Francesco Gaudiomonte

National Institute of Astrophysics | INAF · Astronomical Observatory of Cagliari

Low-frequency aperture arrays represent sensitive instruments to detect signals from radio astronomic sources situated in the universe. In Italy, the Sardinia Aperture Array Demonstrator (SAAD) consists of an ongoing project of the Italian National Institute for Astrophysics (INAF) aimed to install an aperture array constituted of 128 dual-polarize...

Radio frequency interference (RFI) represents all unwanted signals detected by radio receivers of a telescope. Unfortunately, the presence of RFI is significantly increasing with the technological development of wireless systems around the world. For this reason, RFI measurement campaigns are periodically necessary to map the RFI scenario around a...

Radio telescopes are used by astronomers to observe the naturally occurring radio waves generated by planets, interstellar molecular clouds, galaxies, and other cosmic objects. These telescopes are equipped with radio receivers that cover a portion of the radio frequency (RF) and millimetre-wave spectra. The Sardinia Radio Telescope (SRT) is an Ita...

We present a project to implement a national common strategy for the mitigation of the steadily deteriorating Radio Frequency Interference (RFI) situation at the Italian radio telescopes. The project involves the Medicina, Noto, and Sardinia dish antennas and comprised the definition of a coordinated plan for site monitoring as well as the implemen...

The Sardinia Radio Telescope is a quasi-Gregorian system with a shaped 64 m diameter primary reflector and a 7.9 m diameter secondary reflector. It was designed to operate with high efficiency across the 0.3–116 GHz frequency range. The telescope is equipped with a cryogenic coaxial dual-frequency L-P band receiver, which covers a portion of the P-...

Measurement campaigns of radio frequency interferences (RFIs) represent a fundamental aspect to optimize data collected by radio astronomical observations. In order to monitor the state of unwanted man-made signals, every radio telescope needs to have a radio frequency map in the frequencies range of its receivers. The Sardinia Aperture Array Demon...

Space debris (SD) is an important problem for space operations and a hot topic for space surveillance research. A structured network of radar sensors is available worldwide, offering vital information about debris status. Recently, the Sardinia Radio Telescope (SRT), a 64-m dish located in Sardinia, Italy, was introduced in the European plan for SD...

The main characteristics in the radio continuum spectra of Supernova Remnants (SNRs) result from simple synchrotron emission. In addition, electron acceleration mechanisms can shape the spectra in specific ways, especially at high radio frequencies. These features are connected to the age and the peculiar conditions of the local interstellar medium...

The main characteristics in the radio continuum spectra of Supernova Remnants (SNRs) result from simple synchrotron emission. In addition, electron acceleration mechanisms can shape the spectra in specific ways, especially at high radio frequencies. These features are connected to the age and the peculiar conditions of the local interstellar medium...

Space debris represent a major risk for every spacecraft and satellite. In fact, other than cause serious damages to these structures, new collisions could exponentially increase the amount of debris and so the level of threat represented by the objects. To avoid new impacts, the monitoring of the space environment with space-based and ground-based...

Space debris represent an increasing problem for the ongoing space operations and they are the primary reason of the space environment pollution. The study and monitoring of the known objects, as well as the detection of new ones, is essential to prevent the risk of collision between debris and spacecraft but also between debris themselves. Radar m...

In order to prevent the harmful impacts for spacecrafts deriving from the presence of space debris, many surveillance and monitoring programs of the space environment have been started in recent years. The Sardinia Radio Telescope is a new comer in such a scenario, but it has already showed its potential. However, since the actual receiving chain i...

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of with respect to the merger t...

Space debris are orbiting objects that represent a major threat for space operations. In this work a bistatic radar configuration named BIstatic RAdar for LEo Tracking (BIRALET) is used to detect a set of space debris. Signal-to-Noise Ratios, Doppler shift measures as well as the frequency specters for each debris are presented.

Space debris are orbiting objects that represent a major threat for space operations. The most used countermeasure to face this threat is, by far, collision avoidance, namely the set of maneuvers that allow to avoid a collision with the space debris. Since collision avoidance is tightly related to the knowledge of the debris state (position and spe...

Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages of stellar evolution, the properties of the ambient interstellar medium, and the physics of particle acceleration and shocks. For a fraction of SNRs, multi-wavelength coverage from radio to ultra high-energies has been provided, constraining their contr...

[Abridged] The Sardinia Radio Telescope (SRT) is the new 64-m dish operated by INAF (Italy). Its active surface will allow us to observe at frequencies of up to 116 GHz. At the moment, three receivers, one per focal position, have been installed and tested. The SRT was officially opened in October 2013, upon completion of its technical commissionin...

The Space Debris monitoring is part of the INAF-OAC research activity in the framework convention ASI/INAF n. 2015-028-R.O, named “Detriti Spaziali – Supporto alle attività IADC e validazione pre-operativa SST”. In this framework, the INAF participation concerns about the testing of the SRT operative capacities in the detection of signals scattered...

In the period 2012 June–2013 October, the Sardinia Radio Telescope (SRT) went through the technical commissioning phase. The characterization involved three first-light receivers, ranging in frequency between 300MHz and 26GHz, connected to a Total Power back-end. It also tested and employed the telescope active surface installed in the main reflect...

The Sardinia Aperture Array Demonstrator (SAD) is an Italian project aimed at developing new technology in the area of Low-Frequency Aperture Arrays (LFAAs). The final objective of SAD is to test technologies and demonstrate concepts for a possible application in the LFAA instrument of the Square Kilometre Array (SKA). In LFAA, the electronically s...

In the framework of the Square Kilometer Array (SKA) project, the Italian Institute for Astrophysics (INAF) has addressed several efforts in the design and prototyping of aperture arrays for low-frequency radio astronomical research. The Sardinia Array Demonstrator (SAD) is a national project aimed to develop know-how in this area and to test diffe...

The noise temperature of existing radio telescope receivers has actually achieved very low values. In any case, there are other practical ways to increase the observational speed of a single dish antennas without using longer integration time: observe with multi-beam and large bandwidth receiver. In this paper we present the front end and the cryog...

Radio astronomical observations are ordinarily aimed at reaching a specific scientific goal. Radio telescopes are equipped with a certain number of receivers and back-ends, and the choice of the most suitable receiver/back-end combination in order to best match the scientific application of interest is up to the astronomer. However, the opportunity...

Radio Frequency Interferences (RFI) represents one of the major issues especially in single-dish low frequency radioastronomic observations. Several solutions have been investigated to face the problem. Among them a wide-band digital spectrometer is used together to a RFI monitoring station placed close to the radio-telescope and eventually support...

We present a project aimed at realizing an Italian aperture array demonstrator constituted by prototypical Vivaldi antennas designed to operate at radio frequencies below 500 MHz. We focus on an array composed of a core plus a few satellite phased-array stations to be installed at the Sardinia Radio Telescope (SRT) site. The antenna elements are mo...

In this paper, a quite unique mobile laboratory for monitoring radio-frequency interference with a radio-astronomical observatory is described. The unit is fully operational at the new Sardinia Radio Telescope, a 64-m antenna now in the commissioning phase in Italy. The mobile laboratory is mainly used to identify the source of interference with th...

The Sardinia Radio Telescope is approaching to its official inauguration. Nowadays, the technical staff is accomplishing the last remaining activities to set up and integrate the microwave receivers, the digital processing systems and all the equipment necessary to reach a top level in the international scenario of large radio telescopes. Even if t...

A printed log-periodic dipole array (LPDA), oper-ating between 3 and 6 GHz and fed with a coplanar waveguide, is presented. The antenna has been designed starting from Carrel's theory, optimized using CST Microwave Studio 2012, and then realized. The comparison between simulated and measured results shows that the proposed antenna can be used for b...

AbstractA resonant cavity, used to evaluate the effects of the exposition of biological materials or aqueous‐organic mixtures to low‐power electromagnetic fields at microwave frequencies, is presented.The cavity resonator has been designed using CST microwave studio, and then manufactured. The simulations show a very good agreement with measured da...

Microwave holography is a well-established technique for mapping surface errors of large reflector antennas, particularly those designed to operate at high frequencies. We present here a holography system based on the interferometric method for mapping the primary reflector surface of the Sardinia Radio Telescope (SRT). SRT is a new 64-m-diameter a...

A time laboratory was established at the Astronomical Observatory of Cagliari more than one century ago, aimed for time-tagging scientific observations. At present, this laboratory is facing up a deep refurbishment in order to cope with the much tighter specifications on phase noise, time resolution, and frequency stability required by the new scie...

Apart from externally generated Radio Frequency Interference (RFI), the occurrence of self-interference is a major concern at any modern radio telescope site. Antenna servo motor controllers, data acquisition processors, and fast computing capabilities operate very close to extremely sensitive and wideband radio astronomical receivers. In this pape...