Multichannel Non-Crosstalk Sonar System Modulated Using Chaotic Binary Frequency Shift Keying Sequences for Mobile Robots

This paper addresses multichannel non-crosstalk sonar systems for mobile robots. Binary frequency shift keying (BFSK) sequences modulated using chaotic series are proposed to eliminate crosstalk between multichannel ultrasonic ranging transducers. A square wave is used as the carrier of the chaotic BFSK sequence in order to reduce hardware cost. The parameters of the chaotic BFSK sequence are configured to make full use of bandwidth of the sonar transducers. A genetic algorithm is applied to optimize the echo correlation characteristics. Experiments have been conducted using a sonar system that consists of eight-channel Polaroid 600 instrument-grade electrostatic transducers excited with 2 ms chaotic BFSK sequences. Experimental results show that the multichannel ultrasonic ranging transducers excited with the proposed chaotic BFSK sequences can work together without crosstalk.