Difference between pages "IC SG1" and "IC SG5"

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(Objectives)
 
(Planned Activities)
 
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<big>'''JSG 0.10: High-rate GNSS'''</big>
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<big>'''JSG 0.5: Multi-sensor combination for the separation of integral
 +
geodetic signals'''</big>
  
Chair: ''Mattia Crespi (Italy)''<br>
+
Chair: ''F. Seitz (Germany)''<br>
Affiliation:''Commissions 1, 3 4 and GGOS''
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Affiliation: ''Comm. 2, 3 and GGOS''
  
 
__TOC__
 
__TOC__
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===Objectives===
  
===Introduction===
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A large part of the geodetic parameters derived from space geodetic observation techniques are integral quantities of the Earth system. Among the most prominent ones are parameters related to Earth rotation and the gravity field. Variations of those parameters reflect the superposed effect of a multitude of dynamical processes and interactions in various subsystems of the Earth. The integral geodetic quantities provide fundamental and unique information for different balances in the Earth system, in particular for the balances of mass and angular momentum that are directly related to (variations of) the gravity field and Earth rotation. In respective balance equations the geodetic parameters describe the integral effect of exchange processes of mass and angular momentum in the Earth system. In contrast to many other disciplines of geosciences, geodesy is characterized by a very long observation history. Partly, the previously mentioned parameters have been determined over many decades with continuously improved space observation techniques. Thus geodesy provides an excellent data base for the analysis of long term changes in the Earth system and contributes fundamentally to an improved understanding of large-scale processes.
  
Global Navigation Satellite Systems (GNSS) have become for a long time an indispensable tool to get accurate and reliable information about positioning and timing; in addition, GNSS are able to provide information related to physical properties of media passed through by GNSS signals. Therefore, GNSS play a central role both in geodesy and geomatics and in several branches of geophysics, representing a cornerstone for the observation and monitoring of our planet.
+
However, in general the integral parameter time series cannot be separated into contributions of specific processes without further information. Their separation and therewith their geophysical interpretation requires complementary data from observation techniques that are unequally sensitive for individual effects and/or from numerical models. Activities of the study group are focussed on the development of strategies for the separation of the integral geodetic signals on the basis of modern space-based Earth observation systems. A multitude of simultaneously operating satellite systems with different objectives is available today. They offer a broad spectrum of information on global and regional-scale processes at different temporal resolutions. Within the study group it shall be investigated in which way the combination of heterogeneous data sets allows for the quantification of individual contributors to the balances of mass and angular momentum.
  
So, it is not surprising that, from the very beginning of the GNSS era, the goal was pursued to widen as much as possible the range in space (from local to global) and time (from short to long term) of the observed phenomena, in order to cover the largest possible field of applications, both in science and in engineering; two complementary, but primary as well, goals were, obviously, to get these information with the highest accuracy and in the shortest time.  
+
The research activities shall be coordinated between the participating scientists and shall be conducted in interdisciplinary collaboration. At all times the group is open for new contacts and members in order to embed the activities in a wide context. The study group is primarily affiliated with the IAG commissions 2 (Gravity field) and 3 (Earth rotation and geodynamics).
  
The advances in technology and the deployment of new constellations, after GPS (in the next years will be completed the European Galileo, the Chinese Beidou and the Japanese QZSS) remarkably contributed to transform this three-goals dream in reality, but still remain significant challenges when very fast phenomena have to be observed, mainly if real-time results are looked for.
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===Objectives===
 
 
Actually, for almost 15 years, starting from the noble birth in seismology, and the very first experiences in structural monitoring, high-rate GNSS has demonstrated its usefulness and power in providing precise positioning information in fast time-varying environments. At the beginning, high-rate observations were mostly limited at 1 Hz, but the technology development provided GNSS equipment (in some cases even at low-cost) able to collect measurements at much higher rates, up to 100 Hz, therefore opening new possibilities, and meanwhile new challenges and problems.
 
  
So, it is necessary to think about how to optimally process this potential huge heap of data, in order to supply information of high value for a large (and likely increasing) variety of applications, some of them listed hereafter without the claim to be exhaustive: better understanding of the geophysical/geodynamical processes mechanics; monitoring of ground shaking and displacement during earthquakes, also for contribution to tsunami early warning; tracking the fast variations of the ionosphere; real-time controlling landslides and the safety of structures; providing detailed trajectories and kinematic parameters (not only position, but also velocity and acceleration) of high dynamic platforms such as airborne sensors, high-speed terrestrial vehicles and even athlete and sport vehicles monitoring.
+
The primary objective of the study group is the development of strategies for multi-sensor combinations with the aim of separating time series of integral geodetic parameters related to Earth rotation and gravity field. The separation of the parameter time series into contributions of individual underlying effects fosters the understanding of dynamical processes and interactions in the Earth system. This is of particular interest in the view of global change.
  
Further, due to the contemporary technological development of other sensors (hereafter referred as ancillary sensors) related to positioning and kinematics able to collect data at high-rate (among which MEMS accelerometers and gyros play a central role, also for their low-cost), the feasibility of a unique device for high-rate observations embedding GNSS receiver and MEMS sensors is real, and it open, again, new opportunities and problems, first of all related to sensors integration.
+
Individual contributions from various subsystems of the Earth shall be quantified and balanced. In particular our investigations focus on the separation of the Earth rotation parameters (polar motion and variations of length-of-day) into contributions of atmospheric and hydrospheric angular momentum variations, and on the separation of GRACE gravity field observations over continents into the contributions of individual hydrological storage compartments, such as groundwater, surface water, soil moisture and snow.
 +
Investigations in the frame of the study group will exploit the synergies of various observation systems (satellite altimetry, optical and radar remote sensing, SMOS, and others) for the separation of the signals and combine their output with numerical models. Among the most important steps are compilation and assessment of background information for individual observation systems and sensors (mode of operation, sensitivity, accuracy, deficiencies) as well as theoretical studies which (new) information on the Earth system can be gained from a combination of different observation methods.
  
All in all, it is clear that high-rate GNSS (and ancillary sensors) observations represent a great resource for future investigations in Earth sciences and applications in engineering, meanwhile stimulating a due attention from the methodological point of view in order to exploit their full potential and extract the best information. This is the why it is worth to open a focus on high-rate (and, if possible, real-time) GNSS within ICCT.
+
In particular the research comprises the following topics:
 +
* potential und usability of contemporary spaceborne and terrestrial sensors for an improved understanding of processes within atmosphere and hydrosphere,
 +
* analysis of accuracy, temporal and spatial resolution and coverage of different data sets,
 +
* theoretical and numerical studies on the combination of heterogeneous observation types; this comprehends investigations on appropriate methods for parameter estimation including error propagation, the analysis of linear dependencies between parameters and the solution of rank deficiency problems,
 +
* mathematical methods for the enhancement of the information content (e.g., filters),
 +
* quantification of variations of mass and angular momentum in different subsystems from multi-sensor analysis.
 +
* analysis of the consistencies of balances between individ-ual effects and integral geodetic parameters on different spatial scales
 +
* formulation of recommendations for future research and (if possible) for future satellite missions on the basis of balance inconsistencies
  
===Objectives===
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===Planned Activities===
  
* To realize the inventories of:
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* Set-up of a JSG webpage for dissemination of information (activities and a bibliographic list of references) and for presentation and communication of research results.
- the available and applied methodologies for high-rate GNSS, in order to highlight their pros and cons and the open problems
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* Organization of conference sessions / workshops:
- the present and wished applications of high-rate GNSS for science and engineering, with a special concern to the estimated quantities (geodetic, kinematic, physical), in order to focus on related problems (still open and possibly new) and draw future challenges
+
** planned in 2013: Conference Session in the Hotine Marussi Symposium
- the technology (hw, both for GNSS and ancillary sensors, and sw, possibly FOSS), pointing out what is ready and what is coming, with a special concern for the supplied observations and for their functional and stochastic modeling with the by-product of establishing a standardized terminology
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** planned in 2014: 2nd workshop on the Quality of Geodetic Observing and Monitoring Systems (QuGOMS’ 14)
* To address known (mostly cross-linked) problems related to high-rate GNSS as (not an exhaustive list): revision and refinement of functional and stochastic models; evaluation and impact of observations time-correlation; impact of multipath and constellation change; outliers detection and removal; issues about GNSS constellations interoperability; ancillary sensors evaluation, cross-calibration and  integration
+
* Common publications of SG members
* To address the new problems and future challanges arised from the inventories
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* Common fund raising activities (e.g., for PhD. positions)
* To investigate about the interaction with present real-time global (IGS-RTS, EUREF-IP, etc.) and regional/local positioning services: how can these services support high-rate GNSS observations and, on reverse, how can they benefit of high-rate GNSS observations
 
  
===Program of activities===
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===Principal Scientific Outcome/Results===
  
* To launch a questionnaire for the above mentioned inventory of methodologies, applications and technologies.
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By the end of the 4-year period 2011-2015 the following outcome shall be achieved:
* To open a web page with information concerning high-rate GNSS and its wide applications in science and engineering, with special emphasis on exchange of ideas, provision and updating bibliographic list of references of research results and relevant publications from different disciplines.
+
Mature experience in geodetic multi-sensor data combina-tion including data availability, formats, combination strategies and accuracy aspects
* To launch the proposal for two (one science and the other engineering oriented) state-of-the-art review papers in high-rate GNSS co-authored by the JSG Members.
+
Numerical results for separated hydrological contributions to integral mass variations observed by GRACE for selected study areas.
* To organize a session at the forthcoming Hotine-Marussi symposium.
+
Numerical results for separated atmospheric/hydrospheric contributions Earth rotation parameters on seasonal to inter-annual time scales
* To promote sessions and presentation of the research results at international symposia both related to Earth science (IAG/IUGG, EGU, AGU, EUREF, IGS) and engineering (workshops and congresses in structural and geotechnical engineering).
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Initiation of at least one common funded project with posi-tions for PhD students working in the topical field of the study group
  
 
===Members===
 
===Members===
  
'' '''Mattia Crespi (Italy), chair''' <br /> Juan Carlos Baez (Chile) <br /> Elisa Benedetti (United Kingdom) <br /> Geo Boffi (Switzerland) <br /> Gabriele Colosimo (Switzerland) <br /> Athanasios Dermanis (Greece) <br /> Roberto Devoti (Italy) <br /> Jeff Freymueller (USA) <br /> Joao Francisco Galera Monico (Brazil) <br /> Jianghui Geng (Germany) <br /> Kosuke Heki (Japan) <br /> Melvin Hoyer (Venezuela) <br /> Nanthi Nadarajah (Australia) <br /> Yusaku Ohta (Japan) <br /> Ruey-Juin Rau (Taiwan) <br /> Eugenio Realini (Italy) <br /> Chris Rizos (Australia) <br /> Nico Sneeuw (Germany) <br /> Peiliang Xu (Japan) <br />''
+
'' '''Florian Seitz (Germany), chair'''<br />Sarah Abelen (Germany)<br />Rodrigo Abarca del Rio (Chile)<br />Andreas Güntner (Germany)
 +
<br />Karin Hedman (Germany)<br />Franz Meyer (USA)<br />Michael Schmidt (Germany)<br />Manuela Seitz (Germany)<br />Alka Singh (India)<br />''

Revision as of 10:48, 2 July 2012

JSG 0.5: Multi-sensor combination for the separation of integral geodetic signals

Chair: F. Seitz (Germany)
Affiliation: Comm. 2, 3 and GGOS

Objectives

A large part of the geodetic parameters derived from space geodetic observation techniques are integral quantities of the Earth system. Among the most prominent ones are parameters related to Earth rotation and the gravity field. Variations of those parameters reflect the superposed effect of a multitude of dynamical processes and interactions in various subsystems of the Earth. The integral geodetic quantities provide fundamental and unique information for different balances in the Earth system, in particular for the balances of mass and angular momentum that are directly related to (variations of) the gravity field and Earth rotation. In respective balance equations the geodetic parameters describe the integral effect of exchange processes of mass and angular momentum in the Earth system. In contrast to many other disciplines of geosciences, geodesy is characterized by a very long observation history. Partly, the previously mentioned parameters have been determined over many decades with continuously improved space observation techniques. Thus geodesy provides an excellent data base for the analysis of long term changes in the Earth system and contributes fundamentally to an improved understanding of large-scale processes.

However, in general the integral parameter time series cannot be separated into contributions of specific processes without further information. Their separation and therewith their geophysical interpretation requires complementary data from observation techniques that are unequally sensitive for individual effects and/or from numerical models. Activities of the study group are focussed on the development of strategies for the separation of the integral geodetic signals on the basis of modern space-based Earth observation systems. A multitude of simultaneously operating satellite systems with different objectives is available today. They offer a broad spectrum of information on global and regional-scale processes at different temporal resolutions. Within the study group it shall be investigated in which way the combination of heterogeneous data sets allows for the quantification of individual contributors to the balances of mass and angular momentum.

The research activities shall be coordinated between the participating scientists and shall be conducted in interdisciplinary collaboration. At all times the group is open for new contacts and members in order to embed the activities in a wide context. The study group is primarily affiliated with the IAG commissions 2 (Gravity field) and 3 (Earth rotation and geodynamics).

Objectives

The primary objective of the study group is the development of strategies for multi-sensor combinations with the aim of separating time series of integral geodetic parameters related to Earth rotation and gravity field. The separation of the parameter time series into contributions of individual underlying effects fosters the understanding of dynamical processes and interactions in the Earth system. This is of particular interest in the view of global change.

Individual contributions from various subsystems of the Earth shall be quantified and balanced. In particular our investigations focus on the separation of the Earth rotation parameters (polar motion and variations of length-of-day) into contributions of atmospheric and hydrospheric angular momentum variations, and on the separation of GRACE gravity field observations over continents into the contributions of individual hydrological storage compartments, such as groundwater, surface water, soil moisture and snow. Investigations in the frame of the study group will exploit the synergies of various observation systems (satellite altimetry, optical and radar remote sensing, SMOS, and others) for the separation of the signals and combine their output with numerical models. Among the most important steps are compilation and assessment of background information for individual observation systems and sensors (mode of operation, sensitivity, accuracy, deficiencies) as well as theoretical studies which (new) information on the Earth system can be gained from a combination of different observation methods.

In particular the research comprises the following topics:

  • potential und usability of contemporary spaceborne and terrestrial sensors for an improved understanding of processes within atmosphere and hydrosphere,
  • analysis of accuracy, temporal and spatial resolution and coverage of different data sets,
  • theoretical and numerical studies on the combination of heterogeneous observation types; this comprehends investigations on appropriate methods for parameter estimation including error propagation, the analysis of linear dependencies between parameters and the solution of rank deficiency problems,
  • mathematical methods for the enhancement of the information content (e.g., filters),
  • quantification of variations of mass and angular momentum in different subsystems from multi-sensor analysis.
  • analysis of the consistencies of balances between individ-ual effects and integral geodetic parameters on different spatial scales
  • formulation of recommendations for future research and (if possible) for future satellite missions on the basis of balance inconsistencies

Planned Activities

  • Set-up of a JSG webpage for dissemination of information (activities and a bibliographic list of references) and for presentation and communication of research results.
  • Organization of conference sessions / workshops:
    • planned in 2013: Conference Session in the Hotine Marussi Symposium
    • planned in 2014: 2nd workshop on the Quality of Geodetic Observing and Monitoring Systems (QuGOMS’ 14)
  • Common publications of SG members
  • Common fund raising activities (e.g., for PhD. positions)

Principal Scientific Outcome/Results

By the end of the 4-year period 2011-2015 the following outcome shall be achieved: Mature experience in geodetic multi-sensor data combina-tion including data availability, formats, combination strategies and accuracy aspects Numerical results for separated hydrological contributions to integral mass variations observed by GRACE for selected study areas. Numerical results for separated atmospheric/hydrospheric contributions Earth rotation parameters on seasonal to inter-annual time scales Initiation of at least one common funded project with posi-tions for PhD students working in the topical field of the study group

Members

Florian Seitz (Germany), chair
Sarah Abelen (Germany)
Rodrigo Abarca del Rio (Chile)
Andreas Güntner (Germany)

Karin Hedman (Germany)
Franz Meyer (USA)
Michael Schmidt (Germany)
Manuela Seitz (Germany)
Alka Singh (India)