2010-2015 :- 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)