test and measurements of reliability performance on radioreceiver chains for the northern cross radio telescope

Reliability analysis of two radioreceiver chains architecture were performed in order to choose the solution with the highest value of Mean Time Between Failures and minimize faults in the system, with the consequent lower maintenance costs. Located the most stressed devices from a climatic-environmental point of view, we decided to monitor their real thermal solicitation in order to evaluate the proper reliability performances varying temperature and the possible degradation of the critical subsystem and consequently of the entire chain. The design for reliability approach proposed in this research for the reinstrumentation of the Northern Cross Radiotelescope could be an useful aid for the design of the international SKA Telescope. Since it will be extremely large (1 square kilometre) the maintenance costs, related to the reliability, become an important parameter to evaluate. This research activity was developed in partnership with the Istituto di Radioastronomia, Istituto Nazionale di Astrofisica, in the context of the Square Kilometer Array Design Study supported by UE FP6

Project of a multibeam UHF receiver to improve survey capabilities

The Institute of Radioastronomy (IRA-Bologna) of the National Institute for Astrophysics of Italy (INAF – Rome) joined the European group for the Square Kilometer Array Design Study (SKA-DS) in the frame of the FP6 program. One of the goals of the Design Study was the construction and test of a state of the art very small SKA prototype. A segment (1/8) of the N/S arm of the large Northern Cross array (408 MHz+/−8 MHz) was exploited to obtain a prototype array, made up by 8 cylindrical concentrators (23.5 mt×7.5 mt) equipped with 4 receivers each. In this way a 32 receivers array with a total collecting area of about 1400 m2 was obtained. Signals are directly carried from the receivers, located on the focal lines, down to the back end, located in the processing room, via a very cost effective analog optical links. Here a fast back end, presently based on Field Programmable Gate Array (FPGA) Berkeley-Roach boards, takes care of running the required complex algorithms to perform (non-adaptive) multi-beamforming with a 2D FFT. The main advantage of such an already working array is to produce 21 independent 31’×104’ beams located inside a 38 deg2 Field Of View (FoV). Our plan is to search for funds to refit the remaining 56 cylinders of the N/S arm, to dramatically increase both the sensitivity and number of beams (pixels) placed in the same FoV. In this way, it could be possible to perform a deep SETI survey in the UHF band by an about 11.200 m2 antenna (equivalent to a 119 m dish), a 37.6 deg2 FOV and 189 independent beams. The system could be further expanded by installing more receivers on each N/S focal line, increasing the FOV and the number of pixels with the same sensitivity. Assuming that adequate funds could be found for refitting the giant E/W arm as well, an equivalent 180 m dish could be obtained to perform a very deep SETI sky survey with a 120 deg2 FOV at high sensitivity. This would allow a very fast and deep sky survey in the UHF band

A real-time KLT implementation for radio-SETI applications

SETI, the Search for ExtraTerrestrial Intelligence, is the search for radio signals emitted by alien civilizations living in the Galaxy. Narrow-band FFT-based approaches have been preferred in SETI, since their computation time only grows like N*lnN, where N is the number of time samples. On the contrary, a wide-band approach based on the Kahrunen-Lo`eve Transform (KLT) algorithm would be preferable, but it would scale like N*N. In this paper, we describe a hardware-software infrastructure based on FPGA boards and GPU-based PCs that circumvents this computation-time problem allowing for a real-time KLT