GNSS World of China

2017 Vol. 42, No. 4

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Satellite Navigation Signal Monitoring Algorithm Based on Chip Shape
LI Ruidan, TANG Xiaomei, OU Gang
2017, 42(4): 1-9. doi: 10.13442/j.gnss.1008-9268.2017.04.001
Abstract:
 Signal quality monitoring technology is one of the significant means to guarantee the high performance of satellite navigation system. Multicorrelator algorithm and chip shape monitor algorithm. The result proves that selected metrics is more effective than raw metrics. The result also shows that chip shape monitor algorithm is more sensitive for distorted waveform, has stronger applicability to other modulation and has smaller calculation complexity.
Availability Assessment of BDS Satellite
ZHAO Lidu, HU Chuan, FENG Xiao
2017, 42(4): 10-14. doi: 10.13442/j.gnss.1008-9268.2017.04.002
Abstract:
In order to evaluate the availability of BDS satellites and analyze the influence factors of BDS constellation MEO space backup strategy based on the reliability principle, the influence of BDS satellite fault on the availability of single satellite is analyzed based on the actual situation of BDS satellite. The results show that in the orbit design of BDS MEO backup satellites, the height difference constraint of the backup satellite orbit must consider both the orbital inclination allowable drift and the satellite mean interruption time interval. The effect of orbital maneuver on the availability of single star is smaller than that of single particle inversion (recovery time 12h, 24h), and the combined effect of the three faults is greater than that of unilateral factor.
 The Influence of Group Delay under GNSS Multichannel Cascade on Superposition of Zero Value
LIU Jinu, LIU Wenxiang, WANG Feixue
2017, 42(4): 15-21. doi: 10.13442/j.gnss.1008-9268.2017.04.003
Abstract:
 There may be several channels for the navigation signal to propagate from the satellite to the user, of which the group delay characteristics influence the zero value of time delay estimation. It is common practice to simply add the zero value of each channel to obtain zero value of cascaded channel, whether the sum of the zero values of each channel is simply equal to the zero value of the cascade channel has not been studied yet. In this paper, the influence of the group delay characteristics on the zero value is analyzed quantitatively. And the superposition characteristic of the zero value of time delay estimation under the cascade channel is estimated. The result of the simulation is verified on the software receiver. The results show that when the zeroorder group delay channel is equal to zero, it satisfies the superposition characteristic too. For other situations, the zero value does not satisfy the superposition characteristic, while the zero value can be approximately to satisfy it when the group delay coefficient is constrained.
The Impact Analysis of P1C1 Code Bias on Convergence of PPP
GE Xiyou, LI Lei, PAN Yuming
2017, 42(4): 22-26. doi: 10.13442/j.gnss.1008-9268.2017.04.004
Abstract:
This paper analyzed the satellite differential code bias (DCB) generated principle. Deduced the DCB correction formula of PPP. With multiGNSS experiment data and precise clock/orbit/dcb products, this paper undertakes a thorough evaluation of DCB’s influence on convergence of PPP. The results show the convergence time obviously reduced when corrected P1C1 DCB, in which the static PPP convergence time is reduced by an average of 10 minutes, dynamic PPP average reduced by an average of 20 minutes, correct P1C1 DCB on PPP accuracy is generally in millimeter level.
  The Architecture of Internet of Things System Based on BeiDou Satellite System and Wireless Sensor Network
HUANG Jia, YANG Chen
2017, 42(4): 27-31. doi: 10.13442/j.gnss.1008-9268.2017.04.005
Abstract:
  Based on the research of traditional RSSI localization algorithm for wireless sensor networks, the characteristics of poor positioning accuracy and slow response are analyzed. Combining with the advantages of Beidou positioning system, an algorithm combining traditional wireless sensor positioning and Beidou navigation and positioning is proposed. The Kalman filter is used to fuse the data of the two algorithms, and a new fusion localization algorithm is obtained. Through the simulation analysis, the new fusion algorithm has a corresponding improvement in the positioning accuracy and convergence rate compared with the traditional single wireless sensor network node localization algorithm. The simulation results also show that the algorithm is feasible.
  GNSS Observation Based Study of Ionospheric Disturbance Induced by Underground Nuclear Explosion
XIONG Wen, SUN Yang, LIU Ming, YU Ya
2017, 42(4): 32-37. doi: 10.13442/j.gnss.1008-9268.2017.04.006
Abstract:
  Earthquake, Tsunami and nuclear explosion will affect the ionosphere. With the help of Global Navigation Satellite System (GNSS), the ionospheric effect of these phenomena can be well studied. Based on the IGS observed GNSS data, this paper obtains Travelling Ionospheric Disturbance (TID) from Slant Total Electron Content (STEC) and amplifies the disturbance by high order derivatives so as to identify the ionospheric disturbance induced by underground nuclear explosion (UNE). Finally, a new way for nuclear explosion identification is proposed which will be a convenient way to study UNE induced ionospheric effect.
  Analysis of Disciplined Crystal Oscillator Method Based on GNSS
XUE Yicong, GONG Hang, LIU Zengjun, ZHU Xiangwei
2017, 42(4): 38-42. doi: 10.13442/j.gnss.1008-9268.2017.04.007
Abstract:
  Contrast to the huge demand in measurement and testing, monitoring and communication, telecommunications and electricity and finance, a standard frequency source of high stability and high precision is crucial. GNSS disciplined crystal oscillator has combined the advantages of GNSS pulse per second signal which has good longterm stability. So GNSS disciplined crystal oscillator is widely applied for its high precision and low cost. In this paper, least squares algorithm, unbiased moving average filtering and Kalman filtering have been analyzed and compared.Those main filtering methods was applied to crystal oscillators which controlled in the same way.Their advantages and shortcomings have also been summed in this paper. Some meaningful suggestions are provided for the use of disciplined crystal oscillator in GNSS timing receiver.
  The Analysis on GNSS Open Traverse Direction’s Influence on Point Location Precision
JIA Guoxian, TANG Yupei
2017, 42(4): 43-54. doi: 10.13442/j.gnss.1008-9268.2017.04.008
Abstract:
  By comparing processing results from observing data of GNSS open traverse with different lengths, the analyses are detailed about traverse direction’s influence on point location’s precision. The experiment shows that control points’ error accumulations not only have intrinsic relationships with traverse direction lying in longitude, latitude and altitude, but also satisfy some certain regulation along with variations of longitude and latitude.
  The Effect of Ionospheric Scintillation on Receiver
AN Panpan, XIAO Zhibin, TANG Xiaomei, SUN Guangfu
2017, 42(4): 47-53. doi: 10.13442/j.gnss.1008-9268.2017.04.009
Abstract:
  Rapid and random temporal fluctuations in amplitude and phase of GNSS signals caused when they are propagating through irregularities in electron density of the ionosphere are called ionospheric scintillation. Ionospheric scintillation has some influence on the receiver signal acquisition, tracking, demodulation and positioning. In this paper, the influence of ionospheric scintillation on I,Q branch and tracking loop is analyzed by theoretical and simulation methods. The results show that the phase scintillation has an effect on the signal I Q branches, and the amplitude scintillation has a great effect on the I branch. In the place where the phase scintillation is stronger or the Amplitude scintillation is stronger, the signal is more difficult to track. In weak scintillation conditions, the tracking threshold of PLL is about 29 dBHz,and the tracking threshold of DLL is about 20.2 dBHz. In strong scintillation conditions, the tracking threshold of PLL is about 32dBHz,and the tracking threshold of DLL is about 22 dBHz. In contrast, the carrier tracking loop is more fragile. At the same time, the stronger the scintillation, the greater the probability of the carrier cycle slip, the higher the carrier to noise ratio, the stronger the anti-scintillation ability.
Research for Maritime Meteorological Elements Inversion UsingShip-Based BDS    
WANG Yuming, SHAO Limin, ZHANG Shangyue
2017, 42(4): 55-59. doi: 10.13442/j.gnss.1008-9268.2017.04.010
Abstract:
  The marine atmospheric environment has important influence on navigating and fighting. The acquisition of meteorological information in the sea depends on the development of sounding means. However, the marine sounding technology is limited by conventional methods and instruments. Greatly reducing the safety of ships navigational and naval combat effectiveness of the use of weapons. In this paper,propose maritime battlefield meteorological elements inversion using shipbased BDS Meteorological Elements inversion theory. Analyze the main problems of maritime battlefield meteorological elements inversion. And prospect the key techniques about solving the related issues.
  Performance Analysis of BDS Triple-frequency and Dual-frequency Ambiguity Resolution
YAN Chao, XU Mei, XU Wei, ZHANG Guanghan, DU Wenxuan
2017, 42(4): 60-65. doi: 10.13442/j.gnss.1008-9268.2017.04.011
Abstract:
  The global navigation satellite system (GNSS) has entered the age of multisystem. In terms of the two short baselines, compared to BDS dual-frequenc and BDS/GPS dual-frequency,BDS triple-frequency and BDS/GPS triple-frequency are analysed in the ambiguity fixed rate, success rate and positioning accuracy.The results showed that BDS triple-frequency and BDS/GPS triple
  Distributed Processing of GNSS Network’s Baseline VectorsBased on Hadoop
YANG Guoqing, YUE Dongjie, CHEN Hao, YIN Binquan
2017, 42(4): 66-69. doi: 10.13442/j.gnss.1008-9268.2017.04.012
Abstract:
 For the massive data of GNSS observation, the method of conventional centralized data processing is facing the problem of low computational efficiency, distributed to process the baseline by using the technology of Hadoop platform, which can solve this problem effectively. By dividing the subnet, calling the GAMIT software to process the baseline in parallel, the result of 63 IGS stations shows that the acceleration ratio of the three compute nodes is 6.67, and the accuracy of the coordinate points is in the order of millimeters.
  A Forecast Model of Covering Time For Satellites
YU Wenhao, ZHANG Yun, YANG Shuhu, HONG Zhonghua, HAN Yanling
2017, 42(4): 70-76. doi: doi:10.13442/j.gnss.1008-9268.2017.04.013
Abstract:
  Accurate prediction of satellite's covering information is an important application in the military and civil field, it calculates the sub-satellite point track using the orbit parameters and deduces ECEF coordinate of satellite by means of combination of elevation and azimuth, establishing a simple model through the calibration of partial sub-satellite point track, using MATLAB programming to predict the future period of satellite covering time and draw the sub-satellite point track and calculate the elevation/azimuth of satellite's covering period. The model is simple and effective, using the Matlab only instead of professional satellite prediction software.
  Comparative Analysis of Positioning Performance Between GPS System and BDS System
XU Wei, YAN Chao, DU Wenxuan, ZHANG Guanghan, WANG Tao, XU Mei
2017, 42(4): 77-82. doi: 10.13442/j.gnss.1008-9268.2017.04.014
Abstract:
  Based on the simulation of GPS and BDS satellite constellations, this paper analyzes the satellite visibility, DOP value, and positioning accuracy of Harbin, Wuhan, Guangzhou, Lasa and the global satellite visibility, DOP value and positioning precision of the two positioning systems. The results show that the positioning performance of the BDS system in the Asia
  Sea Surface Altimetry Using GNSS-R Signal and Analysis of Retrieval Accuracy Influenced by Wind Speed
SHEN Siming, ZHANG Yun, YANG Shuhu, HAN Yanling, HONG Zhonghua
2017, 42(4): 83-89+101. doi: 10.13442/j.gnss.1008-9268.2017.04.015
Abstract:
   As one of the most important physical parameters of the ocean, sea surface height plays an important role in the prevention of tsunami and storm surge, and is one of the important research content of marine science and remote sensing surveying field. Roughness as an important factor affecting the sea surface altimetry, is mainly caused by the change of wind speed. In order to explore effects of roughness changes caused by wind speed on the accuracy of the height altimetry, two experiments were performed, the lake experiment and the sea experiment, respectively. Through the research of the wind speed and the reflection signal phase RMS relation, qualitative analysis of the influence of surface roughness on the accuracy of the height altimetry was performed. We find that the error of the sea surface altimetry RMS is nearly doubled when the skewing RMS is increased by 0.005 rad.
  Detection and Analysis of BDS/GPS Data Quality in Complex Environments of Bridge
CHEN Hao, YUE Dongjie, CHEN Jian, BAI Tianyang, ZHANG Yanbing
2017, 42(4): 90-95. doi: 10.13442/j.gnss.1008-9268.2017.04.016
Abstract:
  The mechanism of BDS/GPS multipath effects and the corresponding elimination and weakening measures are described respectively in this paper. The statistical analysis method is used to analyze the BDS/GPS multipath effects of monitoring points in complex environments during bridge deformation monitoring. Moreover, the influences of bridge tower, cable, traffic flow on BDS/GPS multipath error are also investigated. According to the measured data, the following conclusions are drawn: compared with BDS satellites, the multipath effect value of GPS, is basically the same as that of IGSO satellite but larger than that of GEO satellite and superior to that of MEO satellite; the multipath error is negatively correlated with the satellite elevation angle; bridge tower, cable and traffic flow are key factors of the multipath effects.
  Research on GPS Height Fitting Method Based on Danish Method
ZHANG Yanbing, TIAN Linya, BI Jixin, WANG Yongmin
2017, 42(4): 96-101. doi: 10.13442/j.gnss.1008-9268.2017.04.017
Abstract:
   In this paper, the traditional GPS height fitting methods, such as contour method and analytic fitting method, are introduced for GPS elevation fitting. The Danish method is used to calculate the weight factor for the first time to construct the equivalent weight matrix, and combined with the overall least squares method to resist the influence of the rough point on the GPS elevation fitting results. The results show that the effect of the contour method is equivalent to the other two methods for fitting the equal precision observation data without gross error. Based on the weight factor calculated by Danish method, The deal result of the robust overall least squares method is better in dealing with the accidental error of the unequal accuracy observation data,and the effect of the rough points on the elevation fitting can be effectively dealt by using the weighting factor, and the fitting effect is better.
  The Application of Precise Point Positioning Technology in Ship-borne Gravity Measurements
YAN Xincun, OUYANG Yongzhong, LIN Jianju, ZHOU Wanli,
2017, 42(4): 102-105. doi: 10.13442/j.gnss.1008-9268.2017.04.018
Abstract:
  Some measurements of the ocean can not be laid the base station can not use the DGPS positioning proposed ship loading capacity measurements, The precise point positioning technology is applied to the shipborne gravimetric survey is confirmed by comparing the calculation results of intersection discrepancy from the precise point positioning measurement mode and the traditional singlepoint positioning in openborne gravimetric survey is solved.
  High-rise Buildings GPS Data Processing Based on Wavelet Analysis
LI Kaiwei, WANG Renyin, CHEN Rui, HAN Li
2017, 42(4): 106-110. doi: 10.13442/j.gnss.1008-9268.2017.04.019
Abstract:
  Using GPS to hightime dynamic observation is considered to be effective, how to deal with massive amounts of GPS observation data vibration is an important issue. In order to improve the automation of process GPS data, based on GPS observation data vibration characteristics, wavelet analysis technology was applied to the GPS observation data processing in this paper. The impact of different wavelet decomposition scales and wavelet bases and threshold criterion to GPS observation data derise buildings, beneficial conclusions are obtained.