GNSS World of China

2018 Vol. 43, No. 4

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Dynamic Positioning for Flexible Pods of UAV Based on Pseudolites
RONG Fengjuan, ZHANG Qinghua, ZHANG Jie, XU Jianhui
2018, 43(4): 1-7. doi: 10.13442/j.gnss.1008-9268.2018.04.001
Abstract:
  In order to solve the problem of difficulty in accurately locating pod of rotor UAV, this paper uses 2.4 GHz wireless ranging device as a pseudolite positioning device, and uses extended Kalman filter to deal with the nonlinear problem in the dynamic positioning algorithm of pseudolite. The experimental results show that using the pseudolite system proposed in this paper and the algorithm to locate the unmanned pod dynamically, it can achieve high positioning accuracy both in the plane and in the vertical direction, which has an important practical application value.
A Changed Coherent Integraltime of the Delay frequency Combined Acquisition Algorithm for GNSS Signal
TIAN Ye, ZHAN Jianjia
2018, 43(4): 8-13. doi: 10.13442/j.gnss.1008-9268.2018.04.002
Abstract:
To acquire the Global Navigation Satellite System signal, we design a changed coherent integraltime of the delayfrequency combined acquisition algorithm. While prolonging the coherent time, the FFT points also can be added for equivalence, so the acquisition performance can be improved. The Monte Carlo simulations check the validity of this changed coherent integrationtime acquisition algorithm, and we get the conclusion that the improved performance of this algorithm can be achieved.
Analysis of Vertical Crustal Displacements Due to Atmospheric Loading Effects at GNSS Stations in China
ZHANG Jianhui, YANG Guolin, LIU Tao, SHAO Ming
2018, 43(4): 14-18. doi: 10.13442/j.gnss.1008-9268.2018.04.003
Abstract:
In order to study the vertical deformation detailing characteristics of the crustal atmospheric loading of GNSS station in China, the 36month atmospheric loading effect of six reference stations in the crustal movement observation network of China have been calculated and analyzed based on the Green function integral and simplification method. The results show that atmospheric loading is the important factor to cause the vertical deformation of the crust. The regional variation and vertical deformation in the earth's crust caused by atmospheric loading effect are the largest in northeastern China and western Xinjiang area. The correction of atmospheric loading effect can further improve the vertical accuracy of GPS.
GNSS Dual Frequency Compatible Interoperation Receiver Signal Acquisition Method
YUAN Jin, LIU Yunfei
2018, 43(4): 19-23. doi: 10.13442/j.gnss.1008-9268.2018.04.004
Abstract:
With the opening of the "global network" of the Beidou navigation and positioning system, the design and implementation of the compatible interoperability of the receiver has become a hot spot in the field of the receiver design. In this paper, aiming at the problems of long processing time, low acquisition precision, large hardware resource consumption and poor compatibility in the design of signal acquisition link of GNSS dual frequency compatible interoperable receiver, a signal capture that can capture GPS, Galileo, GLONASS, BDS signals at the same time, and can capture Doppler frequency offset and code offset quickly, is designed. With the help of Xilinx simulation tool Vivado and its simulation software, the whole capture system is simulated, and the accuracy of the algorithm is verified. In actual engineering verification, this algorithm can better meet the engineering application requirements.
Fast and Precise Measurement on the Railway Track by GNSS/INS
2018, 43(4): 24-28. doi: 10.13442/j.gnss.1008-9268.2018.04.005
Abstract:
A fast precision measurement method for the existing railway based on the GNSS/INS integrated technique is presented in this paper. The system consists of the IMU, GNSS module, odometer and track gage sensors carried on the railway track trolley. In the surveying process, GNSS/INS system calculates the precise coordinates of track midline by using the carrier coordinates, attitude and gauge information. This method uses the rapid mobile surveying model and does not depend on the high precision track control network. The results of field tests on the XUZheng highspeed railway nonballastedtrack show that the measuring errors are less than 6 mm (RMS) and 15 mm (RMS) in the horizontal and vertical directions. And this method can be used for the recovery of existing railway.
Parameter Design of an Improved PMF-FFT Algorithm in P-code Acquisition
YUAN Conglin, TANG Xiaomei, HAN Chunyang, SUN Guangfu
2018, 43(4): 29-35. doi: 10.13442/j.gnss.1008-9268.2018.04.006
Abstract:
The acquisition model of partial matched filter combined with FFT is used in the acquisition of navigation signals in high dynamic environment. Because of its high tolerance to the Doppler frequency error, it can do parallel search in frequency domain, which reduces the acquisition time and enables the whole system to have a high detection probability. This paper analyses the principle of the PMFFFT acquisition algorithm and the loss of each part in the acquisition process in detail by establishing the mathematic model, and then comes up with an improved acquisition method according to the aperiodic characteristics of the Pcode. The overlapandsave method is applied to achieve time domain parallel search in the frequency domain. Through this method, the acquisition time can be further reduced. Finally, according to the principle of the minimum total operation time when reaching the equivalent signaltonoise ratio, some guidance to the optimum design of the parameters in the algorithm is given, which has a certain reference.
Monitoring Temporal and Spatial Variations of Ionospheric TEC Using GPS Measurements
KOU Ruixiong, LI Zhongqin, GAO Zhiyu
2018, 43(4): 36-41. doi: 10.13442/j.gnss.1008-9268.2018.04.007
Abstract:
The study of the ionospheric temporal and spatial variations has important value for satellite navigation, aerospace and communications. In this paper, the GPS dualfrequency observation data provided by the IGS station are used to estimate the hardware delay of the GPS system by using the regional ionosphere model to calculate the total electron content of the absolute ionosphere. On the time scale, we select the data in 2012, 2015 and 2017 of COR1 station for time change analysis. The total ionospheric electron content shows diurnal, monthly and seasonal variations in time. In terms of space, four IGS stations, CRO1, BRMU, UNBJ, and QIKI, with small differences in longitude and uniform distribution in the latitude direction, are selected for analysis. The results show that there is an obvious unimodal effect in latitude direction, and the total electron content of the ionosphere shows a decreasing trend with increasing latitude.
Analysis of the Magnetic Storm’s Influence on Ionospheric in September 2017
LI Yongtao, LI Jianwen, PANG Peng, LIU Dezhi, LI Jing
2018, 43(4): 42-47. doi: 10.13442/j.gnss.1008-9268.2018.04.008
Abstract:
In order to study the effect of magnetic storm on the change of ionospheric TEC, this paper collects TEC global grid data from iGMAS and storm Dst index provided by SEPC during solar grade X93 large flares and magnetic storms on September 6 in 2017, and analyzes the correlation in different stages of magnetic storm between Dst index and TEC at different latitudes in the process of the magnetic storm. The results show that: 1)The large magnetic storm occurres 13 hours after the outbreak of the large flare, and the correlation coefficient between the ionospheric TEC lagging 1 hour and Dst index of the main phase during the magnetic storm is -09997, The ionospheric total electron content increase rapidly with the inten sification of magnetic starms, then decreases rapidly and tends to be stable during the recovery phase; 2) The change of TEC varies with the change of Dst index of magnetic storm, and the trends of the two changes are the same. The intensity of magnetic storm has a strong negative correlation with the change of TEC. The effect of magnetic storm on TEC of different latitudes tends to be consistent, and the degree of influence declines gradually from high latitude to low latitude; 3) The TEC changes in the high, medium and low latitudes after the magnetic storms are not synchronized. and the effect is taken in high, medium and low order. The delay of the influence on the different latitudes during the main phase of the magnetic storm is about 1 hour. The delay between Dst index and TEC delay gradually disappears during the recovery phase. With the storm reducing weak the ionospheric TEC change tends to be stable; 4) The abnormal changes of TEC occurre during the phase of magnetic storm recovery need to be further studied and analyzed.
A Study of Eliminating the Gross Error in Long Range Lightning Localization
SHEN Yu, LIU Yiwen, XIONG Wen, HUANG Xiao, ZHANG Qiong
2018, 43(4): 48-52. doi: 10.13442/j.gnss.1008-9268.2018.04.009
Abstract:
Lightning electromagnetic pulse (LEMP) can be affected by radio frequency interference and radiowave propagation.Thus the distortion of the waveform is generated, which can affect the recognition of the lightning property and the quantitative estimation of the position and strength.In this paper,the correlation coefficient of a large number of measured LEMP waves is studied and analyzed, and the rules of using the waveform correlation coefficient to eliminate the gross error of LEMP are summarized.At the same time, the influence of propagation path on waveform correlation is also analyzed.Finally, a method of eliminating the gross error of LEMP is proposed by comprehensively utilizing time correlation and waveform correlation.
Design of Rapid Networking Scheme for Satellite Communication Vehicle Based on BeiDou Short Message
LEI Silei, HE Wenbao, LI Jianqing, XIONG Zhijian, FENG Yun
2018, 43(4): 53-58. doi: 10.13442/j.gnss.1008-9268.2018.04.010
Abstract:
The existing satellite communication vehicles have complex configuration and long process, and must rely on the existing communication channels to negotiate the parameters. In order to solve the above problems, this paper designs a fast networking scheme for the satellite communication vehicle using the Beidou short message. This paper gives a detailed and detailed scheme, and the hardware structure of the selfcontrollable vehicle central control unit, the reliable transmission protocol of the Beidou short message, the data transmission format and the mechanism of pingpong use of double Beidou terminal are designed. The solution of this paper effectively solves the malpractice of the satellite communication vehicle and achieves rapid networking.
Accuracy Analysis of LEO Satellite Orbit Prediction Based on Dynamic Fitting Method
WANG Youcun, GUO Jinyun, XIA Yaowei, KONG Qiaoli
2018, 43(4): 59-66. doi: 10.13442/j.gnss.1008-9268.2018.04.011
Abstract:
The orbit prediction plays a significant role in the scientific mission of remote sensing satellite. To obtain the longperiod and highprecision orbit prediction, the orbit forecast is performed by a dynamic fitting method. To analyze the effect of orbital height and different fitting arc lengths on the accuracy of orbit forecast, the data of the GRACEA satellite,HYA satellite, Jason2 satellite are used as examples. From the results, it is concluded that the prediction orbit of 3D RMS of 4 h and 8 h arc length of GRACEA satellites,the results are better than 3 m and 10 m respectively; for HY2A and Jason2 the 4 h arc length prediction results are less than 2 dm and 1 dm separately, 24 h arc length prediction results are better than 2.5 m and 2 m respectively.
High Currency Technology of Cloud Service Research Based on CORS Location Service
LIU Wenjian, DENG Sisheng, DING Huaxiang, CHEN Jing, HE Xi
2018, 43(4): 67-72. doi: 10.13442/j.gnss.1008-9268.2018.04.012
Abstract:
According to the contradiction between public requirements of highprecision location and the limited application of CORS high precision positioning such as surveying and mapping, the design of cloud platforms based on CORS location service, and high concurrent access were introduced, by integrating with internet of things, cloud computing, big data and artificial intelligence. A high precision location differential pool was constructed by grid transformation, so that high currency access and high precision position can be realized in cloud. The cloud platform service tests suggest that, the system operation efficiency increases at least 26 times, the number of current users achieves at least 50 thousand, and the internet RTK/RTD of CORS cloud service is nondestructive in precision.
The Design and Implementation of Sharing Bicycle Government Regulation and Service Platform Based on Location Service
LI Kun, XIAO Jihua
2018, 43(4): 73-76. doi: 10.13442/j.gnss.1008-9268.2018.04.013
Abstract:
As a new convenient way to travel sharing the bike , effectively solves the problem of short trip, but along with the delivery and use of shared bicycle, urban management has brought a great challenge. Based on high precision beidou satellite location technology and electronic fence, We set up a shared bicycle supervision and service platform. Depending on the parking area, the high precision beidou acquisition terminals are used to collect the coordinates of polygonal turning points. Comparing the bicycle position data with electronic fence data, We decide whether to park your bike inside or outside the fence, and count the number of bikes in the fence, Then the bicycle which is outside the fence will be warned and punished. In practical application, this platform provides a complete solution.
Parallel Processing of GNSS Network’s Baseline Vectors Based on Spark
BAI Fan, SUN Ning
2018, 43(4): 77-80. doi: 10.13442/j.gnss.1008-9268.2018.04.014
Abstract:
In order to solve the problem that the traditional single machine processing largescale and complex GNSS observation data are low efficiency, the Spark large data cluster is introduced, the subnet partition idea and the GAMIT software are used to calculate the GNSS network’s baseline vector, and the parallel computing is realized. The experimental results show that the efficiency is improved and the performance is better than the whole solution,and the accuracy is in the same order, which satisfies the demand of largescale and complex GNSS data processing.
An Open Loop Multipath Correction Method for GNSS Navigation Signal
GAO Ke
2018, 43(4): 81-84. doi: 10.13442/j.gnss.1008-9268.2018.04.015
Abstract:
Multipath signal can bring orientation error to GNSS receiver, so it is necessary to mitigate multipath for highprecision receiver. Aiming at the advantages and disadvantages of commonly used multipath suppression methods at present, a new method is proposed in this paper. The autocorrelation function of range code is remolded through multiple gate delay for finding the code loop tracking bias caused by multipath signal, and this bias is amended by parabola fit method. The amended bias is used to correct the range between satellite and receiver through open loop method. This multipath mitigation method can optimize the position accuracy with code loop tracking performance and antidynamic performance not changed. Numerical simulations have demonstrated the effectiveness of the approach proposed.
Algorithm and Verification of Position Solution for BeiDou Receiver
LIU Ruihua, DING Qijin
2018, 43(4): 85-90. doi: 10.13442/j.gnss.1008-9268.2018.04.016
Abstract:
As a very important part of satellite navigation and positioning, the accuracy of the receiver position calculation directly affects the positioning accuracy. In this paper, Using BeiDou ephemeris data and pseudorange information collected by NovAtel receiver to verify the classic algorithms used in the position solution process of BeiDou receiver, including the BeiDou satellite position solution algorithm and the leastsquare receiver position solution, and performing the calculations and analytical verifications. The results show that the threedimensional error of the satellite position calculated by the algorithm provided by the BDS spatial signal interface control file is less than 10 meters. The threedimensional error of the receiver position calculated by the leastsquare method is less than 5 meters, and the accuracy of the official performance specification is satisfied. This results verify the correctness and feasibility of the algorithm.
Using RTKLIB to Implement GPS PPP Time Comparison
WANG Yingjian, ZHU Guangyao, KANG Jitong, XIE Zhiyue
2018, 43(4): 91-94. doi: 10.13442/j.gnss.1008-9268.2018.04.017
Abstract:
GPS PPP time transfer is one of the most important high precision time comparison methods for the international authority's punctuality laboratory. The basic principle of time comparison of GPS PPP is introduced, and the time comparison of GPS PPP is proposed by RTKLIB, then the time comparison results of BRUX, IENG, OPMT and PTBB are verified by examples. The experimental results show that the RMS of time comparison using RTKLIB is about 0.1-0.2 ns, and the stability of the day frequency is about 1.5×10-15-2.5×10-15, The result of time comparison is in good agreement with IGS's final clock offset.
Velocity Determination Model and its Accuracy Analysis with Multi GNSS
WU Chao
2018, 43(4): 95-101. doi: 10.13442/j.gnss.1008-9268.2018.04.018
Abstract:
Based on the principle of velocity determiantion with doppler observations, the mathematic model of velocity determination with multiGNSS is introduced and then the accuracy and performance of velocity determination with raw doppler observations,derived doppler observations and the combined observations are tested and analysed.The results show that the combination of multiGNSS can improve the accucary of velocity significantly with raw doppler observations and derived doppler observations.The combination of raw doppler observations and derived doppler observation with single system also can improve accuacy of velocity,but when we use multiGNSS,it does not work very well for lack of rigorous stochastic model.
Middle-Lon- Range Differential Positioning Using TripleFrequency BeiDou Satellite System
YU Wenhao, ZHANG Yun, HAN Yanling, YANG Shuhu
2018, 43(4): 102-109. doi: 10.13442/j.gnss.1008-9268.2018.04.019
Abstract:
Based on the unique advantages of Beidou triple frequency, we use the real measured data to study the performance of differential positioning in middle long baseline and conduct the resolution of triple ambiguity with stepwise method, and resolve the B3 narrow ambiguity with the aid of wide lane ambiguity and ionosphericfree combination. Then using the observation epoch selecting strategy the paper presents that combining the construction of the kalman filter innovation vector using the B3 narrow lane ambiguity in adjoin epoch with the filter divergence condition, it is easy to analyze the impact of narrow lane ambiguity error on the filter performance using the RMS of inner product of kalman filter innovation vector. Finally, we get the centimeterlevel differential positioning accuracy in middlelong baseline and shorten the time to firstfixed solution effectively and improve the fix rate that has a practical significance on promoting BeiDou highprecision positioning.
Experimental Research on GPS Height Fitting Method
FANG Suyang, ZHAO Yong
2018, 43(4): 110-116. doi: 10.13442/j.gnss.1008-9268.2018.04.020
Abstract:
Different methods of GPS height fitting have limitations respectively and the single fitting method does not have universality in different survey areas.Aiming at these problems,this paper mainly studies four kinds of GPS height fitting methods:polynomial curve fitting,multisurface function fitting,quadric surface fitting and BP neural network method. Combined with actual engineering projects, height fitting of the study area is carried out,experimental results are analyzed, and the fitting accuracy is evaluated.Based on the analysis and comparison of the results obtained by the four fitting methods, conclusions are as follows:All four methods meet the requirements of the fourthgradeleveling survey, and the fitting residuals are less than 3 cm;the accuracy of BP neural network fitting is higher than others;according to the characteristics and the scope of application in different fitting method,correct use of the fitting method is necessary condition to obtain high precision normal height.This study has corresponding application and reference value for GPS height fitting in different environments.
Construction and Accuracy Test of the Four Constellation Satellite Navigation and Positioning Service System in Shenyang
TAI He
2018, 43(4): 117-121. doi: 10.13442/j.gnss.1008-9268.2018.04.021
Abstract:
From the construction of satellite navigation and positioning service system from double platform upgrade to a fourstar platform of reality in shenyang, a brief description of the key points of the system upgrade, and the accuracy of the service system after the upgrade is tested, then we provide some experiences for the transformation of the same type in the future satellite navigation service system upgrade.
Practice and Analysis of Height Transmission in Coal Mining Subsidence Area
TIAN Maohu, YANG Hongtao, SUI Chuanke, WANG Yong, HOU Weiwei, CHEN Meng, ZHANG Tao
2018, 43(4): 122-125. doi: 10.13442/j.gnss.1008-9268.2018.04.022
Abstract:
Monitoring of subsidence in coal mining has become an important task for mine production and environmental management. Given the instability of subsidence areas, the establishment and transmission of height datum is particularly important. In this paper, the characteristics and applicability analysis of the height transmission technology are carried out, and the GNSS and thirdorder leveling data of a mining area and its neighboring areas are used to carry out an example analysis of GNSS measurement of longdistanceheight transmission. The results show that the method in this paper can meet the demand of height transmission of the subsidence monitoring datum in the mine area.
Application of BeiDou Satellite Navigation System in Wave Energy Self Powered Marine Buoy
WANG Shiming, TIAN Yuan, TIAN Ka
2018, 43(4): 126-130. doi: 10.13442/j.gnss.1008-9268.2018.04.023
Abstract:
BeiDou satellite navigation system as satellite navigation system designed by china,can well meet the needs of current marine monitoring equipment with precise positioning, precise timing and short message communication functions, This paper designs a marine buoy that can be selfpowered by wave energy, accurate positioning and timing of marine buoys can be achieved through the Beidou satellite navigation system, and reliable information transmission on the buoy monitoring data.This article briefly introduces the wave energy selfpowered buoy structure and its operation principle, and focuses on the application of BeiDou satellite navigation system in positioning, timing and monitoring data transmission of this buoy, and which has provided new ideas for the development of marine monitoring equipment in china.