Methods and systems for determining a location and an identity of a portable device are provided. The system includes apparatus for transmitting timing synchronization information, a plurality of stationary ultrasonic base stations and a plurality of portable devices. Each ultrasonic base station is configured to receive the timing synchronization information and to transmit a corresponding ultrasonic location code in a time period based on the received timing synchronization information. Each portable device is configured to: 1) receive the timing synchronization information, 2) detect the ultrasonic location codes from the ultrasonic base stations and 3) transmit an output signal including a portable device ID representative of the portable device and the detected ultrasonic location code. Each portable device is synchronized to detect the ultrasonic location code in the time period based on the received timing synchronization information.