The aim of the paper is to develop and test a virtual simulator for the control and diagnostic system of a group of unmanned aerial vehicles (UAV) providing radio communication to ground mobile agents (GMA). The work defines the performance criteria of the management and diagnostics system for the UAV group, identifies and groups the parameters for the UAVs and GMAs groups to be monitored by the safety monitor. The architecture of the virtual simulator is proposed, which performs the function of safety monitor for the control and diagnosis of the UAV group. To test the proposed architecture, a simulated experiment has been carried out: application of a group of UAV in urban conditions to ensure the connection of moving GMAs, with constant-altitude flight of the UAVs. Radio coverage of GMAs using a group of UAVs and their movement have been tested in MATLAB modeling environment. Zabbix monitoring system deployed on a separate virtual machine has been used as the core of the safety monitor. Calculated values of the quality of the current state of the UAVs and the quality of the radio communication have been provided. Data transfer scheme within the simulated experiment has been presented, values of decision time ("response") of the UAV group control system using the proposed safety monitor have been calculated (on the example of activation an additional UAV from the base).