Table of Content

24 September 2015, Volume 44 Issue 9

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Instantaneous Attitude Determination Based on Original Multi-antenna Observations Using Adaptively Robust Kalman Filtering

GAN Yu, SUI Lifen, LIU Changjian, DONG Ming

2015, 44(9):  945-951.  doi:10.11947/j.AGCS.2015.20140492

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Attitude determination directly by carrier phase observation makes optimal use of observation and attitude constraints. The phase models based on misalignment angle and multiplicative quaternion error are derived. The state models for attitude estimation with and without external angular rate sensors are both erected. The attitude errors are estimated by adaptively robust filtering, in which the adaptive factors of ambiguity and attitude error are decided respectively following the idea of multi adaptive factor filtering. The factor of attitude is determined by a three-section function containing Ratio. Adaptively robust filtering makes the best use of constraint and historical information, fusing them in the calculation of float solution. As the accuracy of float solution and the structure of covariance matrix are improved greatly, the fix solution can be searched efficiently using LAMBDA (least-squares ambiguity decorrelation adjustment) method merely, perfectly fulfilling the real-time requirement. Field test of a ship-based three-antenna attitude system is used to validate the proposed method. It is showed that direct attitude determination based on adaptively robust filtering has obvious advantages in efficiency and reliability.



The Robust Fusion of Multi-source Gravity Data Based on the Spherical Cap Harmonic Model

WANG Yi, JIANG Xiaodian, LI Deyong

2015, 44(9):  952-957.  doi:10.11947/j.AGCS.2015.20140345

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A robust ridge estimation multi-source data fusion algorithm is proposed based on spherical cap harmonic analysis.The effectiveness is verified through numerical calculations. It is shown that this fused model can not only resist the ill-conditioning of coefficients array but also eliminate the observation errors. Finally, it is analyzed the influence of the observation noise size on the fusion results.



Kalman Filter-based Single-baseline GNSS Data Processing without Pivot Satellite Changing

ZHANG Baocheng, YUAN Yunbin, JIANG Zhenwei

2015, 44(9):  958-964.  doi:10.11947/j.AGCS.2015.20140430

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Single-baseline global navigation satellite system (GNSS) data are able to be processed into a batch of parameters such as positions, timing information as well as atmospheric delays. The applications of relevance, therefore, consist of relative positioning, time and frequency transfer and so forth. To achieve real-time capability, these parameters are usually estimated by means of Kalman-filter. Moreover, the reliability of these parameters can be further strengthened by forming and then successfully fixing a set of independent double-differenced (DD) integer ambiguities. For this purpose, the filter function model is commonly set up based on the DD observation equations (DD filter model). In order to preserve the continuity of the filter, DD filter model needs to explicitly refer to another pivot satellite once the previous one becomes invisible. This thereby implies that, before being predicted to the next epoch, the former filtered DD ambiguity vector has to be “mapped” with respect to the newly-defined pivot satellite. In addition to that, the estimated receiver phase clocks using DD filter model may soak up distinct between-receiver single-differenced (SD) ambiguities belonging to different pivot satellites and would thereby be subject to apparent “integer jumps”. In this contribution, SD observation equations involving estimable DD ambiguity parameters are alternatively selected as the filter function model (SD filter model). Our analyses suggest that, both DD and SD filter models are equivalent in theory, but differ from each other as far as their implementations are concerned. Typically, for SD filter model, no effort should be made to map DD ambiguities, thus implying less intensive computational burden and better flexibility than DD filter model. At the same time, receiver phase clocks determined by SD filter model are free from “integer jumps” and thus are particularly beneficial for frequency transfer.



Torus Approach in Gravity Field Determination from Simulated GOCE Observations

LIU Huanling, WEN Hanjiang, XU Xinyu, ZHU Guangbin

2015, 44(9):  965-972.  doi:10.11947/j.AGCS.2015.20150110

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The principle of Torus method in Earth's gravity field determination from GOCE satellite gradiometry data is discussed. The Earth's gravity field model complete to degree and order 200 is recovered using simulated satellite gradiometry observations on a Torus grid, and the degree error RMS is smaller than 10^-16, which shows the effectiveness of Torus approach. The gravity field model is also resolved using the simulated satellite gradiometry observations given on GOCE orbits of 61 days. The influences of interpolation and polar gaps are analyzed. Without considering the low-order coefficients the geoid degree errors and cumulative errors are very small after three iterations. The maximums of them are only 0.022 mm and 0.099 mm. The white noise with PSD 5 mE/Hz^1/2 is added to the simulated observations and the gravity field model complete to degree and order 200 is also computed. The model is compared with that model which is derived using space-wise LS method and the same observations. It shows that the precision of Torus is slightly lower. Without considering the low-order coefficients the maximum geoid degree errors of Torus and space-wise LS method are 1.58 cm and 1.45 cm, and the maximum cumulative geoid errors are 6.37 cm and 5.55 cm, respectively. But the computational efficiency of Torus is greatly improved by using the two-dimensional FFT and the block-diagonal least-squares adjustment. The numerical results show that Torus method is independent and valid. Meanwhile fast resolution of gravity field based on massive amount of GOCE satellite gradiometry observations is feasible.



Application of the Same Beam Interferometry Measurement in Relative Position Determination on Lunar Surface

HUANG Anyi, XIE Xin, ZHANG Zhibin, LI Hengnian

2015, 44(9):  973-979.  doi:10.11947/j.AGCS.2015.20140142

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Based on the principle and observation model of the same beam interferometry measurement, observation equations of differential time delay and time delay rate for targets on lunar surface are proposed. Restriction of appointed height and digital lunar height model is introduced and a Kalman filter with restriction to determine the relative position is put forward. By data simulation, the arithmetic is then validated and evaluated, which could fleetly and accurately determine the relative position between rover and lander. Low precision of the lander's position is required in the calculation.



Hierarchical Extraction of Multiple Objects from Mobile Laser Scanning Data

DONG Zhen, YANG Bisheng

2015, 44(9):  980-987.  doi:10.11947/j.AGCS.2015.20140339

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This paper proposes an efficient method to extract multiple objects from mobile laser scanning data. The proposed method firstly generates multi-scale supervoxels from 3D point clouds using colors, intensities and spatial distances. Then, a graph-based segmentation method is applied to segment the supervoxels by integrating their colors, intensities, normal vectors, and principal directions. Then, the saliency of each segment is calculated and the most salient segment is selected as a seed to cluster for objects clustering. Hence, the objects are classified and the constraint conditions of object's category are included to re-clustering for more accurate extraction of objects. Experiments show that the proposed method has a promising solution for extracting buildings, ground, street lamps, trees, telegraph poles, traffic signs, cars, enclosures and the objects extraction overall accuracy is 92.3%.



A Non-iterative Space Resection Method Based on Barycentric Coordinates

LI Jiayuan, HU Qingwu, AI Mingyao

2015, 44(9):  988-994.  doi:10.11947/j.AGCS.2015.20140473

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To resolve the problem that iterative space resection algorithms may have no convergence in oblique photogrammetry,a novel non-iterative method based on barycentric coordinates is proposed. This algorithm firstly describes the object space coordinates of control points as barycentric coordinates,based on its coordinate reference independence,the corresponding image space coordinates can be obtained by using total least square method,then absolute orientation using orthonormal matrices is applied and the result is optimized finally. Experimental results show that this algorithm can be suitable for any image attitude angle,and the accuracy is even better than iterative space resection methods.



Atmosphere Refraction Effects in Object Locating for Optical Satellite Remote Sensing Images

YAN Ming, WANG Zhiyong, WANG Chengyi, YU Bingyang

2015, 44(9):  995-1002.  doi:10.11947/j.AGCS.2015.20140211

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The collinear rigorous geometric model contains the atmosphere refraction geometric error in off-nadir observation. In order to estimate and correct the atmosphere refraction geometric error, the ISO international standard atmospheric model and Owens atmosphere refractive index algorithm are applied to calculate the index of atmosphere refraction in different latitude and altitude. The paper uses the weighted mean algorithm to reduce the eight layers ISO standard atmospheric model into a simple troposphere and stratosphere two layers spherical atmosphere. And the LOS vector track geometric algorithm is used to estimate the atmosphere refraction geometric error in different observation off-nadir angle. The results show that the atmosphere refraction will introduce about 2.5 m or 9 m geometric displacement in 30 or 45 degree off-nadir angle individual. Therefore, during geo-location processing of agile platform and extra wide high spatial resolution imagery, there is need to take into account the influence of atmosphere refraction and correct the atmosphere refraction geometric error to enhance the geo-location precision without GCPs.



Incremental Classification Algorithm of Hyperspectral Remote Sensing Images Based on Spectral-spatial Information

WANG Junshu, JIANG Nan, ZHANG Guoming, LI Yang, LV Heng

2015, 44(9):  1003-1013.  doi:10.11947/j.AGCS.2015.20140388

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An incremental classification algorithm INC_SPEC_MP_ext was proposed for hyperspectral remote sensing images based on spectral and spatial information. The spatial information was extracted by building morphological profiles based on several principle components of hyperspectral image. The morphological profiles were combined together in extended morphological profiles (MP_ext). Combine spectral and MP_ext to enrich knowledge and utilize the useful information of unlabeled data at the most extent to optimize the classifier. Pick out high confidence data and add to training set, then retrain the classifier with augmented training set to predict the rest samples. The process was performed iteratively. The proposed algorithm was tested on AVIRIS Indian Pines and Hyperion EO-1 Botswana data, which take on different covers, and experimental results show low classification cost and significant improvements in terms of accuracies and Kappa coefficient under limited training samples compared with the classification results based on spectral, MP_ext and the combination of sepctral and MP_ext.



Geo-registration of Unprofessional and Weakly-related Image and Precision Evaluation

LIU Yingzhen, JIA Fenli, WAN Gang, ZHU Yunqiang, HUO Chao

2015, 44(9):  1014-1021.  doi:10.11947/j.AGCS.2015.20140394

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The 3D geo-spatial model built by unprofessional and weakly-related image is a significant source of geo-spatial information. The unprofessional and weakly-related image cannot be useful geo-spatial information until be geo-registered with accurate geo-spatial orientation and location. In this paper, we present an automatic geo-registration using the coordination acquired by real-time GPS module. We calculate 2D and 3D spatial transformation parameters based on the spatial similarity between the image location in the geo-spatial coordination system and in the 3D reconstruction coordination system. Because of the poor precision of GPS information and especially the unstability of elevation measurement, we use RANSAC algorithm to get rid of outliers. In the experiment, we compare the geo-registered image positions to their differential GPS coordinates. The errors of translation, rotation and scaling are evaluated quantitively and the causes of bad result are analyzed. The experiment demonstrates that this geo-registration method can get a precise result with enough images.



Detecting Development Pattern of Urban Business Facilities Using Reviews Data

JIANG Botao, WANG Yandong, YE Xinyue

2015, 44(9):  1022-1028.  doi:10.11947/j.AGCS.2015.20140556

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This paper reveals and utilizes the growing power of online customer reviews in the space and time context. The location of commercial facilities and online customer reviews offered by Dianping.com provide an important data source for the study of spatial and temporal dynamics of urban commercial facilities. The constraints of road network are taken into account towards computing the density of urban commercial facilities and associated online customer reviews, as well as their spatial distribution, temporal trend, and the coupling relationship between facility number and stratification level. This paper maps the spatial distribution of commercial facilities onto the nearby road network, reflecting the influences of the locations, number and satisfaction levels of other commercial facilities across various street types. Because more and more customers tend to make a final shopping decision by sorting through search results by ratings and feedback, the research conducted in this paper can provide the proof for quantitative evaluation of urban planning on commercial facility development.



OGC Geographic Information Service Deductive Semantic Reasoning Based on Description Vocabularies Reduction

MIAO Lizhi, XU Jie, ZHOU Ya, CHENG Wenchao

2015, 44(9):  1029-1035.  doi:10.11947/j.AGCS.2015.20140021

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As geographic information interoperability and sharing developing, more and more interoperable OGC (open geospatial consortium) Web services (OWS) are generated and published through the internet. These services can facilitate the integration of different scientific applications by searching, finding, and utilizing the large number of scientific data and Web services. However, these services are widely dispersed and hard to be found and utilized with executive semantic retrieval. This is especially true when considering the weak semantic description of geographic information service data. Focusing on semantic retrieval and reasoning of the distributed OWS resources, a deductive and semantic reasoning method is proposed to describe and search relevant OWS resources. Specifically, ①description words are extracted from OWS metadata file to generate GISe ontology-database and instance-database based on geographic ontology according to basic geographic elements category, ②a description words reduction model is put forward to implement knowledge reduction on GISe instance-database based on rough set theory and generate optimized instances database, ③utilizing GISe ontology-database and optimized instance-database to implement semantic inference and reasoning of geographic searching objects is used as an example to demonstrate the efficiency, feasibility and recall ration of the proposed description-word-based reduction model.



Automatic Extraction of Contours of Buildings on Oblique View Maps Based on 3D City Models

ZHU Yuanyuan, ZHU Qing, ZHANG Yeting, PENG Mingjun, GAO Shan

2015, 44(9):  1036-1041.  doi:10.11947/j.AGCS.2015.20140662

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Aiming to deal with the problem that manual extraction of contours of buildings on oblique view maps are expensive and ineffective with low accuracy and coarse detail, we present a method of automatic extraction of contours buildings on oblique view maps which based on 3D city models. We employ depth-buffers to obtain a building object's color-buffers concerning the occlusion blocked by other buildings and the existence of groups of buildings, and then we trace building contours based on color-buffers. And in order to keep the occlusion consistency and match the traced contours with the map, we propose loading 3D city models by block on projection plane. Finally, the validity and feasibility of this method are proved through the experiments on 3D city models of Wuhan.



Fusion Algorithm for Hyperspectral Remote Sensing Image Combined with Harmonic Analysis and Gram-Schmidt Transform

ZHANG Tao, LIU Jun, YANG Keming, LUO Wenshan, ZHANG Yuyu

2015, 44(9):  1042-1047.  doi:10.11947/j.AGCS.2015.20140637

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For the defect that harmonic analysis algorithm for hyperspectral image fusion(HAF) in image fusion regardless of spectral reflectance curves, the improved fusion algorithm for hyperspectral remote sensing image combined with harmonic analysis and Gram-Schmidt transform(GSHAF) is proposed in this paper. On the basis of completely retaining waveform of spectrum curve of fused image pixel, GSHAF algorithm can simplify hyperspectral image fusion to between the two-dimensional image by harmonic residual of each pixel spectral curve and high spatial resolution image. It is that the spectral curve of original hyperspectral image can be decomposed into harmonic residual, amplitude and phase, then GS transform with harmonic residual and high spatial resolution image, which can effectively amend spectral reflectance curve of fused image pixel. At last, this fusion image, harmonic amplitude and harmonic phase are inverse harmonic transformed. Finally, with Hyperion hyperspectral remote sensing image and ALI high spatial resolution image to analysis feasibility for GSHAF, then with HJ-1A and other satellite data to verify universality. The result shows that the GSHAF algorithm can not only completely retained the waveform of spectral curve, but also maked spectral reflectance curves of fused image more close to real situation.



Monitoring the Land Cover Change of China with the Combination of the Topex/Poseidon and Envisat Radar Altimetric Data

KE Baogui, ZHANG Chuanyin, CHANG Xiaotao, ZHANG Liming

2015, 44(9):  1048-1055.  doi:10.11947/j.AGCS.2015.20140634

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The Ku band backscatter coefficients data have been extracted since 2002.5 to 2005.5 from Topex/Poseidon(T/P)GDR-M and Envisat OPR datasets. Based on the continuous tension spline curve gridding method, the time series gridding data was obtained. Then the two different backscatter coefficients time series were compared. Carefully analysis and discussion on the spatial distribution characteristic of the backscattering coefficients in Inner Mongolia plateau, North China Plain, Northeast China Plain, the Qinghai Tibet Plateau, the Yunnan Guizhou Plateau, the Loess Plateau, the Yangtze River Plain indicate that both technologies can be used for monitoring natural disasters and potential environmental change of China and providing decision support for monitoring time series for land cover change.



Continuously Extracting Section and Deformation Analysis for Subway Tunnel Based on LiDAR Points

LI Cheng, LU Xiaoping, ZHU Ningning, LU Yao, WU Yongbin, LI Guoqing

2015, 44(9):  1056-1062.  doi:10.11947/j.AGCS.2015.20140632

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Monitoring measurement of subway in the stage of construction and operation can ensure the stability of tunnel structure and the safety of its surrounding efficiently. Although existing monitoring measures such as using convergence meter or total station can help to obtain high precision monitoring data, received deformation monitoring points are too sparse, which results in difficulty in reflecting overall deformation characteristics of tunnel. This paper proposed a method for continuously vertical section abstraction and deformation analysis for subway tunnel based on terrestrial point clouds through three-dimensional laser scanning technology applied to deformation monitoring of the tunnel, and made deformation analysis of abstracted two-period section data. The results of the research showed that global deformation of tunnel was reflected more visualized through this method and provided a reference for the dynamic monitoring of tunnel deformation.