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Technology assessment in space activities: status and outlook 总被引:1,自引:0,他引:1
Space technology is not only a matter for engineers. In various ways, political authorities and other sections of society are interested in space activities. An of space activities provides a scientific basis on which to tender guidance and advice to decision makers. The authors discuss the growing use of technology assessment in the space field with particular reference to German activities and analyse why it will become more important in the future. 相似文献
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López-Valverde Miguel A. Gerard Jean-Claude González-Galindo Francisco Vandaele Ann-Carine Thomas Ian Korablev Oleg Ignatiev Nikolai Fedorova Anna Montmessin Franck Määttänen Anni Guilbon Sabrina Lefevre Franck Patel Manish R. Jiménez-Monferrer Sergio García-Comas Maya Cardesin Alejandro Wilson Colin F. Clancy R. T. Kleinböhl Armin McCleese Daniel J. Kass David M. Schneider Nick M. Chaffin Michael S. López-Moreno José Juan Rodríguez Julio 《Space Science Reviews》2018,214(1):1-31
Space Science Reviews - Time measured by an ideal clock crucially depends on the gravitational potential and velocity of the clock according to general relativity. Technological advances in... 相似文献
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Michael Bender Ralf Stosius Florian Zus Galina Dick Jens Wickert Armin Raabe 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The German Research Centre for Geosciences (GFZ) operates a GNSS water vapour tomography system using about 350 German GNSS stations. The GNSS data processing at the GFZ works in near real-time and provides zenith total delays, integrated water vapour and slant delay data operationally. This large data set of more than 50,000 slant delays per hour is used to reconstruct spatially resolved humidity fields by means of tomographic techniques. It can be expected that additional observations from the future Galileo system provide more information with improved quality. A simulation study covering 12 h at 14 July 2009 was therefore started to estimate the impact of GPS, Galileo and GLONASS data on the GNSS tomography. It is shown that the spatial coverage of the atmosphere with slant paths is highly improved by combining observations from two or three satellite systems. Equally important for a reliable tomographic reconstruction is the distribution of slant path intersections as they are required to locate the integrated delay information. The number of intersection points can be increased by a factor of 4 or 8 if two or three systems are combined and their distribution will cover larger regions of the atmosphere. The combined data sets can be used to increase the spatiotemporal resolution of the reconstructed humidity fields up to 30 km horizontally, 300 m vertically and 15 min. The reconstruction quality could not be improved considerably using the currently available techniques. 相似文献
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Armin Heinze Kerstin Eckert Marcus J.B. Hauser Stefan Odenbach 《Acta Astronautica》2011,68(7-8):707-716
We present a hybrid algorithm to analyse complex interferograms with significant fringe deformations without an a-priori given zero-phase image containing the optical aberration of the instrument. Situations of this type frequently appear in fluid physics experiments using lateral shearing interferometers. The algorithm proposed employs a wavelet transformation in parallel with an approximation of the phase field directly after the experimental container is filled applying Zernike polynomials. As a result the aberrations of the interferometer can be described by a few coefficients. The subtraction of these phase aberrations can be traced back to a complex multiplication in the wavelet space which strongly reduces the effort of the phase unwrapping using the Goldstein algorithm. We explain the performance of the algorithm, which is not restricted to a particular interferometer type, by applying it to interferograms captured during a recent microgravity experiment. 相似文献
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P.N.A.M. Visser J. van den IJssel T. Van Helleputte H. Bock A. Jäggi G. Beutler D. Švehla U. Hugentobler M. Heinze 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Precise Orbit Determination (POD) for the Gravity field and steady-state Ocean Circulation Explorer (GOCE), the first core explorer mission by the European Space Agency (ESA), forms an integrated part of the so-called High-Level Processing Facility (HPF). Two POD chains have been set up referred to as quick-look Rapid and Precise Science Orbit determination or RSO and PSO, respectively. These chains make use of different software systems and have latencies of 1 day and 2 weeks, respectively, after tracking data availability. The RSO and PSO solutions have to meet a 3-dimensional (3D) position precision requirement of 50 cm and a few cm, respectively. The tracking data will be collected by the new Lagrange GPS receiver and the predicted characteristics of this receiver have been taken into account during the implementation phase of the two chains. 相似文献
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Michael Bender Galina Dick Maorong Ge Zhiguo Deng Jens Wickert Hans-Gert Kahle Armin Raabe Gerd Tetzlaff 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
A GNSS water vapour tomography system developed to reconstruct spatially resolved humidity fields in the troposphere is described. The tomography system was designed to process the slant path delays of about 270 German GNSS stations in near real-time with a temporal resolution of 30 min, a horizontal resolution of 40 km and a vertical resolution of 500 m or better. After a short introduction to the GPS slant delay processing the framework of the GNSS tomography is described in detail. Different implementations of the iterative algebraic reconstruction techniques (ART) used to invert the linear inverse problem are discussed. It was found that the multiplicative techniques (MART) provide the best results with least processing time, i.e., a tomographic reconstruction of about 26,000 slant delays on a 8280 cell grid can be obtained in less than 10 min. Different iterative reconstruction techniques are compared with respect to their convergence behaviour and some numerical parameters. The inversion can be considerably stabilized by using additional non-GNSS observations and implementing various constraints. Different strategies for initialising the tomography and utilizing extra information are discussed. At last an example of a reconstructed field of the wet refractivity is presented and compared to the corresponding distribution of the integrated water vapour, an analysis of a numerical weather model (COSMO-DE) and some radiosonde profiles. 相似文献
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