Generation and Optimization of Pulse Pattern for Multiple Concurrently Operated Sonars Using Genetic Algorithm

Nyakoe George NYAUMA  Makoto OHKI  Suichiro TABUCHI  Masaaki OHKITA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E84-A   No.7   pp.1732-1739
Publication Date: 2001/07/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Ultrasonics
ultrasonic sonar,  crosstalk,  genetic algorithm,  pulse modulation,  

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The ultrasonic wave is widely used for acquiring perceptual information necessary for indoor/outdoor navigation of mobile robots, where the system is implemented as a sound navigation and ranging system (sonar). A robot equipped with multiple ultrasonic sonars is likely to exhibit undesirable operation due to erroneous measurements resulting from cross-talk among the sonars. Each sonar transmits and receives a pulse-modulated ultrasonic wave for measuring the range and identifying its own signal. We propose a technique for generating pulse patterns for multiple concurrently operated ultrasonic sonars. The approach considers pulse-pattern generation as a combinatorial optimization problem which can be solved by a genetic algorithm (GA). The aim is to acquire a pulse pattern satisfying certain conditions in order to avoid cross-talk or keep the probability of erroneous measurement caused by cross-talk low. We provide a method of genotype coding for the generation of the pulse pattern. Furthermore, in order to avoid a futile search encountered when the conventional technique is used, we propose an improved genotype coding technique that yields considerably different results from those of the conventional technique.