Person:
Esteban San Román, Segundo

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First Name
Segundo
Last Name
Esteban San Román
URI
https://hdl.handle.net/20.500.14352/78662
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Informática
Department
Arquitectura de Computadores y Automática
Area
Arquitectura y Tecnología de Computadores
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UCM identifierORCIDScopus Author IDWeb of Science ResearcherIDDialnet IDGoogle Scholar ID

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End date: 2016 × Start date: 2010 ×

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    MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope
    (Proceedings of SPIE, 2016) Gil de Paz, Armando; Gallego Maestro, Jesús; Cardiel López, Nicolás; Castillo Morales, África; Cruz García, Jesús Manuel de la; Esteban San Román, Segundo; López Orozco, José Antonio; Pascual, S.; Picazo, P.; Sánchez-Penim, A.; Zamorano Calvo, Jaime; Pérez González, Pablo Guillermo; otros, ...
    MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma that is being built by a Consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). The instrument is currently finishing AIV and will be sent to GTC on November 2016 for its on-sky commissioning on April 2017. The MEGARA IFU fiber bundle (LCB) covers 12.5x11.3 arcsec(2) with a spaxel size of 0.62 arcsec while the MEGARA MOS mode allows observing up to 92 objects in a region of 3.5x3.5 arcmin(2) around the IFU. The IFU and MOS modes of MEGARA will provide identical intermediate-to-high spectral resolutions (R-FWHM similar to 6,000, 12,000 and 18,700, respectively for the low-, mid-and high-resolution Volume Phase Holographic gratings) in the range 3700-9800 angstrom angstrom. An x-y mechanism placed at the pseudo-slit position allows (1) exchanging between the two observing modes and (2) focusing the spectrograph for each VPH setup. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts a 4kx4k 15-mu m CCD. The unique characteristics of MEGARA in terms of throughput and versatility and the unsurpassed collecting are of GTC make of this instrument the most efficient tool to date to analyze astrophysical objects at intermediate spectral resolutions. In these proceedings we present a summary of the instrument characteristics and the results from the AIV phase. All subsystems have been successfully integrated and the system-level AIV phase is progressing as expected.
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    Signal conditioning for the Kalman filter: application to satellite attitude estimation with magnetometer and sun sensors
    (Sensors, 2016) Esteban San Román, Segundo; Girón Sierra, José María; Angulo, Manuel
    Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.