A signal distribution system includes global positioning system receivers in communication with optical line terminals and a system manager. Each global positioning system receiver receives a signal from a corresponding global positioning system satellite. Each optical line terminal includes a management card and a line card. The management card receives a signal from a corresponding global positioning system receiver. Each line card receives a signal from each management card and determines a signal drift and a phase precision for each signal. The system manager receives a failure communication for a global positioning system signal from a line card when the signal drift of the global positioning system signal is above a threshold signal drift or the phase precision of the signal is below a threshold phase precision. The system manager identifies a failure location of the signal within the system based on one or more received failure communications.