Design Of Data Acquisition And Transmission Unit In Four-element Acoustic Vector Subsurface Buoy

Ocean ambient noise is the background noise in the ocean. It is one of the main interferences to the acoustic detection equipment. As ocean observation is the foundation of ocean development, the measurement of ocean ambient noise has great significance.Submerged buoy system is widely used in the scientific field of ocean ambient noise observation due to its advantages, such as good concealment performance, and long observation time.In this paper, data acquisition and transmission unit in four-element acoustic vector subsurface buoy is designed. Four-element acoustic vector subsurface buoy anchors in a fixed position of the ocean, getting the ocean ambient noise with a vector hydrophone. The acquired signal is transmitted to the acquisition and transmission unit after amplifying and filtering by the analog circuit. The acquisition and transmission unit guarantees the synchronous collection with the help of high-precision atomic clock. The data collected can be stored in the unit or uploaded to the communication buoy through a communication cable, which makes the subsurface buoy elements can upload data to the land station through radio station according to the order.The design of the acquisition and transmission unit mainly includes hardware design andsoftware development. In the hardware design, DSP is employed as a central process chip,which is triggered by a pulse to start the collection for all the four elements synchronously;CF card is used as a storage medium to realize the self-contained storage; a RS485 serial port is connected to the communication buoy to upload the necessary acoustic vector data;MSP430 single chip is designed to be a circuit on duty, which allows the unit to work in low power consumption mode. To the software development, the constant collection?precise synchronization, storing the data in FAT32 file system and accurate uploading address is the emphasis.At last, the acquisition and transmission unit is tested in both the laboratory environment and water pool. The test results show that: the acquisition and transmission unit in the four-element acoustic vector subsurface buoy system functions well and works steadily. The goal of design is realized.