Novel instrumentation and communication system for GMRT�

Abstract

Radio telescopes are indispensable tools for frontline research in astronomy and astrophysics. In all radio telescopes, the control and monitor system provides the necessary coordination between the various building blocks used and is also required to provide the human interface for optimal operation of the radio telescope. However, there are some limitations suffered by the present control and monitor systems. They are: � Highly centralised processing of monitor data � Excessive noise and stray RF radiation generated by the system � Multiplicity of transmission channels for various services � Inadequate voice?communication facilities Considering these limitations and keeping in view recent developments in microcontroller and digital communication systems, a detailed investigation on the data acquisition, control, and communication systems for radio telescopes was conducted with particular reference to their application in newer large radio telescopes. The Giant Metrewave Radio Telescope (GMRT), an aperture?synthesis array, is being set up about 80 km north of Pune. The GMRT, as currently envisaged, consists of an array of 30 fully steerable parabolic dishes, each 45 m in diameter, installed over a region of about 25 km. New ideas and insights resulting from this investigation were tried out in the system design and implementation of the GMRT Instrumentation and Communication System. The result of this investigation is the design and development of a Novel Instrumentation and Communication System for GMRT, which is described in detail in this thesis. The main highlights of the thesis are the design and development of a novel instrumentation and communication system for the GMRT. This design is a departure from existing radio telescope instrumentation systems, and includes: � Detailed study of radio telescope instrumentation and communication systems � Implementation of an integrated voice and data communication system � Distributed processing of radio?telescope monitor data � Use of optical?fiber transmission for computer networking and data communication � Use of low?power, compact, and easy?to?maintain modules with low RFI generation, based on LSI/VLSI technology � Functional testing of the subsystems and overall system integration