Project of a multibeam UHF receiver to improve survey capabilities. (November 2015)

• Record Type: Journal Article
• Authors: Montebugnoli, Stelio; Bortolotti, Claudio; Bianchi, Germano; Monari, Jader; Maccone, Claudio; Perini, Federico; Roma, Mauro; Schiaffino, Marco
• Is Part Of: Acta astronautica. Volume 116(2015)
• Page Start: 382
• Page End: 386
• Publication Date: 2015-11
• Subjects: SETI -- Beamforming algorithms -- Receiver design -- Data processing -- Signal extraction from noise; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2015.07.030
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: 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 m 2 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 deg 2 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 m 2 antenna (equivalent to a 119 m dish), a 37.6 deg 2 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 deg 2 FOV at high sensitivity. This would allow a very fast and deep sky survey in the UHF band. Highlights: We give a short description of both the Medicina radiotelescopes and the planned SETI program. We give a description of the 32 receivers BEST-2 array, to introduce the multi beaming concept. We examine the multi beaming concept multiple advantages for SETI observation activities.