共查询到18条相似文献,搜索用时 140 毫秒
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拖曳系统计算中拖缆与拖体的耦合计算 总被引:4,自引:0,他引:4
针对带有水下设备舱的拖曳系统,提出了一种有效的算法,来获得拖曳系统的运行状态。将拖曳系统分成拖缆和水下拖体两个部分,分别建立运动数学模型。拖缆部分的模型以Ablow和Schechter的运动数学模型为基础;拖体部分的模型采用类似潜器的水下六自由度运动方程。将这两部分方程联立,统一求解,解决两个模型之间的耦合问题。经过数值仿真的检验证明算法具有可行性。 相似文献
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本文描述了多参数拖曳荧光计系统在船模水池和海上进行拖体水动力特性试验,得出:在10kn以内的任意拖曳速度均能水平稳定拖曳,而纵倾角≤±2 的拖点位置;拖索张力T与拖体速度 之间的关系为T=47十31.8 2.08;拖曳速度为10kn时,水动迫沉力约为950kgf,升阻比约为2.4~2.5,满足了拖曳系统的迫沉要求。海上性能试验与应用实验表明:该拖曳系统的荧光传感器对水体、荧光示踪染料、悬浮颗粒物具有很高的分辨率;对罗丹明B水溶液的浓度检测范围为1×10-7~1×10-3mg/dm3;对悬浮物的浓度检测范围为2~2000mg/dm3,使该系统广泛地用于海洋环境检测和评价工程任务中。 相似文献
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水下拖曳升沉补偿系统水动力数学模型研究 总被引:4,自引:2,他引:2
建立变缆长的水下拖曳升沉补偿系统水动力学偏微分方程组和边界条件.拖缆动力学模型基于Ablow and Schechter模型,拖体采用水下运载体六自由度方程模拟,运用有限差分法离散偏微分方程组和牛顿迭代法计算变缆长情况下拖体深度与拖缆各点张力的动态取值.数值计算结果表明采用收放拖缆的升沉补偿方法能够有效削弱母船升沉运动对拖体深度和拖缆张力的影响. 相似文献
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针对海洋测量水下拖曳设备位置确定问题,综合考虑拖缆受力、海流影响以及水下拖体的运动性质,建立了水下拖曳设备的位置计算模型,并仿真计算分析了测量船在不同航行状态下拖曳设备位置确定的规律,探讨了不同海流效应对拖曳设备位置确定的影响。仿真计算结果表明,在海洋动态环境作用下,拖缆各方向的偏移明显呈曲线形状,非简单几何运算所确定。测船各方向的运动均可对水下拖体的位置在相应方向产生一定影响,而水下拖体位置的变化量小于测船拖点位置的变化量。海流对水下拖曳设备定位可造成数米的偏差,需进行相应改正。建议可考虑采取船载式ADCP实时测流辅助水下拖曳设备定位的工作模式。 相似文献
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本文介绍了通过海上实验及理论分析研制的拖曳体。同时对拖曳体的流体动力布局及其微调装置进行了阐述。该拖曳体经过多次海上实验结果表明:在拖速6—10节时,稳定性良好,下潜力大,阻力较小,可以控制机翼冲角的大小来增减下潜力,改变下潜深度,使其行驶于“锯齿形”的剖面上,随深度的变化自动记录温、盐度。如拖速8.5节, 相似文献
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富钴结壳作为一种潜在的海洋矿产资源逐渐引起人们的关注,研究发现海山微地形是影响富钴结壳分布的重要因素。DTA-6000声学深拖系统是我国具有自主知识产权的第一套深海拖曳观测系统,其最大工作深度6 000 m,该设备上安装的高分辨率测深侧扫声纳和浅地层剖面仪能够分别获得高分辨率的海底地形地貌和浅地层剖面。它的测深覆盖范围600 m,侧扫覆盖范围800 m。声学深拖系统因其高效和价格优势,被列为富钴结壳资源调查的常规设备。大洋29航次中,DTA-6000声学深拖系统在采薇海山完成2条测线共约50 km海山斜坡的探测,获得了高分辨率的地形地貌数据和浅地层剖面数据。介绍DTA-6000声学深拖系统及其在富钴结壳探测中的应用,并对探测结果进行了分析。 相似文献
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An experiment aboard the Scripps Institution of Oceanography's RV Thomas Washington has demonstrated the seafloor mapping advantages to be derived from combining the high-resolution bathymetry of a multibeam echo-sounder with the sidescan acoustic imaging plus wide-swath bathymetry of a shallow-towed bathymetric sidescan sonar. To a void acoustic interference between the ship's 12-kHz Sea Beam multibeam echo-sounder and the 11-12-kHz SeaMARC II bathymetric sidescan sonar system during simultaneous operations, Sea Beam transmit cycles were scheduled around SeaMARC II timing events with a sound source synchronization unit originally developed for concurrent single-channel seismic, Sea Beam, and 3.5-kHz profile operations. The scheduling algorithm implemented for Sea Beam plus SeaMARC II operations is discussed, and the initial results showing their combined seafloor mapping capabilities are presented 相似文献
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Historically, measurement and collection of deep‐ocean acoustic imagery are accomplished by towed sidescan systems. Recently, work has been performed to extract acoustic imagery from current hull‐mounted wide‐swath bathymetric sonars with minimal hardware modification. Past work of deriving acoustic imagery from swath sonars has been performed primarily with SeaBeam's sixteen 22/3 ° preformed beams. The Navy is investigating the feasibility of extracting an acoustic image from the Sonar Array Survey Systems (SASS), a high‐resolution (1o beams) wide‐fan (90°) bathymetric system. Due to the large data volume (approximately 1 MB per ping), SASS normally discards the raw acoustic returns once bathymetry is calculated. In early 1991 the Naval Air Development Center (NADC) installed the hardware on board the USNS Maury to capture and record the raw acoustic signal (inphase and quadrature) from the SASS's 144 hydrophones for later inversion to a backscatter image. Preliminary qualitative mosaics of the sidescan images show promising results and warrant further development. 相似文献
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Pierre Cervenka Ute Christina Herzfeld Christian De Moustier 《Marine Geophysical Researches》1994,16(6):407-425
When isobath maps of the seafloor are constructed with a bathymetric sidescan sonar system the position of each sounding is derived from estimates of range and elevation. The location of each pixel forming the acoustic backscatter image is calculated from the same estimates. The accuracy of the resulting maps depends on the acoustic array geometry, on the performances of the acoustic signal processing, and on knowledge of other parameters including: the platform's navigation, the sonar transducer's attitude, and the sound rays' trajectory between the sonar and the seafloor. The relative importance of these factors in the estimation of target location is assesed. The effects of the platform motions (e.g. roll, pitch, yaw, sway, surge and heave) and of the uncertainties in the elevation angle measurements are analyzed in detail. The variances associated with the representation (orientation and depth) of a plane, rectangular patch of the seafloor are evaluated, depending on the geometry of the patch. The inverse problem is addressed. Its solution gives the lateral dimensions of the spatial filter that must be applied to the bathymetric data to obtain specified accuracies of the slopes and depths. The uncertainty in the estimate of elevation angle, mostly due to the acoustic noise, is found to bring the main error contribution in across-track slope estimates. It can also be critical for along-track slope estimates, overshadowing error contributions due to the platform's attitude. Numerical examples are presented.On leave at the Naval Research Laboratory, Code 7420, Washington D.C. 20375-5350, U.S.A. 相似文献
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针对航位推算系统位置误差发散、水声定位系统输出信息波动大的特点,利用基于航位推算/水声定位系统的组合导航方法进行深拖系统导航定位。先利用多普勒速度仪和罗经的输出数据进行航位推算得到拖体位置,然后将此位置与水声定位系统输出的位置进行数据融合,得到连续、平滑的高精度深拖系统导航数据,实现水下拖体的高精度定位。应用此方法对海试实验数据进行了处理,实验结果表明:采用组合方法后,既限制了位置误差的发散,又减小了数据波动幅度,可以得到平滑的高精度位置。 相似文献
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A procedure for postprocessing bathymetry data provided by a phase-measuring sidescan sonar system is presented. The data were collected with the SeaMARC II system, and are generally characterized by a high level of noise and uneven spatial sampling. Before any spatial filtering is applied, data are selected to remove most of the obvious artifacts and to retain instantaneous depth profiles whose slant ranges increase monotonically from a central location to the edges of the swath. An extrapolation scheme, patterned after a potential field, is proposed to fill gaps in the coverage or to extend the bathymetric swath to that of the corresponding sidescan image when regridding the data to a rectangular frame. To fill the near nadir gap typically found in these data, a specific interpolation methodology is developed that takes into account the slant range of the first bottom return as received by the sidescan sonar itself or by a shipboard echo-sounder. Spatial low-pass filtering is applied through convolutions with parabolic windows whose width is proportional to the footprint of the acoustic beam along track and roughly 1/8 of the swath width across track. Mismatches of contour lines between adjacent tracks are reduced through a statistical method design to correct systematic profile errors 相似文献
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TOBI (Towed Ocean Bottom Instrument) is a deep-tow sidescan sonar vehicle from which sidescan sonar data are now routinely collected and archived. This paper describes the algorithms developed for detailed processing of TOBI data. Sonar imagery has a characteristic set of processing challenges and these are addressed. TOBI provides a very large sonar dataset, and to limit the difficulties of handling and processing these data, the raw data are subjected to a data reduction technique prior to further processing. Slant-range correction is improved by editing vehicle altitude data using a median filter. Noise on TOBI imagery can appear in two main forms; speckle noise and line dropouts. Speckle noise is removed by a small median difference kernel and line dropouts are removed using a ratio of two box-car filters, each with appropriate thresholding techniques. Precise geocoding of the imagery requires an accurate estimate of vehicle location, and a method of calculation is presented. Two optional processing algorithms are also; presented; deblurring of imagery to improve along-track resolution at far range, and the suppression of a surface reflection return which may occur when TOBI is operated in relatively shallow water. Several of the techniques presented can be transcribed and modified to suit other datasets 相似文献