2010 Onwards :- Honorary Distingushed Professor, ISRO
2006-2009 :- Director  Centre for Space Science and Technology Education in Asia and the Pacific (CSSTEAP), Affiliated to the United Nations
2003-2006 :- Honorary Distingushed Professor, ISRO
1998-2003 :- Satish Dhawan Distinguished Professor
1994-1998 :- Director, Space Applications Centre, Ahmedabad
1990-1994 :- Associate Director, Space Applications Centre, Ahmedabad
1985-1994 :- Dy. Director (Remote Sensing), Space Applications Centre, Ahmedabad
1975-1985 :- Head, Sensor Development Division, Space Applications Centre, Ahmedabad
1973-1975 :- Scientist/Engineer, Remote Sensing & Meteorology Applications Division,Space
Applications Centre, Ahmedabad
1970-1973 :- Fellow, Tata Institute of Fundamental Research, Bombay
1962-1970 :- Research Associate, Tata Institute of Fundamental Research, Bombay
1961-1962 :- Trainee (Physics), Atomic Energy Establishment School
1959-1961 :- Lecturer in Physics, Union Christian College, Alwaye (Affiliated to the  University of Kerala)