马尔科夫理论的优化灰色模型预测建模

针对GM(1,1)模型易受建模数据随机扰动影响,且模型稳定性较差的问题,该文提出了基于马尔科夫(Markov)理论的GM(1,1)预测优化模型。首先,通过最小二乘原理选取GM(1,1)模型的最优初值,利用指数函数法构造新的背景值,同时利用正化残差序列法进一步修正残差。然后,将优化的GM(1,1)模型和马尔科夫理论有机结合,进一步对优化的GM(1,1)模型进行改进,构建了优化的灰色马尔科夫预测模型。最后,以某建筑物的变形实测数据为基础,进行了传统GM(1,1)预测模型、优化的GM(1,1)预测模型和优化的灰色马尔科夫预测模型的实例计算比较,结果表明:优化的灰色马尔科夫预测模型的拟合精度和预测精度优于传统GM(1,1)预测模型和优化的GM(1,1)预测模型,且适用性更强,稳定性更好。     

GM(1,1)残差修正模型在建筑形变预报中的应用

通过对比建筑形变监测数据的GM(1,1)模型和改进的GM(1,1)残差修正模型建模的预报结果,表明残差修正GM(1,1)模型的预报精度明显高于传统GM(1,1)模型的预报精度,并且二次残差修正GM(1,1)模型的预报精度远高于一次残差修正GM(1,1)模型的预报精度,从而为准确形变预报提供了一种简单而有效地新实践。     

基于残差改正的动态非等时距灰色模型及应用

介绍了动态非等时距GM(1,1)模型的建模原理、建模过程以及精度评定方法,阐明了动态非等时距GM(1,1)模型中维度选择、残差改正的问题,结合高层建筑沉降监测实例进行分析,将动态非等时距残差GM(1,1)模型预测结果与实测值进行比较,得出动态非等时距残差GM(1,1)模型在建筑物沉降监测中具有很高预测精度的结论,证明了该方法的可行性与可靠性,适用于高层建筑沉降监测.     

灰线性马尔科夫模型在建筑物变形监测中的应用

针对传统灰色GM(1,1)预测模型在建筑物变形监测预报中的拟合精度较差、预测精度较低和预测时间较短的问题,文中以传统GM(1,1)、线性回归和马尔科夫模型为理论基础,构建了灰线性马尔科夫预测模型,并结合某建筑物变形监测的观测数据,运用新陈代谢的计算模式进行预测。结果表明,灰线性马尔科夫预测模型的拟合精度和预测精度优于单一的灰色GM(1,1)预测模型和线性回归预测模型,灰线性马尔科夫预测模型具有预测精度高、预测时间长和稳定性高的优势。     

修正指数曲线法与灰色模型和BP神经网络预测在建筑物沉降中的对比分析

变形监测在建筑物施工和运营管理方面是一个至关重要的环节,变形监测的预测模型有很多。选取适当的变形监测预测模型对于预测建筑物的变形尤为重要。本文运用灰色模型GM(1,1)、BP神经网络和曲线拟合中的修正指数曲线对一幢大楼13期的沉降观测数据进行分析。利用前12期沉降观测数据构建预测模型来预测第13期沉降观测的数据,将预测的结果与实际测量的结果进行比较,得出这三种模型预测的精度。结果表明:在这一幢大楼的沉降观测预测中,修正指数曲线法预测的精度要比灰色模型GM(1,1)和BP神经网络预测的精度高。     

基于GM(1,1)等维新息模型的矿山沉降预测

介绍了GM(1,1)灰色模型的建立过程及模型的精度评定方法,采用等维新息模型对某矿工业广场的沉降趋势进行了预测,并用残差序列建立GM(1,1)模型进行修正,通过与实测的结果对比表明,模型的预测具有较高的精度,模型可靠合理。     

改进灰色GM(1,1)模型在滑坡预测中的应用

滑坡形成因素复杂,具有典型的灰色不确定性。为研究滑坡发展趋势,在已有滑坡预测技术的基础上,分析了典型灰色GM(1,1)模型在运算过程的误差原因,建立了改进灰色GM(1,1)模型;并运用滑坡实例验证了改进模型,直观显示曲线拟合情况。结果表明,改进后的模型预测精度等级明显提高,相对误差减小;说明所建滑坡预测模型效果好,在滑坡位移预测中有效可行。     

灰色组合模型在滑坡变形监测中的应用分析

在GM(1,1)模型的基础上,主要研究了改进残差修正模型、灰色BP神经网络模型、灰色线性回归模型在变形数据的预计精度,并且结合实例分析了不同灰色组合模型在滑坡变形预计的精度以及优缺点。     

傅里叶级数修正的动态GM(1,1)模型在沉降预测中的应用

详细地介绍了动态GM(1,1)模型的建立及解算过程,使用傅里叶级数对动态GM(1,1)模型进行修正,然后用修正后的模型对高铁沉降进行预测,并将其与未修正模型结果的精度进行比较。实验结果表明,这种使用傅里叶级数进行修正的动态GM(1,1)模型有较高的预测精度,在沉降监测中有一定的实用性。     

灰色系统理论用于矿震极值预测的初步研究

研究应用灰色系统理论,结合矿震极值数据,建立GM(1,1)预测模型,在此基础上进一步应用残差修正主模型,由构造出的新模型推测出未来的矿震极值。预测结果有较高的精度,为矿震极值预测提供一种可行性方法。     

Examining the C1-P1 Pseudorange Bias

Use of GPS tracking data from different dual-frequency receiver types (cross-correlating vs. codeless) has revealed satellite-dependent biases in pseudorange observables P1 (Y-code) and C1 (C/A, Clear Acquisition code). These biases can have a direct effect on clock estimates, carrier phase bias fixing, and other parameters estimated in GPS data processing. A set of satellite-specific compensatory pseudorange offsets is calculated, and each is applied to a wee of daily global network analyses in which satlellite, receiver, atmospheric, and Earth rotation parameters are estimated. Results from these analyses are then compared to those from corresponding baseline cases in which no biases were applied. There is also some evidence that suggests that the pseudorange biases differ even among codeless receiver models. Hence, a second set of offsets is computed on a different basis, and compared with the baseline model in a similar manner. A preliminary examination of C1-P1 variations over time is presented. Finally, recommendations are made for the use of the calculated offsets, and consideration is given to a future dissemination of updates to these values as necessary. ? 2001 John Wiley & Sons, Inc.     

《基础地理信息数字成果1：50001：100001：250001：500001：100000数字高程模型》修订说明

随着数字摄影测量技术、LiDAR和InSAR等测绘高新技术的发展,数字高程模型在数据获取、生产技术和工艺等方面较以往发生了很大变化。2001年首次发布的行业标准《基础地理信息数字产品1：100001：50000数字高程模型》在很大程度上已经不能反映当前我国DEM生产的实际状况,有必要对该标准进行修订。深入分析和研究美国、英国、加拿大等国DEM相关标准,并充分考虑我国测绘生产的实际状况,对该标准的相关内容和技术指标进行修订,提高标准的现势性,保证相关标准之间的协调性和完整性,能更好地满足测绘生产和用户的实际需要。     

《1:500 1:1000 1:2000外业数字测图规程》修订情况说明

外业数字测图是大比例尺测绘地理信息成果生产的重要方法,GB/T14912《1∶500 1∶1000 1∶2000外业数字测图规程》规定了外业数字测图方法生产大比例尺数字测绘地理信息成果的作业方法和技术规定。这次修订对原标准内容进行了补充和完善,增补了外业数字测图新技术需要规范的内容,同时与相关的测绘地理信息标准进行统一和协调,对外业数字测图作业的技术内容、要求进行约定和规范,指导数字测绘地理信息成果生产,保证作业质量。     

1：2000数字高程模型（DEM）在高速公路设计中的应用

阐述了生产DEM过程中应注意的问题及DEM在高速公路设计中的应用。     

变异时序回归GM(1,1)模型

鉴于在GM(1,1)预测模型中,灰参数与背景值导致的GM(1,1)模型的残差,本文提出将残差引入到时序中,对时序进行变异,利用不同的曲线回归方程对变异时序进行估计.基于对不同回归方程估计结果的误差分析,选用最佳的回归方程作为GM(1,1)变异时序预测方程;并将预测结果作为GM(1,1)模型的变量k.实例计算表明,变异时...     

双树乡1∶1000地形图测量技术设计

设计利用全站仪与GPS-RTK联合作业进行野外数据采集,通过CASS6.0成图软件进行内业成图,完成龙港区双树乡1∶1 000地形图测量工作。主要叙述了RTK技术在地形图图根测量、碎部测量中的可行性和RTK外业测量的操作步骤、注意事项,阐述了RTK定位技术的相关原理,说明了RTK与全站仪联合进行数字化测图是一种高速度、高效率的新方法,对于地形条件复杂的地区,考虑到全站仪与RTK技术的优缺点,可以采用RTK与全站仪联合作业的方式进行地形图的测绘。在测区内不需要进行图根控制测量,使RTK与全站仪优势互补,可大幅度提高测量速度,且可保证测图精度。     

Towards a 1 mGal accuracy and 1 min resolution altimetry gravity field

Over the past three decades, radar altimetry has made a significant contribution to marine gravity field modeling. To improve the accuracy and resolution, we propose a new twin-satellite altimetry. Such a system has several advantages. Among others, it provides (i) twice the number of samples per time epoch, and (ii) information about the cross-track surface gradient with high accuracy because most of the environmental and tidal errors will be common to the simultaneous measurements and therefore cancel out when computing the cross-track gradient computation. We describe a rigorous procedure for the deduction of the sea surface gradient at each altimeter observation point (i.e., not only at the crossovers), from the twin-satellite altimetry system. The precision of the gradient will be slightly affected by orbit errors, instrument drift, and inaccuracies in the geophysical corrections to be applied. We also demonstrate that a 1 mGal accuracy and 1 min resolution marine altimetry gravity field can be obtained if certain conditions are met. To achieve the expected goal, we recommend an orbital configuration, phasing two satellites in 4-s time delay such that the Earth rotation creates a natural baseline between the two satellites, and a 18 kHz SAR altimeter.     

Atmospheric Correction Methods for GF-1 WFV1 Data in Hazy Weather

Increasing hazy weather in the eastern area of China limits the potential application of high-resolution satellite data and poses a huge challenge for the atmospheric correction of remote sensing images. Consequently, it is necessary to find the most suitable atmospheric correction method under hazy condition. In this study, five kinds of atmospheric correction models, including 6S, COST, FLAASH, QUAC, and ATCOR2, are applied to the GaoFen-1 Wild Field Camera (GF-1 WFV1) data in the eastern area of China, and examined by both quantitative and qualitative analyses using the measured spectrum data. Experimental results indicated that ATCOR2 achieves the best performance among the atmospheric correction methods qualitatively and quantitatively. Hence, specifically for the study area and GF-1 WFV1 dataset, ATCOR2 is the most suitable atmospheric correction approach under hazy in the eastern area of China.     

Pass processing of IRS-1C/1D PAN subscene blocks

This paper describes a method for pass processing of IRS-1C/1D imagery acquired by the three CCD arrays of the panchromatic (PAN) camera. It is based on the fact that during a single pass, the image data stream from the three CCD arrays of the PAN camera can be adjusted together as a single image, exploiting the knowledge of the internal geometry and the angular relationships between the CCD arrays. The geometry of this extended image can be rectified with a single ground control point (GCP). A full PAN scene consists of nine subscenes, each with a dimension of 23.5 km×23.5 km. The method is not restricted in the number of continuous full scenes (in the same pass) that can be adjusted. The scale variations between the images from the three detectors are corrected by computing the relative focal lengths of detectors 1 and 3 with respect to detector 2. Two tests were conducted to verify the accuracy of the adjustment procedure. Average root-mean-square (RMS) errors of ±10.5 m in the latitude direction and ±11.3 m in the longitude direction were obtained with a single surveyed GCP and a set of survey points used as checkpoints. The results of the tests show that the adjustment of full PAN scenes, as proposed in this paper, is an effective means of reducing the number of GCPs required for precise determination of ground coordinates.