Abstract: A special tracking error of the ultrashort-base line underwater acoustic tracking system called "quadrant hopping" is caused by the influence of boundaries. Both analysis and computer simulation of this phenomenon are presented. The necessary conditions under which the "quadrant hopping" error could be observed are described and the method for overcoming the error, especially by software is also shown. The experiments made in a lake show that the theory and methods overcoming the "quadrant hopping" error are effective.