Integrated velocity field from ground and satellite geodetic techniques: application to Arenal volcano

Measurements of ground deformation can be used to identify and interpret geophysical processes occurring at volcanoes. Most studies rely on a single geodetic technique, or fit a geophysical model to the results of multiple geodetic techniques. Here we present a methodology that combines GPS, Total Station measurements and InSAR into a single reference frame to produce an integrated 3-D geodetic velocity surface without any prior geophysical assumptions. The methodology consists of five steps: design of the network, acquisition and processing of the data, spatial integration of the measurements, time series computation and finally the integration of spatial and temporal measurements. The most significant improvements of this method are (1) the reduction of the required field time, (2) the unambiguous detection of outliers, (3) an increased measurement accuracy and (4) the construction of a 3-D geodetic velocity field. We apply this methodology to ongoing motion on Arenal's western flank. Integration of multiple measurement techniques at Arenal volcano revealed a deformation field that is more complex than that described by individual geodetic techniques, yet remains consistent with previous studies. This approach can be applied to volcano monitoring worldwide and has the potential to be extended to incorporate other geodetic techniques and to study transient deformatio

Auscultation tridimensionnelle d'ouvrages d'art

Depuis quelques années, le laboratoire de topométrie de la Haute école d’ingénierie et de gestion du canton de Vaud HEIG-VD) développe et teste un concept d’auscultation tridimensionnelle d’ouvrages d’art. La détection de mouvements absolus et relatifs implique la combinaison de mesures GNSS et terrestres. Pour conserver l’information tridimensionnelle des observations, l’ajustement est réalisé avec le logiciel Trinet+ élaboré par ce même laboratoire. Des applications sur des ponts autoroutiers et sur le volcan Arenal au Costa Rica ont démontré la validité du procédé.Seit einigen Jahren entwickelt und testet das Labor für geodätische Messtechnik der Hochschule für Technik und Wirtschaft Waadt HEIG-VD) ein Konzept zur 3DBauwerksüberwachung. Der Nachweis von absoluten und relativen Bewegungen erfordert die Kombination von GNSS-Messungen und terrestrischen Aufnahmen. Damit die dreidimensionale Information der Beobachtungen erhalten bleibt, wird die Ausgleichung mit dem Program Trinet+ ausgeführt, welches vom gleichen Labor entwickelt wurde. Die Gültigkeit des Verfahrens wurde bei Anwendungen mit Autobahnbrücken und auf dem Vulkan Arenal in Costa Rica nachgewiesen.Da alcuni anni, il laboratorio di topografia dell’Haute école d’ingénierie et de gestion du canton de Vaud HEIG-VD) sviluppa un metodo di monitoraggio tridimensionale di ponti e strutture in genere. La rilevazione dei movimenti assoluti e relativi di una struttura implica l’utilizzo simultaneo di misure GNSS e terrestri. Al fine di non perdere informazioni durante la restituzione dei dati tridimensionali, Trinet+, un software dedicato, è stato sviluppato presso i laboratori della HEIG-VD. La validità del metodo e del software è stata dimostrata dall’applicazione ai ponti autostradali e sul vulcano Arenal in Costa Rica

Quantification of the dependence of the results on several network adjustment applications

[EN] The dependency of the results from a network adjustment on the application used is investigated. For that purpose, the results obtained by each tested application on several sets of simulated measurements are compared. In each simulation, only one parameter varies. We first present our comparison methodology and the method that was used to add Gaussian-like errors to theoretical measurements. We then apply it to study the impact of the side length of the network and of the ellipsoidal height difference among points in the network for several network adjustment applications: Columbus, CoMeT, Geolab, JAG3D, LGC, Move3, Star*Net and Trinet+.Durand, S.; Lösler, M.; Jones, M.; Cattin, P.; Guillaume, S.; Morel, L. (2023). Quantification of the dependence of the results on several network adjustment applications. Editorial Universitat Politècnica de València. 69-77. https://doi.org/10.4995/JISDM2022.2022.13671697

Evaluation of Compatibility among Network Adjustment Software: CoMeT, LGC, and Trinet+

A network adjustment program is an essential tool for surveyors. It allows the computation of point coordinates and confidence regions from measurements undertaken in the field. It also helps surveyors in the design of optimal networks, both in terms of accuracy and reliability. Conservatoire national des arts et métiers (Cnam), European Organization for Nuclear Research (CERN), and School of Management and Engineering Vaud (HEIG-VD) are three institutions that have developed their own network adjustment applications: Compensation de Mesures Topographiques (CoMeT), Logiciel Général de Compensation (LGC), and Trinet+, respectively. In all these applications, three-dimensional (3D) mathematical functional models are used to process conventional observations and global navigation satellite system (GNSS) 3D vectors. However, some discrepancies may exist in the obtained results between these applications due to differences in the implementation of the functional models. The main objective of this work is to study software effects, and to ensure compatibility and interoperability between these three network adjustment applications. We first present the relevant differences between these applications and then the processing methodology adopted to ensure the best compatibility and interoperability between them. Using generated measurements, which include Gaussian errors, we have been able to study the impact of any differences in the implementation of the functional models on the estimated variance factor and adjusted parameters

Quantification of the dependence of the results on several network adjustment applications

The dependency of the results from a network adjustment on the application used is investigated. For that purpose, the results obtained by each tested application on several sets of simulated measurements are compared. In each simulation, only one parameter varies. We first present our comparison methodology and the method that was used to add Gaussian-like errors to theoretical measurements. We then apply it to study the impact of the side length of the network and of the ellipsoidal height difference among points in the network for several network adjustment applications: Columbus, CoMeT, Geolab, JAG3D, LGC, Move3, Star*Net and Trinet+

Passive and active tracking of electrochemical impedance of a drone battery

International audienceMore and more applications rely on batteries, for instance in the field of transport (electrical vehicles), of smart grid, and connected objects. Therefore, the development of battery has become a crucial issue. Unfortunately, a battery is a complex electrochemical system which depends on many parameters and whose performance deteriorates over time. Thus the development of an efficient battery management system (BMS) to avoid damages, to extend lifespan and to optimize the use of batteries is a priority. One way to obtain interesting information representative of the present state of the battery is to estimate its electrochemical impedance. If most of impedance estimation methods rely on the hypothesis of linearity and time invariance, the developed methods intentionally move away from this hypothesis. The goal of the presented work is not only to accurately estimate the impedance over a predetermined frequency range thanks to an algorithm which can be easily implemented in an embedded system but also to be able to track the temporal variations of the impedance. Different methods to estimate impedance both in time and frequency domains are developed and compared. Indeed the aim is first to precisely follow the evolution of the battery impedance in both active and passive identification cases. The evolutionary impedance estimation is then applied to a drone battery. The impedance estimator is used to evaluate the state of charge of the drone battery and other crucial indicators like the remaining flight time thanks to an extended Kalman filter

Integrated velocity field from ground and satellite geodetic techniques: Application to Arenal volcano

ISSN:0956-540XISSN:1365-246

Integrated velocity field from ground and satellite geodetic techniques:application to Arenal volcano

Measurements of ground deformation can be used to identify and interpret geophysical processes occurring at volcanoes. Most studies rely on a single geodetic technique, or fit a geophysical model to the results of multiple geodetic techniques. Here we present a methodology that combines GPS, Total Station measurements and InSAR into a single reference frame to produce an integrated 3-D geodetic velocity surface without any prior geophysical assumptions. The methodology consists of five steps: design of the network, acquisition and processing of the data, spatial integration of the measurements, time series computation and finally the integration of spatial and temporal measurements. The most significant improvements of this method are (1) the reduction of the required field time, (2) the unambiguous detection of outliers, (3) an increased measurement accuracy and (4) the construction of a 3-D geodetic velocity field. We apply this methodology to ongoing motion on Arenal’s western flank. Integration of multiple measurement techniques at Arenal volcano revealed a deformation field that is more complex than that described by individual geodetic techniques, yet remains consistent with previous studies. This approach can be applied to volcano monitoring worldwide and has the potential to be extended to incorporate other geodetic techniques and to study transient deformation.Las mediciones de la deformación del suelo pueden utilizarse para identificar e interpretar los procesos geofísicos que tienen lugar en los volcanes. La mayoría de los estudios se basan en una sola técnica geodésica o ajustan un modelo geofísico a los resultados de múltiples técnicas geodésicas. Aquí presentamos una metodología que combina las mediciones del GPS, la estación total y el InSAR en un único marco de referencia para producir una superficie de velocidad geodésica tridimensional integrada sin ninguna suposición geofísica previa. La metodología consta de cinco pasos: diseño de la red, adquisición y procesamiento de los datos, integración espacial de las mediciones, cálculo de las series temporales y, por último, integración de las mediciones espaciales y temporales. Las mejoras más significativas de este método son (1) la reducción del tiempo de campo necesario, (2) la detección inequívoca de valores atípicos, (3) una mayor precisión de las mediciones y (4) la construcción de un campo de velocidad geodésico en 3D. Aplicamos esta metodología al movimiento en curso en el flanco occidental del Arenal. La integración de múltiples técnicas de medición en el volcán Arenal reveló un campo de deformación que es más complejo que el descrito por las técnicas geodésicas individuales, aunque sigue siendo coherente con los estudios anteriores. Este enfoque puede aplicarse a la vigilancia de volcanes en todo el mundo y tiene el potencial de ser ampliado para incorporar otras técnicas geodésicas y para estudiar la deformación transitoria.Universidad Nacional, Costa Rica.Observatorio Vulcanológico y Sismológico de Costa Ric

Regards sur l'évolution de l'agriculture et du monde rural

Economie rurale publie aujourd'hui son numéro 300. C'est un événement, pour une parution ininterrompue ! Et pour confirmer et illustrer ces années de publication, cette livraison débute par la présentation en faximiles des premières pages du tout premier Bulletin de la SFER, paru en 1949, annonçant la naissance de l'association. En 1953, il s'intitulera Economie rurale. Nombreux sont les chercheurs, les économistes ruraux et les agronomes qui ont fait honneur à ce support éditorial ! Ainsi est-il possible de dire aujourd'hui qu'au fil des ans Economie rurale confirme son statut de revue savante. Finalement voilà 60 ans que la SFER et Economie rurale regardent le monde agricole et rural. L'arrivée de ce numéro 300 est symbolique de la continuité de la revue. C'est le moment pour des observateurs, analystes , acteurs et temoins de s'exprimer : Economie rurale leur donne la parole. Agricultures, Alimentations, Territoires : dans cette sphère si complexe, quels sont les événements  qui les ont marqués ? Quels sont les sujets qui méritent attention parce qu'ils contribuent à expliquer l'évolution économique et sociologique de l'agriculture et du monde rural ? Quelles conséquences peuvent-ils augurer pour l'avenir de la société et de la recherche ? Débat et controverse Quelle politique agricole pour l'Europe ? Réflexion d'un groupe d'agroéconomistes, membres de l'Académie d'Agriculture de France