Abstract
An Acoustical Positioning System that consists of several signal transmitters encircling the object area and a receiver on a vehicle is proposed. The method of the system features no synchronizing connection from the transmitters to the receiver. Each transmitted signal is Phase Reversal Keying (PRK) of one of the Gold sequences in order that the receiver can distinguish from which transmitter originates it. The receiver includes a microphone and a signal processor which detects signals with the matched filter of complex absolute detection type being free from errors caused by unknown phase shift. The receiver, which cannot know the point in time of signal originated, estimates the position of the vehicle in the area with the differences of arrival moments among signals from the several transmitters. The estimation method is based on the Maximum A Posteriori (MAP) criterion applying to the equation of motion.
