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分析比对了GPS单点测速技术与其他已有测波手段的不同,讨论了基于多普勒频移的GPS测速方法,并分析了各类误差对测速精度的影响。分别利用原始多普勒值和导出多普勒值进行了静态测速试验和动态测速试验,将导出多普勒测速结果与RTK(RealTimeKinematic,实时动态测量系统)位置差分测速进行了比测。结果表明,使用静态数据采用高频导出多普勒值测速的精度可以达到亚厘米级每秒,而采用原始多普勒观测值进行测速因接收机型号的不同,结果差异较大;动态测速试验中,采用导出多普勒测速的方法与RTK位置差分测速的符合精度可达cm/s。 相似文献
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为了在非理想环境的测速场或者没有测速场进行相对计程仪的准确测速,在通用方法基础上,论述了两种切实可行有效的测速新方法,通过理论及实验证明,实用性较强,具有一定的推广价值。 相似文献
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研究了一种基于复相关测频原理的多普勒测速算法,针对该算法受信噪比影响较大的情况提出了一种基于遍历噪声修正的测速优化算法。仿真结果表明:该优化算法能减弱噪声对测速精度的影响,尤其在低信噪比的情况下,能有效提高多普勒测速精度。 相似文献
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国内外在声学多普勒测速误差分析和修正算法方面已作了大量的研究工作.一般认为JANUS配置方式下,多普勒频移公式的简化误差可忽略.文中从理论上对多普勒测速的原理公式的简化过程进行分析,研究了大倾角状态下的测速公式的相对误差,认为在高速、大倾角工况下公式简化误差不可忽略,并提出了修正公式. 相似文献
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为解决GNSS伪距变率双差测速和高斯投影、墨卡托投影坐标系中的速度投影计算问题,以大地坐标速度为未知数,推导GNSS伪距变率双差测速解法,基于高斯投影、墨卡托投影公式,推导其速度投影算法。建立了以大地坐标速度为未知数的GNSS伪距变率双差测速数学模型,建立了高斯投影、墨卡托投影坐标系速度投影计算方法,给出了应用试验和算例。结果表明,GNSS伪距变率双差测速大地坐标分量精度达到毫米/秒级,高斯投影、墨卡托投影坐标系速度投影算法正确。提出的GNSS伪距变率双差测速解法具有重要的应用价值。提出的高斯投影、墨卡托投影坐标系速度投影数学模型,可以满足低、中、高速应用需要。 相似文献
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为了更加合理、有效地利用海流测速数据,必须进行误差分解和校正。通过分析相控阵声学多普勒海流剖面仪(PAADCP)测试海流流速的原理,提出了海试数据粗差区别与动态校正的算法,采用小波多尺度分析方法,降低了系统误差和随机误差,建立了海流流速的误差分析与校正方法。利用海试实测的垂向流速数据,分析了一般情况下的海流流速的误差,得到垂向流速的均值±0.02 m/s,误差精确度小于0.23 m/s,验证了方法的有效性及合理性。所得算法和方法对于海流测速数据的实时处理和后处理具有实用价值。 相似文献
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Mathematical modeling conducted in this study evaluated the hydrodynamic performance of a wave-driven artificial upwelling device in ocean waves off the Hawaiian islands. The device consisted of a buoy (4.0 m in diameter) and a tail pipe (1.2 m in diameter, 300 m in length) with a flow controlling valve. Random ocean waves off the Hawaiian islands used in the device's modeling analysis were synthesized from a wave spectrum obtained from available data. For comparison, the device's performance was also evaluated in regular waves whose height and period are the same as the significant wave height and wave period of random Hawaiian waves. Modeling results indicated that an upwelling flow of 0.95 m3/sec can be generated by this device in random Hawaiian waves and an upwelling flow rate of 0.45 m3/sec can be generated in regular waves. A simple mathematical model which assumed that the device exactly follows the incident waves was used in previous studies. Analysis results also indicated that the simple model cannot satisfactorily simulate the relative velocity and acceleration of the water column in the device. Since the relative velocity and acceleration are important factors in determining the rate of upwelling flow, the simple model must be applied with caution. 相似文献
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非通航孔桥墩自适应拦截网防撞装置实船拦截试验与水动力计算 总被引:1,自引:0,他引:1
针对非通航孔桥墩,研发了一种自适应拦截网防船舶撞击装置,主要由系泊大浮体、系泊锚链和固定锚、自适应小浮筒、拦截网、恒阻力缆绳以及触发钢索所组成。阐述了该防撞装置设计原理,即偏航船舶撞击该防撞装置,小浮筒会带动拦截网自适应地从水平状态竖起展开,包裹住来撞船首,再通过相连浮体的运动阻力和恒阻力缆绳来吸收船舶动能,拦截住船舶,保护非通航孔桥墩安全。随后介绍在福建平潭海峡大桥引桥附近海域实施的实船撞击自适应拦截网防撞装置的大型试验,试验结果显示:自适应拦截网成功升起,船舶被安全拦截,从而实验证实了设计原理与设计方案的可行性和可靠性。最后,采用大型水动力分析软件AQWA对防撞装置拦截船舶过程进行数值模拟,模拟结果与实验结果基本一致,说明了数值仿真具有较好的计算精度和可靠性,能够为该防撞装置的结构设计与优化提供重要的参考。 相似文献
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校园网防雷电及过压保护系统设计与实施 总被引:1,自引:0,他引:1
雷电及过电压对计算机网络硬件设备的危害很大,轻则造成数据丢失、控制设备误操作、死机,重则毁坏设备,中断服务,使整个校园网瘫痪。雷电危害计算机网络系统主要通过电源线路和各种网络线路以及地电位反击。因此,防止雷电危害应采取综合措施,做好各种线路的防护和等电位处理。文中给出了承德医学院校园网具体的防雷电及过压保护系统的设计实施方案。 相似文献
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R. F. Coombs 《新西兰海洋与淡水研究杂志》2013,47(1-2):194-205
A device for detecting and measuring the locomotor activity of large marine crustaceans in captivity is described. The sensor is essentially a simple galvanic cell, of which the electrolyte is the sea water in which the animal is maintained. A punched‐tape recording system used with the device is also described. 相似文献
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You Yage
YuZhi Associated Professor Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou
. Professor Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 《中国海洋工程》1995,(4)
In this paper, the extreme wave loads on an on-shore wave power device are investigated. First, boundary element method is applied to solve the three dimensional potential problem based on the small amplitude wave assumption. Then the motion of the Oscillating Water Column (OWC) inside the device and its laods on the device are calculated in time domain. Several protective techniques often applied are simulated by changing the constraint of the upper end of the chamber of the device. Numerical results are used to judge the effectiveness of these techniques. The investigation shows that damping can not effectively restrain the motion of OWC when the period of incident wave is long, which may cause dangerous loads on the structure. The shut chamber can effectively restrain the motion of OWC, but alternatively cause high pressure in the chamber. A Contracting opening with a Taper (CT) can exhaust a great amount of kinetic energy of OWC, and significantly decrease the loads. It is a promising protective tec 相似文献