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Zhang J.,Chinese Academy of Surveying and Mapping | Li W.,State Bureau of Surveying and Mapping | Zhai L.,Chinese Academy of Surveying and Mapping
International Journal of Digital Earth | Year: 2011

China will, as a component of 'Digital Earth,' establish a Geomatics Informatization Technology System (GITS) which is characterized by real-time acquisition, automatic processing, networking service, and socialized application with fundamental geographical information. The basic composition of GITS is proposed. GITS covers four layers and six platforms. The four layers are data acquisition, processing, management, and application and services. The six platforms are informatic geodetic datum, high-precision geo-spatial data acquisition, automatic geo-spatial data processing, grid-based geo-spatial information management, comprehensive geo-spatial information sharing and service, and geo-spatial information integration and application. The informatic geodetic datum platform provides a carrier for all the four layers and a base for the other five platforms. The high-precision geo-spatial data acquisition platform belongs to the acquisition layer. The automatic geo-spatial data processing platform belongs to the processing layer. The grid-based geo-spatial information management platform belongs to the management layer and is a bridge connecting geospatial data acquisition and spatial information sharing service and integrated applications. The comprehensive geo-spatial information sharing and service platform belongs to the application and service layer. Finally, this paper presents thoughts for constructing GITS. © 2011 Taylor & Francis. Source


Yue Q.,State Bureau of Surveying and Mapping | Tang X.,State Bureau of Surveying and Mapping | Gao X.,State Bureau of Surveying and Mapping
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

This paper details a meticulous ground model using triangular networks and furring texture images as well as imaging simulations of TDI CCD cameras for surveying and mapping. The sight target index was built by projecting the ground triangular network to the image, and then evaluated to see if a ground point was visible in the camera and sun direction by “imaging” in these two directions, and creating a shadow. The TDI CCD plane was divided into small CCDs and the irradiance of every small CCD was computed to get the “continuous focal plane irradiance image”. The static MTF was simulated by filtering the “continuous focal plane irradiance image” using PSF. The integration time was divided and the filtered static image computed for every sub-time, then the images added for every sub-time to get the “ time mean static image”. Then, graupel noise was added to every “time mean static image” of every line CCD, and then, adding the “time mean static image” of the same target by different CCD lines to get the average energy image, thus realizing TDI CCD multistage dynamic imaging simulation. In this manner, it was possible to derive the camera setting angle and optical panel point transfer function from platform coordinates to object coordinates, realizing an imaging simulation for any incline angle and setting angle by integrating attitude and CCD distortion parameters. ©, 2015, Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University. All right reserved. Source


Yue Q.,Wuhan University | Qiu Z.,State Bureau of Surveying and Mapping | Jia Y.,Wuhan University
2011 International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2011 - Proceedings | Year: 2011

Remote sensing camera imaging simulation can analysis effects on camera parameters, imaging environment, platform characteristics quantificationally. So it has important significance. This paper implements spaceborn TDI CCD camera imaging simulation with Monte Carlo ray tracing method. On the basis of assimilating strongpoint of conventional ray tracing, it pays attention to special imaging characteristics of sensor and other correlative factors, and brings forward retrorse Monte Carlo ray tracing method aiming at spaceborn sensor imaging simulation. It divides the simulation into several process, i.e. ascertain fixing center of CCD, create start list of rays, create inpupil rays, rays in the satellite body, rays in orbit coordinate, rays on earth, compute the point of intersection and normal, get the luminance of the point, get the luminance of in-pupil, get the average luminance in integration time region, sensor response synthetically and output of digital image. The sample time and space distribution of original rays adopt Monte Carlo sampling method. In the ray tracing process, it strings factors such as atmosphere, PSF of optical system, motorial characteristic of platform, object radiation character, heterogeneous response character of sensor, radiant resolving power and noise, which are rarely involved in traditional ray tracing. It implements full link simulation of spaceborn TDI CCD camera. © 2011 IEEE. Source


Zhang G.,Wuhan University | Qiang Q.,Wuhan University | Luo Y.,Wuhan University | Zhu Y.,Zhejiang Academy of Surveying and Mapping | And 2 more authors.
Photogrammetric Record | Year: 2012

It has been widely accepted that the rational polynomial coefficient (RPC) model can be used as an alternative to rigorous sensor models of high resolution optical satellites for photogrammetric processing. In the application of the RPC model to synthetic aperture radar (SAR) image processing, it has been confirmed that the range-Doppler model can be replaced by the RPC model. Until now, however, orthorectification with the RPC model in SAR image processing has not been considered. This paper investigates how to perform orthorectification in SAR image processing with the RPC model. Following a brief introduction about the RPC model for spaceborne SAR imagery, an optimisation model is established and a method of conducting simulations with the RPC model is proposed. Finally, a series of experiments are performed in order to verify the correctness of the theory using TerraSAR-X, COSMO-SkyMed, ERS-2 and Envisat ASAR images as test data. By comparing the actual accuracy and the theoretical accuracy of the orthorectified imagery, the theory and methodology proposed in this paper are confirmed. © 2012 The Authors. The Photogrammetric Record © 2012 The Remote Sensing and Photogrammetry Society and Blackwell Publishing Ltd. Source


Junyong C.,State Bureau of Surveying and Mapping | Yanping Z.,State Bureau of Surveying and Mapping | Janli Y.,State Bureau of Surveying and Mapping | Chunxi G.,State Bureau of Surveying and Mapping | Peng Z.,State Bureau of Surveying and Mapping
Survey Review | Year: 2010

Since the 1960s China has carried out several geodetic campaigns for measuring the height of Qomolangma Feng-Mt. Everest independently or in cooperation with foreign countries. Large scale geodetic field work and data processing have been done in the campaigns, dealing with positioning, height determination, gravimetry, astronomical measurement and atmospheric reflection observation etc. Some survey tasks were done in order to improve the accuracy and reliability for the height determination of Mt. Everest. These tasks include setting up of a survey target on the summit of Mt. Everest (MES) in the 1975, 1992 and 2005 campaigns, joint use of GPS, laser ranging and trigonometric levelling in the 1992 and 2005 campaigns, exploration of the thickness of the ice-snow layer on the summit and refinement of the local gravity field including the geoid in the northern slope area with new surface ground gravity data, DTM and astro-gravity levelling or GPS levelling results in the campaigns mentioned. It is the first time in China that the thickness of the ice-snow layer on the summit was measured by ground penetrating radar integrated with GPS in the 2005 campaign. The orthometric heights of the snow surface and rock surface of the summit were determined as 8847.93m and 8844.43m respectively in the 2005 campaign. The rate of decrease of the snow summit of Mt. Everest between 1992 and 2005 was 1.8cm/a. © 2010 Survey Review Ltd. Source

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