An Experiment of Underwater Acoustic Positioning with Data Transmission Using DSSS

The super short base line (SSBL) method of the acoustic underwater positioning is commonly used due to the simplicity to operation. Though the accuracy of each single shot positioning is not so high. The SSBL for the autonomous underwater vehicle (AUV) becomes more accurate and helpful to navigate the AUV by transmitting the data obtained in each side of seabed and surface such as Global Positioning System (GPS). The direct sequence spread spectrum (DSSS) method is used in this study as same as GPS. In the observation near the seabed, the inter-symbol interference (ISI) is generated due to the reflection from the seabed. In this paper it is shown that the influence of this ISI degrades the accuracy of the positioning with ocean experimental results.