METHOD AND APPARATUS FOR LOCATING A MOBILE DEVICE WITHIN AN INDOOR ENVIRONMENT

摘要

A method for locating a mobile device is disclosed. Initially, a set of modulated ultrasound signals and a set of radio signals are separately broadcast from a group of transmitters. The ultrasound signals include at least one symbol configured for pulse compression. After the receipt of a demodulated ultrasound signal from a mobile device, wherein the demodulated ultrasound signal is derived from the modulated ultrasound signals, transmitter identifier and timing information are extracted from the demodulated ultrasound signal. Timing information include, for example, the arrival time of the demodulated ultrasound signal in relation to the start time of its transmission. After the locations of the transmitters have been ascertained from the transmitter identifier information, the location of the mobile device can be determined based on the timing information and the locations of the transmitters.

主权项

1. A method for locating a mobile device, said method comprising:
periodically transmitting radio signals via a transmitter; transmitting a modulated ultrasound signal via said transmitter, wherein said modulated ultrasound signal includes at least one symbol configured for pulse compression; in response to the receipt of a demodulated ultrasound signal sent from a mobile device, wherein said demodulated ultrasound signal is derived from said modulated ultrasound signal, extracting transmitter identifier and timing information from said demodulated ultrasound signal and radio signals; determining a location of said transmitter based on said transmitter identifier information; and determining a location of said mobile device based on said timing information and said determined location of said transmitter.