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Determination of the position of an acoustic transmitter in a room in three dimensions has multiple applications. We are designing a system that will track the position of a person in a room in two or three dimensions using techniques that could be expandable to multiple rooms. The transmitter emits an acoustic pulse that is detected by four or five receivers in the room. The receiver array sends the analog signal as it is received with noise to a signal conditioner. The signal conditioner consists of an active band-pass filter, an envelope detector and a comparator and its output is a digital signal corresponding to a time-delayed version of the original pulse. The rising edge of each receiver's digital signal will trigger a microcontroller to capture the time of arrival of that signal. One of two location algorithms will be used. Either the initial start time of the emitted pulse and the Time of Arrival (TOA) of each rising edge pulse will yield the Time of Flight (TOF) for each received signal of the TOA of each signal will be used to calculate a series of Time Differences of Arrival (TDOA) of the signals. A matrix-based location algorithm will use wither the TOF or TDOA information to determine the two or three dimensional position of the ultrasonic transmitter in the room.
Collins, Charlie J.; Ohlendorf, Tracy D.; and Sheffield, Amy E., "Tracking the Position of an Ultrasonic Transmitter in a Room" (1998). Engineering Senior Design Reports. 3.