Space debris is becoming a very important and urgent problem for present and future space activities. For that reason many public and private Institutions in the world are being involved in order to monitor and control the debris population increase and to understand which facilities can be used for improving the surveillance and tracking capabilities. In this framework in 2014 we performed some preliminary observations in a beam parking, CW mode and a bistatic configuration, with a transmitter of 4 kW of the Italian Air Force and the SRT (Sardinia Radio Telescope) a 64 meters radiotelescope used as a receiver. We performed the observations in P band at 410 MHz, receiving the signal diffused from some debris of different sizes and distances in LEO orbit, in order to understand the performances and capabilities of the system. In this article we will describe the results of this observations campaign, the simulation work done for preparing it, the RCS (radar cross section) observed, the level of the received signals, the Doppler measurements, and the work we are doing for developing a new and higher performing digital back end, able to process the data received.
In this article, we present the design and performances of the radio receiver system installed at the Sardinia Radio
Telescope (SRT). The three radio receivers planned for the first light of the Sardinian Telescope have been installed in
three of the four possible focus positions. A dual linear polarization coaxial receiver that covers two frequency bands,
the P-band (305-410 MHz) and the L-band (1.3-1.8 GHz) is installed at the primary focus. A mono-feed that covers the
High C-band (5.7-7.7 GHz) is installed at the beam waveguide foci. A multi-beam (seven beams) K-band receiver (18-
26.5 GHz) is installed at the Gregorian focus. Finally, we give an overview about the radio receivers, which under test
and under construction and which are needed for expanding the telescope observing capabilities.
We present the control system of the 84-116 GHz (3 mm band) Superconductor-Insulator-Superconductor (SIS)
heterodyne receiver to be installed at the Gregorian focus of the Sardinia Radio Telescope (SRT). The control system is
based on a single-board computer from Raspberry, on microcontrollers from Arduino, and on a Python program for
communication between the receiver and the SRT antenna control software, which remotely controls the backshorttuned
SIS mixer, the receiver calibration system and the Local Oscillator (LO) system.
The Sardinia Radio Telescope (SRT) Metrology team has started to install the initial group of devices on the new 64 meters radio-telescope. These devices will be devoted for the realization of the antenna deformation control system: an electronic inclinometer able to monitor the alidade deformations and a Position Sensing Device (PSD) able to map the secondary mirror (M2) displacements and tilts. The inclinometer is used to map the rail conditions, the azimuthal axis inclination and the thermal effects on the alidade structure. The PSD will be used to measure the secondary mirror displacements induced by the gravity and by the thermal deformations that produce shifts and tilts with respect to it s ideal optical alignment. The PSD will be traced by a laser diode installed on a mechanically stable position inside the vertex room. Preliminarly we decided to characterize excursion range of M2, in order to know if the PSD measuring range of about +/- 10 mm is enough for our purposes. We designed, built and tested an optical measuring device, based on commercial CMOS with a wider measurement range of +/- 40 mm and with a resolution of around 0.1 mm. After a laboratory characterization at the 23 meters real distance, the PSD and the laser have been installed in the antenna. In this paper we show the results of the measurements performed by moving the antenna in elevation.