共查询到19条相似文献，搜索用时 156 毫秒
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为保障水下探测量值准确可靠,研究水下成像声纳计量测试方法及量传溯源技术。基于大型试验水池和位移/回转机构,采用比较校准法对成像声纳声学参数和几何参数进行了计量测试,以全站仪、标准水听器、信号采集器、标准目标块套组作为计量主标准器,完成了对成像声纳工作频率、波束宽度、成像距离和鉴别阈的计量性能试验。参考标准值与标称值比对结果表明,被检成像声纳工作频率示值误差0.059kHz,垂直波束宽度示值误差-0.07°,水平波束开角示值误差1.3°,成像距离优于180m,鉴别阈5cm,并给出了测量结果的扩展不确定度。海洋测绘仪器计量标准的建立,有助于规范评价国内外产品的关键性能,保障测量成果质量。 相似文献
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EM1002S与GeoSwath多波束声纳系统测深精度比较分析 总被引：1，自引：0，他引：1
多波束勘测之前,为了保证多波束成果质量,需要对多波束声纳系统进行一系列设备安装校准和精度评估工作.基于在渤海湾开展的多波束海底地形地貌勘测项目,在项目勘测之前,对EM1002S与GeoSwath多波束声纳系统进行了安装校准,并对2套多波束声纳系统的测深精度进行了比较分析,通过计算得到两套系统之间的最大测深误差为-0.38 m,测深误差主要为0～0.2 m,无超限数据,结果分析显示2套多波束声纳系统的测深精度满足勘测技术要求,为我们调查工作的顺利开展奠定了良好的基础. 相似文献
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相干声纳多波束与传统型多波束测深系统综合对比与实验分析 总被引：1，自引：0，他引：1
在工作原理、技术参数、采集软件和处理软件功能与操作,以及数据实测等方面对相干声纳多波束测深系统Geoswath Plus和传统型多波束测深系统Seabeam 1180进行了详细对比。对比表明,两套多波束系统的工作原理完全不同;传统型多波束测深系统在探头下方数据密集,两侧的数据逐渐变稀,相干声纳多波束测深系统在探头正下方的数据比较稀疏,探头两侧的数据较密集;相干声纳多波束测深系统Geoswath Plus的采集和处理软件实现了一体化,具有较直观的数据质量监控功能,传统型多波束测深系统Seabeam 1180可应用的后处理软件较多,功能更丰富;通过实测数据验证,两套多波束测深系统在数据测量精度上具有较好的一致性,不符值数列的标准偏差为3%—4%。对比为多波束测深系统的引进和选型提供了参考依据。 相似文献
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Automatic Registration of TOBI Side-Scan Sonar and Multi-Beam Bathymetry Images for Improved Data Fusion 总被引：1，自引：0，他引：1
Deep towed side-scan sonar vehicles such as TOBI acquire high quality imagery of the seafloor with very high spatial resolution but poor locational accuracy. Fusion of the side-scan sonar data with bathymetry data from an independent source is often desirable to reduce ambiguity in geological interpretations, to aid in slant-range correction and to enhance seafloor representation. The main obstacle to fusion is accurate registration of the two datasets.The application of hierarchical chamfer matching to the registration of TOBI side-scan sonar images and multi-beam swath bathymetry is described. This matches low level features such as edges in the TOBI image, with corresponding features in a synthetic TOBI image created by simulating the flight of the TOBI vehicle through the bathymetry. The method is completely automatic, relatively fast and robust, and much easier than manual registration. It allows accurate positioning of the TOBI vehicle, enhancing its usefulness as a research tool. The method is illustrated by automatic registration of TOBI and multi-beam bathymetry data from the Mid-Atlantic Ridge. 相似文献
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The feasibility of adding an interferometric swath bathymetric system to GLORIA, a 6.6 kHz long-range sidescan sonar, is discussed. The size of GLORIA's low-frequency transducer arrays and towfish precludes significant modifications, but even without such changes bathymetric errors could be several tens of metres over a usable swath somewhat smaller than the normal GLORIA swath. A swath bathymetry based on GLORIA will have random errors depending strongly on wind speed, water depth, and swath width. Within the range of these parameters, root-mean-square bathymetry errors in the range of 1-100 m can be expected 相似文献
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Le Bas T.P. Somers M.L. Campbell J.M. Beale R. 《Oceanic Engineering, IEEE Journal of》1996,21(4):545-553
For many years, GLORIA has been producing sonar images of the deep ocean floor. In the mid-1980's, the SeaMARC II system came to prominence producing depth values as well as sonar images. The basic method compares the phases of the signals returning from the seafloor to two rows of transducers. The phase differences are converted into angles of arrival and together with the arrival times converted into range and depth values. This capability has now been added to the GLORIA system. The fact that GLORIA uses a 2s FM pulse means the backscattered reverberation can come from a strip of seafloor up to 1.5 km wide. To accommodate this, overlapping complex FFT's are used to produce a time-frequency matrix for the returning signals. In this matrix, a constant range feature appears as a diagonal. Phases are then calculated using a least-mean-squares estimate along diagonals. The main source of error and bias is due to surface reflection, and this is taken into account. The GLORIA swath bathymetry system was tested on two cruises and it was possible to produce depth contours with a good level of confidence. The total swath width was over eight water depths and would have been greater with a more favorable velocity profile. Comparison with other bathymetry data (such as multibeam systems) showed excellent correlation, having a standard deviation of only 4% of total water depth 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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Digital filters designed using wavelet theory are applied to high resolution deep-towed side-scan sonar data from the median valley walls, crestal mountains, and flanks of the Mid-Atlantic Ridge at 29°10 N. With proper tuning, the digital filters are able to identify the location, orientation, length, and width of highly reflective linear features in sonar images. These features are presumed to represent the acoustic backscatter from axis-facing normal faults. The fault locations obtained from the digital filters are well correlated with visual geologic interpretation of the images. The side-scan sonar images are also compared with swath bathymetry from the same area. The digitally filtered bathymetry images contain nine of the eleven faults identified by eye in the detailed geologic interpretation of the side-scan data. Faults with widths (measured perpendicular to their strike) of less than about 150 m are missed in the bathymetry analysis due to the coarser resolution of these data. This digital image processing technique demonstrates the potential of wavelet-based analysis to reduce subjectivity and labor involved in mapping and analyzing topographic features in side-scan sonar and bathymetric image data. 相似文献
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There is a pressing need for standardization of data derived from bathy‐metric swath‐mapping systems. Currently several dozen multibeam and sidescan sonar data formats exist within the oceanographic community, and more can be expected as new systems are developed. Without some standardization of swath‐mapping data formats, the capability for use and integration of data from different systems will be severely compromised. This paper presents a strategy for organizing swath bathymetry data in a logical modular fashion that will allow data from all current swath bathymetric sonar systems to be stored and accessed in a common fashion. We have chosen the approach of defining compact efficient modules for each logically independent portion of a data record and storing it in a manner that is portable between diverse computer architectures and operating systems. This approach is extensible to accommodate new types of data. Although specifically developed for swath bathymetry, this format is also capable of supporting digital sidescan data and other types of swath data. 相似文献
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G. Lastras M. Canals D. Amblas M. Ivanov B. Dennielou L. Droz A. Akhmetzhanov 《Geo-Marine Letters》2006,26(4):225-233
After obtaining full-coverage swath bathymetry data in 1995 and very high-resolution acoustic profiles in 2002, four slides at the Balearic Margin of the Eivissa Channel in the western Mediterranean Sea were revisited in 2004 when side-scan sonar data were collected using a MAK-1M deep-towed acoustic system. These new findings, higher in resolution than those for the swath bathymetry, show two main features previously undetected within these submarine landslides: (1) a series of step-forming inclined and detached slabs oriented perpendicular to the slide movement and located in the uppermost part of the slides, and (2) arcuate regular positive ridges oriented also normal to the slide movement and located in the depositional lobes of some of the slides. The former are interpreted as extensional ridges, suggesting a retrogressive post-failure evolution of the slides. The latter are interpreted as compression ridges, related to plastic deformation of the sediment before movement freezing. Moreover, the new data show that fluid escape features are even more widespread in the Eivissa Channel than previously thought, dozens of new pockmarks less than 20 m in diameter having been identified. 相似文献
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Simon Allerton Bramley J. Murton Roger C. Searle Malcolm Jones 《Marine Geophysical Researches》1995,17(1):37-61
The combination of multi-beam echo-sounder swath bathymetry and high-resolution deep-towed sidescan sonar provides a powerful database from which to examine mid-ocean ridge processes. We have used such a database, gathered from the Mid-Atlantic Ridge north of the Kane Fracture Zone (the MARNOK area), to examine the relationship between tectonic, volcanic, and bathymetric segmentation. We have identified structural domains, with different fault distributions, and neovolcanic segments that are distinct from the 2nd or 3rd order bathymetric segmentation.From their mutual relationships, a model is proposed for the magmatic accretion of oceanic crust at slow spreading ridges that relates the local melt supply to the tectonic style. We suggest that these are mutually interactive, and determine whether volcanic extrusion along the ridge is continuous and slow, or episodic and rapid. 相似文献
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Bourgeois B.S. Martinez A.B. Alleman P.J. Cheramie J.J. Gravley J.M. 《Oceanic Engineering, IEEE Journal of》1999,24(4):414-423
This paper describes the Autonomous Bathymetry Survey System (AutoSurvey), a system that provides automation of swath sonar bathymetric surveys. This system enables faster surveying of an area through environmentally adaptive techniques while ensuring adequate coverage and data quality. AutoSurvey assesses data quality and coverage in real time and generates next-trackline waypoints based on actual system performance. The need for real-time performance assessment is discussed. A primary factor considered is the effect of the environment on swath bathymetry system performance, which is difficult to predict a priori. The system's features, design, and implementation are discussed in this paper. Simulation and sea trial results are presented, as well as an analysis of the system's ability to reduce survey time 相似文献