scholarly journals VERIFICATION OF THE SENTINEL-4 FOCAL PLANE SUBSYSTEM

2017 ◽  
Vol XLII-1/W1 ◽  
pp. 567-573 ◽  
Author(s):  
C. Williges ◽  
R. Hohn ◽  
H. Rossmann ◽  
S. Hilbert ◽  
M. Uhlig ◽  
...  
Keyword(s):  
Focal Plane ◽  
Vacuum Chamber ◽  
Integrating Sphere ◽  
Atmospheric Conditions ◽  
Thermal Vacuum ◽  
Camera System ◽  
Set Up ◽  
German Aerospace ◽  
Flight Model ◽  
Reference Detector

The Sentinel-4 payload is a multi-spectral camera system which is designed to monitor atmospheric conditions over Europe. The German Aerospace Center (DLR) in Berlin, Germany conducted the verification campaign of the Focal Plane Subsystem (FPS) on behalf of Airbus Defense and Space GmbH, Ottobrunn, Germany. The FPS consists, inter alia, of two Focal Plane Assemblies (FPAs), one for the UV-VIS spectral range (305 nm … 500 nm), the second for NIR (750 nm … 775 nm). In this publication, we will present in detail the opto-mechanical laboratory set-up of the verification campaign of the Sentinel-4 Qualification Model (QM) which will also be used for the upcoming Flight Model (FM) verification. The test campaign consists mainly of radiometric tests performed with an integrating sphere as homogenous light source.<br><br> The FPAs have mainly to be operated at 215 K ± 5 K, making it necessary to exploit a thermal vacuum chamber (TVC) for the test accomplishment. This publication focuses on the challenge to remotely illuminate both Sentinel-4 detectors as well as a reference detector homogeneously over a distance of approximately 1 m from outside the TVC. Furthermore selected test analyses and results will be presented, showing that the Sentinel-4 FPS meets specifications.

scholarly journals SPACE SIMULATION OF THE CHINA-BRAZIL EARTH RESOURCES SATELLITE – CBERS

2004 ◽  
Vol 3 (2) ◽  
Author(s):  
E. C. Garcia ◽  
M. B. Dos Santos ◽  
J. S. De Almeida ◽  
D. L. Panissi
Keyword(s):  
Heat Sink ◽  
Vacuum Chamber ◽  
Thermal Vacuum ◽  
Operational Conditions ◽  
Cold Plates ◽  
Vacuum Test ◽  
Proper Operation ◽  
Flight Model ◽  
Simulation Chamber

Space Simulation Tests are performed in spacecraft in order to verify equipment proper operation under thermal vacuum conditioning and to verify the correct workmanship in the assembling of the flight spacecraft as a whole. This paper presents the space simulation (thermal vacuum test) developed in the China Brazil Earth Resources Satellite, Flight Model no. 2, that took place at the Integration and Tests Laboratory – LIT, INPE. Measuring approximately 1.8 x 2.0 x 2.2m, weighting 1,500 kg and carrying three cameras as the main payload, this spacecraft is scheduled to be launched in China. The spacecraft was installed in the 3x3m space simulation chamber and the tests run 24 hours a day completing a total of 350 hours. Using the technique of skin-heaters complemented by the thermal vacuum chamber thermally conditioned shrouds and cold plates, dedicated heat inputs and heat sink where applied at the spacecraft surfaces in order to obtain the required high and low acceptance values of temperature and, subsequently, simulating the operational conditions for the necessary electronic subsystems functioning tests of the spacecraft. This test campaign included teams from both China and Brazil, summing a total of 67 people directly involved.

scholarly journals Endoscopic Pan/Tilt Camera for Thorax Interventions – Design and first results

2019 ◽  
Vol 5 (1) ◽  
pp. 517-519
Author(s):  
Alexander Mrokon ◽  
Peter P. Pott ◽  
Volker Steger
Keyword(s):  
Minimally Invasive ◽  
Inclination Angle ◽  
Magnetic Circuit ◽  
Mechanical Stability ◽  
Fem Simulation ◽  
Camera System ◽  
Design Changes ◽  
First Results ◽  
Set Up ◽  
Future Work

AbstractMinimally invasive surgery in some cases suffers from a limited view because certain areas are obscured by others. In this paper, a system is described, which can be used in minimally invasive procedures as an addition to a standard endoscope to improve the range of view. Through FEM simulation a magnetic circuit was designed to position the camera head. Subsequently, a camera positioning system was set up that includes an extracorporeal and an intracorporeal unit. The first controls the intracorporeal system. The latter has a camera inclination angle of up to 65° and an additional vertically downward viewing angle when aligned in parallel (inclination angle 0°). The panning angle is 360°. The camera system was evaluated in lab and cadaver trials. It has been found that the size of the intracorporeal system (16 × 10 × 150 mm) represents a major problem. Future work will focus of the reduction of the system’s size, the improvement of the camera image quality, and design changes considering mechanical stability.

scholarly journals GEOMETRIC CALIBRATION AND VALIDATION OF ULTRACAM AERIAL SENSORS

2016 ◽  
Vol XL-3/W4 ◽  
pp. 51-53
Author(s):  
Michael Gruber ◽  
Bernhard Schachinger ◽  
Marc Muick ◽  
Christian Neuner ◽  
Helfried Tschemmernegg
Keyword(s):  
Aerial Images ◽  
Camera System ◽  
Geometric Calibration ◽  
Calibration And Validation ◽  
Camera Systems ◽  
Laboratory Calibration ◽  
Software Product ◽  
Validation Procedure ◽  
Set Up

We present details of the calibration and validation procedure of UltraCam Aerial Camera systems. Results from the laboratory calibration and from validation flights are presented for both, the large format nadir cameras and the oblique cameras as well. Thus in this contribution we show results from the UltraCam Eagle and the UltraCam Falcon, both nadir mapping cameras, and the UltraCam Osprey, our oblique camera system. This sensor offers a mapping grade nadir component together with the four oblique camera heads. The geometric processing after the flight mission is being covered by the UltraMap software product. Thus we present details about the workflow as well. The first part consists of the initial post-processing which combines image information as well as camera parameters derived from the laboratory calibration. The second part, the traditional automated aerial triangulation (AAT) is the step from single images to blocks and enables an additional optimization process. We also present some special features of our software, which are designed to better support the operator to analyze large blocks of aerial images and to judge the quality of the photogrammetric set-up.

Representative Terrestrial Solar Brightness Profiles

2002 ◽  
Vol 124 (2) ◽  
pp. 198-204 ◽  
Author(s):  
Andreas Neumann ◽  
Andreas Witzke ◽  
Scott A. Jones ◽  
Gregor Schmitt
Keyword(s):  
Energy Systems ◽  
Brightness Distribution ◽  
Statistical Weight ◽  
Image Size ◽  
Solar Thermal Energy ◽  
Lawrence Berkeley Laboratory ◽  
Camera System ◽  
Solar Brightness ◽  
Average Profile ◽  
German Aerospace

Solar thermal energy systems often use optical imaging concentrators. The image size and shape produced in the focal plane of the concentrator system depends on the solar brightness distribution. Therefore, the forward scattering of solar radiation by the Earth’s atmosphere modifies the solar brightness distribution and creates a circumsolar aureole. The circumsolar ratio, the energy contained in the solar aureole compared to total energy, can impact the performance of these concentrating systems. Based on about 2300 sunshape measurements from sites in France, Germany, and Spain made with a camera system developed by the German Aerospace Center (DLR), average solar brightness profiles with a circumsolar ratio of about 0%, 5%, 10%, 20%, 30%, and 40% were generated. These profiles are compared to the measurements taken by the Lawrence Berkeley Laboratory (LBL) in the late 1970s and a commonly used limb-darkened solar brightness profile, as known from astronomy. A statistical analysis gives information on the frequency of occurrence of each of the average profiles. The profiles combined with the statistical weight should offer a numerical database for calculating the influence of variable conditions of the sunlight scattering on solar concentrating systems. Furthermore, a single average profile was calculated from the DLR data.

Validation of a Strategy for Deformation Monitoring of the Herschel Spacecraft Under Ambient Conditions by Photogrammetry

2009 ◽  
Vol 52 (1) ◽  
pp. 20-42
Author(s):  
Jafar Parian ◽  
Alessandro Cozzani ◽  
Matteo Appolloni ◽  
Gianluca Casarosa
Keyword(s):  
Local Oscillator ◽  
Deformation Monitoring ◽  
Ambient Conditions ◽  
Thermal Vacuum ◽  
Large Space ◽  
Balance Test ◽  
Vacuum Chambers ◽  
Network Simulations ◽  
Set Up ◽  
Global Accuracy

In the frame of the development of a videogrammetric system to be used in thermal/vacuum chambers at the ESA-ESTEC and other sites across Europe, the design of a network using micro-cameras was specified by ESA-ESTEC. The selected test set-up is the photogrammetric test of the Herschel Spacecraft Flight Model in the ESTEC Large Space Simulator. The videogrammetric system will be used to verify the Herschel Telescope alignment and Telescope positioning with respect to the Local Oscillator Unit inside the Large Space Simulator during thermal/vacuum/balance test phases. We designed a close-range photogrammetric network by heuristic simulation with a global accuracy of 1:100,000. A thermal/vacuum qualified videogrammetric system, which is able to work in vacuum and at cryo-temperatures in order to acquire images according to the designed network, was constructed by ESA-ESTEC Test Centre Division. In this paper we will present the videogrammetric system, the photogrammetric considerations, accuracy aspects, the result of photogrammetric network simulations, and real measurements. The results of real videogrammetric measurements of a dummy setup similar to the setup of Herschel spacecraft show a successful performance of the system in terms of functionality and accuracy.

The effect of temperature, water content and composition of the atmosphere on the viability of carrot, onion and parsnip seeds in storage

1948 ◽  
Vol 38 (1) ◽  
pp. 84-89 ◽  
Author(s):  
R. Gane
Keyword(s):  
Water Content ◽  
Effect Of Temperature ◽  
Atmospheric Conditions ◽  
Set Up ◽  
Temperature Water

SUMMARYCertain vegetable seeds show such a marked loss of viability on storage that they are generally useless after 1–2 years storage under average commercial conditions; the most valuable seeds which store particularly badly are parsnip, onion and carrot. Storage experiments were therefore designed and set up to show the effect of the following factors on the viability of the seeds:(a) The water content as determined by the humidity of the atmosphere in which the seeds were stored.(b) Atmospheric conditions, viz. ventilated air, unventilated air and nitrogen.(c) Temperature.

Spectroscopy of transfermium nuclei using the GABRIELA set up at the focal plane of the VASSILISSA recoil separator

2010 ◽  
Author(s):  
K. Hauschild ◽  
A. Lopez-Martens ◽  
Ch. Briançon ◽  
P. Désesquelles ◽  
S. Garcia-Santamaria ◽  
...  
Keyword(s):  
Focal Plane ◽  
Recoil Separator ◽  
Set Up

scholarly journals An airborne perfluorocarbon tracer system and its first application for a Lagrangian experiment

2014 ◽  
Vol 7 (7) ◽  
pp. 6791-6822
Author(s):  
Y. Ren ◽  
R. Baumann ◽  
H. Schlager
Keyword(s):  
Stratospheric Ozone ◽  
Lagrangian Model ◽  
Research Vessel ◽  
Gas Chromatography Mass Spectrometry ◽  
Sampling System ◽  
Tracer System ◽  
Research Aircraft ◽  
Set Up ◽  
German Aerospace ◽  
First Time

Abstract. A perfluorocarbon tracer system (PERTRAS), specifically designed for Lagrangian aircraft experiments, has been developed by the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center, DLR). It consists of three main parts: a tracer release unit (RU), an adsorption tube sampler (ATS) and a tracer analytical system. The RU was designed for airborne tracer release experiments; meanwhile, it can be used on various platforms for different experimental purpose (here research vessel). PERTRAS was for the first time applied in the field campaign Stratospheric ozone: halogen Impacts in a Varying Atmosphere (SHIVA) in November 2011. An amount of 8.8 kg perfluoromethylcyclopentane (PMCP) was released aboard the research vessel Sonne (RV Sonne) near the operational site of this campaign, Miri, Malaysia, on 21 November. The tracer samples collected using the ATS on board the DLR research aircraft Falcon were analyzed in the laboratory using a thermal desorber/gas chromatography/mass spectrometry (TD/GC/MS) system. Guided by forecasts calculated with the Lagrangian model, Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT), 64 tracer samples were collected onboard the Falcon approximately 5 and 25 h after the release, respectively, mostly with a time resolution of 1 min. Enhanced PMCP concentrations relative to ambient PMCP background values (mean: 6.62 fmol mol−1) were detected during three intersects of the fresh tracer plume (age 5 h), with a maximum value of 301.33 fmol mol−1. This indicates that the fresh tracer plume was successfully intercepted at the forecasted position. During the second flight, 25 h after the release, the center of tracer plume was not detected by the sampling system due to a faster advection of the plume than forecasted. The newly developed PERTRAS system has been successfully deployed for the first time. The instrumental set-up and comparisons between the measurements and HYSPLIT simulations are presented in this study.

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