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Chengdu, China

Huang K.,61287 Troops
Journal of Geomatics | Year: 2015

Satellite navigation system's pseudo-range measurement directly determines the positioning accuracy of navigation receivers. For satellite navigation system's pseudo-range measurement problem, this article firstly introduces the principle of pseudo-range measurement. And then it analyzes the pseudo-range measurement errors which depend on the clock error, propagation effects of ionosphere, troposphere, and multipath error, etc. For multipath error, it gives the qualitative basis pseu-dorange multipath effects firstly. And then it focuses on pseudo-range multipath error theoretical analysis, signal multipath propagation effect model were given to characterize pseudo-range's multipath error. Finally, the pseudo-range s multipath error were simulated and analyzed. Source


Li Q.,Zhengzhou University | Fan D.,Zhengzhou University | Lei R.,Zhengzhou University | Ji S.,Zhengzhou University | Zhang W.,61287 Troops
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2016

Using high accuracy match points extracted between the multi-spectral images that obtained at the same time, a position model of the CCD chips of the ZY-3 multi-spectral camera was proposed. Relative interior orientation relationship parameters were calculated and accurate band-to-band automatic registration of ZY-3 multi-spectral image was achieved based on the position model. The experimental result indicates that the band-to-band automatic registration accuracy of ZY-3 multi-spectral image is better than 0.3 pixels with the proposed method. © 2016, Surveying and Mapping Press. All right reserved. Source


Li B.,61287 Troops | Li G.,95956 Troops | Li G.,75711 Troops
Journal of Geomatics | Year: 2014

In order to analyze the effects on satellite orbit determination by different data sources, three kinds of data combination schemes are selected, based on many data from Beidou monitoring receiver. Firstly, orbit determination method and three kinds of data combination schemes are introduced. Then, the orbit determination accuracy of different schemes is analyzed from the orbit residuals and overlapping arcs. Finally, the precise orbit accuracy is analyzed through comparing of three kinds of schemes. The results show that the precision orbit is slightly better by using schemes two and three than that of scheme one. Source


Wang K.,Center for Engineering Design and Research under the Headquarters of General Equipment | Liu X.,Xian Research Institute of Surveying and Mapping | Liu X.,Wuhan University | Li J.,61287 Troops | Mao L.,61287 Troops
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2013

With spherical layer distribution and Airy compensation models, the application of CRUST 2.0 in the establishment of isostatic potential model was studied here. Calculation models of the isostatic EGM were derived. Then, the contributions of CRUST 2.0 and compensation depth towards the models were discussed. Numerical experiments show that 22.97 km is not the best compensation depth, while 40 km is better than the others, and compensation depths do little help to the ultra-high-degree part of the original model. Besides, the crustal model could modify the ideal model between degree 361 and 1080. Finally, it is hard to figure out which one is better than the other when spherical layer distribution and Airy compensation model have the same compensation depth. Source


Wang K.,Center for Engineering Design and Research under the Headquarters of General Equipment | Wang K.,Stake Key Laboratory of Geodesy and Earths Dynamics | Zhang C.-D.,University of Chinese Academy of Sciences | Wu X.,Center for Engineering Design and Research under the Headquarters of General Equipment | And 2 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2014

Isostasy is a key method in the gravity data extrapolation where no measurement information is available, which has already been used in the establishment of the Earth's Gravity Models(EGM). Based on topographic data, the construction of topographic/isostatic (t/i) EGM was studied here. The depths of compensation of the two isostatic models were analyzed to show the proper ones are 50 km and 40 km, respectively. According to gravity model from satellite gradiometry data only, the precision of layer condensation model is better than that of the Airy model in low frequencies till degree 120, while on the contrary between degree 121 and 250. Besides, combined model is better than any single model. Then, based on EGM2008, the quasi-stable analysis of the t/i potential model was made with gravity anomalies of various resolutions. It shows that the t/i spectrum of the quasi-stable model with 30' datum almost meets with that of EGM2008 up to degree 360. Compared to EGM2008, the relative accumulative geoid height error up to degree 140 is 6.83cm while the relative accumulative gravity anomaly error up to degree 220 is 1.10 mGal. Source

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