Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

Pupillo, G.; Naldi, G.; Bianchi, G.; Mattana, A.; Monari, Jader; Perini, Federico; Poloni, M.; Schiaffino, Marco; Bolli, Pietro; Lingua, Andrea Maria; Aicardi, Irene; Bendea, H.; Maschio, Paolo Felice; Piras, Marco; Virone, G.; Paonessa, Fabio; Farooqui, Z.; Tibaldi, Alberto; Addamo, Giuseppe; Peverini, O. A.; Tascone, R.; Wijnholds, Stefan J.

doi:10.1007/s10686-015-9456-z

Cited by 61 publications

(36 citation statements)

References 10 publications

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“…Fringe patterns were produced by means of UAV rectilinear flights across the field of view (FoV). After the calibration the alignment of the main fringe maxima at zenith for all the acquired baselines demonstrates an accurate array phase calibration in that direction [ Pupillo et al , ].…”

Section: Insights In the Mad Calibrationmentioning

confidence: 99%

From MAD to SAD: The Italian experience for the low‐frequency aperture array of SKA1‐LOW

Bolli

Pupillo²,

Virone

et al. 2016

Radio Science

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This paper describes two small aperture array demonstrators called Medicina and Sardinia Array Demonstrators (MAD and SAD, respectively). The objectives of these instruments are to acquire experience and test new technologies for a possible application to the low‐frequency aperture array of the low‐frequency telescope of the Square Kilometer Array phase 1 (SKA1‐LOW). The MAD experience was concluded in 2014, and it turned out to be an important test bench for implementing calibration techniques based on an artificial source mounted in an aerial vehicle. SAD is based on 128 dual‐polarized Vivaldi antennas and is 1 order of magnitude larger than MAD. The architecture and the station size of SAD, which is along the construction phase, are more similar to those under evaluation for SKA1‐LOW, and therefore, SAD is expected to provide useful hints for SKA1‐LOW.

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Section: Insights In the Mad Calibrationmentioning

confidence: 99%

From MAD to SAD: The Italian experience for the low‐frequency aperture array of SKA1‐LOW

Bolli

Pupillo²,

Virone

et al. 2016

Radio Science

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“…In addition to video cameras, multi-UAV missions have exploited various relative sensing systems for information gathering, such as Radio-Frequency (RF)-based ranging [27], LIDAR-based ranging [17], etc. The main advantages relevant to vision systems are: (1) no additional sensors are needed; (2) visual cameras are extremely small, light and inexpensive with respect to the other sensors; (3) cameras can provide accurate line-of-sight information, which is often required in specific applications.…”

Section: Introductionmentioning

confidence: 99%

Eye in the Sky

Zhang

Wang

Lei

et al. 2019

Proceedings of the 27th ACM International Conference on Multimedia

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Drones, or general UAVs, equipped with a single camera have been widely deployed to a broad range of applications, such as aerial photography, fast goods delivery and most importantly, surveillance. Despite the great progress achieved in computer vision algorithms, these algorithms are not usually optimized for dealing with images or video sequences acquired by drones, due to various challenges such as occlusion, fast camera motion and pose variation. In this paper, a drone-based multi-object tracking and 3D localization scheme is proposed based on the deep learning based object detection. We first combine a multi-object tracking method called TrackletNet Tracker (TNT) which utilizes temporal and appearance information to track detected objects located on the ground for UAV applications. Then, we are also able to localize the tracked ground objects based on the group plane estimated from the Multi-View Stereo technique. The system deployed on the drone can not only detect and track the objects in a scene, but can also localize their 3D coordinates in meters with respect to the drone camera. The experiments have proved our tracker can reliably handle most of the detected objects captured by drones and achieve favorable 3D localization performance when compared with the state-of-the-art methods.

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“…Recent advances have been made in using commercially available drones to fly a radio emitter to achieve this (e.g. Ustuner et al 2014;Chang et al 2015;Picar et al 2015;Pupillo et al 2015;Paonessa et al 2016). These experiments have the advantage of being able to run at multiple frequencies and along a controlled flight path.…”

Section: Introductionmentioning

confidence: 99%

In situ measurement of MWA primary beam variation using ORBCOMM

Line

McKinley

Rasti

et al. 2018

Publ. Astron. Soc. Aust.

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We provide the first in situ measurements of antenna element (tile) beam shapes of the Murchison Widefield Array (MWA), a low radio-frequency interferometer and an SKA * precursor. Most current MWA processing pipelines use an assumed beam shape, errors in which can cause absolute and relative flux density errors, as well as polarisation 'leakage'. This makes understanding the primary beam of paramount importance, especially for sensitive experiments such as a measurement of the 21 cm line from the epoch of reionisation (EoR). The calibration requirements for measuring the EoR 21 cm line are so extreme that tile to tile beam variations may affect our ability to make a detection. Measuring the primary beam shape from visibilities alone is challenging, as multiple instrumental, atmospheric, and astrophysical factors contribute to uncertainties in the data. Building on the methods of Neben et al. (2015), we tap directly into the receiving elements of the MWA before any digitisation or correlation of the signal. Using ORBCOMM satellite passes we are able to produce all-sky maps for 4 separate tiles in the XX polarisation. We find good agreement with the cutting-edge 'fully' embedded element (FEE) model of Sokolowski et al. (2017), and observe that the MWA beamformers consistently recreate beam shapes to within ∼ 1dB in the reliable areas of our beam maps. We also clearly observe the effects of a missing dipole from a tile in one of our beam maps, and show that the FEE model is able to reproduce this modified beam shape. We end by motivating and outlining additional onsite experiments to further constrain the primary beam behaviour.beam, which has a full-width half-maximum of ∼ 25 • at 150 MHz (Tingay et al. 2013). The regular spacing of the dipoles means that the quantised beamformer delays are exactly correct for a set of pointings, reducing the complexity of the instrument. By using identical receiving elements, a number of computational simplifications can be made to calibration and imaging, as beam corrections can be made in image space, avoiding costly convolutions in visibility space.Many calibration schemes make assumptions on beams/receiving elements (e.g. Kazemi et al. 2013;Tasse et al. 2013), and others explicitly use the beam 1 arXiv:1808.04516v1 [astro-ph.IM]

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Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

Cited by 61 publications

References 10 publications

From MAD to SAD: The Italian experience for the low‐frequency aperture array of SKA1‐LOW

From MAD to SAD: The Italian experience for the low‐frequency aperture array of SKA1‐LOW

Eye in the Sky

In situ measurement of MWA primary beam variation using ORBCOMM

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