Indoor position information providing apparatus, position notifier apparatus and program

A position information providing apparatus for providing present position information indicating a present position to a position notifier apparatus having a function to notify the present position, the position information providing apparatus comprising:

• an ultrasonic wave output device that outputs ultrasonic wave having a predetermined ultrasonic frequency;
• a controller that
• has a plurality of predetermined detectable frequencies which are within a frequency range detectable by a speech input device of the position notifier apparatus and which are lower than the ultrasonic wave frequency,
• sequentially selects one detectable frequency as a modulation frequency from among the plurality of detectable frequencies in accordance with contents of the present position information, and
• controls the ultrasonic wave output device so that a maximum value or a minimum value of amplitude of the ultrasonic wave varies with the selected modulation frequency, wherein,
• the ultrasonic wave output device is configured to output a sound pressure level, the sound pressure level gradually decreasing with increasing distance from a center corresponding to a center position of the ultrasonic wave output device such that the position notifier apparatus calculates the center position relative to the center by detecting the sound pressure level of the ultrasonic wave.

A position information providing apparatus for providing present position information indicating a present position to a position notifier apparatus having a function to notify the present position, the position information providing apparatus comprising:

• an ultrasonic wave output device that outputs ultrasonic wave having a predetermined ultrasonic frequency;
• a controller that
• has a plurality of predetermined detectable frequencies which are within a frequency range detectable by a speech input device of the position notifier apparatus and which are lower than the ultrasonic wave frequency,
• sequentially selects one detectable frequency as a modulation frequency from among the plurality of detectable frequencies in accordance with contents of the present position information, and
• controls the ultrasonic wave output device so that a maximum value or a minimum value of amplitude of the ultrasonic wave varies with the selected modulation frequency, wherein,
• the ultrasonic wave output device is configured to output two sound pressure levels, the two sound pressure levels denoting the sound pressure levels along different straight lines from a center corresponding to a center position of the ultrasonic wave output device such that the position notifier apparatus calculates the center position relative to the center by detecting the sound pressure levels of the ultrasonic wave.