共查询到20条相似文献，搜索用时 109 毫秒
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利用误差理论对三星时差定位系统的定位误差进行了定性分析和定量推导。在此基础上,尝试将测量学中的差分方法应用在三星时差技术体制的无源定位系统中,以期提高定位精度。仿真试验和数据验证分析表明,该方法能一定程度上提高其定位精度。 相似文献
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针对超宽带室内定位系统中的标准偏差和非视距误差问题,该文设计了一种基于改进卡尔曼滤波动态定位方法。该方法首先针对双向到达时间测距信息进行标定,利用线性拟合剔除测距信息中的标准偏差,针对超宽带平面定位系统中的非线性量测方程推导得到线性化的量测方程,将改正后的测距信息作为改进卡尔曼滤波量测信息,通过设定阈值调整卡尔曼滤波增益,从而剔除非视距误差。实验结果表明,该方法能有效抑制标准偏差和非视距误差的影响,视距环境下能达到厘米级精度,非视距环境下亚分米级精度,实现室内环境下的高精度动态定位。 相似文献
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超短基线系统水下定位误差分析 总被引：1，自引：0，他引：1
介绍了超短基线定位的研究现状和定位精度,分析了超短基线水下定位系统误差的来源、各种数据融合过程中的误差和定位精度,最后提出了提高水下定位系统精度的几点措施。 相似文献
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介绍了徕卡360°棱镜定位原理和结构特点,对该棱镜的性能指标(主要是棱镜的定位精度)进行了全面、系统的测试;给出了该棱镜定位精度的主要误差来源及其误差的大小和性质.首次发现徕卡360°棱镜的上棱镜面和上棱镜面的反射中心不一致,在垂直方向上存在5 mm的定位互差.分析了该棱镜偏转对棱镜定位精度的影响以及定位误差的变化规律,并给出其变化的原因.这为该棱镜的应用场合和使用方法提供了参考依据.建议在测量中尽可能地观测该棱镜的正对同一棱镜面,以避免不同棱镜面定位差别和棱镜偏转带来的影响. 相似文献
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基于GPS/INS空对地定位系统的误差分析和精度估计 总被引：1，自引：0，他引：1
基于GPS/INS的空对地定位系统,可以不需要地面控制点对像片上对应的地面点直接定位.介绍该系统的基本原理,重点分析各项误差源及其对定位结果的影响,并通过仿真试验进行不同情况下的精度估计. 相似文献
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基于云闪的雷电定位系统的误差分析 总被引：3，自引：0，他引：3
雷电可分为地闪和云闪.云闪主要采用时间到达法或干涉法进行空间三维定位.主要探讨基于"时间到达法"的云闪雷电三维定位系统的误差分析.雷电定位精度主要和观测误差及探测站图形因素有关,在研究消除或减弱观测误差方法的同时,有必要研究探测站间的位置关系,用以指导探测站定位网的优化设计和计算,以提高定位精度. 相似文献
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Monte Carlo simulations of the impact of troposphere,clock and measurement errors on the repeatability of VLBI positions 总被引：6，自引：5，他引：1
Within the International VLBI Service for Geodesy and Astrometry (IVS) Monte Carlo simulations have been carried out to design
the next generation VLBI system (“VLBI2010”). Simulated VLBI observables were generated taking into account the three most
important stochastic error sources in VLBI, i.e. wet troposphere delay, station clock, and measurement error. Based on realistic
physical properties of the troposphere and clocks we ran simulations to investigate the influence of the troposphere on VLBI
analyses, and to gain information about the role of clock performance and measurement errors of the receiving system in the
process of reaching VLBI2010’s goal of mm position accuracy on a global scale. Our simulations confirm that the wet troposphere
delay is the most important of these three error sources. We did not observe significant improvement of geodetic parameters
if the clocks were simulated with an Allan standard deviation better than 1 × 10−14 at 50 min and found the impact of measurement errors to be relatively small compared with the impact of the troposphere.
Along with simulations to test different network sizes, scheduling strategies, and antenna slew rates these studies were used
as a basis for the definition and specification of VLBI2010 antennas and recording system and might also be an example for
other space geodetic techniques. 相似文献
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Comparing the Kalman filter with a Monte Carlo-based artificial neural network in the INS/GPS vector gravimetric system 总被引：4，自引：1，他引：3
X. Li 《Journal of Geodesy》2009,83(9):797-804
Rigorous physical and mathematical analysis has been intensively developed to obtain the gravity disturbance vector from the
inertial navigation system and the global positioning system. However, the combination of the observation noise and the systematic
INS errors make it very challenging to accurately and efficiently describe the dynamics of the system with rigorous equations.
Thus, the accuracy of the gravity disturbance estimates, especially in the horizontal components, is limited by the insufficient
error models. To overcome the difficulty of directly modeling the systematic errors with exact mathematical equations, a Monte
Carlo based artificial neural network is successfully applied in the moving base gravimetric system. The computation results
show significant improvement in the precision of all components of the gravity disturbance estimates. 相似文献
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基于单基站的超长基线定位技术在地壳形变监测、高精度授时等领域具有广泛应用,但仍有诸多因素制约着超长基线解算精度。从观测方程出发,利用单差观测值对长（超长）基线(146~1 724 km)解算中的卫星轨道误差、对流层延迟误差、地球潮汐误差和相位缠绕误差等误差特性进行了详细分析。分析结果表明,当基线小于500 km时广播星历误差可忽略不计;超过500 km时需要采用精密星历, 同时需要考虑地球潮汐误差的影响;利用参数估计法同时估计基线两端的天顶对流层延迟误差可获得1~2 cm精度; 相位缠绕误差对基线小于2 000 km的解算影响可忽略。基于估计天顶对流层延迟的方法解算了5条长(超长)基线（146 km、491 km、837 km、1 043 km和1 724 km）。实验结果表明,当基线小于500 km时,采用广播星历可获得水平方向优于0.05 m、高程方向优于0.08 m的定位精度;当基线小于2 000 km时,采用超快速精密星历可获得水平方向优于0.025 m、高程方向优于0.055 m的定位精度。解算的初始收敛时间随着基线长度增加而缩短。 相似文献
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基于区域参考站网的网络实时动态定位(real-time kinematic,RTK)方法是实现全球定位系统(global positioning system,GPS)、北斗卫星导航系统(BeiDou satellite navigation system,BDS)高精度定位的主要手段。研究了一种长距离GPS/BDS双系统网络RTK方法,首先采用长距离参考站网GPS/BDS多频观测数据确定宽巷整周模糊度,利用引入大气误差参数的参数估计模型解算GPS/BDS双差载波相位整周模糊度;然后按照长距离参考站网观测误差特性的不同,分类处理参考站观测误差,利用误差内插法计算流动站观测误差,以改正流动站GPS/BDS双系统载波相位观测值的观测误差;最后使用流动站多频载波相位整周模糊度解算方法确定GPS/BDS载波相位整周模糊度并解算位置参数。使用长距离连续运行参考站(continuously operating reference stations,CORS)网的实测数据进行实验,结果表明,该方法能够利用长距离GPS/BDS参考站网实现流动站的厘米级定位。 相似文献
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Accuracy assessment of lidar-derived digital elevation models 总被引：2，自引：0，他引：2
Despite the relatively high cost of airborne lidar-derived digital elevation models (DEMs), such products are usually presented without a satisfactory associated estimate of accuracy. For the most part, DEM accuracy estimates are typically provided by comparing lidar heights against a finite sample of check point coordinates from an independent source of higher accuracy, supposing a normal distribution of the derived height differences or errors. This paper proposes a new methodology to assess the vertical accuracy of lidar DEMs using confidence intervals constructed from a finite sample of errors computed at check points. A non-parametric approach has been tested where no particular error distribution is assumed, making the proposed methodology especially applicable to non-normal error distributions of the type usually found in DEMs derived from lidar. The performance of the proposed model was experimentally validated using Monte Carlo simulation on 18 vertical error data-sets. Fifteen of these data-sets were computed from original lidar data provided by the International Society for Photogrammetry and Remote Sensing Working Group III/3, using their respective filtered reference data as ground truth. The three remaining data-sets were provided by the Natural Environment Research Council's Airborne Research and Survey Facility lidar system, together with check points acquired using high precision kinematic GPS. The results proved promising, the proposed models reproducing the statistical behaviour of vertical errors of lidar using a favourable number of check points, even in the cases of data-sets with non-normally distributed residuals. This research can therefore be considered as a potentially important step towards improving the quality control of lidar-derived DEMs. 相似文献
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分别采用基于梯度、基于泊松积分和基于快速傅里叶变换（FFT）的地面重力向上延拓方案,并提出交叉检验方法估计地面重力数据误差及其空中误差传播,对毛乌素测区GT-2A航空重力测量系统采集的空中测线数据进行外符合精度评价。对比结果表明：地面重力格网插值误差和代表性误差对空中点的影响达到0.66~0.92 mGal（1 Gal=1×10-2 m/s2）,航空重力数据误差估计必须扣除这一影响;基于泊松积分和基于FFT的地面重力向上延拓方法能够客观评价航空重力观测值的外符合精度,二者表现相当;扣除地面重力误差影响后,在包含残余边界效应的情况下,毛乌素测区GT-2A航空重力空中测线重力扰动的外符合精度优于1.42 mGal。 相似文献
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遥感影像配准误差传递模型及模拟分析 总被引：3，自引：0，他引：3
在遥感影像配准过程中,通常假设控制点是“完美的”。然而,在实际情况中,由于控制点本身不可避免的带有一定的误差导致这种假设在一定情况下并不成立,并且将会影响遥感影像几何校正的精度。普通最小二乘方法OLS(O rd inary Least Square)是遥感影像配准常用的校正估计模型,令人遗憾的是,在控制点存在误差的情况下,它的估计是有偏的,并且不能够正确传递和估计校正影像的误差大小。引入一致校正最小二乘方法CALS(ConsistentAd justed Least Squares),在此基础上提出的一个改进的方法,称之为松弛一致校正最小二乘方法RCALS(Relaxed ConsistentAd justed Least Squares)。这类回归模型具有改正控制点(解释变量)中的误差和跟踪回归模型中的误差传递的能力。为了验证CALS和RCALS模型的有效性,本文利用模拟影像进行分析。这里着重分析OLS,CALS和RCALS模型在几何校正过程中的比较。结果表明,RCALS和CALS的结果优于OLS估计结果。 相似文献
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Tobias Nilsson Robert Heinkelmann Maria Karbon Virginia Raposo-Pulido Benedikt Soja Harald Schuh 《Journal of Geodesy》2014,88(5):491-502
In this paper we investigate the accuracy of the earth orientation parameters (EOP) estimated from the continuous VLBI campaign CONT11. We first estimated EOP with daily resolution and compared these to EOP estimated from GNSS data. We find that the WRMS differences are about 31 $\upmu $ as for polar motion and 7 $\upmu $ s for length of day. This is about the precision we could expect, based on Monte Carlo simulations and the results of the previous CONT campaigns. We also estimated EOP with hourly resolution to study the sub-diurnal variations. The results confirm the results of previous studies, showing that the current IERS model for high-frequency EOP variations does not explain all the sub-diurnal variations seen in the estimated time series. We then compared our results to various empirical high-frequency EOP models. However, we did not find that any of these gave any unambiguous improvement. Several simulations testing the impact of various aspects of, e.g. the observing network were also made. For example, we made simulations assuming that all CONT11 stations were equipped with fast VLBI2010 antennas. We found that the WRMS error decreased by about a factor five compared to the current VLBI system. Furthermore, the simulations showed that it is very important to have a homogenous global distribution of the stations for achieving the highest precision for the EOP. 相似文献