Optimal pseudo-random sequence determination method, position detection system, position detection method, the transmitting device and the receiving device

摘要

It makes it possible to not receive the influence of the reflected ultrasonic wave signal, and to accurately calculate the propagation time of the direct wave reaching the earliest from the ultrasonic source. Is transmitted from the sender to the receiver ultrasonic plurality of signals are generated based on the M sequence of the plurality of different, the receiver generates a model waveform of M multiple series, the waveform of the ultrasonic signal and the model waveform and performs correlation processing with the to detect the secondary peak of the correlation value that appears when both waveforms are partially matched, generates a secondary peak minimum of the secondary peaks detected in all correlation is determined as the optimum M series M series that was. The sender sends to the receiving ultrasonic signal which is modulated by the optimal M sequence generated based on the electromagnetic signal, the initial conditions for the optimum M sequence. Detecting the main peak of the first correlation value calculating a correlation value between a model waveform of the ultrasonic wave which is modulated by the optimal M sequence with the ultrasonic signal, is calculated, the receiver receives the electromagnetic signal I want to calculate the ultrasonic propagation time from the detection time of the main peak and time.