights from satellite data, taking into account the deviations of the plumb lines

2018 ◽  
Vol 937 (7) ◽  
pp. 2-10 ◽  
Author(s):  
M.G. Mustafin ◽  
Thanh Son Tran
Keyword(s):  
Satellite Data ◽  
Plumb Line ◽  
High Mountains ◽  
Labor Costs ◽  
Normal Height ◽  
Engineering Geodesy ◽  
Normal Heights ◽  
Specific Object ◽  
Difficult Terrain ◽  
Geodetic Coordinate System

Currently, using in Vietnam for constructing is normal height and method of leveling geometry. During the construction, it is necessary to transfer height through difficult terrain, such as large rivers or high mountains. In such situations, the transfer of altitude with the help of GNSS will allow to reduce labor costs in comparison with the transfer of altitude using the geometric method. However, the key issue is interpret the altitude defined by the GNSS to a normal height with an accuracy that meets the requirements for leveling grids in engineering geodesy. In this article has been offered algorithm for determining normal altitudes from satellite data and taking into account the deviations of the plumb line. Using GNSS technology are determined coordinates in the geodetic coordinate system or in the spatial one corresponding to the ellipsoid WGS-84. The technique for determining the normal heights from the data of satellite determinations is considered. A computational algorithm is proposed that includes taking into account the deviations of the plumb line and their determination by rotation of the ellipsoid, and also assuming the presence of geometric leveling data. An example of the implementation of an algorithm on a specific object is shown.

On the advantage of normal heights

2018 ◽  
Vol 939 (9) ◽  
pp. 2-9
Author(s):  
V.V. Popadyev
Keyword(s):  
Gravitational Field ◽  
Tide Gauge ◽  
General Term ◽  
Reference Ellipsoid ◽  
Height Anomaly ◽  
Normal Height ◽  
Anomalous Field ◽  
Normal Heights ◽  
Basic Concepts ◽  
Orthometric Heights

The author analyzes the arguments in the report by Robert Kingdon, Petr Vanicek and Marcelo Santos “The shape of the quasigeoid” (IX Hotin-Marussi Symposium on Theoretical Geodesy, Italy, Rome, June 18 June 22, 2018), which presents the criticisms for the basic concepts of Molodensky’s theory, the normal height and height anomaly of the point on the earth’s surface, plotted on the reference ellipsoid surface and forming the surface of a quasigeoid. The main advantages of the system of normal heights, closely related to the theory of determining the external gravitational field and the Earth’s surface, are presented. Despite the fact that the main advantage of Molodensky’s theory is the rigorous determining the anomalous potential on the Earth’s surface, the use of the system of normal heights can be shown and proved separately. To do this, a simple example is given, where the change of marks along the floor of a strictly horizontal tunnel in the mountain massif is a criterion for the convenience of the system. In this example, the orthometric heights show a change of 3 cm per 1.5 km, which will require corrections to the measured elevations due the transition to a system of orthometric heights. The knowledge of the inner structure of the rock mass is also necessary. It should be noted that the normal heights are constant along the tunnel and behave as dynamic ones and there is no need to introduce corrections. Neither the ellipsoid nor the quasi-geoid is a reference for normal heights, because so far the heights are referenced to initial tide gauge. The points of the earth’s surface are assigned a height value; this is similar to the ideas of prof. L. V. Ogorodova about the excessive emphasis on the concept of quasigeoid. A more general term is the height anomaly that exists both for points on the Earth’s surface and at a distance from it and decreases together with an attenuation of the anomalous field.

scholarly journals Strategy for Connecting to the IHRF: Case Study for the Tide Gauge of Cananeia-SP

2021 ◽  
Vol 44 ◽  
Author(s):  
Fabio Luiz Albarici ◽  
Gabriel Do Nascimento Guimarães ◽  
Marcelo Carvalho Santos ◽  
Jorge Luiz Alves Trabanco
Keyword(s):  
Standard Deviation ◽  
Tide Gauge ◽  
Tide Gauges ◽  
Normal Height ◽  
Numerical Tests ◽  
Lower Accuracy ◽  
Normal Heights ◽  
Congruence Analysis ◽  
Orthometric Heights

In July 2018, IBGE launched the new heights of the Brazilian Geodetic System (BGS), the normal height, which has associated gravity. These new heights are replacing the old normal-orthometric ones, in which there was only the non-parallelism correction. The IBGE informs that the values farther from the origin, have less accuracy. This lower accuracy may interfere in the future, the connection of the local tide gauges to IHRF (International Reference Frame Height). Thus, this paper proposes the integration of the local tide gauge of Cananeia-SP to the IHRF. In order to validate the methodology, the normal, Helmert, and rigorous orthometric heights using two distinct references: the Imbituba-SC tide gauge, as the origin of the BGS and the Cananeia-SP tide gauge, as a local tide gauge to be integrated into the IHRF. Calculating the three heights through these two origins, we analyzed the discrepancies in comparison to the heights calculated by IBGE. Numerical tests indicate that there was an improvement in terms of a mean and standard deviation when using the Cananeia gauge as origin in the calculation of normal, Helmert, and rigorous heights. In the congruence analysis, the calculations indicate that the highest standard deviation is presented when using IBGE normal heights. Thus, we have a new origin that is reliable and functional, can be integrated with the IHRF, where the Helmert and rigorous orthometric heights have the best statistical results.

scholarly journals Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model

2015 ◽  
Vol 95 (4) ◽  
pp. 103-124 ◽  
Author(s):  
Oleg Odalovic ◽  
Danilo Joksimovic ◽  
Sanja Grekulovic ◽  
Miljana Todorovic-Drakul ◽  
Jovan Popovic
Keyword(s):  
Global Navigation Satellite Systems ◽  
Geopotential Model ◽  
Navigation Satellite ◽  
Normal Height ◽  
Satellite Systems ◽  
Normal Heights ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
Ellipsoid Heights

This paper presents geometrically and physically defined height systems, along with their evaluation by the means of Global Navigation Satellite Systems (GNSS) and Global Geopotential Models (GGM). The paper defines ellipsoid heights as an instance of geometrically defined heights; with physically defined heights being represented by definitions of orthometric and normal heights. Methods of normal heights calculation by the means of ellipsoid heights are presented in detail, as determined using the GNSS and height anomalies calculated from the GGM application. Apart from the above, numerical part of the paper evaluates normal height values and compares them to their conditionally accurate values at 1073 points with relatively uniform distribution over the entire territory of Serbia. Conditionally accurate values had been determined by the means of classical geodetic terrestrial methods. Under the procedure of evaluating normal height values, GGM - GGM05C was used, as created in 2016 by the Center for Space Research, University of Texas at Austin. In order to evaluate the quality of applying the model above, data on normal heights evaluation were also presented, using the GGM EGM96, created in 1996 by the National Imagery and Mapping Agency (NIMA), Goddard Space Flight Center (GSFC - NASA) and Ohio State University, presently being the most commonly used model. The comparison above indicates that application of the GGM05C model provides 50 % greater quality of normal heights evaluations against the ones obtained using the EGM96 model.

On the dynamics of physical heights and their use for the determination of accurate orthometric/normal heights

2021 ◽  
Author(s):  
Walyeldeen Godah ◽  
Malgorzata Szelachowska ◽  
Jan Krynski
Keyword(s):  
River Basin ◽  
Temporal Variations ◽  
Earth Model ◽  
Specific Reference ◽  
Normal Height ◽  
The Earth ◽  
Love Numbers ◽  
Normal Heights ◽  
Vertical Deformations

<p>Physical heights, e.g. orthometric and normal heights, are, so far, practically considered as static heights in the majority of land areas over the world. They were traditionally determined without considering the dynamic processes of the Earth induced from temporal mass variations within the Earth’s system. The Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite missions provided unique data that allow the estimation of temporal variations of geoid heights and vertical deformations of the Earth’s surface, and thereby the dynamics of physical heights. They revealed that for the large river basin of a strong hydrological signal (e.g. the Amazon river basin), peak to peak variations of orthometric/normal height changes reach 8 cm. The objective of this research is to discuss the need of considering the dynamics of physical heights for the determination of accurate orthometric/normal heights. An approach to determine the dynamics of physical heights using the release 6 (RL06) GRACE-based Global Geopotential Models (GGMs) as well as load Love numbers from the Preliminary Reference Earth Model (PREM) was proposed. Then, the dynamics of orthometric/normal heights was modelled and predicted using the seasonal decomposition (SD) method. The proposed approach was tested over the area of Poland. The main findings reveal that the dynamics of orthometric/normal heights over the area investigated reach the level of a couple of centimetres and can be modelled and predicted with a millimetre accuracy using the SD method. Accurate orthometric/normal heights can be obtained by combining modelled dynamics of orthometric/normal heights with static orthometric/normal heights referred to a specific reference epoch.</p><p><strong>Keywords:</strong> dynamics of physical heights, GRACE, accurate orthometric/normal heights, temporal variations of geoid/quasigeoid heights, vertical deformations of the Earth’s surface</p>

Merging of the Canadian Triangulation Network with the 1973 Doppler Satellite Data

1974 ◽  
Vol 28 (5) ◽  
pp. 487-495 ◽  
Author(s):  
A. E. Peterson
Keyword(s):  
Coordinate System ◽  
Satellite Data ◽  
Orthogonal System ◽  
Preliminary Results ◽  
Triangulation Network ◽  
Two Systems ◽  
Systems Transformation ◽  
Geodetic Coordinate System

Coordinate estimates resulting from an adjustment of Canadian triangulation were adjusted simultaneously with 1973 reduced Doppler satellite data to investigate differences in scale and rotation between the two systems. Transformation and adjustment involving the geodetic coordinate system and earth centered orthogonal system are discussed and preliminary results of merging the two systems are summarized.

scholarly journals On the geoid and orthometric height vs. quasigeoid and normal height

2018 ◽  
Vol 8 (1) ◽  
pp. 115-120
Author(s):  
Lars E. Sjöberg
Keyword(s):  
Density Distribution ◽  
Bouguer Anomaly ◽  
Equipotential Surface ◽  
Geoid Model ◽  
Normal Height ◽  
Numerical Resolution ◽  
Numerical Studies ◽  
Normal Heights ◽  
Orthometric Heights ◽  
The Difference

Abstract The geoid, but not the quasigeoid, is an equipotential surface in the Earth’s gravity field that can serve both as a geodetic datum and a reference surface in geophysics. It is also a natural zero-level surface, as it agrees with the undisturbed mean sea level. Orthometric heights are physical heights above the geoid,while normal heights are geometric heights (of the telluroid) above the reference ellipsoid. Normal heights and the quasigeoid can be determined without any information on the Earth’s topographic density distribution, which is not the case for orthometric heights and geoid. We show from various derivations that the difference between the geoid and the quasigeoid heights, being of the order of 5 m, can be expressed by the simple Bouguer gravity anomaly as the only term that includes the topographic density distribution. This implies that recent formulas, including the refined Bouguer anomaly and a difference between topographic gravity potentials, do not necessarily improve the result. Intuitively one may assume that the quasigeoid, closely related with the Earth’s surface, is rougher than the geoid. For numerical studies the topography is usually divided into blocks of mean elevations, excluding the problem with a non-star shaped Earth. In this case the smoothness of both types of geoid models are affected by the slope of the terrain,which shows that even at high resolutions with ultra-small blocks the geoid model is likely as rough as the quasigeoid model. In case of the real Earth there are areas where the quasigeoid, but not the geoid, is ambiguous, and this problem increases with the numerical resolution of the requested solution. These ambiguities affect also normal and orthometric heights. However, this problem can be solved by using the mean quasigeoid model defined by using average topographic heights at any requested resolution. An exact solution of the ambiguity for the normal height/quasigeoid can be provided by GNSS-levelling.

scholarly journals DEVELOPMENT OF LATVIAN NATIONAL 2ND ORDER LEVELING NETWORK

2016 ◽  
Vol 42 (4) ◽  
pp. 136-139
Author(s):  
Madara Znotina ◽  
Ivars Liepins ◽  
Ksenija Kosenko
Keyword(s):  
Geospatial Data ◽  
European Countries ◽  
Eastern European ◽  
Network Development ◽  
Normal Height ◽  
First Order ◽  
Height System ◽  
Normal Heights ◽  
Eastern European Countries ◽  
Height Data

Latvian National First Order Levelling Network consist of 15 polygons and 51 lines and was reestablished in 2011. From 1st of December of year 2014 in Latvia Republic is new Latvian normal height system at epoch 2000,5. Normal heights are widely used in origination and application of geospatial data in civil engineering and quasigeoid computation etc. The main objective of this work is to describe 2nd order leveling network development idea, purpose and process. Essential of work is option, check, used and analyze historical height data, which has all Eastern European countries, and newly measured height data.

scholarly journals Application of laser scanning for monitoring condition of buildings and structures during reconstruction

2021 ◽  
pp. 33-36
Author(s):  
Irina Rudneva
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
New Technology ◽  
Three Dimensional ◽  
Return Time ◽  
Measurement Methods ◽  
Laser Beams ◽  
Operational Control ◽  
Labor Costs ◽  
Engineering Geodesy

Ground-based laser scanning technology has been increasingly used in the last 15 years to solve problems not only in engineering geodesy, but also in the inspection of buildings and structures, in particular to identify damage and deformation during operation and reconstruction, as well as operational control of construction. and monitoring of their condition during operation, 3D-modeling of complex architectural objects. The growing popularity of laser scanning is due to a number of advantages provided by the new technology in comparison with other measurement methods. Among the advantages are the main ones: increasing the speed of work and reducing labor costs. The emergence of new more productive models of scanners, improving software capabilities allows us to hope for further expansion of the scope of ground-based laser scanning. Three-dimensional laser scanning emits millions of laser beams and, by calculating their return time, can accurately and accurately calculate their three-dimensional locations to make multiple high-speed scans combined into one system. This works by digitally recording the dimensions and spatial communication of objects by reflecting laser radiation.

Study of the process of forming a hole for a thread at manufacturing a high nut

2020 ◽  
Vol 76 (8) ◽  
pp. 841-846
Author(s):  
I. G. Shubin ◽  
A. A. Kurkin
Keyword(s):  
Metal Flow ◽  
Nonlinear Dependence ◽  
Geometrical Parameters ◽  
Relative Height ◽  
Forming Process ◽  
Normal Height ◽  
Accuracy Class ◽  
Limit Values ◽  
Program Complex ◽  
Class B

During manufacturing nuts of increased height, a problem of obtaining correct cylindrical form of the hole for thread and overall geometrical parameters arises. To solve the problem it is necessary to know regularity of the blank forming process. Results of the study of a technological process of high hexahedral nuts forming presented. The nuts were M18 of 22 mm height, M16 of 19 mm height and M12 of normal height 10 mm according to GOST 5915–70, accuracy class B, steel grade 10 according to GOST 10702–78. The volumetric stamping was accomplished at the five-position automatic presses of АА1822 type. It was determined, that unevenness of the metal flow in the process of plastic deformation of blanks of increased height nuts was caused by different stress conditions by their sections. To simulate the mode of deformation, the program complex QForm-3D was chosen. The complex ensured to forecast with necessary accuracy the metal flow in a blank, as well as to define the deformation force and arising stress in the working instrument. The simulation showed the presence of regularity between preliminary formed buffle and deviation of dimensions and form of a blank wall after its finishing piercing, which can be expressed by a nonlinear dependence. The limit values of the relative height of the buffle С/D = 0.56–0.588 defined, exceeding which will result in rejection of the finished product. Accounting the limit values of the relative height of the buffle will enable to correct a mode of technological operations and technological instruments at stamping of high hexahedral nuts.

Sign in / Sign up

Export Citation Format

Share Document