Positioning system, positioning method, and positioning program

A positioning method executed by a positioning system including at least a fixed receiver, a plurality of signal sources, and a mobile terminal, comprising:

• a first acquisition step of acquiring a reception log, indicating that the fixed receiver receives signal source-specific inaudible sounds from the plurality of signal sources, in association with a receiver ID of the fixed receiver;
• a second acquisition step of acquiring, from a storage unit, signal source information on the plurality of signal sources corresponding to the fixed receiver installed near the mobile terminal, wherein the signal source information contains information for identifying a signal source from inaudible sound, transmission timing of inaudible sound at the signal source, and a location of the signal source;
• and
• a positioning step in which, when the mobile terminal receives a plurality of inaudible sounds, a plurality of signal sources that emit the plurality of inaudible sounds are identified based on signal source information acquired in the second acquisition step, and a current location of the mobile terminal is calculated using the signal source information on the plurality of identified signal sources, and a reception log of the plurality of inaudible sounds at the mobile terminal.

A positioning system for positioning a location of a mobile terminal, comprising:

• a requesting unit makes a request to a plurality of signal sources for current time information on the plurality of signal sources;
• an acquisition unit acquires signal source information on the plurality of signal sources, wherein the signal source information contains information for identifying a signal source from each of inaudible sounds emitted by the plurality of signal sources;
• and
• a table creation unit creates a transmission schedule table of the inaudible sound of each signal source based on the current time information from each signal source and information for identifying the signal source.