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Guo J.-Y.,Shandong University of Science and Technology | Guo J.-Y.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Gao Y.-G.,Fuzhou University | Chang X.-T.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | And 2 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2010

Waveform retracking is an effective method to improve the accuracy of sea surface height measurement with the satellite altimetric technique. The improved threshold retracking algorithm is optimized in the paper. Several waveform retracking algorithms are analyzed. Then a waveform retracking system is programmed. Several retracking methods are used to retrack the EnviSat waveform over the Mediterranean Sea. The improved threshold retracking algorithm is the most robust retracking method and more suitable for the EnviSat waveform retracking over the coastal Mediterranean.


Guo J.,Shandong University of Science and Technology | Guo J.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Sun J.,Shandong University of Science and Technology | Sun J.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | And 5 more authors.
Terrestrial, Atmospheric and Oceanic Sciences | Year: 2011

Climate change can sometimes be reflected in variations in lake levels, thus understanding variations in lake levels and their relationship to climate change plays an important role in studying climate change. In this study, about 10 years of Topex/ Poseidon (T/P) altimetric data and 6 years of Jason-1 data were used to compute time series of level variations of six lakes in the Central and East Asia. The study sites were Hongze, La-ang, Ulungur, Khanka, Issyk-kul and Baikal Lakes. Time series of level variations were analyzed by means of the wavelet spectrum for inter-annual (between 2 to 4 years), annual and semiannual signals. Since 2000, water level variations of Issyk-kul, Ulungur and Khanka lakes were larger than those of Baikal and Hongze. Correlations between the NIN03.4 sea surface temperature (SST) and the level variations of the six lakes were analyzed. For Baikal and Khanka Lakes, the correlations were significant (+0.3834 and +0.3334) for 3 - 5 months after the occurrence of ENSO, while the correlation for La-ang Lake was the weakest (< 0.1 ), indicating that ENSO showed a lag influence on variation in lake levels in the Central and East Asia.


Zheng Z.,Chinese Academy of Surveying and Mapping | Zheng Z.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Zheng Z.,Shandong University of Science and Technology | Lu X.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | And 3 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2010

City spatial data acquisition is the key to digital city. In allusion to the limits of traditional differential positioning model with 3DSurs, and with the development of regional continuous operational reference system or stations (CORS), 3DSurs precise positioning technique based on CORS is put forward. Firstly, we compute the approximate coordinate of 3DSurs. Then, we calculate the synthetical error correction of 3DSurs from CORS. At last, we calculate its coordinate precisely based on the front two steps. Taking the data from QDCORS for example to analyze the positioning precision of 3DSurs based on CORS, we find that the positioning precision is prior to 10 cm, and it can meet the need of city spatial data acquisition and positioning.


Sun J.,Huaihai Institute of Technology | Sun J.,Shandong University of Science and Technology | Sun J.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Guo J.,Shandong University of Science and Technology | And 4 more authors.
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2011

About 10 a (1992-2002) of TOPEX/Poseidon(T/P) and 6 a (2003-2008) Jason-1altimetry data which have been corrected, edited, reduced and filtered, have been used to compute time series of lake level for Balkhash Lake. The time series is analyzed with Fourier transform and wavelet transformation, respectively. The mean periods are 1007 d, 364 d, 313 d and 184 d. The amplitudes of annual and semiannual variations are 0.1418 m and 0.035 m respectively based on the least square approach. The trend of water level variation of Balkhash Lake is +0.092 m/a, which indicates the water level is ascending. The gravity anomaly is also monitored with GRACE data. The mean change periods of gravity anomaly are 1019 d, 366 d and 186 d with Fourier transform and wavelet transformation, respectively. The amplitudes of annual and semiannual variations are 0.5731 mGal and 0.0918 mGal respectively based on the least square approach. The correlation coefficient and confidence level between water level change monthly and gravity anomaly is respectively 0.7729 and 99%, which indicates the two kinds of data have a stronger correlation. Analysis of the correlation between NINO3.4SST and water level change of Balkhash Lake shows NINO3.4 SST has a lag influence on the water variation of Balkhash Lake. When the lag is about 5 months, the correlation coefficient between them is max.


Guo J.,Shandong University of Science and Technology | Guo J.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Yu L.,Shandong University of Science and Technology | Liu X.,Shandong University of Science and Technology | And 2 more authors.
Applied Mechanics and Materials | Year: 2011

Trigonometric leveling method is often used to connect the height over sea. Error analysis of trigonometric leveling is made. in order to automatically achieve the trigonometric leveling over long distance, an automatic trigonometric leveling system is put forward with the combination of GPS and the automatic target recognition (ATR) techniques in this paper. The primary design of the system prototype including the structure and the software is given. The practical principle tests are also made to prove the system performance. The results indicate that the leveling precision of the system can satisfy the requirement of fourth order leveling. © (2011) Trans Tech Publications.


Zheng Z.,Chinese Academy of Surveying and Mapping | Zheng Z.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Zheng Z.,Shandong University of Science and Technology | Lu X.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | And 5 more authors.
2010 International Conference on Multimedia Technology, ICMT 2010 | Year: 2010

Convergent time (CT) is one important aspect of GPS kinematic precise point positioning (PPP). There are many factors which affect performance, including the effect of different sample rates of observations and GPS satellite clock bias (SCB) (or satellite clock offset), different positioning accuracy on CT of kinematic PPP is discussed deeply in this paper, taking GPS observations from twelve stations in a GPS network from Shanghai, China, we analyzed the relationship between CT and sample rate, positioning accuracy and convergence behavior. ©2010 IEEE.


Sun J.,Huaihai Institute of Technology | Guo J.,Shandong University of Science and Technology | Guo J.,Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM | Guo S.,Huaihai Institute of Technology
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2014

The paper analyzes the chaotic properties of ionospheric total electron content based on the 600 TEC data from 101~150 d in 2008 over 120° E and 45° N. Calculation results show that the TEC time series is chaotic when correlation dimension is 2.263 2, embedding is 5 and largest Lyapunov exponent is 0.083 3. A new method to choose the more similar phase points is advanced based on cosine and cluster analysis while the weighted one-rank local-region forecasting method is used sucessfuly to forecast the time series of TEC. The search results show that the paper's method can hunt more similar phase points than the euclidean distance and cosine in 5 dimensional space. Forecasting results show that the STD (0.618 TECU) and RMS (0.623 TECU) based on cosine and cluster analysis are less than the other two methods. Therefore, the method can choose by rule and line similar phase points and improve forecasting precision.

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