The question is whether you want to do the assessment at the group level or at the individual level.
Autonomy at the individual level could be conceptualised as empowerment and you could use the measuring instrument of Spreitzner (maybe only the subscale self-determination):
Spreitzer, G. M. (1995). Psychological empowerment in the workplace: Dimensions, measurement, and validation. Academy of management Journal, 38(5), 1442-1465.
If you want to do survey at group level, you could maybe use the TCI:
Anderson, N. R., & West, M. A. (1998). Measuring climate for work group innovation: development and validation of the team climate inventory. Journal of Organizational Behavior: The International Journal of Industrial, Occupational and Organizational Psychology and Behavior, 19(3), 235-258.