Dr. Gerd Joachim Ulbrich Profile

Dr. Gerd Joachim Ulbrich

at European Space Research and Technology Ctr

SPIE Involvement:

Author

Publications (14)

Proceedings Article | 21 November 2017 Open Access

Radiation impact on the characteristics of optical glasses test results on a selected set of materials

Michel Fruit, Andrei Gussarov, Francis Berghmans, Dominic Doyle, Gerd Ulbrich

Proceedings Volume 10569, 105691R (2017) https://doi.org/10.1117/12.2307918

KEYWORDS: Glasses, Refractive index, Wavefronts, Absorption, Cerium, Optical components, Optical testing, Astronomical imaging, Transmittance, Atmospheric optics

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Proceedings Article | 21 November 2017 Open Access

Development of optical ground verification method for um to sub-mm reflectors

Y. Stockman, C. Thizy, P. Lemaire, M. Georges, E. Mazy, A. Mazzoli, Y. Houbrechts, P. Rochus, S. Roose, D. Doyle, G. Ulbrich

Proceedings Volume 10568, 105681K (2017) https://doi.org/10.1117/12.2307965

KEYWORDS: Reflectors, Holography, Diffusers, Cameras, Mirrors, Interferometers, Holographic interferometry, Holograms, Spherical lenses, Interferometry

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Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. Scientific observatories require large telescopes with precisely shaped reflectors for collecting the electro-magnetic radiation from faint sources. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of the reflector shapes and antenna structures and to verify their performance under simulated space conditions (vacuum, low temperatures). Due to the specific surface characteristics of reflectors operating in these spectral regions, standard optical metrology methods employed in the visible spectrum do not provide useful measurement results.

The current state-of-the-art commercial metrology systems are not able to measure these types of reflectors because they have to face the measurement of shape and waviness over relatively large areas with a large deformation dynamic range and encompassing a wide range of spatial frequencies. 3-D metrology (tactile coordinate measurement) machines are generally used during the manufacturing process. Unfortunately, these instruments cannot be used in the operational environmental conditions of the reflector.

The application of standard visible wavelength interferometric methods is very limited or impossible due to the large relative surface roughnesses involved. A small number of infrared interferometers have been commercially developed over the last 10 years but their applications have also been limited due to poor dynamic range and the restricted spatial resolution of their detectors. These restrictions affect also the surface error slopes that can be captured and makes their application to surfaces manufactured using CRFP honeycomb technologies rather difficult or impossible.

It has therefore been considered essential, from the viewpoint of supporting future ESA exploration missions, to develop and realise suitable verification tools based on infrared interferometry and other optical techniques for testing large reflector structures, telescope configurations and their performances under simulated space conditions.

Two methods and techniques are developed at CSL.

The first one is an IR-phase shifting interferometer with high spatial resolution. This interferometer shall be used specifically for the verification of high precision IR, FIR and sub-mm reflector surfaces and telescopes under both ambient and thermal vacuum conditions.

The second one presented hereafter is a holographic method for relative shape measurement. The holographic solution proposed makes use of a home built vacuum compatible holographic camera that allows displacement measurements from typically 20 nanometres to 25 microns in one shot. An iterative process allows the measurement of a total of up to several mm of deformation. Uniquely the system is designed to measure both specular and diffuse surfaces.

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Proceedings Article | 1 November 2005 Paper

Signal-to-noise ratio of pseudo-random noise continuous wave backscatter lidar with analog detection

Valentin Mitev, Renaud Matthey, João Pereira do Carmo, Gerd Ulbrich

Proceedings Volume 5984, 598404 (2005) https://doi.org/10.1117/12.627638

KEYWORDS: Signal to noise ratio, LIDAR, Signal detection, Interference (communication), Backscatter, Continuous wave operation, Receivers, Semiconductor lasers, Modulation, Aerosols

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Proceedings Article | 21 October 2005 Paper

Calibration facility for airborne imaging spectrometers

Birgit Suhr, Peter Gege, Jens Nieke, Klaus Itten, Gerd Ulbrich

Proceedings Volume 5978, 59780R (2005) https://doi.org/10.1117/12.646691

KEYWORDS: Calibration, Sensors, Spectrometers, Mirrors, Spectral calibration, Collimators, Sensor calibration, Lamps, Airborne remote sensing, Tungsten

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Proceedings Article | 20 October 2005 Paper

Dynamic holography for the space qualification of large reflectors

C. Thizy, Y. Stockman, D. Doyle, P. Lemaire, Y. Houbrechts, M. Georges, A. Mazzoli, E. Mazy, I. Tychon, G. Ulbrich

Proceedings Volume 5965, 59650W (2005) https://doi.org/10.1117/12.624788

KEYWORDS: Reflectors, Holography, Cameras, Diffusers, Interferometers, Holographic interferometry, Mirrors, Holograms, Metrology, Image quality

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Proceedings Article | 4 November 2004 Paper

Calibration methodology for the airborne dispersive pushbroom imaging spectrometer (APEX)

Jens Nieke, Johannes Kaiser, Daniel Schlaepfer, Jason Brazile, Klaus Itten, Peter Strobl, Michael Schaepman, Gerd Ulbrich

Proceedings Volume 5570, (2004) https://doi.org/10.1117/12.566364

KEYWORDS: Calibration, Spectroscopy, Spectral calibration, Sensors, Data acquisition, Algorithm development, Short wave infrared radiation, Optical filters, Collimators, Atmospheric modeling

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Proceedings Article | 4 November 2004 Paper

APEX-airborne prism experiment: the realization phase of an airborne hyperspectral imager

Gerd Ulbrich, Roland Meynart, Jens Nieke

Proceedings Volume 5570, (2004) https://doi.org/10.1117/12.566471

KEYWORDS: Calibration, Spectroscopy, Short wave infrared radiation, Sensors, Imaging systems, Prisms, Hyperspectral imaging, Detector arrays, Thermography, Infrared radiation

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Proceedings Article | 26 October 2004 Paper

APEX: current status of the airborne dispersive pushbroom imaging spectrometer

Jens Nieke, Klaus Itten, Johannes Kaiser, Daniel Schlapfer, Jason Brazile, Walter Debruyn, Koen Meuleman, Pieter Kempeneers, Andreas Neukom, Hans Feusi, Peter Adolph, Renzo Moser, Thomas Schilliger, Marie van Quickelberghe, John Alder, Dominique Mollet, Lieve De Vos, Peter Kohler, Markus Meng, Jens Piesbergen, Peter Strobl, Michael Schaepman, Jose Gavira, Gerd Ulbrich, Roland Meynart

Proceedings Volume 5542, (2004) https://doi.org/10.1117/12.561430

KEYWORDS: Spectroscopy, Calibration, Algorithm development, Sensors, Human-machine interfaces, Prisms, Short wave infrared radiation, Imaging systems, Data acquisition, Computing systems

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Proceedings Article | 13 September 2004 Paper

Experimental investigations of the potential of commercial laser sources for spaceborne imaging laser sensors

Andreas Ullrich, Joao Pereira do Carmo, Gerd Ulbrich

Proceedings Volume 5412, (2004) https://doi.org/10.1117/12.542490

KEYWORDS: Pulsed laser operation, Laser sources, Sensors, Fiber lasers, Image sensors, Semiconductor lasers, Optical sensors, Stereoscopy, 3D modeling, Laser systems engineering

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Proceedings Article | 2 February 2004 Paper

APEX: current status of the airborne dispersive pushbroom imaging spectrometer

Michael Schaepman, Klaus Itten, Daniel Schlaepfer, Johannes Kaiser, Jason Brazile, Walter Debruyn, Andreas Neukom, Hans Feusi, Peter Adolph, Renzo Moser, Thomas Schilliger, Lieve De Vos, Guido Brandt, Peter Kohler, Markus Meng, Jens Piesbergen, Peter Strobl, Jose Gavira, Gerd Ulbrich, Roland Meynart

Proceedings Volume 5234, (2004) https://doi.org/10.1117/12.513745

KEYWORDS: Spectroscopy, Calibration, Data acquisition, Interfaces, Human-machine interfaces, Algorithm development, Prisms, Sensors, Control systems, Navigation systems

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Proceedings Article | 20 November 2003 Paper

Canister-free videogrammetry system for thermal vacuum and space applications

Stephane Roose, Yvan Stockman, Jean-Christophe Bolsee, Dominic Doyle, Gerd Ulbrich

Proceedings Volume 5190, (2003) https://doi.org/10.1117/12.503457

KEYWORDS: Cameras, Imaging systems, Calibration, Metrology, 3D acquisition, Holography, Charge-coupled devices, Target recognition, Reflectors, 3D metrology

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Proceedings Article | 26 October 2000 Paper

Space radiation sensitivity of glasses: first results toward a comprehensive dose coefficients database

Michel Fruit, Andrei Gusarov, Dominic Doyle, Gerd Ulbrich, Alex Hermanne

Proceedings Volume 4134, (2000) https://doi.org/10.1117/12.405352

KEYWORDS: Glasses, Refractive index, Radiation effects, Absorption, Astronomical imaging, Signal attenuation, Wavefronts, Aerospace engineering, Databases, Error analysis

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