GNSS World of China

2020 Vol. 45, No. 5

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The performance analysis of three common methods of cycle slip detection and repair
XIA Siqi, YU Xianwen, QI Chen
2020, 45(5): 1-5. doi: 10.13442/j.gnss.1008-9268.2020.05.001
Abstract:
Aiming at the problem of reasonable selection of cycle slip detection and repair methods in GNSS data processing, this paper evaluates and analyzes the performance of three common cycle slip detection and repair methods. A new method for evaluating the reliability of cycle slip detection results based on mathematical statistics is given. The new method is used to evaluate the reliability of cycle slip detection results obtained by polynomial fitting method and the TurboEdit method on the same set of dual-frequency real data, and the reliability of the cycle slip detection results obtained by the polynomial fitting method and the triple-frequency geometric-free combination method on the same set of three frequency measured data is analyzed.Based on the evaluation results of the two groups,it can be seen that the detection effect of the TurboEdit method is better than that of the polynomial fitting method for the dual-frequency real data while for the triple-frequency real data,the detection effect of the triple-frequency geometric free combination method is better than the polynomial fitting method;The polynomial fitting method can detect and repair cycle slips on dual-frequency and triple-frequency observation data, so it has a wider applicability.
Analysis of PPP period error of LEO satellite spaceborne GPS
HOU Furong, TU Rui, FENG Yi, ZHANG Rui, HAN Junqiang, HONG Ju
2020, 45(5): 6-13. doi: 10.13442/j.gnss.1008-9268.2020.05.002
Abstract:
Using space-borne GPS observation data of GRACE for kinematic precise point positioning, it is found that the positioning error has obvious periodic characteristics. The first characteristic is that the waveforms of the positioning error sequences at intervals of four days basically coincide, and the second characteristic is that the positioning error sequences of two adjacent days have a tendency to shift along the abscissa. Based on the above two characteristics, two methods for eliminating periodic errors are proposed, which are the periodic item error elimination method based on median modeling and the periodic error elimination method based on translation prediction. The former improves the accuracy of the intermediate sequence in a group of data series obviously, while the latter is more stable on the whole. A comprehensive analysis of the improvement effect of the two methods is carried out. Finally, the positioning accuracy is improved from 5 dm to 2 dm. The RMS values in the three directions are obtained significantly reduced.
GAMIT 10.71 resolution GNSS long baseline precision analysis
Mu renhai, Chang chuntao, Dang yamin, Cheng yingyan
2020, 45(5): 14-19. doi: 10.13442/j.gnss.1008-9268.2020.05.003
Abstract:
GAMIT/GLOBK has released the latest version of 10.71 on March 9,2020,mainly adding BDS-3 data processing and solar pressure model.This article uses GAMIT10.71 software,combined with the old version (GAMIT10.7_2019/09/14),to process the GNSS data of 35 MGEX (Multi-GNSS Experiment) tracking stations on the 51st to 60th days of 2020 in the world. The square root error(NRMS),baseline repetition rate,baseline mean square error,baseline solution accuracy and point accuracy are compared and analyzed for GPS and BDS solution results.The experimental results show that the root-mean-square error of each solution can reach an accuracy of less than 0.22;the GPS baseline repetition rate is slightly better than BDS.The relative and absolute baseline repetition rates of the old and new versions of the long baseline are both accurate which can achieve 1×10-9 and 1×10-2 respectively;the new version of the baseline length calculation accuracy and the adjustment result of many days are slightly better than the old version,and the adjustment result of many days GPS accuracy is slightly better than BDS;Overall test shows that the new version of GAMIT software has a better performance.But for the accuracy of the single BDS system,there are still many problems worth discussing.
GNSS ambiguity integer estimation methods graph visualization software design and application analysis
WU Tangting, LIU Lijing, ZHAO Baogui, LU Liguo
2020, 45(5): 20-26. doi: 10.13442/j.gnss.1008-9268.2020.05.004
Abstract:
The key of high-precision GNSS positioning is fast and accurate ambiguity estimation.There are three kinds of integer estimation methods which are commonly used for ambiguity estimation,including Integer Rounding, Integer Bootstrapping and Integer Least-Squares.Although it is easy to realize the three kinds of estimation methods, there is little research on how to construct the geometry of integer estimate values based on the ambiguity float solution and precision,which is not conducive for us to intuitively understand the process of integer estimation.Therefore, this paper theoretically gives the general forms of the three kinds of estimation methods, and then designs a set of visualization analysis software for the construction of two-dimensional geometric figures based on MATLAB GUI. The functions of the software include pull-in region construction, map graph construction, Monte Carlo simulation and success rate calculation. The experimental results show that the software designed in this paper can intuitively express the processes of the three kinds of integer estimation and its resolution performance in terms of geometry.
Movement trend and time series analysis of CORS station in Taizhou area
XU Chuangfu, WANG Heng, JI Yuanming, LIU Yu
2020, 45(5): 27-33. doi: 10.13442/j.gnss.1008-9268.2020.05.005
Abstract:
Based on the 2017-2019 time series of 15 CORS stations in Taizhou area,linear fitting is carried out to construct three-dimensional velocity field,and the periodic characteristics of CORS stations are analyzed by power spectrum analysis and wavelet transform.It is found that in Taizhou CORS,the average station speed in the horizontal direction is 33.58 mm/a,with movement driection to the southeast,while the maximum lifting rate in the vertical direction is 3 mm/a,and the maximum settlement rate is 1 mm/a.From the perspective of cycle,the vertical direction of CORS station is much more obvious than that in the horizontal direction,with obvious annual cycle,half year cycle and seasonal cycle.
Research on the county area scale fitting methods for GNSS height anomaly
XIE Mengli, JIANG Yongtao, LIU Guoshi
2020, 45(5): 34-39. doi: 10.13442/j.gnss.1008-9268.2020.05.006
Abstract:
The key to improve the accuracy of height anomaly fitting is to select the appropriate fitting model. Based on the GNSS and leveling data in Xinhua County, Hunan Province,this paper studies and evaluates the fitting accuracy of height anomaly by using inverse distance weighting method,polynomial interpolation method, radial basis function method(RBF),Kriging interpolation method and other surface fitting methods.The results show that the radial basis function interpolation has the highest interpolation accuracy,and the error is ±0.0158 m.The local polynomial interpolation method owns the highest extrapolation accuracy,in which the error is ±0.0104 m.That means the local polynomial interpolation method has the highest accuracy in county scale elevation fitting.The research conclusion of this paper can be important reference significance for the selection of GNSS Height Fitting Method in small areas.
GNSS high precision velocity determination model considering satellite non-circular orbit correction
WANG Yongzhen, YANG Fan, ZHU Yaguang
2020, 45(5): 40-45. doi: 10.13442/j.gnss.1008-9268.2020.05.007
Abstract:
The calculation formula of satellite non-circular orbit correction and the processing strategy of high-precision velocity determination considering this correction were introduced.Observations of 12 IGS stations distributed around the world were used to evaluate the influence of the correction.The results show that the accuracy of velocity determination method based on carrier phase difference improve by 8%, 9% and 10% in E, N and U after correction, respectively and the accuracy of three-dimensional velocity is corrected from 9.9 mm/s to 8.9 mm/s.For the raw Doppler velocity determination method, the correction values of E and N are the same as the carrier phase difference method,and the correction value of U is about half of the carrier phase difference method.
Performance analysis of typical airports' BDS based on STK
NI Bowen
2020, 45(5): 46-50. doi: 10.13442/j.gnss.1008-9268.2020.05.008
Abstract:
In order to analyze the navigation performance of BeiDou Navigation Satellite System (BDS) at airports in China,the BDS constellation is established by use of the Satellite Simulation Toolkit (STK),and the number of visible satellites and the geometry dilution of precision (GDOP) at 11 typical airports are simulated and analyzed.The simulation results show that there are more visible satellites and lower GDOP values for the BDS at most typical airports. By comparing the results with the table the GDOP values correspond to the positioning accuracy classification,it can be concluded that the BDS can provide superior navigation services at most typical airports in China,and the good technical support for the implementation of approach can be provided with the BDS.
Timing difference of the BDS under different service system
XIN Jie, LIU Shuai, CHANG Zhiqiao, SHI Xin, WU Yukuan, LIU Changjie
2020, 45(5): 51-56. doi: 10.13442/j.gnss.1008-9268.2020.05.009
Abstract:
As the launch of the BeiDou navigation satellite system (BDS) completed,it realizes the three-step development strategy,which can provide RNSS service for global users and RDSS and SBAS service for regional users.In order to analyze the differences of the timing in different services,we have compare the timing and space reference,operating requirement and device delay in RDSS one-way/two-way timing,RNSS signal single frequency/double frequency and SBAS signal single frequency,and provide different timing results based on different models proposed in the paper.It can provide reference for the development,production and testing for the timing user with BDS.
Relative positioning accuracy analysis of BDS-2/BDS-3/QZSS combination short baseline
ZHENG Lei, LIU Cheng
2020, 45(5): 57-61. doi: 10.13442/j.gnss.1008-9268.2020.05.010
Abstract:
In view of the impact of QZSS on the relative positioning performance of BDS-2 and BDS-3 short baselines,this paper analyzes the short baselines of different combinations of QZSS,BDS-2 and BDS-3 based on the 5km and 10km short baselines composed of IGS tracking stations relative positioning accuracy.It is found that QZSS can effectively improve the BDS-2 and BDS-3 satellite visibility and satellite space geometry,while the satellite visibility and satellite space geometry of BDS-2/BDS-3 combination is superior to any single system.In terms of positioning accuracy,the combined positioning accuracy of BDS-3 and QDSS is equivalent to BDS-2 in the case of missing data.At the same time.QZSS can effectively improve the relative positioning accuracy of BDS-2 and BDS-2/BDS-3.while BDS-3 shows better performance than QZSS in improvement of positioning accuracy of BDS-2.
GEO satellite's quantitative improvement analysis of BDS-3 pseudorange single point positioning performance
PENG Jinsong
2020, 45(5): 62-66. doi: 10.13442/j.gnss.1008-9268.2020.05.011
Abstract:
GEO satellites are the main components of the BDS constellation.In order to analyze its impact on the positioning performance of BDS-3,this paper analyzed the impact of GEO satellites on the positioning accuracy of BDS-3 pseudorange single point based on the measured data of MGEX tracking station.The research found that the GEO satellite can effectively improve the BDS-3 satellite visible number and satellite space geometry,and can effectively improve the BDS-3 pseudorange single-point positioning accuracy.The BDS-2/BDS-3 GEO satellites make the BDS-3 pseudorange single-point positioning accuracy better than that of any single-system GEO satellite.The horizontal positioning accuracy of BDS-3 GEO satellites pseudorange single-point positioning is improved within 30%,and the positioning accuracy for elevation direction is improved within 20%.
Quantitative analysis of BDS-3 pseudo-range positioning performance improvement by different types of BDS-3 satellites
HE Chengqiang
2020, 45(5): 67-71. doi: 10.13442/j.gnss.1008-9268.2020.05.012
Abstract:
Based on the measurement data of tracking stations released by iGMAS,the BDS-3 GEO,IGSO,MEO,and all BDS-3 satellites are analyzed for the impact of BDS-3 different types of satellites on the BDS-2 pseudorange single-point positioning performance.The impact of satellite visibility, PDOP value, and pseudorange single-point positioning accuracy.The research found that BDS-3 satellites have different degrees of improvement in BDS-2 satellite visibility,satellite space geometry and pseudorange single-point positioning accuracy.MEO satellites are better than IGSO satellites than GEO satellites.The sum of the satellite positioning performance improvements to BDS-2 is the same as that of all BDS-3 satellite positioning performance improvements to BDS-2.
Design of bionic fish control system based on BDS for water quality inspection
CUI Xiufang, LI Peipei, SHI Fuxiao, WANG Hongyu, CHEN Gang
2020, 45(5): 72-76. doi: 10.13442/j.gnss.1008-9268.2020.05.013
Abstract:
With the rapid development of industrial technology and robot technology,robot research based on the principle of bionics has become a hot project.Bionic robot fish has attracted the interest of many scientific researchers as an underwater vehicle.Now that a new era of global networking of the BeiDou Satellite Navigation System has begun,this paper proposes a bionic fish control system based on the BDS to realize the remote detection of water quality.The embedded control board STM32 as the main controller is responsible for receiving and processing data from various sensors.Based on BDS positioning,navigation,timing and two-way short message communication functions,it can realize autonomous swimming,obstacle avoidance,deep water quality detection and real-time data transmission to remote monitoring and other functions.This design can improve work efficiency and has good prospect for application.
Sampled-data control of Markov jump system via a fragmentation functional
WANG Qing, ZHANG Yi
2020, 45(5): 77-83. doi: 10.13442/j.gnss.1008-9268.2020.05.014
Abstract:
Markovian jump systems is a most important mixed stochastic system in practice application,the sampled-data control problem of Markov jump system is studied in this paper.According to a continuous Markov jump system model and Lyapunov-Krasovskii stability theorem,the whole sampling interval is divided into four parts by introducing two adjustable parameters.Based on the four sampling intervals,two corresponding expressions of state space are proposed.Novel Lyapunov-Krasovskii functional which can fally use the status information of four frogmentation interual is built.then,using the integral inequality methods to estimate functional derivative,a new sampled-data control Markov jump system stability criterion is obtained.Finally,an example of a nonlinear mass spring damper system and an actual ship positioning system are given.After the establishment of simulation,the maximum sampling interval obtained is much larger than the results of similar literatures,indicating the superiority of the method.
Design and evaluation of a new data modulation and channel coding scheme for eLoran system
LI Wanqing, WANG Jianhui, LI Shifeng, FU Qixiang
2020, 45(5): 84-89. doi: 10.13442/j.gnss.1008-9268.2020.05.015
Abstract:
Enhanced Loran system (eLoran) is an important source of precise time-frequency information and an effective backup of global satellite navigation system.Aiming at the problems of single modulation mode and low data transmission rate of eLoran signal and in order to make full use of the time-frequency resources,expand the amount of data broadcast and application range,this paper proposes a modulation method to improve the carrying ability of signal information and a channel coding method with higher coding gain.The transmission rate of 40~200 bps can be achieved by adding the pulse group that only used for data transmission in the novel modulation mode.The simulation results show that LDPC coding can give better consideration to both coding gain and signal frame length when the length of data information is about 215 bit.
Testing and analysis of precise time synchronization protocol for 5G network applications
LI Youyou, WU Jianfeng, WANG Kang
2020, 45(5): 90-96. doi: 10.13442/j.gnss.1008-9268.2020.05.016
Abstract:
With the popularity of 5G and the construction of base stations,higher requirements have been placed on the accuracy of time synchronization between base stations.At present,Precision Timing Protocol (PTP) can only reach tens of nanoseconds,and the frequency distribution effect is poor.When combined with SyncE technology,the frequency of all clocks on the network can be synchronized with the clock source.WR (White Rabbit) adds an all-digital dual-mixing phase detector(DDMTD)on the basis of PTP+SyncE can adjust and compensate the phase difference between nodes to eliminate the out-of-synchronization caused by the accumulation of phase noise for a long time,So as to realize the clock synchronization of the entire network node.This article introduces the principle and implementation process of the synchronization method combining SyncE and PTP、the WR synchronization method.At the end,an experimental platform is built,to verify the synchronization process.The test proves that the jitter of 100 picoseconds and tens of picoseconds can be achieved respectively,and the synchronization accuracy can reach the nanosecond and sub-nanosecond levels.
Research on the computer aided design of UAV aerial photography scheme
WANG Hao, YANG Dehong, LI Hui, LI Hongbin
2020, 45(5): 97-102. doi: 10.13442/j.gnss.1008-9268.2020.05.017
Abstract:
With the development of science and technology,UAV aerial photogrammetry has gradually become an important means of modern surveying and mapping technology with the advantages of high timeliness,flexibility and high accuracy of data acquisition,playing an increasingly important role in the field of Surveying and mapping.However,at present,the design of UAV aerial photography scheme mainly relies on manual work,which is not assisted by system equipment.It needs a lot of work and is difficult to meet the specific work requirements of UAV aerial photography.In view of the problems,this paper puts forward a technical method of using computer-aided design for aerial photogrammetry scheme of UAV,and develops a scheme design book according to the design of navigation area and relevant parameters before the UAV flies.It is convenient for the staff to verify the feasibility and safety of UAV flight operation in theory,improve the automation process of aerial photography scheme design,improve the work efficiency,and provide technical and safety guarantee for carrying out photogrammetry.
A research on water storage changes in the Indus-Ganges river basin based on GRACE time-varying gravity field
WEN Zhiqiang, HUANG Zhengkai
2020, 45(5): 103-107. doi: 10.13442/j.gnss.1008-9268.2020.05.018
Abstract:
The Indus and Ganges rivers are important rivers in Asia,and the two basins the two rivers passed are also the most populous areas in Indian subcontinent.It is of great significance to study the water storage changes in this region to ensure the local ecological environment and economic development.In this paper, the GRACE_RL05 Time-varying gravity field model was used to calculate the change of total water storages of Indus-Ganges River Basin from 2002s to 2016s,and the GLDAS hydrological model was used to calculate the changes of groundwater storages.The study found that,the Total Water Storages (TWS) and Groundwater Water Storages (GWS) of the Indus and Ganges showed a downward trend from 2002s to 2016,and the rate of groundwater decline (respectively-7.2 mm/year and-4.7 mm/year) in both basins exceeded the TWS decline rate.Comprehensive hydrological model data analysis shows that the reason for the decline in water reserves in this area is caused by excessive pumping pipelines in excessive agricultural irrigation against the background of rising evaporation and continuous reduction of precipitation.
Design and implementation of remote sensing image classification program based on multi-classifier fusion
SUN Hao, GAN Shu, YUAN Xiping
2020, 45(5): 108-112. doi: 10.13442/j.gnss.1008-9268.2020.05.019
Abstract:
In the application of remote sensing image classification,the classification accuracy and efficiency of the classification results obtained by using different kinds of classifiers to operate on the original image are different.In this paper the multi classifier fusion classification experiment are designed and completed.The experiment can combine the advantages of different single classifiers with appropriate methods,so as to obtain better classification accuracy and efficiency than single classifier Method.On this basis,the voting principle is used to design the multi classifier of abstract level fusion and complete the experiment.The design results show that the classification accuracy of multi classifier fusion is higher than that of single classifier.
Analysis of the impact of GNSS transitional development on military logistics
GUO Ling, DU Weiwei, LIU Ling, LI Rui, WAN Ping
2020, 45(5): 113-118. doi: 10.13442/j.gnss.1008-9268.2020.05.020
Abstract:
In 2020,as GNSS is fully completed and put into service, especially the official opening of China's BDS-3, it marks a new stage in the development of GNSS and its application.The leap-forward development of satellite navigation and positioning technology will inevitably lead to its application Field changes.Modern military logistics is an important guarantee for military operations under the conditions of informatization. Satellite navigation and positioning technology is widely used in various fields and links.Research on the development trend of GNSS and its influence on the development of military logistics is essential to improve military logistics support benefits.According to the practical exploration of the development needs of modern military logistics,research and analyze the development status of GNSS and its development trends in three aspects of system,positioning technology and application.Finally combining with satellite navigation technology as the core,integrating cloud computing,big data,Internet of things,artificial intelligence and 5G communications,etc.Research and analysis on the development prospects of military logistics theory,positioning and tracking,delivery and navigation,dynamic scheduling,regulation and management,etc.