Abstract: A personnel locator system for monitoring the locations of classes of pernel. Members of classes of personnel carry portable, infrared transmitters which transmit pulse trains during discrete burst periods. Transmitters carried by members of different classes of personnel transmit pulse trains of different, predetermined frequencies to identify the classes, and transmit the pulse trains during distinct burst periods to prevent phase synchronization between pulse trains transmitted by the different transmitters. Infrared receivers are positioned to receive the transmitted pulse trains in order to monitor the continued presence locations of the members of the classes of personnel. The system utilizes pulse trains having pulses of short pulse widths during a relatively long time period in order to allow increased battery life while transmitting at high energy levels to saturate the area of reception. The pulses are of less than 40 microseconds during a 55 millisecond time frame.