Synchronization is widely considered as an important service in distributed systems which may simplify protocol design. Phase clock is a general synchronization tool that provides a form of a logical time. This paper presents a self-stabilizing (one that tolerates transient statecorrupting faults) phase clock algorithm suited to the model of population protocols with covering. This model proposed recently for large-scale mobile sensor networks. In the model, an unknown number of anonymous finite-state mobile agents interact in pairs and in an asynchronous way subject to constraints expressed in terms of the cover times of agents. The cover time expresses the"frequency" of an agent to communicate with all the others and abstracts agent's communication characteristics (e.g. moving speed/patterns, transmitting/receiving capabilities). We show that a phase clock is impossible in the model of constant-state agents. Hence, we assume an existence of a resourceful agent - the ba...