Abstract

The Giant Metrewave Radio Telescope (GMRT), located near Pune, India, is today a major international facility for work in Radio Astronomy in the frequency range of 150 MHz to 1500 MHz. Consisting of 30 fully steerable antennas of 45 metre diameter each, it can be used as an aperture-synthesis array to produce maps of the radio brightness of extended sources, as well as a phased array with a highly directive beam to study compact radio sources. Each antenna is equipped with multi-frequency feeds and a low noise, high gain heterodyne receiver system, the signal from which is transmitted to a central station using optical fibres. At the central station, multi-purpose back end receivers to process and combine the signals from the 30 antenna stations include (i) a 256 spectral channel correlator and (ii) a phased array combiner followed by a high time resolution pulsar receiver. The sophisticated electronics is backed up with state of the art computing facilities, control and analysis software, to exploit the full capability and versatility of the GMRT .

In this talk, we will present an overview of the working of the GMRT . Some of the new and interesting results from the GMRT will also be highlighted. Finally, we will describe the plans for an upgrade of the GMRT , which is expected to significantly increase the scientific potential of the instrument.

As part of the upgrade plans, we will describe the design and implementation of a software back-end for the GMRT . Using primarily COTS components, we have built a 32 antenna, 32 MHz band, dual polarisation back-end. This back-end works in a real-time mode, and also supports a baseband recording mode. It will play the dual role of a correlator and a single beam incoherent and phased array pulsar receiver for the GMRT . We will present examples of improved data processing that is possible with this software back-end, and highlight possible future applications.