An autonomous ultrasonic indoor location system includes a location beacon transmitting apparatus and a location beacon receiving apparatus. The location beacon transmitting apparatus is configured to sequentially transmit US signals at a predetermined time interval upon transmission of a signal containing synchronization information. The location beacon receiving apparatus is configured to synchronize with the location transmitting apparatus when synchronization information is detected, determine transmission order of the received US signals based on the obtained synchronization timing, infer transmission timings of the respective US signals based on the determined transmission order, calculate TOA information corresponding to each of the received US signal from the transmission timings and reception timings of the respective US signals, and determine location of the location beacon receiving apparatus on basis of the positions of the US transmitters in the transmitting apparatus and the calculated TOA information sequence.