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Performance tests of geodetic receivers with tilt sensors in obstructed environments using the NRTK GNSS technique / Puttipol Dumrongchai in Journal of applied geodesy, vol 17 n° 1 (January 2023)  

Public [article]  inJournal of applied geodesy > vol 17 n° 1 (January 2023) . - pp 39 - 51 Titre : Performance tests of geodetic receivers with tilt sensors in obstructed environments using the NRTK GNSS technique Type de document : Article/Communication Auteurs : Puttipol Dumrongchai, Auteur ; Jittranud Patsadutarn, Auteur ; Chalermchon Satirapod, Auteur Année de publication : 2023 Article en page(s) : pp 39 - 51 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] centrale inertielle [Termes IGN] Continuously Operating Reference Station network [Termes IGN] délimitation [Termes IGN] lever cadastral [Termes IGN] microsystème électromécanique [Termes IGN] positionnement cinématique en temps réel [Termes IGN] récepteur GNSS [Termes IGN] signal GNSS [Termes IGN] station virtuelle de référence [Termes IGN] Thaïlande Résumé : (auteur) The Department of Lands (DOL), Thailand, has adopted the Network-based Real-Time Kinematic (NRTK) Global Navigation Satellite System (GNSS) surveying technique using a Virtual Reference Station (VRS) to support cadastral surveys since 2011. Determining accurate coordinates of parcel boundary markers at building corners or near fences and walls is difficult because a GNSS range pole cannot be leveled with a circular bubble. This study aims to evaluate the performance of the receivers equipped with tilt sensors for horizontal and vertical positioning. Two types of tilt sensors used for evaluation were a magnetometer and micro-electro-mechanical system (MEMS) and an inertial measurement unit (IMU). Conducting the NRTK GNSS surveying tests was based on the pole tilt angles of 0°, 15°, 25°, 35°, and 45° from a plumb line in controlled and obstructed environments. The IMU-based tilt sensor had more advantage of accurately positioning over the MEMS sensor. The results showed that using the IMU, better than 4 cm horizontal positioning accuracy was achievable when the pole was tilted by 15° or less under non-multipath and open-sky conditions. The vertical accuracy was of a few centimeter levels and least sensitive to tilt angles using either type of sensor. However, none of the sensors precisely compensated for pole tilt in strong-multipath and complex environments, causing increased horizontal errors in decimeter levels. Numéro de notice : A2023-111 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2022-0047 Date de publication en ligne : 07/11/2022 En ligne : https://doi.org/10.1515/jag-2022-0047 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102470 [article]

A low-cost integrated MEMS-based INS/GPS vehicle navigation system with challenging conditions based on an optimized IT2FNN in occluded environments / Elahe S. Abdolkarimi in GPS solutions, Vol 24 n° 4 (October 2020)  

Public [article]  inGPS solutions > Vol 24 n° 4 (October 2020) . - 19 p. Titre : A low-cost integrated MEMS-based INS/GPS vehicle navigation system with challenging conditions based on an optimized IT2FNN in occluded environments Type de document : Article/Communication Auteurs : Elahe S. Abdolkarimi, Auteur ; Mohammad-Reza Mosavi, Auteur Année de publication : 2020 Article en page(s) : 19 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] centrale inertielle [Termes IGN] classification floue [Termes IGN] classification par réseau neuronal [Termes IGN] filtrage du bruit [Termes IGN] filtre de Kalman [Termes IGN] GPS-INS [Termes IGN] microsystème électromécanique [Termes IGN] modèle d'incertitude [Termes IGN] rapport signal sur bruit [Termes IGN] transformation en ondelettes Résumé : (auteur) Integration of both global positioning system (GPS) and inertial navigation system (INS) assures a continuous and accurate navigation system. In low-cost low-precision micro-electromechanical system (MEMS)-based INS/GPS integration navigation systems, one of the major concerns is high-level stochastic noise and uncertainties existing in INS sensors and complex model of real noisy data. In such uncertainty-oriented environments, an intelligence structure with extra degrees of freedom which can handle and model a high-level of uncertainties in INS sensors, and an efficient denoising technique as a precursor to the intelligence structure can be efficient solutions. Our approach to these problems is taken in different steps. First, a denoising technique based on empirical mode decomposition (EMD) is used to provide more accurate INS sensor outputs and better generalization ability. Second, an optimized interval type-2 fuzzy neural network is used to model and handle a high-level of uncertainties efficiently and estimate the positioning error of INS sensors when GPS signals are blocked, and still meet both accuracy maximization and complexity minimization. Fast learning and convergence of the algorithm and less computational complexity can be achieved by using an extended Kalman filter in the learning of algorithm and an accurate and simple type-reduction, respectively, which can be utilized in real-time applications with significant performance. The results of EMD-based denoising technique, as a preprocessing phase, verify superior performance in comparison with the discrete wavelet transform denoising method in the signal-to-noise ratio improvement for raw and noisy signals of INS sensors. To verify the effectiveness of our proposed model, we applied challenging conditions consisting of low-cost low-precision inertial sensors based on MEMS technology, long-term outages of GPS satellites, a high-speed experimental test vehicle and noisy real-world data in the real-time flight experiments. The achieved experimental accuracies are compared with the results that we have achieved in other methods, and our proposed method verifies significant improvements. Numéro de notice : A2020-521 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-01023-9 Date de publication en ligne : 18/08/2020 En ligne : https://doi.org/10.1007/s10291-020-01023-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95692 [article]

Robust deformation monitoring of bridge structures using MEMS accelerometers and image-assisted total stations / Mohammad Omidalizarandi (2020)  

Public Titre : Robust deformation monitoring of bridge structures using MEMS accelerometers and image-assisted total stations Type de document : Thèse/HDR Auteurs : Mohammad Omidalizarandi, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2020 Collection : DGK - C, ISSN 0065-5325 num. 859 Importance : 260 p. Format : 21 x 30 cm Note générale : bibliographie Diese Arbeit ist gleichzeitig veröffentlicht in: Wissenschaftliche Arbeiten der Fachrichtung Geodäsie und Geoinformatik der Universität Hannover, ISSN 0174-1454, Nr. 366 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] accéléromètre [Termes IGN] algorithme espérance-maximisation [Termes IGN] auscultation d'ouvrage [Termes IGN] méthode robuste [Termes IGN] microsystème électromécanique [Termes IGN] pont [Termes IGN] surveillance d'ouvrage [Termes IGN] tachéomètre électronique [Termes IGN] topométrie de précision Résumé : (auteur) Today, short- and long-term structural health monitoring (SHM) of bridge structures has received considerable attention. However, permanent, cost-effective, and reliable monitoring are still challenging issues. From a surveying or civil engineer's point of view, vibration-based SHM is often carried out by inspecting the changes in the dynamic responses of bridge structures known as modal parameters, such as eigen frequencies, eigenforms and modal damping. The use of cost-effective micro-electro-mechanical-systems (MEMS) accelerometers with a high sampling frequency is becoming more affordable and feasible for the aforementioned monitoring task. Within this dissertation, a three-step scenario is proposed to choose a suitable MEMS accelerometer despite of its purchase price, measurement range and sampling frequency. Firstly, a robust calibration procedure is proposed and implemented to model MEMS related systematic errors such as biases, scale factors, and non-orthogonality angles between the axes. Secondly, a controlled excitation experiment is conducted by using a high-precision shaker. Thirdly, a statictest experiment is accomplished over a long period. Robust, accurate, and automatic estimation of the modal parameters is particularly challenging when vibration measurements are contaminated with a high coloured measurement noise, e.g., due to cost-effective MEMS acceleration data. This is even more challenging when the structure is continuously under imposed forces due to moving vehicles or wind. For this purpose, a robust and automatic vibration analysis procedure the so–called robust time domain modal parameter identification (RT-MPI) approach is proposed and implemented. It is a novel approach in the sense of automatic excitation (e.g. ambient) window selection, automatic and reliable identification of initial eigen frequencies even closely spaced ones as well as robustly and accurately estimating the modal parameters. To estimate frequencies, damping ratio coefficients, amplitudes, and phase shifts, an observation model consisting of a damped harmonic oscillation (DHO) model, an autoregressive model of coloured measurement noise and a stochastic model in the form of the heavy-tailed family of scaled t-distributions with unknown degree of freedom and scale factor, is employed. The aforementioned three parametric models are jointly adjusted by means of a generalised expectation maximisation (GEM) algorithm. The proposed RT-MPI algorithm is also able to estimate amplitudes in a metric unit and with a high accuracy for the recorded acceleration data by means of double integration of the DHO model. The eigenforms are characterised in a subsequent step, and by using the estimated parameters from the GEM algorithm. In addition, having amplitudes in the metric unit allows to characterise deflection eigen forms in their true scales for selected excitation windows within short time intervals. The deformation/displacement monitoring by merely using the MEMS accelerometer is challenging, since it suffers from accuracy degradation with time for absolute position/displacement estimates. Therefore, the MEMS accelerometers and an image-assisted total station (IATS) are fused by performing one-dimensional (1D) coordinate update within the Kalman filtering framework. To generate 1D displacement data from the IATS, video frames of a passive target, that is attached to a bridge structure, are captured by means of a telescope camera of the IATS. A passive target centroid detection algorithm is proposed and implemented, which is robust and reliable with respect to poor environmental conditions, such as low lighting, dusty situations, and skewed angle targets. Next, an angular conversion factor of the telescope camera is calibrated, which allows to convert the generated displacement data from pixel to metric unit. Experiments are performed in four case studies including simulation, controlled excitation and two real applications of a footbridge structure and a synthetic bridge. The estimated modal parameters are compared and validated by their true values as well as their corresponding estimates obtained from reference sensors such as reference accelerometer, geophone, and laser tracker. Additionally, the estimated eigen frequencies and damping ratio coefficients are compared with a well-known covariance driven stochastic subspace identification (SSI-COV) approach. The results show that the MEMS accelerometers are suitable for identifying all occurring eigen frequencies of the bridge structures. Moreover, the vibration analysis procedure demonstrates that amplitudes are estimated in submillimetre range accuracy, frequencies with an accuracy of better than 0.1 Hz and damping ratio coefficients with an accuracy of better than 0.1 and 0.2%for modal and system damping, respectively. The analysis reveals the superiority of the proposed RT-MPI algorithm compared to the SSI-COV algorithm. Finally, a high accurate displacement time series at the level of submillimetre is generated by fusion of the IATS and the MEMS measurements. Numéro de notice : 17680 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère En ligne : https://dgk.badw.de/fileadmin/user_upload/Files/DGK/docs/c-859.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98021

Indoor localization for pedestrians with real-time capability using multi-sensor smartphones / Catia Real Ehrlich in Geo-spatial Information Science, vol 22 n° 2 (June 2019)  

Public [article]  inGeo-spatial Information Science > vol 22 n° 2 (June 2019) . - pp 73 - 88 Titre : Indoor localization for pedestrians with real-time capability using multi-sensor smartphones Type de document : Article/Communication Auteurs : Catia Real Ehrlich, Auteur ; Jörg Blankenbach, Auteur Année de publication : 2019 Article en page(s) : pp 73 - 88 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] altitude barométrique [Termes IGN] Bluetooth [Termes IGN] méthode de Monte-Carlo [Termes IGN] microsystème électromécanique [Termes IGN] navigation à l'estime [Termes IGN] navigation pédestre [Termes IGN] positionnement en intérieur [Termes IGN] téléphone intelligent Résumé : (Auteur) The localization of persons or objects usually refers to a position determined in a spatial reference system. Outdoors, this is usually accomplished with Global Navigation Satellite Systems (GNSS). However, the automatic positioning of people in GNSS-free environments, especially inside of buildings (indoors) poses a huge challenge. Indoors, satellite signals are attenuated, shielded or reflected by building components (e.g. walls or ceilings). For selected applications, the automatic indoor positioning is possible based on different technologies (e.g. WiFi, RFID, or UWB). However, a standard solution is still not available. Many indoor positioning systems are only suitable for specific applications or are deployed under certain conditions, e.g. additional infrastructures or sensor technologies. Smartphones, as popular cost-effective multi-sensor systems, is a promising indoor localization platform for the mass-market and is increasingly coming into focus. Today’s devices are equipped with a variety of sensors that can be used for indoor positioning. In this contribution, an approach to smartphone-based pedestrian indoor localization is presented. The novelty of this approach refers to a holistic, real-time pedestrian localization inside of buildings based on multi-sensor smartphones and easy-to-install local positioning systems. For this purpose, the barometric altitude is estimated in order to derive the floor on which the user is located. The 2D position is determined subsequently using the principle of pedestrian dead reckoning based on user's movements extracted from the smartphone sensors. In order to minimize the strong error accumulation in the localization caused by various sensor errors, additional information is integrated into the position estimation. The building model is used to identify permissible (e.g. rooms, passageways) and impermissible (e.g. walls) building areas for the pedestrian. Several technologies contributing to higher precision and robustness are also included. For the fusion of different linear and non-linear data, an advanced algorithm based on the Sequential Monte Carlo method is presented. Numéro de notice : A2019-325 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10095020.2019.1613778 Date de publication en ligne : 21/05/2019 En ligne : https://doi.org/10.1080/10095020.2019.1613778 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93327 [article]

Design and implementation of a model predictive observer for AHRS / Jafar Keighobadi in GPS solutions, vol 22 n° 1 (January 2018)  

Public [article]  inGPS solutions > vol 22 n° 1 (January 2018) Titre : Design and implementation of a model predictive observer for AHRS Type de document : Article/Communication Auteurs : Jafar Keighobadi, Auteur ; Hamid Vosoughi, Auteur ; Javad Faraji, Auteur Année de publication : 2018 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] angle d'Euler [Termes IGN] attitude and heading reference system AHRS [Termes IGN] erreur instrumentale [Termes IGN] erreur systématique [Termes IGN] estimateur [Termes IGN] filtre de Kalman [Termes IGN] GPS-INS [Termes IGN] microsystème électromécanique [Termes IGN] véhicule Résumé : (auteur) A GPS-aided Inertial Navigation System (GAINS) is used to determine the orientation‚ position and velocity of ground and aerial vehicles. The data measured by Inertial Navigation System (INS) and GPS are commonly integrated through an Extended Kalman Filter (EKF). Since the EKF requires linearized models and complete knowledge of predefined stochastic noises‚ the estimation performance of this filter is attenuated by unmodeled nonlinearity and bias uncertainties of MEMS inertial sensors. The Attitude Heading Reference System (AHRS) is applied based on the quaternion and Euler angles methods. A moving horizon-based estimator such as Model Predictive Observer (MPO) enables us to approximate and estimate linear systems affected by unknown uncertainties. The main objective of this research is to present a new MPO method based on the duality principle between controller and observer of dynamic systems and its implementation in AHRS mode of a low-cost INS aided by a GPS. Asymptotic stability of the proposed MPO is proven by applying Lyapunov’s direct method. The field test of a GAINS is performed by a ground vehicle to assess the long-time performance of the MPO method compared with the EKF. Both the EKF and MPO estimators are applied in AHRS mode of the MEMS GAINS for the purpose of real-time performance comparison. Furthermore‚ we use flight test data of the GAINS for evaluation of the estimation filters. The proposed MPO based on both the Euler angles and quaternion methods yields better estimation performances compared to the classic EKF. Numéro de notice : A2018-017 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-017-0696-4 En ligne : https://doi.org/10.1007/s10291-017-0696-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89114 [article]

Concept of AHRS algorithm designed for platform independent IMU attitude alignment / Dariusz Tomaszewski in Reports on geodesy and geoinformatics, vol 104 n° 1 (December 2017)  

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Low-cost warning system for the monitoring of the Corinth Canal / George Hloupis in Applied geomatics, vol 9 n° 4 (December 2017)  

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Improving MEMS-IMU/GPS integrated systems for land vehicle navigation applications / S. Sasani in GPS solutions, vol 20 n° 1 (January 2016)  

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Tightly coupled integration of GPS precise point positioning and MEMS-based inertial systems / Mahmoud Abd Rabbou in GPS solutions, vol 19 n° 4 (october 2015)  

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Integrated navigation: GPS/BeiDou/INS performance in two hemispheres / Yong Li in Inside GNSS, vol 8 n° 6 (November - December 2013) 

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Getting closer to everywhere: accurately tracking smartphones indoors / Ramsey Faragher in GPS world, vol 24 n° 10 (October 2013)

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GNSS test standards for cellular location / Peter Anderson in GPS world, vol 24 n° 5 (May 2013)

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Introduction to a portable stereo mapping system for unmanned vehicles / Julien Li-Chee-Ming in Geomatica, vol 66 n° 4 (December 2012)  

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