This definition appears somewhat frequently
See other definitions of RAI
Samples in periodicals archive:
Welcome to Radio Astronomy at the University of Calgary
Radio Astronomy builds on the scientific and technical strengths in the Faculty of Science and in the Schulich School of Engineering, and on our relationship with the National Research Council, to create at the University of Calgary, University of Lethbridge and Athabasca University a unique national institute that will advance the national agenda for radio astronomy.
The Haystack Observatory is an interdisciplinary research center of the Massachusetts Institute of Technology (MIT) engaged in radio astronomy, geodesy, upper atmospheric physics, and radar applications.