  We consider the rich variety of collective motion patterns emerging when
aligning active particles move in the presence of randomly distributed
obstacles - representing quenched noise in two dimensions. In order to get
insight into the involved complex flows and the transitions between them we use
a simple model allowing the observation and analysis of behaviors that are less
straightforwardly accessible by experiments or analytic calculations. We find a
series of symmetry breaking states in spite of the applied disorder being
isotropic. In particular, as the level of perturbations is increased, the
system of self-propelled particles changes its collective motion patterns from
i) directed flow ii) through a mixed state of locally directed or locally
rotating flow to iii) a novel, globally synchronized rotating state thereby the
system violating overall chiral symmetry. Finally, this phase crosses over to a
state in which iv) clusters of locally synchronized rotations are observed. The
way of change from polar flow to overall synchronization can be interpreted as
indicating a non-reciprocal phase transition. Our simulations suggest that when
both present, quenched rather than shot noise dominates the behaviors.
