GENESIS: Co-location of Geodetic Techniques in Space

Improving and homogenizing time and space reference systems on Earth and, more directly, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1mm and a long-term stability of 0.1mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation for predicting natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities which has enunciated geodesy requirements for Earth sciences. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, proposed as a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this white paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology.Comment: 31 pages, 9 figures, submitted to Earth, Planets and Space (EPS

Terrestrial reference frames and their internal accuracy at coordinate system level

International audienceThe accuracy assessment of terrestrial reference frames (TRFs) at coordinate system level is a key task to ensure their successful use in Earth studies, satellite navigation and other geodetic positioning applications. Currently, the TRF quality specifications for the most demanding users dictate that the origin, orientation and scale should be determined at an accuracy level of 1 mm, and they should remain stable over time at a rate of 0.1 mm/yr. To evaluate the conformity of the internal accuracy of modern TRFs to such requirements, an appropriate mapping is needed to convert frame coordinate errors (and their CV matrix) in a terrestrial network to matching errors (and their CV matrix) in the realized coordinate system. Several projection schemes may be considered for this mapping problem, all of which aim at extracting the correlated part of the estimation error in TRF coordinates that is describable by small random perturbations in their coordinate system. The goal of the present paper is to investigate the inference problem of frame accuracy at coordinate system level, and to discuss not only the theoretical aspects of the required covariance projectors, but also the practical impact on the results obtained by their implementation in space geodetic solutions. For this purpose, a relevant case study is performed to evaluate the accuracy of the realized origin, orientation and scale in the ITRF frame series based on the formal CV matrices for their estimated positions and velocities in the four technique subnetworks (DORIS, SLR, VLBI, GNSS)

Study of the earth's crust displacements in the area of Greece analyzing GNSS data

The goal of this thesis is the analysis of the earth's crust displacements in Greece, using recent continuous data of almost perfectly distributed permanent GPS stations, established in Greece since 2007. A network of 122 GPS stations was processed and adjusted using the Bernese GPS software v5.0, where the most rigorous methods have been used for data processing. Various strategies and mathematic models were applied for the estimation of displacements for GPS permanent stations. Besides Bernese v5.0 software, a new one software package, created by the author (H&D MOGS), was used for specific processes, such as the estimation of the displacements considering non linear mathematical models. The comparison of different models and strategies, in relation to the time interval of GPS data, resulted in significant conclusions with respect to the accuracy of the estimated displacements. The last part of this thesis is dedicated to the creation of a new velocity model for Greece. The estimated velocity model takes into account a proper division of Greece in homogeneous velocity areas, by means of the Euler's Pole model and Least Squares Collocation.Σκοπός της παρούσας διατριβής είναι να εκμεταλλευτεί τα δορυφορικά δεδομένα των μόνιμων σταθμών που έχουν εγκατασταθεί στην Ελλάδα από το 2007 και να μελετήσει τις μετακινήσεις του ελληνικού γήινου φλοιού. Για το σκοπό αυτό δημιουργήθηκε ένα δίκτυο αποτελούμενο από 122 σταθμούς GPS, 105 εκ των οποίων βρίσκονται κατανεμημένοι σε όλη την Ελλάδα. Η επεξεργασία των δορυφορικών δεδομένων υλοποιήθηκε με τη βοήθεια του λογισμικού Bernese v5.0. Στη συνέχεια εφαρμόστηκαν διαφορετικές στρατηγικές και μαθηματικά μοντέλα για την εκτίμηση των μετακινήσεων των μόνιμων σταθμών GPS είτε με τη βοήθεια του λογισμικού Bernese v5.0 είτε μέσω του νέου λογισμικού H&D MOGS, το οποίο δημιουργήθηκε από το συγγραφέα της παρούσας διατριβής. Για παράδειγμα η εκτίμηση των μετακινήσεων έγινε είτε για κάθε ένα σταθμό ξεχωριστά εφαρμόζοντας γραμμικά και διευρυμένα μοντέλα μετακίνησης, είτε συνολικά ως δίκτυο. Οι συγκρίσεις μεταξύ των στρατηγικών σε σχέση με τα μαθηματικά μοντέλα και το χρονικό διάστημα των δεδομένων καταλήγουν σε πολύ σημαντικά συμπεράσματα ως προς την εσωτερική και εξωτερική ακρίβεια (αξιοπιστία) εκτίμησης των μετακινήσεων. Ακόμη ελέγχονται οι επιδράσεις στην εκτίμηση των μετακινήσεων του γήινου φλοιού που προέρχονται από τους διάφορους τρόπους επεξεργασίας των διαχρονικών δορυφορικών δεδομένων. Από την ανάλυση των διαχρονικών παρατηρήσεων προκύπτουν οι εκτιμήσεις των ταχυτήτων μετακίνησης, οι οποίες επιβεβαιώνουν παλαιότερες μελέτες αλλά και παρέχουν νέα σημαντικά αποτελέσματα για τον τρόπο μετακίνησης του γήινου φλοιού κυρίως στη Βόρεια Ελλάδα και τα νησιά των Κυκλάδων. Το τελευταίο κομμάτι της διατριβής ασχολείται με την εύρεση των επιμέρους περιοχών στην Ελλάδα που μετακινούνται σύμφωνα με το μοντέλο του πόλου του Euler. Στόχος αυτής της διαδικασίας είναι να χωριστεί ο ελληνικός γήινος φλοιός σε περιοχές ομοιογενούς μετακίνησης. Επιπλέον η εφαρμογή της μεθόδου της σημειακής προσαρμογής για τις οριζόντιες μετακινήσεις, είχε ως αποτέλεσμα τη δημιουργία ενός νέου κινηματικού μοντέλου για το σύνολο του ελληνικού γήινου φλοιού

Linear and Nonlinear Deformation Effects in the Permanent GNSS Network of Cyprus

The authors would like to acknowledge the “CUT Open Access Author Fund” for covering the open access publication fees of the paper.Permanent Global Navigation Satellite Systems (GNSS) reference stations are well established as a powerful tool for the estimation of deformation induced by man-made or physical processes. GNSS sensors are successfully used to determine positions and velocities over a specified time period, with unprecedented accuracy, promoting research in many safety-critical areas, such as geophysics and geo-tectonics, tackling problems that torment traditional equipment and providing deformation products with absolute accuracy. Cyprus, being located at the Mediterranean fault, exhibits a very interesting geodynamic regime, which has yet to be investigated thoroughly. Accordingly, this research revolves around the estimation of crustal deformation in Cyprus using GNSS receivers. CYPOS (CYprus POsitioning System), a network of seven permanent GNSS stations has been operating since 2008, under the responsibility of the Department of Lands and Surveys. The continuous flow of positioning data collected over this network, offers the required information to investigate the behavior of the crustal deformation field of Cyprus using GNSS sensors for the first time. This paper presents the results of a multi-year analysis (11/2011-01/2017) of daily GNSS data and provides inferences of linear and nonlinear deforming signals into the position time series of the network stations. Specifically, 3D station velocities and seasonal periodic displacements are jointly estimated and presented via a data stacking approach with respect to the IGb08 reference frame

CyCLOPS: A National Integrated GNSS/InSAR Strategic Research Infrastructure for Monitoring Geohazards and Forming the Next Generation Datum of the Republic of Cyprus

The objective of this paper is to introduce CyCLOPS, a novel strategic research infrastructure unit, and present its current progress of implementation, and integration in the National geodetic, geophysical and geotechnical infrastructure of the government-controlled areas of the Republic of Cyprus. CyCLOPS is co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research and Innovation Foundation under the grant agreement RIF/INFRASTRUCTURES/1216/0050. CyCLOPS is developed via the collaboration of the Cyprus University of Technology (CUT) and the German Aerospace Center (DLR), and supported by the Cyprus Geological Survey Department and the Department of Lands and Surveys. The main objective of CyCLOPS is to establish an integrated infrastructure for space-based monitoring of geohazards using the most prominent earth observation technologies (EO), such as GNSS and InSAR. Furthermore, the infrastructure will densify and form the backbone for the definition of the next generation national datum of the Republic of Cyprus. Eleven Tier-1/2 state-of-the-art GNSS CORS, precise weather stations, tiltmeters and specifically designed InSAR triangular trihedral corner reflectors will be deployed, in a collocated fashion, at selected locations throughout the government-controlled areas of Cyprus. The collocated configuration will be established and installed to be compliant with the most stringent CORS monumentation specifications, support all current GNSS constellations and SAR missions. Finally, one of CyCLOPS’ fundamental aims is to actively contribute to the on-going efforts and growing demand for more precise positioning services and high-quality modern reference frames, in conformity with the recommendations of the UN-GGIM (and its Subcommittee of Geodesy) to establish and enhance national geodetic infrastructures to support the sustainable management of geospatial information on the changing Earth

GENESIS: co-location of geodetic techniques in space

Improving and homogenizing time and space reference systems on Earth and, more specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a long-term stability of 0.1 mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, such as those located at tide gauges, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation, contributing to a better understanding of natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities, including the International Association of Geodesy (IAG), which has enunciated geodesy requirements for Earth sciences. Moreover, the United Nations Resolution 69/266 states that the full societal benefits in developing satellite missions for positioning and Remote Sensing of the Earth are realized only if they are referenced to a common global geodetic reference frame at the national, regional and global levels. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology. This paper has been written and supported by a large community of scientists from many countries and working in several different fields of science, ranging from geophysics and geodesy to time and frequency metrology, navigation and positioning. As it is explained throughout this paper, there is a very high scientific consensus that the GENESIS mission would deliver exemplary science and societal benefits across a multidisciplinary range of Navigation and Earth sciences applications, constituting a global infrastructure that is internationally agreed to be strongly desirable.ISSN:1343-8832ISSN:1880-598

GENESIS: co-location of geodetic techniques in space

International audienceAbstract Improving and homogenizing time and space reference systems on Earth and, more specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a long-term stability of 0.1 mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, such as those located at tide gauges, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation, contributing to a better understanding of natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities, including the International Association of Geodesy (IAG), which has enunciated geodesy requirements for Earth sciences. Moreover, the United Nations Resolution 69/266 states that the full societal benefits in developing satellite missions for positioning and Remote Sensing of the Earth are realized only if they are referenced to a common global geodetic reference frame at the national, regional and global levels. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology. This paper has been written and supported by a large community of scientists from many countries and working in several different fields of science, ranging from geophysics and geodesy to time and frequency metrology, navigation and positioning. As it is explained throughout this paper, there is a very high scientific consensus that the GENESIS mission would deliver exemplary science and societal benefits across a multidisciplinary range of Navigation and Earth sciences applications, constituting a global infrastructure that is internationally agreed to be strongly desirable. Graphical Abstrac