Software Design Of Underwater Obstacle Avoidance Sonar System

Due to the unpredictability of underwater environment, UUV need to spy on the obstaclethrough the trip. The obstacle voidance sonar is aimed to find obstacle, estimate the distanceand position exactly. It provides the basis of collision avoidance for UUV. In this paper, thesoftware design was spread out around the collision avoidance sonar system on UUV. Thedistance and position estimation of obstacles on5horizontal directions and vertical directionsare realized by the collision avoidance sonar system.In horizontal direction, phased array technology, which combining the frequencydivision and time division, and echo signal split array beam-forming were used to detect theobstacle and estimate it’s distance and position on5horizontal directions on the front ofUUV. The CW and LFM combination form of detection signal was designed. The envelopedetection and correlation detection were used to detect and estimate the time delay. In verticaldirection, the short CW signal form and the same envelope detection were used to detect theobstacle and estimate the distance.In the envelope detection, the adaptive notch filter was used to abstract the signalenvelope, and then the width identification and amplitude identification were used to detectthe obstacle. And the front of the envelope was taken as time delay estimation value, whichwas used to compute the distance of obstacle. The accurate time delay and the geometricrelation of horizontal array were used to compute the position of the obstacle.In this paper, the theoretical analysis research and performance simulation of obstacledetection method used by collision avoidance sonar system were finished. The software ofcollision avoidance sonar system was carried out based on OMAPL137minimum system. Inthe laboratory, the function test of collision avoidance sonar system was completed usingelectric simulator, and the joint debugging with the other part of UUV was achieved favorably.Finally, the system was tested in Qiandao Lake. The possibility of the theoretical method wasproved, and the design demand was met well.