for Journals by Title or ISSN for Articles by Keywords help
 Subjects -> COMPUTER SCIENCE (Total: 2007 journals)     - ANIMATION AND SIMULATION (30 journals)    - ARTIFICIAL INTELLIGENCE (98 journals)    - AUTOMATION AND ROBOTICS (98 journals)    - CLOUD COMPUTING AND NETWORKS (60 journals)    - COMPUTER ARCHITECTURE (9 journals)    - COMPUTER ENGINEERING (9 journals)    - COMPUTER GAMES (16 journals)    - COMPUTER PROGRAMMING (24 journals)    - COMPUTER SCIENCE (1169 journals)    - COMPUTER SECURITY (46 journals)    - DATA BASE MANAGEMENT (13 journals)    - DATA MINING (32 journals)    - E-BUSINESS (22 journals)    - E-LEARNING (29 journals)    - ELECTRONIC DATA PROCESSING (21 journals)    - IMAGE AND VIDEO PROCESSING (39 journals)    - INFORMATION SYSTEMS (108 journals)    - INTERNET (92 journals)    - SOCIAL WEB (50 journals)    - SOFTWARE (34 journals)    - THEORY OF COMPUTING (8 journals) COMPUTER SCIENCE (1169 journals)                  1 2 3 4 5 6 | Last
 CEAS Space Journal   [SJR: 0.221]   [H-I: 5]   [1 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1868-2510 - ISSN (Online) 1868-2502    Published by Springer-Verlag  [2355 journals]
• MONTE: the next generation of mission design and navigation software
• Authors: Scott Evans; William Taber; Theodore Drain; Jonathon Smith; Hsi-Cheng Wu; Michelle Guevara; Richard Sunseri; James Evans
Abstract: Abstract The Mission analysis, Operations and Navigation Toolkit Environment (MONTE) (Sunseri et al. in NASA Tech Briefs 36(9), 2012) is an astrodynamic toolkit produced by the Mission Design and Navigation Software Group at the Jet Propulsion Laboratory. It provides a single integrated environment for all phases of deep space and Earth orbiting missions. Capabilities include: trajectory optimization and analysis, operational orbit determination, flight path control, and 2D/3D visualization. MONTE is presented to the user as an importable Python language module. This allows a simple but powerful user interface via CLUI or script. In addition, the Python interface allows MONTE to be used seamlessly with other canonical scientific programming tools such as SciPy, NumPy, and Matplotlib. MONTE is the prime operational orbit determination software for all JPL navigated missions.
PubDate: 2018-01-06
DOI: 10.1007/s12567-017-0171-7

• Editorial
• Authors: Andreas Fix; Giampiero Naletto; Ian Hutchinson; Nikos Karafolas; Wolfgang Riede
Pages: 367 - 369
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0182-4
Issue No: Vol. 9, No. 4 (2017)

• NanoVipa: a miniaturized high-resolution echelle spectrometer, for the
monitoring of young stars from a 6U Cubesat
• Authors: G. Bourdarot; E. Le Coarer; X. Bonfils; E. Alecian; P. Rabou; Y. Magnard
Pages: 411 - 419
Abstract: Abstract We introduce to astrophysical instrumentation and space optics the use of virtually imaged phased array (VIPA) to shrink échelle spectrometers and/or increase their resolution. Here, we report on both a concept of an echelle spectrometer with resolution $$R=50{,}000$$ (@653nm), which fits a 6U nanosatellite platform ( $${{1{\rm U}= 10\,{\rm cm} \times 10\,{\rm cm} \times 10\,{\rm cm}}}$$ ), and on our laboratory tests on a $$R=200{,}000$$ demonstrator. The outline of our paper is as follows: Sect. 1 introduces our concept of a 6U payload comprising an échelle spectrometer based on the VIPA. We present also the science cases of monitoring young stars, and the wider science landscape amenable with larger telescopes. Section 2 gives a more detailed description of the VIPA and of its implementation in a cross-dispersed spectrometer. Section 3 shows the first results at $$R=200{,}000$$ we already achieved at the Institut de Planétologie et d’Astrophysique de Grenoble (IPAG). Finally, Sect. 4 is a discussion on the remaining technical points to study.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0168-2
Issue No: Vol. 9, No. 4 (2017)

• Development of micro-mirror slicer integral field unit for space-borne
solar spectrographs
• Authors: Yoshinori Suematsu; Kosuke Saito; Masatsugu Koyama; Yukiya Enokida; Yukinobu Okura; Tomoyasu Nakayasu; Takashi Sukegawa
Pages: 421 - 431
Abstract: Abstract We present an innovative optical design for image slicer integral field unit (IFU) and a manufacturing method that overcomes optical limitations of metallic mirrors. Our IFU consists of a micro-mirror slicer of 45 arrayed, highly narrow, flat metallic mirrors and a pseudo-pupil-mirror array of off-axis conic aspheres forming three pseudo slits of re-arranged slicer images. A prototype IFU demonstrates that the final optical quality is sufficiently high for a visible light spectrograph. Each slicer micro-mirror is 1.58 mm long and 30 $$\upmu$$ m wide with surface roughness $$\le$$ 1 nm rms, and edge sharpness $$\le$$ 0.1 $$\upmu$$ m, etc. This IFU is small size and can be implemented in a multi-slit spectrograph without any moving mechanism and fore optics, in which one slit is real and the others are pseudo slits from the IFU. The IFU mirrors were deposited by a space-qualified, protected silver coating for high reflectivity in visible and near IR wavelength regions. These properties are well suitable for space-borne spectrograph such as the future Japanese solar space mission SOLAR-C. We present the optical design, performance of prototype IFU, and space qualification tests of the silver coating.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0157-5
Issue No: Vol. 9, No. 4 (2017)

• Fused silica GRISMs manufactured by hydrophilic direct bonding at moderate
heating
• Authors: G. Kalkowski; K. Grabowski; G. Harnisch; T. Flügel-Paul; U. Zeitner; S. Risse
Pages: 433 - 440
Abstract: Abstract For high-resolution spectroscopy in space, GRISM elements—obtained by patterning gratings onto a prism surface—find increasing applications. We report on GRISM manufacturing by joining the individual functional elements—prisms and gratings—to suitable components by the technology of hydrophilic direct bonding. Fused silica was used as a substrate material and binary gratings were fabricated by standard e-beam lithography and dry etching. Alignment of the grating dispersion direction to the prism angle was realized by passive adjustment on dedicated bonding gear matched to the substrate geometry. Materials adapted bonds of high transmission, stiffness, and strength were obtained after heat treatment at temperatures of about 200 °C in vacuum. Examples for bonding uncoated as well as coated grating surfaces are given. The results illustrate the great potential of hydrophilic glass direct bonding for manufacturing transmission optics to be used in space or other heavy duty applications.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0158-4
Issue No: Vol. 9, No. 4 (2017)

• Complex optical interference filters with stress compensation for space
applications
• Authors: Thomas Begou; Hélène Krol; Dragan Stojcevski; Fabien Lemarchand; Michel Lequime; Catherine Grezes-Besset; Julien Lumeau
Pages: 441 - 449
Abstract: Abstract We present hereafter a study of complex bandpass optical interference filters with central wavelengths ranging in blue region or in the near infrared. For these applications, the required functions are particularly complex as they must present a very narrow bandwidth as well as a high level of rejection over a broad spectral range. Moreover, these components must have a good flatness meaning that the stress induced by the different layers has to be taken in account in the filter design. We present a thorough study of these filters including their design, fabrication using Plasma Assisted Reactive Magnetron Sputtering (PARMS) and characterization. Excellent agreement between experimental and theoretical spectral performances associated with a final sag of 326 and 13 nm, and uniformity from −0.05 to 0.10 and −0.10 to 0.20% are demonstrated for the two manufactured filters.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0149-5
Issue No: Vol. 9, No. 4 (2017)

• Wavefront error measurement of the concave ellipsoidal mirrors of the
METIS coronagraph on ESA Solar Orbiter mission
• Authors: P. Sandri
Pages: 451 - 458
Abstract: Abstract The paper describes the alignment technique developed for the wavefront error measurement of ellipsoidal mirrors presenting a central hole. The achievement of a good alignment with a classic setup at the finite conjugates when mirrors are uncoated cannot be based on the identification and materialization at naked eye of the retro-reflected spot by the mirror under test as the intensity of the retro-reflected spot results to be ≈1E−3 of the intensity of the injected laser beam of the interferometer. We present the technique developed for the achievement of an accurate alignment in the setup at the finite conjugate even in condition of low intensity based on the use of an autocollimator adjustable in focus position and a small polished flat surface on the rear side of the mirror. The technique for the alignment has successfully been used for the optical test of the concave ellipsoidal mirrors of the METIS coronagraph of the ESA Solar Orbiter mission. The presented method results to be advantageous in terms of precision and of time saving also when the mirrors are reflective coated and integrated into their mechanical hardware.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0150-z
Issue No: Vol. 9, No. 4 (2017)

• The PILOT optical alignment for its first flight
• Authors: B. Mot; Y. Longval; J.-Ph. Bernard; P. Ade; Y. André; J. Aumont; L. Bautista; N. Bray; P. deBernardis; O. Boulade; F. Bousquet; M. Bouzit; V. Buttice; A. Caillat; M. Chaigneau; C. Coudournac; B. Crane; F. Douchin; E. Doumayrou; J.-P. Dubois; C. Engel; P. Etcheto; P. Gélot; M. Griffin; G. Foenard; S. Grabarnik; P. Hargrave; A. Hughes; R. Laureijs; Y. Lepennec; B. Leriche; S. Maestre; B. Maffei; A. Mangilli; J. Martignac; C. Marty; W. Marty; S. Masi; F. Mirc; R. Misawa; J. Montel; L. Montier; J. Narbonne; J-M. Nicot; F. Pajot; G. Parot; E. Pérot; J. Pimentao; G. Pisano; N. Ponthieu; I. Ristorcelli; L. Rodriguez; G. Roudil; M. Saccoccio; M. Salatino; G. Savini; S. Stever; O. Simonella; P. Tapie; J. Tauber; C. Tibbs; J.-P. Torre; C. Tucker
Pages: 459 - 471
Abstract: Abstract PILOT is a balloon-borne astronomy experiment designed to study the polarization of dust emission in the diffuse interstellar medium in our Galaxy at wavelengths 240 and 550 µm  with an angular resolution of about two arc-min. PILOT optics is composed of an off-axis Gregorian telescope and a refractive re-imager system. All these optical elements, except the primary mirror, are in a cryostat cooled to 3K. We used optical and 3D measurements combined with thermo-elastic modeling to perform the optical alignment. This paper describes the system analysis, the alignment procedure, and finally the performances obtained during the first flight in September 2015
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0159-3
Issue No: Vol. 9, No. 4 (2017)

• Parasitic light scattered by complex optical coatings: modelization and
metrology
• Authors: Myriam Zerrad; Michel Lequime; Simona Liukaityte; Claude Amra
Pages: 473 - 484
Abstract: Abstract Optical components realized for space applications have to be mastered in term of parasitic light. This paper present the last improvements performed at the Institute Fresnel to predict and measure scattering losses of optical components with a special care to complex optical coatings. Agreement between numerical models and metrology is now excellent. Some examples will be presented.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0156-6
Issue No: Vol. 9, No. 4 (2017)

• Developments of high frequency and intensity stabilized lasers for space
gravitational wave detector DECIGO/B-DECIGO
• Authors: Aru Suemasa; Ayumi Shimo-oku; Ken’ichi Nakagawa; Mitsuru Musha
Pages: 485 - 491
Abstract: Abstract In Japan, not only the ground-based gravitational wave (GW) detector mission KAGRA but also the space GW detector mission DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) and its milestone mission B-DECIGO have been promoted. The designed strain sensitivity of DECIGO and B-DECIGO are δL/L < 10−23. Since the GW detector requires high power and highly-stable light source, we have developed the light source with high frequency and intensity stability for DECIGO and B-DECIGO. The frequency of the Yb-doped fiber DFB lasers are stabilized to the iodine saturated absorption at 515 nm, and the intensity of the laser at 1 Hz (observation band) is stabilized by controlling the pump source of an Yb-doped fiber amplifier. The intensity of the laser at 200 kHz (modulation band) is also stabilized using an acousto-optic modulator to improve the frequency stability of the laser. In the consequences, we obtain the frequency stability of δf = 0.4 Hz/√Hz (in-loop) at 1 Hz, and the intensity stability of δI/I = 1.2 × 10−7/√Hz (out-of-loop) and δI/I = 1.5 × 10−7/√Hz (in-loop) at 1 Hz and 200 kHz, respectively.
PubDate: 2017-12-01
DOI: 10.1007/s12567-017-0151-y
Issue No: Vol. 9, No. 4 (2017)

• Architectural elements of hybrid navigation systems for future space
transportation
• Authors: Guilherme F. Trigo; Stephan Theil
Abstract: Abstract The fundamental limitations of inertial navigation, currently employed by most launchers, have raised interest for GNSS-aided solutions. Combination of inertial measurements and GNSS outputs allows inertial calibration online, solving the issue of inertial drift. However, many challenges and design options unfold. In this work we analyse several architectural elements and design aspects of a hybrid GNSS/INS navigation system conceived for space transportation. The most fundamental architectural features such as coupling depth, modularity between filter and inertial propagation, and open-/closed-loop nature of the configuration, are discussed in the light of the envisaged application. Importance of the inertial propagation algorithm and sensor class in the overall system are investigated, being the handling of sensor errors and uncertainties that arise with lower grade sensory also considered. In terms of GNSS outputs we consider receiver solutions (position and velocity) and raw measurements (pseudorange, pseudorange-rate and time-difference carrier phase). Receiver clock error handling options and atmospheric error correction schemes for these measurements are analysed under flight conditions. System performance with different GNSS measurements is estimated through covariance analysis, being the differences between loose and tight coupling emphasized through partial outage simulation. Finally, we discuss options for filter algorithm robustness against non-linearities and system/measurement errors. A possible scheme for fault detection, isolation and recovery is also proposed.
PubDate: 2017-12-27
DOI: 10.1007/s12567-017-0187-z

• Experimental validation of solid rocket motor damping models
• Authors: Cristina Riso; Sebastiaan Fransen; Franco Mastroddi; Giuliano Coppotelli; Francesco Trequattrini; Alessio De Vivo
Abstract: Abstract In design and certification of spacecraft, payload/launcher coupled load analyses are performed to simulate the satellite dynamic environment. To obtain accurate predictions, the system damping properties must be properly taken into account in the finite element model used for coupled load analysis. This is typically done using a structural damping characterization in the frequency domain, which is not applicable in the time domain. Therefore, the structural damping matrix of the system must be converted into an equivalent viscous damping matrix when a transient coupled load analysis is performed. This paper focuses on the validation of equivalent viscous damping methods for dynamically condensed finite element models via correlation with experimental data for a realistic structure representative of a slender launch vehicle with solid rocket motors. A second scope of the paper is to investigate how to conveniently choose a single combination of Young’s modulus and structural damping coefficient—complex Young’s modulus—to approximate the viscoelastic behavior of a solid propellant material in the frequency band of interest for coupled load analysis. A scaled-down test article inspired to the Z9-ignition Vega launcher configuration is designed, manufactured, and experimentally tested to obtain data for validation of the equivalent viscous damping methods. The Z9-like component of the test article is filled with a viscoelastic material representative of the Z9 solid propellant that is also preliminarily tested to investigate the dependency of the complex Young’s modulus on the excitation frequency and provide data for the test article finite element model. Experimental results from seismic and shock tests performed on the test configuration are correlated with numerical results from frequency and time domain analyses carried out on its dynamically condensed finite element model to assess the applicability of different equivalent viscous damping methods to describe damping properties of slender launch vehicles in payload/launcher coupled load analysis.
PubDate: 2017-12-21
DOI: 10.1007/s12567-017-0191-3

• Design and validation of a GNC system for missions to asteroids: the AIM
scenario
• Authors: A. Pellacani; P. Kicman; M. Suatoni; M. Casasco; J. Gil; I. Carnelli
Abstract: Abstract Deep space missions, and in particular missions to asteroids, impose a certain level of autonomy that depends on the mission objectives. If the mission requires the spacecraft to perform close approaches to the target body (the extreme case being a landing scenario), the autonomy level must be increased to guarantee the fast and reactive response which is required in both nominal and contingency operations. The GNC system must be designed in accordance with the required level of autonomy. The GNC system designed and tested in the frame of ESA’s Asteroid Impact Mission (AIM) system studies (Phase A/B1 and Consolidation Phase) is an example of an autonomous GNC system that meets the challenging objectives of AIM. The paper reports the design of such GNC system and its validation through a DDVV plan that includes Model-in-the-Loop and Hardware-in-the-Loop testing. Main focus is the translational navigation, which is able to provide online the relative state estimation with respect to the target body using exclusively cameras as relative navigation sensors. The relative navigation outputs are meant to be used for nominal spacecraft trajectory corrections as well as to estimate the collision risk with the asteroid and, if needed, to command the execution of a collision avoidance manoeuvre to guarantee spacecraft safety
PubDate: 2017-12-14
DOI: 10.1007/s12567-017-0189-x

• Experimental assessment of the performance of ablative heat shield
materials from plasma wind tunnel testing
• Authors: S. Löhle; T. Hermann; F. Zander
Abstract: Abstract A method for assessing the performance of typical heat shield materials is presented in this paper. Three different material samples, the DLR material Zuram, the Airbus material Asterm and the carbon preform Calcarb were tested in the IRS plasma wind tunnel PWK1 at the same nominal condition. State of the art diagnostic tools, i.e., surface temperature with pyrometry and thermography and boundary layer optical emission spectroscopy were completed by photogrammetric surface recession measurements. These data allow the assessment of the net heat flux for each material. The analysis shows that the three materials each have a different effect on heat flux mitigation with ASTERM showing the largest reduction in surface heat flux. The effect of pyrolysis and blowing is clearly observed and the heat flux reduction can be determined from an energy balance.
PubDate: 2017-12-11
DOI: 10.1007/s12567-017-0186-0

• Modal analysis of passive flow control for the turbulent wake of a generic
planar space launcher
• Authors: S. Loosen; V. Statnikov; M. Meinke; W. Schröder
Abstract: Abstract The turbulent wake of a generic planar space launcher equipped with two passive flow control devices is simulated using a zonal RANS–LES method and analyzed by dynamic mode decomposition (DMD). In the first approach, the effect of a classical boat tail on the wake is examined. In the second concept, a flow control device consisting of semi-circular lobes integrated at the base shoulder of the main body is used. The objective of the two concepts is to reduce the reattachment length and thus the lever arm of the forces as well as to stabilize the separated shear layer. Using a boat tail, the reattachment length can be reduced by 50%. Furthermore, it is shown that the semi-circular lobes enhance the turbulent mixing and the shear layer growth rate. Hence, they significantly reduce the reattachment length by about 75%. The semi-circular lobes partially reduce undesired low-frequency pressure fluctuations on the nozzle surface. However, this reduction is achieved at the expense of an increase of high-frequency pressure fluctuations due to intensified small turbulent scales. The DMD analysis of the velocity field reveals that the large-scale coherent structures featuring a wave length of two step heights observed in the reference configuration without flow control can be suppressed by the lobes. The spanwise wave length of the coherent structures seems to depend on the geometry of the lobes, since all detected spatial DMD modes show a spanwise periodicity being equal to the distance between two lobes.
PubDate: 2017-12-08
DOI: 10.1007/s12567-017-0183-3

• Fading characteristics of maritime propagation channel for beyond
geometrical horizon communications in C-band
• Authors: Wei Wang; Ronald Raulefs; Thomas Jost
Abstract: Abstract The design of a maritime communication system requires the understanding of the wireless propagation channel above the sea. For broadband communication systems, a carrier frequency in the C-band is of interest because of allocatable spectrum. Therefore, the German Aerospace Center performed a long-distance channel measurement campaign at 5.2 GHz on the North sea to investigate large and small-scale fading characteristics. The results show that our measurement data conforms with the ITU-R and the Bullington’s path loss model to predict the power loss caused by diffraction over the Earth’s surface. Further, the first tap of the channel impulse response experiences Rician fading due to superposition of a strong line-of-sight (LoS) path and multipath components originating from the sea surface and ship body. We found that the fading of the second tap follows a Rician distribution, but with a much smaller K-factor compared to the first tap. The K-factor showed a dependence on the distance between the transmitter and receiver. Particularly, the K-factor of the first tap decreases significantly when the distance between the transmitter and receiver is larger than the clearance distance of the first Fresnel zone. Therefore, we propose a distance-dependent K-factor model for the first and the second tap.
PubDate: 2017-12-04
DOI: 10.1007/s12567-017-0185-1

• HgCdTe APDs for time-resolved space applications
• Authors: J. Rothman; G. Lasfargues; B. Delacourt; A. Dumas; F. Gibert; A. Bardoux; M. Boutillier
Abstract: Abstract The use of HgCdTe avalanche photodiodes (APDs) for resolving the temporal variation of faint light level signals is analyzed. The analysis is based on the performance characteristics such as the gain, the response time, and dark currents in the APDs, measured as a function of operating temperature and Cd composition, and on recently developed detector demonstrator modules. The choice of Cd composition in the APDs is strongly dependent on the application needs in terms of electrical bandwidth and signal-to-noise ratio. A performance model has been developed and used to predict the performance of the future detector modules for different applications such as high bandwidth and/or deep space free space optical telecommunications and lidar, associated with sensitivities down to single photon level at low operating temperature and close to single-photon operation at bandwidth of 10 GHz at room temperature. The predictions are corroborated by the results obtained on detector modules that have been developed and used in lidar and deep space optical communications. In a first lidar prototype, integrating a 200 µm APD, we obtained a maximum sensitivity of 25 fW/√Hz at T = 190 K operating temperature. The detector has been used for differential absorption lidar estimations of the absorption due to presence of CO2 in the atmosphere. A random error of 3–10% was obtained for the estimation of the optical thickness at a distance of 100–3000 m, for a range resolution of 100 m and using and averaging time of 4 s. The pursuit of this development is pending on the space qualification of the technology. Results from first proton and irradiation tests are reported that shows on a close to constant performance during and after the irradiation and endurance tests.
PubDate: 2017-11-23
DOI: 10.1007/s12567-017-0169-1

• The design and development of low- and high-voltage ASICs for space-borne
CCD cameras
• Authors: N. Waltham; Q. Morrissey; M. Clapp; S. Bell; L. Jones; M. Torbet
Abstract: Abstract The CCD remains the pre-eminent visible and UV wavelength image sensor in space science, Earth and planetary remote sensing. However, the design of space-qualified CCD readout electronics is a significant challenge with requirements for low-volume, low-mass, low-power, high-reliability and tolerance to space radiation. Space-qualified components are frequently unavailable and up-screened commercial components seldom meet project or international space agency requirements. In this paper, we describe an alternative approach of designing and space-qualifying a series of low- and high-voltage mixed-signal application-specific integrated circuits (ASICs), the ongoing development of two low-voltage ASICs with successful flight heritage, and two new high-voltage designs. A challenging sub-system of any CCD camera is the video processing and digitisation electronics. We describe recent developments to improve performance and tolerance to radiation-induced single event latchup of a CCD video processing ASIC originally developed for NASA’s Solar Terrestrial Relations Observatory and Solar Dynamics Observatory. We also describe a programme to develop two high-voltage ASICs to address the challenges presented with generating a CCD’s bias voltages and drive clocks. A 0.35 μm, 50 V tolerant, CMOS process has been used to combine standard low-voltage 3.3 V transistors with high-voltage 50 V diffused MOSFET transistors that enable output buffers to drive CCD bias drains, gates and clock electrodes directly. We describe a CCD bias voltage generator ASIC that provides 24 independent and programmable 0–32 V outputs. Each channel incorporates a 10-bit digital-to-analogue converter, provides current drive of up to 20 mA into loads of 10 μF, and includes current-limiting and short-circuit protection. An on-chip telemetry system with a 12-bit analogue-to-digital converter enables the outputs and multiple off-chip camera voltages to be monitored. The ASIC can drive one or more CCDs and replaces the many discrete components required in current cameras. We also describe a CCD clock driver ASIC that provides six independent and programmable drivers with high-current capacity. The device enables various CCD clock parameters to be programmed independently, for example the clock-low and clock-high voltage levels, and the clock-rise and clock-fall times, allowing configuration for serial clock frequencies in the range 0.1–2 MHz and image clock frequencies in the range 10–100 kHz. Finally, we demonstrate the impact and importance of this technology for the development of compact, high-performance and low-power integrated focal plane electronics.
PubDate: 2017-11-07
DOI: 10.1007/s12567-017-0181-5

• Ka-band to L-band frequency down-conversion based on III–V-on-silicon
photonic integrated circuits
• Authors: K. Van Gasse; Z. Wang; S. Uvin; B. De Deckere; J. Mariën; L. Thomassen; G. Roelkens
Abstract: Abstract In this work, we present the design, simulation and characterization of a frequency down-converter based on III–V-on-silicon photonic integrated circuit technology. We first demonstrate the concept using commercial discrete components, after which we demonstrate frequency conversion using an integrated mode-locked laser and integrated modulator. In our experiments, five channels in the Ka-band (27.5–30 GHz) with 500 MHz bandwidth are down-converted to the L-band (1.5 GHz). The breadboard demonstration shows a conversion efficiency of − 20 dB and a flat response over the 500 MHz bandwidth. The simulation of a fully integrated circuit indicates that a positive conversion gain can be obtained on a millimeter-sized photonic integrated circuit.
PubDate: 2017-11-03
DOI: 10.1007/s12567-017-0179-z

• Space gravitational wave antenna DECIGO and B-DECIGO
• Authors: Mitsuru Musha; DECIGO Working Group
Abstract: Abstract Since the direct detection of gravitational wave will give us a fruitful insight about the early universe or life of stars, laser interferometric gravitational wave detectors with the strain sensitivity of higher than 10−22 have been developed. In Japan, the space gravitational wave detector project named DECi-hertz Gravitational wave Observatory (DECIGO) has been promoted which consists of three satellites forming equilateral triangle-shaped Fabry–Perot laser interferometer with the arm length of 1000 km. The designed strain sensitivity of DECIGO is 2 × 10−24/√Hz around 0.1 Hz whose targets are gravitational waves originated from the inspiral and the merger of black hole or neutron star binaries and from the inflation at the early universe, and no ground-based gravitational wave detector can access this observation band. Before launching DECIGO in 2030s, a milestone mission named B-DECIGO is planned which is a downsized mission of DECIGO. B-DECIGO also has its own scientific targets in addition to the feasibility test for DECIGO. In the present paper, DECIGO and B-DECIGO projects are reviewed.
PubDate: 2017-11-02
DOI: 10.1007/s12567-017-0177-1

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs