GNSS World of China

2024 Vol. 49, No. 1

2024, 49(1)
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2024, 49(1): 126-126.
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Special Column on “Application Technology of BDS in National Key Infrastructure Fields”
2024, 49(1): 1-1. doi: 10.12265/j.gnss.24-01daodu
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2024, 49(1): 2-2. doi: 10.12265/j.gnss.24-01bwh
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The design and application research of the BeiDou application system for electric power
CHEN Xiangdong, ZHAO Jianwei, FU Ning
2024, 49(1): 3-8. doi: 10.12265/j.gnss.2024005
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With the maturity of the BeiDou Navigation Satellite System (BDS), the application of BeiDou in the electric power industry has continuously expanded and deepened, establishing a relatively comprehensive application framework. This paper discusses the research and design of the electric power of BDS application system structure, emphasizing the system’s utilization in planning and construction, facility and equipment management, marketing, dispatch control, and material logistics management. Additionally, it presents an analysis of future development trends of BDS application in the electric power industry and offers corresponding recommendations for growth.
Research on BeiDou global maritime distress and safety service system
PANG Bobo
2024, 49(1): 9-18, 44. doi: 10.12265/j.gnss.2023178
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With the BeiDou message service system (BD-MSS), BeiDou search and rescue service being recognized by international organizations and the application of BeiDou short message service in domestic ships, BeiDou maritime distress and safety service has been initially formed. In this paper, the concept of the BeiDou global maritime distress and safety service system is proposed. The system architecture is given by introducing generalized BeiDou mission control center (BD-MCC). Functional characteristics of the system in Asia-Pacific and global sea area are analyzed from BeiDou featured services, maritime communication business to systems’ service. The architecture and specifications are sorted out of BeiDou message service system, BeiDou search and rescue service system, BeiDou emergency position indication system, BeiDou long-range identification and tracking system (LRIT), BeiDou ship security alarm system (SSAS) and the BeiDou maritime safety information broadcast system. The systematization, internationalization and customization of the system are given. The paper has reference value for the systematic application of BeiDou system in global maritime distress and safety business field.
Research progress and prospects of ground-based BDS/GNSS water vapor monitoring in the field of water conservancy
SUN Minghan, PANG Zhiguo, LYU Juan, ZHANG Pengjie, CUI Xiangrui
2024, 49(1): 19-33. doi: 10.12265/j.gnss.2023179
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Almost all water vapor on Earth is concentrated in the troposphere, the content of it has a significant impact on global temperature, precipitation, and other meteorological factors, which can to some extent affect Earth’s climate change and regulate heat balance on a global scale. Tropospheric water vapor monitoring plays a crucial role in water resource management, extreme weather warning, and climate change research. In the process of continuous development and improvement of BDS/GNSS global satellite navigation technology, the retrieval of precipitable water vapor by BDS/GNSS has gradually become a new type of water vapor detection technology. Compared with traditional water vapor detection technology, BDS/GNSS can achieve high-precision and near real-time monitoring of water vapor. To deepen researchers’ understanding of BDS/GNSS precipitable water vapor (PWV), the paper provides a systematic review of the development process and research status of the retrieval of BDS/GNSS PWV, elucidating its inversion principles and methods. It mainly analyzes the application and development direction of ground-based BDS/GNSS water vapor monitoring in the field of water conservancy from high-precision water vapor monitoring, short-term and imminent rainfall forecasting, climate change, and drought & flood monitoring.
Research progress of GNSS-R water level monitoring and its application prospect in China’s water conservancy industry
ZHANG Pengjie, PANG Zhiguo, LU Jingxuan, JIANG Wei, LYU Juan, SUN Minghan
2024, 49(1): 34-44. doi: 10.12265/j.gnss.2023180
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Water level monitoring is crucial for the fields of hydrology, hydraulic engineering, and disaster prevention and control. Traditional methods of monitoring water levels have several drawbacks, including high costs and limited coverage. The Global Navigation Satellite System (GNSS) serves multifaceted functions, including navigation, positioning, and timing. Additionally, it can harness its reflection signal to extract characteristic information from the reflecting surface, a technique known as GNSS reflection signal remote sensing (GNSS-R). In recent years, GNSS-R technology has emerged as a novel approach for water level monitoring, offering advantages such as cost-effectiveness, all-weather operability, and high temporal and spatial resolution. This paper provides a comprehensive review of the current state of research in GNSS-R water level monitoring. It discusses the influencing factors of different methodologies and identifies challenges encountered in the application process. Furthermore, it proposes future development trends and anticipates its potential application in China’s water conservancy industry.
Application analysis of PPP-RTK technology based on the BeiDou Navigation Satellite System in UAV power inspection
BAI Tianyang, ZHANG Chunguang, CHEN Xiangdong, WANG Donghua, LENG Hongyu
2024, 49(1): 45-53, 101. doi: 10.12265/j.gnss.2023199
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In order to solve the problem that high-precision positioning service is not available for UAV power inspection in areas with no public network or complex terrain conditions, this paper proposes to use precise point positioning-real-time kinematic (PPP-RTK) technology based on BeiDou Navigation Satellite System (BDS) to provide high-precision positioning service for UAV power inspection. Using data from the electric power BeiDou precise positioning service network in Sichuan province to calculate the PPP-RTK server-side product and conduct user-side simulated dynamic positioning experiments. The experimental results show that under the conditions of using BDS-based PPP-RTK services, when the user-side adopts BDS or BDS+GPS for PPP-RTK integer ambiguity resolution, convergence can be achieved within 1 minute. After convergence, the horizontal direction root mean square (RMS) is less than 5 cm, and the vertical direction RMS is less than 8 cm. The experimental results can provide design reference for the construction of power BeiDou PPP-RTK service and its application in UAV inspection.
Application of BeiDou in tower pole settlement monitoring system
JIN Fuming, DUAN Yi, LIU Zhihui, ZHANG Peng, LUAN Junqing
2024, 49(1): 54-59. doi: 10.12265/j.gnss.2023185
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This article introduces a monitoring system for transmission line steel pipe rod settlement monitoring system. The system relies on core technologies in the field of secure IoT, such as single-tower target disaster prediction and overall risk prediction of towers in the region, to create a secure IoT support platform for the subsidence of steel pipe towers in power transmission lines, providing overall solutions and system services throughout the life cycle. The system is based on the BeiDou Satellite Navigation System (BDS) and tilt monitoring and warning technology, with the output of the BDS’s raw data, including carrier phase observation data, ephemeris data, etc., as the core. The data is transmitted to the control center via 4G wireless network. The control center calculates the three-dimensional coordinates of each monitoring point in real-time through monitoring software, and then forms real-time differential data under different monitoring systems or environments according to the comparative analysis of real-time displacement data. Finally, the deformation of the subsidence area of the power tower is corrected according to the differential data and detailed data. This system can effectively prevent various accidents caused by tower inclination and improve the safety operation level of the power grid.
Application of railway inspection technology based on BeiDou high-precision positioning
WANG Shaoxin, WENG Yanbin
2024, 49(1): 60-67. doi: 10.12265/j.gnss.2023203
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Railway inspection work is the most important for the safe operation of railways. However, the complex environment within railway stations significantly reduces the performance of conventional satellite navigation systems, making it unable to meet the requirements of inspection. This article analyzes the characteristics of positioning scenarios made by railway track canyon mode, examines and statistically analyzes high-precision enhancement modes such as BeiDou RTK, CORS, and SBAS. Finally, a handheld BeiDou high-precision positioning terminal that integrates multiple positioning modes is used in conjunction with Qianxun CORS data for testing on tracks at Chengdu Gongxing Station. The analysis results show a significant improvement in positioning accuracy, indicating that high-precision positioning results can meet the requirements of railway inspections and provide valuable references for developing intelligent inspection management systems in the future.
Design of BeiDou application scheme in the transportation field
LIU Xiaobing, ZHOU Yukai, WANG Jian
2024, 49(1): 68-74. doi: 10.12265/j.gnss.2023211
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The BeiDou System has realized global networking and provides navigation and positioning services with global coverage. In the field of transportation, the BeiDou system is widely used in vehicle positioning monitoring, intelligent navigation, path planning and fleet management, providing more efficient, safe and reliable services for the transportation industry, and playing a positive role in promoting the development and modernization of China’s transportation field. Under the requirements of transportation industry planning and construction in the new era, there are still problems in the construction and development of intelligent operation and maintenance system, such as lack of unified standards, poor information, bottleneck of centralized scheduling, and repetitive construction of facilities. In this case, making full use of BeiDou technology in the application of intelligent operation and maintenance will help the high-quality development of transportation industry. The design of this scheme aims to systematically study the application scheme of BeiDou technology, complete the integrated design of monitoring, scheduling and resource deployment, achieve cost reduction and efficiency increase, and contribute to the industrial development and systematic application of Beidou. This paper conducted specific research and discussion from the overall structure, system composition and platform construction, realized the top-level application scheme design of intelligent operation and maintenance in the field of transportation, and improved transportation efficiency, safety and management ability through the large-scale application of BeiDou satellite system.
Comprehensive PNT New Technology
A high-precision time-frequency synthesis and time keeping method
DAI Qunxiong, YIN Jikai
2024, 49(1): 75-81. doi: 10.12265/j.gnss.2023195
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In the construction of modern information platform, the time-frequency system provides a unified time-frequency reference for the platform, and its time keeping performance is the key factor for the efficient linkage and stable work of all components of the platform. Through the analysis and research of frequency reference source optimization and multi-clock integrated time-frequency processing technology, a high-precision time-frequency synthesis and time keeping method is proposed, and a high-precision time-frequency synthesis and time keeping system is designed, through selecting rubidium atomic clock as frequency reference source, atomic time synthesis and control based on multiple rubidium atomic clocks, and real-time cross-comparison of similar sources to select the optimal master clock and the backup master clock, to improve the system's time keeping performance. The feasibility and effectiveness of this method are verified by comparison experiments with the traditional method.
Theory and Discussion
Joint neural network and diagonal loading-based GNSS outage positioning algorithm
LU Dan, GAO Penghua
2024, 49(1): 82-88. doi: 10.12265/j.gnss.2023176
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The GNSS/INS integrated navigation system can provide long-term, high-precision navigation information for mobile carriers. However, in adverse environments where filter measurement vectors cannot be obtained, it leads to rapid divergence in navigation positioning results. To address this issue, an increasing number of researchers are employing artificial neural networks to directly fuse information in the integrated navigation system. However, the inherent characteristics of the inertial navigation system (INS) result in errors in previously trained network models, and inertial navigation errors continue to accumulate during interruption periods. Therefore, an intelligent positioning algorithm for GNSS interruptions is proposed. This algorithm utilizes backpropagation (BP) neural networks to train filter measurement vectors and then updates the Kalman filter (KF) by incorporating diagonal-loaded reconstructed measurement noise covariance matrices. This approach reduces the impact of neural network training errors on the integrated navigation algorithm, enabling the navigation system to maintain relatively reliable navigation performance even during prolonged GNSS signal interruptions.
Analysis of the impact of GNSS observation types on the accuracy of short baseline geodetic height difference
WANG Hengyi, TAN Rongjie, YANG Hanrong, CHEN Hua
2024, 49(1): 89-93. doi: 10.12265/j.gnss.2023109
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Based on observation data from a C-grade network in a city, the impact of four different baseline calculation strategies on the accuracy of geodetic height difference for short baselines is analyzed, which uses different raw observations and ionosphere-free combination. The result shows that it is difficult to evaluate the baseline processing accuracy of different calculation strategies through the analysis of repeated baseline differences. Therefore, external verification of baseline results was carried out through the combination of second-class leveling measurements and a quasi-geoid model. It is found that there is a systematic error of about 2.2 cm in the geodetic height difference in the results of using ionosphere-free combination, while the results of using raw dual-frequency measurements have the highest accuracy which is the best strategy for processing short baselines.
Analysis of the correlation between GNSS PWV and atmospheric particulate matter during dust storms based on PWV difference method
XIE Peng
2024, 49(1): 94-101. doi: 10.12265/j.gnss.2023193
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In response to the dust storm event that occurred in northern China on March 15, 2021, a method based on the precipitable water vapor (PWV) difference (ΔGNSS PWV) is proposed to investigate the correlation between PWV retrieved from Global Navigation Satellite System (GNSS) stations and the concentration of atmospheric particulate matter (PM). Three GNSS stations located in Zhongwei, Ningxia (NXZW), Fangshan, Beijing (BJFS), and Changchun, Jilin (CHAN), along with nearby atmospheric particulate matter concentration data, were selected for analysis. The results indicate that under non-dust storm conditions, the PWV accuracy derived from GNSS calculations is satisfactory, with mean and standard deviation differences from ERA5_PWV both around 2 mm, demonstrating the reliability of the retrieval results. Prior to the occurrence of the dust storm, the correlation between PWV at each station and atmospheric particulate matter concentration is less than 20%, indicating a weak correlation. During the dust storm event, this correlation significantly increases, particularly at BJFS and CHAN stations, where the correlation between PWV and atmospheric particulate matter concentration exceeds 60%. After eliminating phase lag, the correlation at the NXZW station even reaches 70.25%. Further analysis reveals that during the dust storm occurrence, the correlation between ΔGNSS PWV and SUM_PM (PM10+PM2.5) also significantly increases, with correlations exceeding 70% at BJFS and CHAN stations. Comprehensive analysis suggests that during dust storms, the correlation between ΔGNSS PWV and SUM_PM further intensifies, indicating that atmospheric particulate matter contributes significantly more to ΔGNSS PWV than to PWV, highlighting the potential application value of the PWV difference method in monitoring atmospheric particulate matter concentration. Therefore, this study provides a novel research approach and method, laying the foundation for further exploration of the complex interplay between atmospheric particulate matter concentration and meteorological conditions.
Analysis and prediction of BDS-3 satellite differential code bias based on LSTM
LIU Xiaowen
2024, 49(1): 102-107. doi: 10.12265/j.gnss.2023216
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When the satellite differential code bias (DCB) constraints and benchmarks change, there will be a relatively large difference in its value,which affects the accuracy of navigation and positioning. This paper analyzes the time series changes of the BDS-3 satellite DCB in 2021, synthesizes the solar radiation flux and the geomagnetic index,and uses the LSTM neural network to predict and analyze the accuracy of the satellite DCB. The experimental results show that the prediction effect of the LSTM neural network model is better than that of the polynomial fitting method. The mean absolute deviation (MAE) and root mean squared error (RMSE) are less than 0.2 ns and 0.5 ns respectively. The errors of the forecast results for many days in the future are all less than 0.2 ns. LSTM neural network can effectively predict satellite DCB and provide reference for missing DCB products.
Technical Report and Application
Grid network RTK regional accuracy solution
LI Xueqing, CHEN Mingjian
2024, 49(1): 108-113. doi: 10.12265/j.gnss.2023125
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In order to improve the service performance of grid network real-time kinematic (RTK) and eliminate the impact of terrain on positioning accuracy, the paper derived a grid RTK positioning error model with terrain elevation difference based on grid network RTK technology, and selected three regions of plain, transition areas and mountainous areas to carry out grid RTK positioning experiments with different grid densities, analyzed and determined the grid density standards for different terrain. The results show that the higher the density of grid, the higher the positioning accuracy of grid RTK, while under the same grid density, the positioning accuracy of plain, transition areas and mountainous areas decreases step by step due to the impact of terrain elevation difference. When 9'×9', 6'×6' and 3'×3' grids are used in plain, transition areas and mountainous areas, positioning accuracy of 1 cm can be achieved. It can provide the corresponding basis for setting the grid partitioning criterion.
Using signal recording and playback instrument detect the RTK performance of GNSS receiver
HONG Wei, HE Haopeng, PENG Youzhi, WANG Yangjian, SONG Xiao
2024, 49(1): 114-119. doi: 10.12265/j.gnss.2023146
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Owing to various observation environment, the real-time kinematic (RTK) performance of Global Navigation Satellite System (GNSS) receiver has not been reasonably evaluated. Signal recording and playback instrument detecting the RTK performance of GNSS receiver is proposed. The stability of playback signal and diversity with real GNSS signal are studied. The result show the stability of signal recording and playback instrument is less than 1 mm, this reveals that playback signal has high repeatability. Compared with real GNSS signal, the RTK accuracy of receiver detected by signal recording and playback instrument is lower due to the instrument noise, but accuracy error does not exceed 1/3 of the nominal RTK accuracy, signal recording and playback instrument meets the requirements as test instrument. Therefore, it is feasible to utilize signal recording and playback instrument with high stability detect the RTK performance of GNSS receiver. This method can solve the trouble of poor GNSS receiver consistency, owe to various observation environment. signal recording and playback instrument will be instructive for GNSS receiver research, production and detection.
BDS observation data quality and dynamic PPP performance analysis
HE Congcong, WANG Zhongyuan, ZHANG Tan
2024, 49(1): 120-126. doi: 10.12265/j.gnss.2023183
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In order to analyze the global data quality, dynamic precise point positioning (PPP) performance and performance differences of BeiDou Navigation Satellite System (BDS) in different regions, we select the observation data of a total of 9 Multi-GNSS Experiment (MGEX) continuous tracking stations in 3 different region, using GPS as a reference, and from the satellite visibility, pseudo-range multipath effect, data integrity rate and signal-to-noise ratio (SNR), PPP positioning accuracy and other aspects to analyze the data quality and positioning accuracy of BDS in five aspects. The results show that the satellite visibility of BDS has regional differences, and the multipath effect and SNR ratio do not show regional characteristics. The data quality of BDS-3 is better than that of BDS-2, and the data quality of BDS at different frequency points is also significantly different. Difference, poor data quality at B1I frequency points. The dynamic positioning accuracy of BDS is slightly weaker than that of GPS, and multiple systems have a significant effect on improving positioning accuracy.