A Study On Multi-Beam Sounding System Seafloor Tracking & Data Processing Techniques

Multi-Beam Sounding System (MBSS) is a high-density integration of modern signal processing,computer application,high precision navigation and positioning and other technologies. Based on the instrument of H/HCS-017 Multi-Beam Echo Sounder developed independently by us,this dissertation studied aspects of different kinds of techniques related to multi-beam surveying.In the aspect of detection and high precision estimation of seafloor backscattering,algorithms of Fast Convergence of Energy Center and Correlation of Eigen-replica were developed. Also studded were processing methods of Weighted Mean Time (WMT) and Bearing Direction Indicator (BDI) based on FFT beam forming as well as high precision detection and estimation of Time Of Arrival (TOA) and Direction Of Arrival (DOA) using Split Beams Phase Difference Detection technique. All the research results were tested with experiments data collected on sea,which shown that the conclusion was correct. Therefore,it is of important reference and application value for the improvement of technical features of future MBSS systems.Real Time Seafloor Tracking Technique is the critical technique to ensure smooth seafloor surveying with full coverage and high efficiency. After detailed investigation on stochastic features of seabed reverberation produced by MBSS systems,the author presented an algorithm and a set of relevant key coefficients for real time seafloor tracking,taking into account of characteristics of signal processing and timing sequence of the real system and introducing theorems of terrain surveying. As an achievement,a mathematical model was established based on the technique of centered filtering. Applicable software was also developed accordingly by the author,which was proven theoretically correct and functioned satisfactory in several sea trials.MBSS system is a complex system with different kinds of sensors. The author analyzed the main sources of error of the system,studied the synthetic error compensation method for sonar array. Besides,methods for pre-processing of on-ship data and combined processing of time and space for depths were also studied,which could remove extremes and enhance the quality of digitized final come out efficiently.The precision acceptance of MBSS systems is usually carried out on sea. There are not yet acceptance standards for MBSS systems in our country. Resulting from researches and experience accumulated in MBSS practice for years,the author suggested a precision estimation model of depth and position for the acceptance of MBSS systems,and presented further a stochastic model of double observation for data quality estimation. These models could be introduced to the designed national MBSS acceptance standards.Finally,the author studied the developing trends of multi-beam surveying techniques and analyzed the needs of potential customers in recent years,leading to the conclusion that model diversification,volume minimization,multi-functioning and high precision will be the future developing trends of MBSS systems.