A Design of Underwater Acoustic Responder Based on Spread-Spectrum Communication

In order to satisfy the requirement of the underwater acoustic positioning system for offshore oil exploration, a design idea for an underwater acoustic responder which used on USBL positioning system was proposed. The hardware adopted MSP430F5438 as the core of controlling and the digital signal processor TMS320VC5509A for computing, and made a detailed analysis for the low-power hardware design. Gold sequence direct sequence spread-spectrum was used on communication system, while modulation was PSK. An appropriate spread-spectrum synchronization mode was presented for the system. MATLAB-based simulation and experiments show that the responder is working reliably and supporting multi-user communication. Meanwhile, the standby quiescent current is less than 2 mA.