Ultrasonic locationing system using regional addressing with ultrasonic tones

摘要

An ultrasonic locationing system includes an emitter operable to emit at least two ultrasonic frequency tones sequentially in one ultrasonic burst. These tones, which may contain multiple frequency components, define a unique regional address. A mobile device with a microphone is operable to receive the ultrasonic burst and have a processor determine the sequential tones. A location of the device can be found from a table of predefined tones assigned to known regional addresses.