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Corvers, Matthew (author)In this thesis, the development of a deployment mechanism for a primary mirror of a space telescope is discussed. A mistake has been found in the earlier work on the design of this subsystem, due to which the design is set back to a concept selection phase. A trade-off has been made between several concepts. A simplified thermal model that...master thesis 2018
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Wang, Kan (author), Khodabandeh, Amir (author), Teunissen, P.J.G. (author), Nadarajah, Nandakumaran (author)The real-time kinematic precise point positioning (PPP-RTK) technique enables integer ambiguity resolution by providing singlereceiver users with information on the satellite phase biases next to the standard PPP corrections. Using undifferenced and uncombined observations, rank deficiencies existing in the design matrix need to be eliminated to...journal article 2018
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Mao, X. (author), Visser, P.N.A.M. (author), van den IJssel, J.A.A. (author)The European Space Agency (ESA) Swarm mission is a satellite constellation launched on 22 November 2013 aiming at observing the Earth geomagnetic field and its temporal variations. The three identical satellites are equipped with high-precision dual-frequency Global Positioning System (GPS) receivers, which make the constellation an ideal...journal article 2018
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Khodabandeh, A. (author), Teunissen, P.J.G. (author)Integer ambiguity resolution (IAR) is the key to fast and precise GNSS positioning and navigation. Next to the positioning parameters, however, there are several other types of GNSS parameters that are of importance for a range of different applications like atmospheric sounding, instrumental calibrations or time transfer. As some of these...journal article 2018
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Wang, Kan (author), Chen, Pei (author), Teunissen, P.J.G. (author)In this contribution, we study the phase-only ambiguity resolution and positioning performance of GPS for short baselines. It is well known that instantaneous (single-epoch) ambiguity resolution is possible when both phase and code (pseudorange) data are used. This requires, however, a benign multipath environment due to the severe effects...journal article 2018
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Massaad Mouawad, J.M. (author), van Neer, P.L.M.J. (author), van Willigen, D.M. (author), de Jong, N. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author)Typically, ultrasonic flow meters assume linear wave propagation. Nevertheless, if the transducers of an ultrasonic flow sensor excite a pressure wave with a high amplitude, nonlinear wave propagation effects become significant. The appearance of higher harmonics increases the bandwidth of the received signal, which may potentially lead to a...conference paper 2018
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Lampaert, S.G.E. (author), Fellinger, B. J. (author), Spronck, J.W. (author), van Ostayen, R.A.J. (author)Ferrofluid bearings have been demonstrated to be very interesting for precision positioning systems. The friction of these bearings is free of stick-slip which results in an increase of precision. More knowledge on the friction behaviour of these bearings is important for there application in precision positioning systems. This paper...journal article 2018
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Lampaert, S.G.E. (author), Spronck, J.W. (author), van Ostayen, R.A.J. (author)A ferrofluid pocket bearings is a type of hydrostatic bearing that uses a ferrofluid seal to encapsulate a pocket of air to carry a load. Their properties, combining a high stiffness with low (viscous) friction and absence of stick-slip, make them interesting for applications that require fast and high precision positioning. Knowledge on the...journal article 2018
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Zhang, Baocheng (author), Teunissen, P.J.G. (author), Yuan, Yunbin (author), Zhang, Hongxing (author), Li, Min (author)Vertical total electron content (VTEC) parameters estimated using global navigation satellite system (GNSS) data are of great interest for ionosphere sensing. Satellite differential code biases (SDCBs) account for one source of error which, if left uncorrected, can deteriorate performance of positioning, timing and other applications. The...journal article 2018
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Chen, Linda (author)In high-tech industry (sub)nanometre precision motion control is essential. For example wafer scanners, used for production of integrated circuits, have to provide (sub)nanometre precision positioning whilst satisfying challenging requirements on speed at the same time. It is in demanding cases like this that different requirements begin to...master thesis 2017
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Broxterman, Stefan (author)Topology optimization is a strong approach for generating optimal designs which cannot be obtained using conventional optimization methods. Improving structural characteristics by changing the internal topology of a design domain has been fascinating scientists and engineers for years. Topology optimization can be described as a distribution of...master thesis 2017
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de Bakker, P.F. (author), Tiberius, C.C.J.M. (author)Precise Point Positioning (PPP) is a popular Global Positioning System (GPS) processing strategy, thanks to its high precision without requiring additional GPS infrastructure. Single-Frequency PPP (SF-PPP) takes this one step further by no longer relying on expensive dual-frequency GPS receivers, while maintaining a relatively high...journal article 2017
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Haagmans, Gaston (author)Since GPS tends to fail for indoor positioning purposes, alternative methods like indoor positioning systems (IPS) based on Bluetooth low energy (BLE) are developing rapidly. Generally, IPS are deployed in environments covered with obstacles such as furniture, (partition-) walls, people and electronics influencing the signal propagation. The...master thesis 2017
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Fellinger, B.J. (author)The repeatability of precision positioning systems can be improved by reducing the effects of stick-slip in the system. Stick-slip effects introduce a spontaneous jerking motion when overcoming the static friction coefficient, creating accelerations that are hard to predict. Contactless bearing types, such as magnetic levitation or fluid...master thesis 2017
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Kortleve, J.P. (author)From the results it can be concluded that a fixed and a free voice-coil actuated impact drive mechanism can be used as a positioning system in a precision environment, such as the semiconductor industry and extreme large telescopes, to position an object within 1 nanometer and hold the position passively stable within 10nm/hr. The empirically...master thesis 2017
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Haagmans, G. G. (author), Verhagen, S. (author), Voûte, R.L. (author), Verbree, E. (author)Since GPS tends to fail for indoor positioning purposes, alternative methods like indoor positioning systems (IPS) based on Bluetooth low energy (BLE) are developing rapidly. Generally, IPS are deployed in environments covered with obstacles such as furniture, walls, people and electronics influencing the signal propagation. The major factor...conference paper 2017
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Dheenathayalan, P. (author), Caro Cuenca, M. (author), Hoogeboom, P. (author), Hanssen, R.F. (author)In recent years, synthetic aperture radar interferometry has become a recognized geodetic tool for observing ground motion. For monitoring areas with low density of coherent targets, artificial corner reflectors (CRs) are usually introduced. The required size of a reflector depends on radar wavelength and resolution and on the required...journal article 2017
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Gonen, B. (author), Sebastiano, F. (author), Quan, Rui (author), van Veldhoven, Robert (author), Makinwa, K.A.A. (author)This paper presents the first dynamic zoom ADC. Intended for audio applications, it achieves 109-dB DR, 106-dB signal-to-noise ratio, and 103-dB SNDR in a 20-kHz bandwidth, while dissipating only 1.12 mW. This translates into the state-of-the-art energy efficiency as expressed by a Schreier FoM of 181.5 dB. It also achieves the state-of-the...journal article 2017
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Urbano, Julián (author), Marrero Llinares, M. (author)The Kendall tau and AP correlation coefficients are very commonly use to compare two rankings over the same set of items. Even though Kendall tau was originally defined assuming that there are no ties in the rankings, two alternative versions were soon developed to account for ties in two different scenarios: measure the accuracy of an...conference paper 2017
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Peter-Contesse, H. (author), Jäggi, Adrian (author), Fernández, JJ (author), Escobar, D. (author), Ayuga, F. (author), Arnold, D (author), Wermuth, M. (author), Hackel, S. (author), Otten, M. (author), Simons, W.J.F. (author), Visser, P.N.A.M. (author), Hugentobler, U. (author), Féménias, P. (author)Sentinel-1A is the first satellite of the European Copernicus programme. Equipped with a Synthetic Aperture Radar (SAR) instrument the satellite was launched on April 3, 2014. Operational since October 2014 the satellite delivers valuable data for more than two years. The orbit accuracy requirements are given as 5. cm in 3D. In order to...journal article 2017