4 results on '"Tim Flohrer"'
Search Results
2. Daylight space debris laser ranging
- Author
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Tim Flohrer, Beatriz Jilete, Georg Kirchner, Franz Koidl, Peiyuan Wang, and Michael Steindorfer
- Subjects
0301 basic medicine ,business.product_category ,media_common.quotation_subject ,Science ,General Physics and Astronomy ,02 engineering and technology ,General Biochemistry, Genetics and Molecular Biology ,Article ,law.invention ,03 medical and health sciences ,Space physics ,law ,Daylight ,lcsh:Science ,Remote sensing ,media_common ,Multidisciplinary ,Satellite laser ranging ,General Chemistry ,021001 nanoscience & nanotechnology ,Laser ,Retroreflector ,030104 developmental biology ,Rocket ,Sky ,Physics::Space Physics ,Environmental science ,lcsh:Q ,Astrophysics::Earth and Planetary Astrophysics ,0210 nano-technology ,business ,Space debris - Abstract
Satellite laser ranging allows to measure distances to satellites equipped with retroreflectors in orbits up to 36000 km. Utilizing a higher powered laser, space debris laser ranging detects diffuse reflections from defunct satellites or rocket bodies up to a distance of 3000 km. So far space debris laser ranging was only possible within a few hours around twilight while it is dark at the satellite laser ranging station and space debris is illuminated by the sun. Here we present space debris laser ranging results during daylight. Space debris objects are visualized against the blue sky background and biases corrected in real-time. The results are a starting point for all space debris laser ranging stations to drastically increase their output in the near future. A network of a few stations worldwide will be able to improve orbital predictions significantly as necessary for removal missions, conjunction warnings, avoidance maneuvers or attitude determination., Space debris laser ranging is a technique to measure distances to defunct satellites or rocket bodies in orbits around Earth which was only possible within a few hours around twilight. Here, the authors show the first space debris laser ranging results during daylight while correcting inaccurate predictions using a real-time target detection software.
- Published
- 2020
3. Application of Attributables to the Correlation of Surveillance Radar Measurements
- Author
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Benedikt Reihs, Tim Flohrer, Jan Siminski, Thomas Schildknecht, and Alessandro Vananti
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Computer science ,media_common.quotation_subject ,FOS: Physical sciences ,Aerospace Engineering ,02 engineering and technology ,01 natural sciences ,law.invention ,0203 mechanical engineering ,Low earth orbit ,law ,Region of interest ,0103 physical sciences ,Radar ,United States Space Surveillance Network ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,media_common ,Earth and Planetary Astrophysics (astro-ph.EP) ,020301 aerospace & aeronautics ,business.industry ,520 Astronomy ,Process (computing) ,Pattern recognition ,Orbit ,Sky ,Orbit (dynamics) ,Artificial intelligence ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,Secondary surveillance radar ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Space surveillance by radar is especially used for the low Earth orbit to maintain a database, also called catalogue, of objects on orbit. Among others, surveillance radars which are constantly scanning a region of interest in the sky are used for this purpose. The detections from such a radar which cannot be assigned to an already known catalogue object might not contain enough information to obtain a reliable initial orbit for a new catalogue entry from a single measured pass, also called tracklet. Instead, two tracklets can be combined to improve the quality of the initial orbit which leads to the correlation problem. This means that it has to be tested whether two tracklets belong to the same object and an initial orbit has to be derived by combining the tracklets. A common approach to condense the information in the tracklet is fitting them with so-called attributables. Because radar observations include different types of observables, the fitting of these attributables has to be considered as an important part of the entire correlation process. This paper analyses the effect of the attributable fitting considering the achieved accuracy and influence on the tracklet correlation. A new singularity-free coordinate system is introduced, which improves the results of the fitting and correlation. Finally, a test on a simulated survey scenario introduces two additional filters to remove false positive correlations. It is shown that the attributable-based approach can be applied successfully to tracklets of up to three minutes length with different detection frequencies., 36 pages, 33 figures
- Published
- 2020
4. Impact of End-of-Life manoeuvres on the collision risk in protected regions
- Author
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Benjamin Bastida Virgili, Tim Flohrer, Volker Gass, Stefan Frey, and Stijn Lemmens
- Subjects
020301 aerospace & aeronautics ,business.product_category ,010504 meteorology & atmospheric sciences ,Meteoroid ,Debris flux ,Aerospace Engineering ,02 engineering and technology ,Graveyard orbit ,Geodesy ,Collision ,01 natural sciences ,Collision risk ,EOL manoeuvres ,Mitigation guidelines ,0203 mechanical engineering ,Rocket ,Geostationary orbit ,Environmental science ,Orbit (control theory) ,business ,0105 earth and related environmental sciences ,Space debris ,Remote sensing - Abstract
The Inter-Agency Space Debris Coordination Committee (IADC) Space Debris Mitigation Guidelines, issued in 2002 and revised in 2007, address the post mission disposal of objects in orbit. After their mission, objects crossing the Low Earth Orbit (LEO) should have a remaining lifetime in orbit not exceeding 25 years. Objects near the Geostationary Orbit (GEO) region should be placed in an orbit that remains outside of the GEO protected region. In this paper, the impact of satellites and rocket bodies performing End-of-Life (EOL) orbital manoeuvres on the collision risk in the LEO and GEO protected regions is investigated. The cases of full or partial compliance with the IADC post mission disposal guideline are studied. ESA's Meteoroid and Space Debris Terrestrial Environment Reference (MASTER) model is used to compare the space debris flux rate of the object during the remaining lifetime estimated for the pre-EOL-manoeuvre and for the post-EOL-manoeuvre orbit. The study shows that, on average, the probability of collision can be significantly decreased by performing an EOL-manoeuver.
- Published
- 2017
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