A Terrestrial Reference Frame (TRF), coordinates and velocities for South American stations: contributions to Central Andes geodynamics

Mackern, María Virginia; Mateo, María Laura; Robin, A. M.; Calori, Andrea

doi:10.5194/adgeo-22-181-2009

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…To ignore seasonal variations at reference stations can introduce systematic errors in the datum realization and the networks can be significantly deformed [13].…”

Section: Discussionmentioning

confidence: 99%

Adjustment Methodology in a Regional Densification of a Terrestrial Reference Frame

Mateo¹,

Mackern²

2012

New Approach of Indoor and Outdoor Localization Systems

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/50548 IntroductionThe measurement of geodetic networks by satellite positioning is becoming more and more common, given the advantages of this technology to solve the main problems of geodesy: Planimetric geo-reference to a geocentric system  Independence of intervisibility between points  Increase of relative precision.The purpose of working under the Network scheme is to have superabundant observations that allow adjustment by estimating parameter (coordinates) values and precisions.Given the versatility of the method of indirect or parametric observations, it has become the most widely used as a method of geodetic adjustment.The Adjustment Method by Non-Conditioned Indirect Observations, also known as Method of Coordinate Variation, or Parametric Method has been widely accepted in Geodesy. by means of the use of observation equations, in which the parameters are the coordinates.This adjustment made under the application of the method of minimum squares, estimates parameters as well as their precisions.It allows to incorporate equations of coordinates, which are essential when introducing the reference frame and generating an external control.In the adjustment, an appropriate management of the coordinates requires: The introduction of fiducial coordinates with a precision better than the precision of the network to be adjusted. The adoption of appropriate weights to these coordinates, in order not to create unnecessary deformations. New Approach of Indoor and Outdoor Localization Systems 28These objectives, as will be shown in this chapter, are strongly correlated.The strict frame introduction by fixing the fiducial points could often result in an unfavorable option because it induces loss of precision to the network, caused by internal deformation. On the contrary it is possible to generate a free or quasi free adjustment omitting the introduction of the datum in order not to cause deformation to the network. Finally, it is possible to achieve a condition of balance by adopting the appropriate strategy, the optimum quantity and distribution of fiducial points. This solution must achieve the required precisions and the densification of the selected reference frame [2]. Adjustment strategy Internal precisionBefore the datum input it is necessary to estimate the internal precision of the network to be adjusted. Knowledge of network internal precision will allow the definition of tolerances when datum is introduced.This analysis is possible because of the existence of superabundant observations that is to say in the presence of degrees of freedom. In the satellite positioning techniques the adjustment over observations made in different periods or days is very important since these observations are affected by factors that change through time such as the tropospheric and ionospheric delay, oceanic and terrestrial tides, etc. This is the reason why it is necessary to measure the points of the networks in different sessions...

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“…To ignore seasonal variations at reference stations can introduce systematic errors in the datum realization and the networks can be significantly deformed [13].…”

Section: Discussionmentioning

confidence: 99%

Adjustment Methodology in a Regional Densification of a Terrestrial Reference Frame

Mateo¹,

Mackern²

2012

New Approach of Indoor and Outdoor Localization Systems

View full text Add to dashboard Cite

show abstract

“…Within this research work, the site-specific ZTD SIR were estimated for approximately 100 GNSS SIRGAS stations (SIRGAS-CON-D-SUR) (Mackern et al 2009) with a global formal precision of few millimeters, as described in detail in Calori et al (2013). Figure 1 shows the overall distribution of the used GNSS stations over the South American region.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Different Techniques for Tropospheric Wet Delay Retrieval Over South America and Surrounding Oceans

Calori

Colosimo

Crespi

et al. 2015

VIII Hotine-Marussi Symposium on Mathematical Geodesy

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Water vapour (WV) plays a fundamental role in several weather processes that deeply influence human activities. Satellite based radiometers, Ground based Global Navigation Satellite Systems (GNSS) and Numerical Weather Models (NWM) permit to obtain either measurements or estimates or forecasts of WV. This work presents a 2 years systematic comparison to address the agreement on the tropospheric wet delay retrieved by the three mentioned independent techniques over permanent stations belonging to SIRGAS (Sistema de Referencia para las Américas) GNSS network. SIRGAS tropospheric total delay estimations are compared with the official International GNSS Service (IGS) ones, with the measurements from the Jason-1 satellite radiometer (JMR) in terms of Zenith Wet Delays (ZWD) and, finally, with the ZWD computed from ERA Interim, the last reanalysis dataset from the European Center for Medium-Range Weather Forecasts (ECMWF). All the differences between the techniques, which were considered in order to yield a reliable comparison, are discussed. . It has been clearly understood that the knowledge of high accurate WV content and its distribution in the atmosphere improves short term weather forecasts significantly. At the same time, WV reveals very rapid changes both in the temporal and in the spatial domains such that, at present, there are no theoretical models that can reliably predict its behaviour. Retrieving WV content in the atmosphere can be performed in different ways using independent techniques: starting from the more traditional and established ones, such as radiosondes and ground-based microwave radiometers, up

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Zenith Wet Delay Retrieval Using Two Different Techniques for the South American Region and Their Comparison

Calori

Colosimo

Crespi

et al. 2013

International Association of Geodesy Symposia

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(IAG) also had its quadrennial General Assembly. The IAG co-organised and contributed to several Union Symposia, as well as to Joint Symposia with other Associations. It also organised seven symposia of its own, one dedicated to each of the four commissions and three dedicated to specific scientific issues. This volume contains the proceedings of 13 symposia, which are listed below with the name of their associate editor(s):

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A Terrestrial Reference Frame (TRF), coordinates and velocities for South American stations: contributions to Central Andes geodynamics

Cited by 3 publications

References 7 publications

Adjustment Methodology in a Regional Densification of a Terrestrial Reference Frame

Adjustment Methodology in a Regional Densification of a Terrestrial Reference Frame

Comparison of Different Techniques for Tropospheric Wet Delay Retrieval Over South America and Surrounding Oceans

Zenith Wet Delay Retrieval Using Two Different Techniques for the South American Region and Their Comparison

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