- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - peration of a Carbon Nanotube Field-Emission Cathode in Low Earth Orbit
摘要： A carbon nanotube-based field emission cathode (FEC) has been researched and developed by the Japan Aerospace Exploration Agency mainly for space debris removal systems with electrodynamic tether (EDT) propulsion. An in- orbit experiment to demonstrate the EDT technologies including the FEC was planned and conducted in early 2017. The FEC operated well without any critical trouble during the one-week mission period. The data obtained includes its electron emission capability to space plasma and its durability in low Earth orbit, which suggest the prospect of using the FEC in space.
关键词： in-orbit experiment,electrodynamic tether,field emission cathode,carbon nanotube,space debris
更新于2025-09-23 15:21:21
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Tumbling object deorbiting using spaceborne laser engagement a?? A CubeSat case study
摘要： This paper demonstrates active space debris removal using spaceborne laser systems. The laser beam and the surface of the target are discretised into multiple rays and finite elements, respectively, for laser-target interaction modelling, in which the laser ablation process is investigated. A high-fidelity attitude/orbit propagator tool is developed to account for both the linear impulse and angular impulse induced by the laser engagement and other perturbations. The laser system is activated only when three switch criteria are satisfied. In numerical simulations, laser pulses from international space station are generated to deorbit a 3U CubeSat with initially tumbling modes. The results validate the effectiveness of deorbiting tumbling CubeSats using spaceborne laser engagement, with the perigee height lowered by approximately 2:4 km in around 30 min after 2 h propagation. It is also found that the laser engagement becomes more effective for an initially faster rotating object.
关键词： Coupled attitude/orbit dynamics,Spaceborne laser system,Tumbling CubeSat,Space debris
更新于2025-09-19 17:13:59
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3-D-Printed Modified Butler Matrix Based on Gap Waveguide at W-Band for Monopulse Radar
摘要： This article presents the design and fabrication of low-loss, -weight, and -cost, modified Butler matrix in groove gap waveguide technology at W-band, implemented by additive manufacturing. The design, simulations, and measurements of the elements that conform to the modified Butler each of matrix are presented. The proposed modified Butler matrix is asymmetric and oriented to an easy assembly with a radial antenna in order to obtain simultaneous sum and difference patterns for a narrowband radar application. The measured individual components of the modified Butler matrix fit very well with the simulations. As for the full modified Butler matrix, measurements provide a 0.7% bandwidth below ?20 dB for sum and difference ports centered at 94 GHz. The amplitude and phase imbalance are below 1.5 dB and 20?, respectively. This narrow bandwidth is due to the difference in length between input and output ports due to the asymmetry of the design. The total losses of the modified Butler matrix are below 1 dB.
关键词： low profile,distribution network,Additive manufacturing,butler matrix,low cost,W-band,point-to-point communications,low weight,groove gap waveguide (GGW),radar,low loss,monopulse,space debris
更新于2025-09-16 10:30:52
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Highly compact nanosecond laser for space debris tracking
摘要： This study demonstrated the use of a highly compact nanosecond laser system operating at 532 nm and producing a maximum output power of 70 W with a pulse width of 5 ns at 0.5 kHz, for space debris tracking. To improve the ranging accuracy while minimizing the influence of the pulse noise, a bidirectional Q-switch was adopted in the oscillator to generate a short pulse width with less tailing. The laser was applied for low-Earth-orbit space debris tracking, and space debris with the farthest distance of 1701.9 km at the minimum radar cross-section of 1 m2 could be detected with a ranging precision of up to 26.90 cm.
关键词： Solid-state laser,Space debris tracking,Bidirectional Q-switch,Nanosecond
更新于2025-09-12 10:27:22
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The progress of laser ranging technology at Shanghai Astronomical Observatory
摘要： As an important station of International Laser Ranging Service (ILRS), Shanghai Astronomical Observatory (SHAO) has upgraded Satellite Laser Ranging (SLR) system with high repetition rate and achieved some technological progress. There are a lot of improvements for overall system performance, such as annual observation passes, measurement precision and quality of observation data. SLR technology with repetition rate of 10 kHz is accomplished ?rstly in China, and space debris laser ranging technology with 200 Hz laser is promoted and proved to be more detective for weak echo, which lead to successful measurement for 40,000 km satellites and space debris within 3000 km. At the same time, SLR based on multi-telescopes and 1064 nm wavelength are planned to make a breakthrough of detection capabilities, and also to expand its application ?elds. These progresses will be introduced in this paper in detail.
关键词： Detection capability,Satellite laser ranging,Space debris,Data quality
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Torino, Italy (2019.6.19-2019.6.21)] 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - LED-based attitude reconstruction and back-up light communication: experimental applications for the LEDSAT CubeSat
摘要： Optical observations are intensively applied to space debris monitoring for the achievement of orbit determination and for gathering information on their attitude motion, even if constrained by light conditions. Light Emitting Diodes (LEDs) installed on the external surfaces of a satellite could increase the visibility interval to the whole eclipse time. LEDSAT (LED-based small SATellite) is a 1-Unit CubeSat aimed at demonstrating the effectiveness of LEDs for the improvement of space debris optical monitoring algorithms. The LEDSAT experimental mode includes flashing patterns that will allow the CubeSat attitude reconstruction and the testing of a back-up light-based communication method. This paper will describe the features of the LEDSAT experimental mode, by describing the needed measurements for achieving the satellite LED-based attitude reconstruction and the features of the back-up LED communication.
关键词： orbit determination,attitude reconstruction,CubeSat,space debris,LED,light communication
更新于2025-09-11 14:15:04
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Analysis of Laser Ranges and Angular Measurements Data Fusion for Space Debris Orbit Determination
摘要： In the framework of space debris, the orbit determination process is a fundamental step, both, for researchers and for satellite operators. The accurate knowledge of the orbit of space debris objects is needed to allow space debris characterization studies and to avoid unnecessary collision avoidance maneuvers. The accuracy of the results of an orbit determination process depends on several factors as the number, the accuracy, the kind of processed measurements, their distribution along the orbit, and the object-observer relative geometry. When the observation coverage of the target orbit is not homogeneous, the accuracy of the orbit determination can be improved processing di?erent kind of observables. Recent studies showed that the satellite laser ranging technique can be successfully applied to space debris. In this paper, we will investigate the bene?ts of using laser ranges and angular measurements for the orbit determination process. We will analyze the in?uence of the number of used observations, of the covered arc of orbit, of each observable, and of the observation geometry on the estimated parameters. Finally, using data acquired on short observation arcs, we analyze the achievable accuracies for the orbital regimes with the highest space debris density, and to the consequences of the data fusion on catalog maintenance operations. The results shown are obtained using only real data (both angular and laser measurements) provided by sensors of the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald owned by the Astronomical Institute of the University of Bern (AIUB) and for some studies also using ranges provided from other stations of the International Laser Ranging Service (ILRS).
关键词： orbit determination,real range measurements,data fusion,real angular measurements,accuracy improvements,space debris
更新于2025-09-11 14:15:04
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3-D Inverse Synthetic Aperture Ladar Imaging and Scaling of Space Debris Based on the Fractional Fourier Transform
摘要： The inverse synthetic aperture ladar (ISAL) is an important method for observation and imaging of space targets. Here, a 3-D ISAL imaging algorithm is proposed for spinning targets such as space debris. Since laser wavelength is 4–5 orders of magnitude smaller than that of microwave, the Doppler frequency caused by target motion is more pronounced in ISAL. Doppler frequency modulation rates can be estimated by the fractional Fourier transform with respect to azimuth slow time even when the rotation angle is small such that scattering centers do not migrate through a range cell. Then, slant range, Doppler frequency, and Doppler frequency modulation rates form a 3-D space. The angular velocity and the incident angle can be estimated by the position relationship between the scattering centers in two observations. After image scaling, the 3-D shape and size of the target can be obtained. The 3-D structure of the target in the simulation experiment is accurately reconstructed. Monte Carlo experiments are conducted to discuss the effect of the signal-to-noise ratio and observation time on the algorithm. Finally, the effectiveness and robustness of the algorithm are veri?ed.
关键词： space debris,3-D imaging,inverse synthetic aperture radar (ISAR),fractional Fourier transform (FrFT),laser radar
更新于2025-09-10 09:29:36