Positioning of Horizontal Geodetic Datums

1974 ◽  
Vol 28 (5) ◽  
pp. 531-538 ◽  
Author(s):  
P. Vanicek ◽  
D. E. Wells
Keyword(s):  
Coordinate System ◽  
Basic Assumption ◽  
Classical Problem ◽  
Network Adjustment ◽  
Control Networks ◽  
Geodetic Networks ◽  
Geocentric Coordinates ◽  
Horizontal Control

This paper treats the classical problem of positioning horizontal geodetic datums. By ‘classical problem’ we mean the problem we face when dealing with the usual horizontal control networks, as opposed to some of the more modern ideas, such as the use of geocentric coordinates, or the ideas of Hotine [1959, 1969]. Our basic assumption is that a coordinate system is a fixed framework (i.e., invariant with respect to network adjustment, readjustment, or expansion) for describing geodetic networks. Our view is that a coordinate system and the network it describes are two different things (this view is not universally accepted within the geodetic community).

Geodetic Networks in Canada

1974 ◽  
Vol 28 (5) ◽  
pp. 457-461 ◽  
Author(s):  
C. D. McLellan
Keyword(s):  
Long Range ◽  
North American ◽  
Control Networks ◽  
Geodetic Networks ◽  
Vertical Control ◽  
Satellite Positioning ◽  
Horizontal Control

Geodetic networks in Canada are concentrated in the southern populated regions and tend to reflect immediate demands. A long-range plan has now been undertaken to establish and maintain horizontal and vertical control frameworks that can adequately meet needs in any part of the country. A shorter term phase of this plan is the new North American Datum and adjustment, and this is the current priority. Doppler satellite positioning will play an important role in Canadian horizontal control networks.

Readjustment of Canadian Secondary Horizontal Control Networks

1978 ◽  
Vol 32 (4) ◽  
pp. 433-442
Author(s):  
C.D. McLellan ◽  
J.P. Henderson ◽  
J.D. Boal
Keyword(s):  
Least Squares ◽  
Approximate Method ◽  
Lower Order ◽  
Early Stage ◽  
Geodetic Survey ◽  
Secondary Control ◽  
Control Networks ◽  
Least Squares Adjustment ◽  
Secondary Networks ◽  
Horizontal Control

The readjustment of the Canadian secondary and lower order control networks is scheduled to take place in 1983 following the adoption of new primary framework values. Some 200 000 points are involved. 75 000 of which are the responsibility of the Geodetic Survey. These networks are to be evaluated, strengthened, densified and extended as necessary, prior to integration. The project will be done by regions defined, for the most part, by arcs of framework control. Secondary networks will be integrated with the framework by least squares adjustment; some lower order control may be recomputed by an approximate method. Considering the amount of secondary control to be readjusted, it is essential that agreement on the sharing of responsibilities between the federal and provincial agencies involved be reached at an early stage.

An evaluation of horizontal control networks in Canada

1974 ◽  
Vol 114 (1) ◽  
pp. 335-347
Author(s):  
C. David McLellan
Keyword(s):  
Control Networks ◽  
Horizontal Control

scholarly journals CRITERION FOR COMPARING THE VARIANCE COMPONENT ESTIMATION METHODS USED FOR ADJUSTING HORIZONTAL CONTROL NETWORKS

2012 ◽  
Vol 32 (1) ◽  
pp. 6-13
Author(s):  
Erol Yavuz ◽  
Orhan Baykal
Keyword(s):  
Stochastic Model ◽  
Variance Component ◽  
Statistical Tests ◽  
Estimation Methods ◽  
Variance Component Estimation ◽  
Control Networks ◽  
Component Estimation ◽  
Using Data ◽  
Horizontal Control

Determination of which stochastic model taken in hand for this study is suitable under conditions, when comparing stochastic models, used for adjusting horizontal control networks, is the aim of this study. Some well-known variance component estimation methods like Conventional, Helmert, MTNQUE, AUE, and Förstner, which have been developed to determine the stochastic model, necessary to be formed in a real way for adjusting geodetic nets, have been compared. For comparing the models mentioned above, concrete deciding criteria, using statistical tests, have been defined and the determination of which model is superior has been studied. For comparison of the models, numerical experiment using data, which belong to the part of Istanbul Metropolitan Triangulation Network (Asiatic side of Istanbul), has been performed.

scholarly journals Statistical significance of displacements in heterogeneous control networks

2013 ◽  
Vol 62 (2) ◽  
pp. 139-156 ◽  
Author(s):  
Krzysztof Nowel ◽  
Waldemar Kamiński
Keyword(s):  
Statistical Significance ◽  
Control Network ◽  
Theoretical Discussion ◽  
Control Networks ◽  
Local Variance ◽  
Deformation Measurements ◽  
Horizontal Control

Abstract This paper proposes a modification of the classical process for evaluating the statistical significance of displacements in the case of heterogeneous (e.g. linear-angular) control networks established to deformation measurements and analysis. The basis for the proposed solution is the idea of local variance factors. The theoretical discussion was complemented with an example of its application on a simulated horizontal control network. The obtained results showed that the evaluation of the statistical significance of displacements in the case of heterogeneous control networks should be carried out using estimators of local variance factors.

scholarly journals THE ISSUE OF LS-OPTIMIZATION SATELLITE GEODETIC NETWORKS IN THE TERRESTRIAL COORDINATE SYSTEM

2020 ◽  
Vol 1 (1) ◽  
pp. 120-128
Author(s):  
Vladimir A. Padve ◽  
Nikolay S. Kosarev
Keyword(s):  
Coordinate System ◽  
Spatial Data ◽  
Computational Experiment ◽  
Satellite Network ◽  
Geodetic Networks ◽  
Measurement Results ◽  
Gnss Measurements ◽  
Parametric Version ◽  
New Item

The issue of processing GNSS measurements performed to add a new item into a "hard" network is discussed. Two variants of this add: «beam» and «network» are compared. A fragment of the satellite network, which includes five "hard" points of the main network and one defined, acted as the object on which the computational experiment was carried out, testing the theory of this question. The processing of observational materials is implemented in to Excel electronic computational table using an algorithm synthesized version of the parametric version of LS-optimization of spatial data. The «insert» coordinates obtained as a result of this processing and their average square errors were identical for both variants, which is what follows from the theory of LS-optimization of measurement results taking into account of the errors of the coordinates of «hard» points.

scholarly journals Determination Of Horizontal Geodetic Control Networks For Engineering Objects Using Optoelectronic Techniques

2015 ◽  
Vol 98 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Kazimierz Ćmielewski ◽  
Janusz Kuchmister ◽  
Piotr Gołuch ◽  
Izabela Wilczyńska ◽  
Krzysztof Kowalski
Keyword(s):  
Measurement Accuracy ◽  
Control Points ◽  
Control Networks ◽  
Laboratory Conditions ◽  
Optoelectronic Method ◽  
Geodetic Control ◽  
And Control ◽  
Horizontal Control

AbstractThe correctness of the geodetic service of an engineering object not seldom requires designing, alignment or renewing of geodetic situational control points. Building robots often cause that fixed situational control points are partly or completely inaccessible. For setting the position of these control points, there is worked out the methodology using the optoelectronic method. The prepared set of tools realizes the method’s assumptions and enables to determine the sides and control points based on the set of laser planes. In this article there is presented the innovative set of geodetic equipment for fixing horizontal control points. The presented set has been experimentally tested under laboratory conditions taking its functionality, operation range and applied accuracy into account. The measurement accuracy of the set of tools, resulting from identification of the energetic centres of laser planes’ edges, visualizing the sides of geodetic control networks, is within the range of ±0.02mm - ±0.05mm. There were also discussed exemplary versions of shapes and structures of horizontal geodetic control networks (regular and irregular), which are possible to be fixed with the use of the constructed set of tools.

scholarly journals On the Helmert-blocking technique: its acceleration by block Choleski decomposition and formulae to insert observations into an adjusted network

2015 ◽  
Vol 2 (4) ◽  
pp. 140417
Author(s):  
Eduardo Del Rio ◽  
Leonardo Oliveira
Keyword(s):  
Processing Time ◽  
Global Network ◽  
Network Adjustment ◽  
Geodetic Networks ◽  
Block System

The Helmert-blocking technique is a common approach to adjust large geodetic networks like Europeans and Brazilians. The technique is based upon a division of the network into partial networks called blocks. This way, the global network adjustment can be done by manipulating these blocks. Here we show alternatives to solve the block system that arises from the application of the technique. We show an alternative that optimizes its implementation as the elapsed processing time is decreased by about 33%. We also show that to insert observations into an adjusted network it is not necessary to readjust the whole network. We show the formulae to insert new observations into an adjusted network that are more efficient than simply readjusting the whole new network.

scholarly journals AN OUTLIER DETECTION METHOD IN GEODETIC NETWORKS BASED ON THE ORIGINAL OBSERVATIONS

2014 ◽  
Vol 20 (3) ◽  
pp. 578-589 ◽  
Author(s):  
BAHATTIN ERDOGAN
Keyword(s):  
Outlier Detection ◽  
Mean Value ◽  
Least Square ◽  
Detection Methods ◽  
Random Errors ◽  
Network Adjustment ◽  
Mean Values ◽  
Geodetic Networks ◽  
First Case ◽  
The Mean

The observations in geodetic networks are measured repetitively and in the network adjustment step, the mean values of these original observations are used. The mean operator is a kind of Least Square Estimation (LSE). LSE provides optimal results when random errors are normally distributed. If one of the original repetitive observations has outlier, the magnitude of this outlier will decrease because the mean value of these original observations is used in the network adjustment and outlier detection. In this case, the reliability of the outlier detection methods decreases, too. Since the original repetitive observations are independent, they can be used in the adjustment model instead of the estimating mean value of them. In this study, to show the effects of the estimating mean value of the original repetitive observations, a leveling network that contains both outward run and backward run observations were simulated. Tests for outlier, Huber and Danish methods were applied to two different cases. First, the mean values of the original observations (outward run and return run) were used; and then all original observations were considered in the outlier detection. The reliabilities of the methods were measured by Mean Succes Rate. According to the obtained results, the second case has more reliable results than first case.

scholarly journals Modeling a Microgravity System for Ground Testing of Transformable Space Structures

2021 ◽  
Vol 2096 (1) ◽  
pp. 012144
Author(s):  
T Ezangina ◽  
S A Gayvoronsiy ◽  
S Sobol
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Coordinate System ◽  
Mechanical System ◽  
Space Structures ◽  
Electromechanical Systems ◽  
Ground Testing ◽  
Horizontal Control

Abstract The article develops a mathematical model of a microgravity system that simulates the conditions of weightlessness during ground tests of spacecraft. The microgravity system consists of vertical and horizontal control channels, providing a link opening in a twodimensional coordinate system. The channels are two-mass electromechanical systems with elastic connections. To simulate the microgravity system, mathematical models of these channels are obtained. To check the adequacy of the obtained models in Simulink Matlab, we simulated the opening of a link of a mechanical system. As a result of modeling, the permissible indicators of the accuracy of simulating weightlessness were obtained.

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