Design And Key Technology Research Of Sonar Buoy Signal Acquisition System

In this information era with the swift development of science and technology,the attention of mankind to the utilization and development of resources has transferred from land to the larger area by degrees.Accompanied by human’s in-depth exploration of ocean resources,the sonobuoy signal acquisition system that can accurately preprocess underwater acoustic acquisition signals and real-time reliable communication transmission has become a hot spot in marine resource research.Aiming at the defects of large dynamic range of underwater acoustic signal and poor real-time performance and reliability of sonobuoy system,this article conducts in-depth research on the technologies of weak signal preprocessing,high reliability data transmission and data compression coding in sonobuoy signal acquisition system.And a sonobuoy signal acquisition system with wide dynamic range,reliability and real-time performance is designed based on the visual operation interface.According to the requirements of the sonobuoy signal acquisition system,this article analyzes the system composition,working principle,main functions and technical indicators.It completes the overall structure design of the sonobuoy signal acquisition system.In order to solve the problems of how to obtain weak underwater acoustic signals in the system and how to ensure the reliability and real-time performance of data transmission,three key technologies in the sonobuoy signal acquisition system are clarified: weak signal preprocessing technology,highly reliable data transmission technology and data compression coding technology.In order that the sonobuoy signal acquisition system exactly can obtain underwater acoustic signals,the system preprocesses the weak underwater acoustic acquisition signal.According to the limits of the acquisition range of weak underwater acoustic signals from several microvolts to several hundred microvolts,and the acquisition passband range of underwater acoustic signals from 100 Hz to 20 kHz,this article proposes various technical indicators of the system’s underwater differential weak underwater acoustic signal preprocessing.This article completes the software and hardware design of the weak signal preprocessing module through the technical indicators,and finally realized the weak underwater acoustic signal of the sonobuoy signal acquisition system with a fixed gain of 80 dB,a dynamic gain of 40 dB,a frequency range of 100Hz-20 kHz,and a sampling frequency of 60 kHz.In response to the issue of low data readability when interacting with multiple communication protocols within the sonar buoy signal acquisition system,this system implements highly reliable data communication transmission based on the Modbus communication protocol.The data communication of this system is mainly divided into coaxial cable and network communication.This article completes the communication interface hardware design based on two kinds of data communication,and sets the coaxial cable and ethernet protocol frame data format of the sonobuoy signal acquisition system according to the Modbus communication protocol format.This article completed the software design of the system data transmission communication protocol,and finally used MFC to complete the software design of the visual interface.In order to reduce the transmission delay of a large amount of underwater acoustic acquisition data during communication transmission and improve the real-time transmission performance of the sonar buoy signal acquisition system,this system compresses and processes the underwater acoustic acquisition data.At the same time,considering the integrity of underwater acoustic data collection,this system uses lossless compression to process the data.Through the performance comparison of various lossless data compression algorithms,this system,in the last resort,adopts the LZW compression algorithm as its method for data compression processing.In addition,this article optimizes the defects of the dictionary memory size and the dictionary update method that affect the compression performance in the traditional LZW algorithm in order to further enhance the algorithm performance of the LZW compression algorithm.Last but not least,the improved and optimized LZW data compression coding is verified in terms of algorithm accuracy and compression performance.In order to verify the feasibility of the sonobuoy signal acquisition system,this article conducts experimental tests on three key technologies in the system.And a joint performance test of the entire sonar buoy signal acquisition system,in this article,is conducted in an experimental environment of an anechoic water pool.The experimental test results indicate that the system meets the actual design requirements.In the field of sonobuoy signal collection,the designed system carries enormous application value.