共查询到19条相似文献，搜索用时 171 毫秒
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精密多波束测量中GPS高程误差的综合修正法 总被引：3，自引：0，他引：3
在精密多波束测量中,GPS RTK/PPK高程在提供瞬时垂直基准方面起着重要的作用.为获取高质量的换能器瞬时垂直基准,需对GPS RTK/PPK高程进行质量控制.为此,提出一种综合的质量控制方法,即利用Heave短时修正法、潮位联合吃水和Heave的长时间综合修正法,该法以融合后的记录来代替GPS高程中的异常记录,有效地消除了异常GPS RTK/PPK高程的影响,提高了多波束在垂直方向的最终成果精度.实践验证了该方法的正确性. 相似文献
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对RTK高程和Heave信号在合成之前进行了预处理，确保了短周期内两者监测尺度和时间上的一致；然后利用数字信号处理技术实现这两个信号的融合；并通过一个实验对信号合成方法的精度进行了全面的分析和评估，认为该方法可以达到约6～7cm的精度，将传统多波束数据处理方法的精度提高了1倍。 相似文献
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《测绘文摘》2007,(3)
CH20071509多波束勘测声速剖面场的EOF表示方法=Expression of Multi-beam Echo Sounding Sound Velocity Profile with Empirical Orthogonal Functions/丁继胜,周兴华(国家海洋局第一海洋研究所),唐秋华,陈义兰∥武汉大学学报(信息科学版).-2007,32(5).-446~449提出了根据实测声速剖面,利用经验正交函数建立了声速剖面场的数学模型,得到了任意点位的声速剖面对边缘波束数据进行声线折射改正的方法。该方法对提高多波束勘测效率和精度具有重要意义。图4表1参8CH20071510RTK高程和Heave信号的融合及精度分析=Blend of RTK Height… 相似文献
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精密多波束测量中时延的确定方法研究 总被引：1，自引：0，他引：1
针对精密多波束测量中多波束系统与GPS系统间存在时间延迟的问题,提出了两种确定时延的方法,即坐标匹配法和竖向时序相似法.前者需根据NMEA0183电文和NAV电文中坐标对及其对应时标确定时延;后者根据GPS与heave呈现船体垂直运动时序的一致性,通过质量控制、姿态改正和垂直运动波形的相似性来确定时延.两种方法在时延确定中均取得了较高的精度. 相似文献
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给出了一种用于对抗干扰的GPS接收盲自适应波束形成算法。该方法基于一种新的解扩器和一阶恒模算法。优点是在形成波束对准期望信号并消除干扰时,不需要直接给出这些信号的DOA（信号来向）信息。计算机仿真结果给出了对抗干扰的性能。 相似文献
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GaryF.Hatke 《GPS天线及其抗干扰技术》2002,(4M):32-38
军用GPS系统必须能在敌方干扰时工作。由于附近干扰机和远距离卫星源之间存在巨大的功率差，所以GPS信号的扩频增益对实现抗干扰（A／J）保护能力是不够的。本提出了采用自适应天线调零系统来实现附加的抗干扰（A／J）保护能力，但是目前的系统，如AB－1就不能抑制与安装在飞机上阵列相关的近场多径干扰。本分析了GPS调零时空自适应（STAP）波束形成器的设计，包括STAP处理器对GPS位置计算的影响，该位置通过测量不同卫星信号的到达时差（TDOA）来计算。本提出了两种新疑结构，其性能通过在1：4比例大小的F－16飞机上进行的多次测量来模拟确定。 相似文献
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ZHAO Jianhu ZHANG Hongmei John E. Hughes Clarke 《地球空间信息科学学报》2007,10(4):250-254
To overcome the shortcomings of the traditional multibeam survey and data processing, a new method is presented for the precise determination of the instantaneous height at the multibeam transducer by ... 相似文献
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利用GPS载波相位差分测量技术，借助时间偏差改正、姿态改正、高程转换、信号处理和吃水改正，获得了测船处精密在航潮位。该方法已在几个GPS在航潮位测量实验中得到了验证，并取得了理想的结果。 相似文献
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无验潮模式下的GPS水下地形测量技术 总被引：1，自引：2，他引：1
传统的水下地形测量模式定型于利用GPS测定水底点的平面位置,利用测深仪测定水底点的深度,附之以瞬时潮位资料,获得点位的高程。这种模式在上述条件具备的情况下,可取得完满的结果。但当验潮条件不具备时,该模式将不能获得测点的高程。为了弥补这一缺陷,简化工作流程,提高水下地形测量的精度,本文提出了一种无验潮模式下的水下地形测量思想,该思想不用专门测定潮位,而直接利用GPS的RTK测量技术,辅之以姿态测量和补偿,从而获得高精度的水底点高程。该方法被验证是正确的,希望进一步推广应用。 相似文献
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针对在导航实践中低成本MEMS使用传统紧耦合方法计算精度受到限制的问题,提出了一种采用载波相位平滑伪距GNSS PPP/INS紧耦合的算法。实验表明,使用相位平滑伪距的GNSS PPP/INS紧耦合方法后低精度的MEMS和GPS组合位置精度为dm级,速度精度为cm/s甚至mm/s,比传统C/A码紧耦合定位精度高,有较好的收敛性;其次当增加相位平滑的历元数后精度也相应提高。当出现GPS信号中断时,该方法能够加速中断以后滤波收敛的速度,将导航精度控制在中高精度惯导作业要求范围内。该方法节约了导航作业的设备成本,具有一定实际意义。 相似文献
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Multipath disturbance is one of the most important error sources in high-accuracy global positioning system (GPS) positioning and navigation. A new data filtering method, based on the Vondrak filter and the technique of cross-validation, is developed for separating signals from noise in data series, and applied to mitigate GPS multipath effects in applications such as deformation monitoring. Both simulated data series and real GPS observations are used to test the proposed method. It is shown that the method can be used to successfully separate signals from noise at different noise levels, and for varying signal frequencies as long as the noise level is lower than the magnitude of the signals. A multipath model can be derived, based on the current-day GPS observations, with the proposed method and used to remove multipath errors in subsequent days of GPS observations when taking advantage of the sidereal day-to-day repeating characteristics of GPS multipath signals. Tests have shown that the reduction in the root mean square (RMS) values of the GPS errors ranges from 20% to 40% when the method is applied. 相似文献
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Improved amplitude- and phase-scintillation indices derived from wavelet detrended high-latitude GPS data 总被引：1，自引：1，他引：0
Sajan C. Mushini P. T. Jayachandran R. B. Langley J. W. MacDougall D. Pokhotelov 《GPS Solutions》2012,16(3):363-373
Accuracy and validity of scintillation indices estimated using the power and phase of the GPS signal depend heavily on the detrending method used and the selection of the cutoff frequency of the associated filter. A Butterworth filter with a constant cutoff frequency of 0.1?Hz is commonly used in detrending GPS data. In this study, the performance of this commonly used filter is evaluated and compared with a new wavelet-based detrending method using GPS data from high latitudes. It was observed that in detrending high-latitude GPS data, a wavelet filter performed better than Butterworth filters as the correlation between amplitude- and phase-scintillation indices in S 4 and ?? ? improved significantly from 0.53, when using a Butterworth filter, to 0.79, when using the wavelet filtering method. We also introduced an improved phase-scintillation index, ?? CHAIN, which we think is comparatively a better parameter to represent phase scintillations at high latitudes as the correlation between S 4 and ?? CHAIN was as high as 0.90. During the analysis, we also noted that the occurrence of the ??phase scintillation without amplitude scintillation?? phenomenon was significantly reduced when scintillation indices were derived using the wavelet-based detrending method. These results seem to indicate that wavelet-based detrending is better suited for GPS scintillation signals and also that ?? CHAIN is a better parameter for representing GPS phase scintillations at high latitudes. 相似文献
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The squat phenomenon, that is, the sinkage of a vessel due to its motion can affect the safety of navigation and reduce the accuracy of hydrographic bathymetry. Therefore, it is necessary to model and predict the squat of vessels as a function of cruise speed. We present a Global Navigation Satellite Systems–based squat modeling method for both hydrographic and navigation applications. For implementation of the proposed method, onboard GPS antennae configurations are offered to model bow squat for full-form ships such as supertankers or ore–bulk–oil carriers as well as stern squat for fine-form vessels such as passenger liners or container ships. In the proposed methodology, the onboard GPS observations are used to determine cruise ground speed, heave, attitude, and controlling the quality of kinematic positioning via fixed baselines. The vessel squat is computed from ellipsoidal height differences of the onboard antennae with respect to a reference state, after removal of all disturbing effects due to roll, pitch, heave, tide, vessel load, and geoidal height variations. The final products of the proposed approach are the analytical squat models usable for hydrographic and navigation applications. As the case study, the method is applied to a survey vessel in the offshore waters of Kish harbor. Numerical results indicate that the experimental precision of the derived analytical squat models is in the range of 0.003–0.028 m. The computed navigation squat of the test vessel at a speed of 12.64 knots is 30 % of the vessel draft and about twice its hydrographic squat. Although the field test was performed on a survey vessel, the method can be applied to any ship at any waterway. The proposed method can address the inevitable demand of reliable squat models for delicate hydrographic projects and high-speed marine traffic. 相似文献
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为了削弱结构动态监测中GPS随机噪声的影响,本文研究了一种基于集成经验模态分解(EEMD)技术的滤波方法。根据信号自身尺度分解信号,基于分解产生的本征模态函数(IMF)的Fourier变换频谱特征,构造了EEMD时空滤波器。对不同信噪比的仿真非平稳数据进行去噪处理并与小波去噪法相比较,各项指标表明基于EEMD滤波器的去噪方法与小波去噪方法效果相当,但避免了小波基的选择,具有更大的自适应性。应用于GPS动态监测数据的去噪结果表明该方法能有效分解信号消除GPS高频噪声及低频噪声的影响,提取有用振动信号,为进一步结构分析提供有效数据。 相似文献