A new data acquisition and processing system for profiling sonar

A multi-beam chirp sonar based on IP connections and DSP processing nodes was proposed and designed to provide an expandable system with high-speed processing and mass-storage of real-time signals for multi-beam profiling sonar. The system was designed for seabed petroleum pipeline detection and orientation, and can receive echo signals and process the data in real time, refreshing the display 10 times per second. Every node of the chirp sonar connects with data processing nodes through TCP/IP. Merely by adding nodes, the system＇s processing ability can be increased proportionately without changing the software. System debugging and experimental testing proved the system to be practical and stable. This design provides a new method for high speed active sonar.     

桥梁桩底溶洞声呐探测法的应用研究

在我国喀斯特地貌分布地区,溶洞极为发育,对工程建设产生较大影响。在未探明桩底岩溶发育情况下进行桩基施工和终孔,易发生溶洞漏浆、溶洞顶板承载能力不足的问题。由于桩基自重较大且承担桥梁上、下部结构传下来的荷载,若处理不当,将引起塌孔、地面沉降、埋钻等严重事故。钻孔灌注桩在掘进过程中需要泥浆护壁,但现行的物探方法难以透过钻孔灌注桩的泥浆对桩底基岩溶洞发育情况进行有效勘查。本研究结合3个工程实例,运用现有桩底溶洞声呐探测技术,通过汇总、整理、分析喀斯特地貌广泛分布地区的3个项目的桩底探溶声呐实测数据,总结了该探测技术的应用效果和方法,验证了探测方法的探测精度和可靠性,并提出了该方法的不足之处和改进建议。     

声呐腔流激噪声场空间互功率谱及相干性研究

随着声呐基阵孔径的增大及探测频率的不断降低，声呐自噪声场特性研究需要由自功率谱空间分布特性扩展到空间互功率谱及相干特性。针对矩形腔和弹性矩形板透声窗组合的声呐腔结构，考虑弹性平板与内外声场的耦合作用，采用模态法建立了矩形板受湍流边界层脉动压力激励的腔内水动力噪声场空间互功率谱及空间相干性计算模型，计算分析了在不同频率和不同噪声场空间场点位置情况下的声呐腔水动力噪声场空间互功率谱和相干性特征，计算结果与实船声呐舱水动力噪声测试结果一致。