BeiDou-3 Global Positioning System Officially Initiates Construction

China’s Bei Dou-3 global positioning system has been officially initiated construction with four global networking satel ites to be launched by the end of this year,according to the announcement at the Sixth China Annual Meeting of Satellite Navigation and Location Services in Shenzhen on September 16 and the First Satellite Application International Exposition held.

Relativistic Effects in the Global Positioning System

The Global Positioning System (GPS) uses accurate atomic clocks in satellites and on the ground to provide world-wide position and time determination. These clocks have gravitational and motional frequency shifts which are so large that, without properly accounting for relativistic effects, the system would not work. As a practical matter, therefore, many individuals who use the GPS need to understand how relativistic effects accounted for in the system. This paper discusses relativistic effects arising from both special relativity and general relativity, and how these effects are incorporated in GPS operations. Two introductory sections on kinematics in special and general relativity, respectively, are followed by a section which describes how relativistic effects should be accounted for. The concept of synchroization in the Earth-Centered Inertial frame is discussed in detail. Numerical and experimental examples are given, showing the sizes of the various effects. The treatment of special and general relativity is sufficiently complete that a person should be able to follow the development without much reference to external material, except that a few standard results have been quoted from textbooks without derivation.

Modeling of Selective Availability for Global Positioning System

To degrade location accuracy for unauthorized GPS users, US government applied Selective Availability (SA) to Global Positioning System (GPS). In this paper we discuss an anti-SAapproach to improve location accuracy which is very important in landing position, and then we derived the SA error by eliminating almost all other errors including ionospheric and tropospheric timedelays and clock errors both in satellites and in receiver, etc. By means of the system identificationtheory, an SA errorl all SA error model with the second-order Gauss-Maukov stochastic process wasderived and simulated. With the selected parameters of the stochastic process) the simulation resultsshow that there is the excellent agreement between the simulated SA error model and that of reallyapplied in GPS system.

Vehicle Ego-Localization Based on Streetscape Image Database Under Blind Area of Global Positioning System

Vehicle positioning is critical for inter-vehicle communication, navigation, vehicle monitoring and tracking. They are regarded as the core technology ensuring safety in everyday-driving. This paper proposes an enhanced vehicle ego-localization method based on streetscape image database. It is most useful in the global positioning system(GPS) blind area. Firstly, a database is built by collecting streetscape images, extracting dominant color feature and detecting speeded up robust feature(SURF) points. Secondly, an image that the vehicle shoots at one point is analyzed to find a matching image in the database by dynamic programming(DP)matching. According to the image similarity, several images with higher probabilities are selected to realize coarse positioning. Finally, different weights are set to the coordinates of the shooting location with the maximum similarity and its 8 neighborhoods according to the number of matching points, and then interpolating calculation is applied to complete accurate positioning. Experimental results show that the accuracy of this study is less than 1.5 m and its running time is about 3.6 s. These are basically in line with the practical need. The described system has an advantage of low cost, high reliability and strong resistance to signal interference, so it has a better practical value as compared with visual odometry(VO) and radio frequency identification(RFID) based approach for vehicle positioning in the case of GPS not working.

Applying Global Positioning System Real-Time Kinematic Technology to Collection and Analysis of Rowing Information

To obtain higher accuracy of information concerning boat motion, the use of global positioning system (GPS) real-time kinematic (RTK) technology was investigated. Through RTK technology, a measurement precision of the ±1 cm range can be achieved. The research equipment included a GPS receiver and a personal digital assistant as a data control and processing unit. Real-time GPS data was captured and processed to acquire various parameters, including the boat track, velocity curve, stroke rate, and stroke distance. Using this data, the quantitative information related to rowing training can be achieved. The results are helpful for analyzing the biomechanical parameters of rowing techniques and for evaluating training efficiency.

Absolute and relative sea-level rise in the New York City area by measurements from tide gauges and satellite global positioning system

The absolute and relative rates of rise of the sea level are computed for the New York City area by coupling global positioning system records of the position of fixed domes nearby tide gauges,with the tide gauges’records.Two tide gauges are considered,one long-term trend,more reliable,The Battery,in lower Manhattan,and one shorter,less reliable,Sandy Hook,in New Jersey.The relative rates of rise of the sea level are+2.851 and+4.076 mm/yr.The subsidence rates are-2.151 and-3.076 mm/yr.The absolute rates of rise of the sea level are+0.7 and+1.0 mm/yr.The relative sea-level acceleration,reliable only in The Battery,is about+0.008 mm/yr².This acceleration is about the same as the world average long-term trend tide gauge,as well as the average long-term trend tide gauge of the East Coast of North America.The absolute rate of rise of the sea level by 2050 in the lower Manhattan area will be likely less than 30 mm,and the absolute rate of rise of the sea level by 2100 likely less than 80 mm.The relative rate of rise of the sea level by 2050 in the Manhattan area will be likely 85 mm,and the relative rate of rise of the sea level by 2100 likely 228 mm,because of the overwhelming subsidence contribution.

Locating Global System for Mobile Communication(GSM)Base Stations Using Geographic Information System(GIS)

The global system for mobile communication(GSM)is planned to meet the needs of the whole subscribers.The number of subscribers increased as the population increased due to the acceptance of GSM services by the subscribers.Thus,there should be a way to monitor base stations that will meet the increasing demand of subscribers in any area as a population surge will lead to more subscriptions.This will allow GSM network operators to serve their subscribers better and ease network congestion.This work presents a review of mobile evolution from the first generation to the fifth generation.A review of global positioning system(GPS)technology and its applications to geographic information systems(GIS)was done.The coordinates of these base stations were taken using a GPS device.These base station coordinates were then exported to QGIS for the design of the map.Thereafter,the output map was then integrated into the website.The discussions on the results followed and some useful suggestions given will go a long way to help the operators of GSM in Nigeria and in general.If the propositions given are adhered to,it will go a long way to help the operators reduce congestion on their network and thereby increase the satisfaction of the subscribers.

Cycle slip detection approach based on time-relative positioning theory

An efficient cycle slip detection method is proposed for high precision positioning and navigation results with global positioning system （GPS）,which is based on the assumption of a high sampling interval, measurement errors are so small that they can be ignored in the temporal single difference observables. And ambiguities are ordinarily equal to zero,but could be the number of cycles that have ＂slipped＂ if loss-of-lock has occurred.Therefore,cycle slips are estimated as parameters of time-relative positioning observation equations.Because the temporal single difference observables are taken at different epochs and different stations with a single GPS receiver,if time-relative positioning observation equations are linearized as that of conventional relative positioning,the design matrix will be rank defective.To obtain a stable linearization scheme,time-relative positioning observation equations are further analyzed,and the concept of virtual measurement is applied.A sample of data collected on a vehicle test shows that a cycle slip detection approach based on time-relative positioning theory can detect slips at the value of one cycle.The results also indicate if two satellites are so near to each other that they have the same equivalent to satellite-receiver geometry,cycle slip detection will be difficult and may get wrong results.Cycle slips of different satellites also affect detection by satellite-receiver geometry.

Slip rate and interseismic coupling along the Moxi-Shimian segment of the Xianshuihe fault, Eastern Qinghai-Xizang Plateau

On September 5,2022,the Luding M6.8 earthquake occurred in the Moxi-Shimian segment of the Xianshuihe fault,coinciding with the historical ruptured zone of the 1786 Moxi earthquake.Its seis-mogenic environment provides a foundation for comprehending the mechanism of the earthquake and its future hazard.In the Moxi-Shimian segment,we establish a series of near-field Global Navigation Satellite Systems(GNsS)stations to enhance the spatial resolution of observational data for the inversion of the interseismic kinematic parameters.In this study,with an elastic screw dislocation model con-strained by GNsS observations,the slip rate of the Moxi-Shimian segment is estimated to be 10.9±1.0 mm/yr,while the locking depth is 15.7±6.2 km.Additionally,we utilize a block-dislocation model to invert the interseismic fault coupling along the Kangding-Moxi-Shimian segment.The result indicates a gradual deepening of the locking depth along the section from Kangding to Shimian.The coseismic rupture of the 2022 event occurred within the high coupling regions in the Kangding-Moxi-Shimian segment,which indicates that the rupture kinematics in this event might be controlled by the interseismic deformation.The seismic moment accumulated within the ruptured zone of the Luding earthquake since 1786 ranges in[1.42-3.40]×10^(19) N-m,which is significantly greater than the seismic moment released during the 2022 event.As a result,we infer that the Luding earthquake released only a portion of the accumulated energy within the original rupture zone since 1786,indicating that the 2022 event has not caused a complete rupture in the Moxi-Shimian segment.Consequently,there remains a substantial seismic hazard in this area.

A three-dimensional positioning method based on three satellites

A three-dimensional positioning method for global positioning system(GPS)receivers based on three satellites was proposed.In the method,the measurement equation used for positioning calculation was expanded by means of two measures.In this case,the measurement equation could be solved,and the function of positioning calculation could be performed.The detailed steps of the method and how to evaluate the positioning precision of the method were given,respectively.The positioning performance of the method was demonstrated through some experiments.It is shown that the method can provide the three-dimensional positioning information under the condition that there are only three useful satellites.

A GPS/BDS dual-mode positioning algorithm for a train based on CIPSO_EKF

When using global positioning system/BeiDou navigation satellite(GPS/BDS)dual-mode navigation system to locate a train,Kalman filter that is used to calculate train position has to be adjusted according to the features of the dual-mode observation.Due to multipath effect,positioning accuracy of present Kalman filter algorithm is really low.To solve this problem,a chaotic immune-vaccine particle swarm optimization_extended Kalman filter(CIPSO_EKF)algorithm is proposed to improve the output accuracy of the Kalman filter.By chaotic mapping and immunization,the particle swarm algorithm is first optimized,and then the optimized particle swarm algorithm is used to optimize the observation error covariance matrix.The optimal parameters are provided to the EKF,which can effectively reduce the impact of the observation value oscillation caused by multipath effect on positioning accuracy.At the same time,the train positioning results of EKF and CIPSO_EKF algorithms are compared.The eastward position errors and velocity errors show that CIPSO_EKF algorithm has faster convergence speed and higher real-time performance,which can effectively suppress interference and improve positioning accuracy.

RESEARCH ON THE METHODS OF IMPROVING DGPS POSITIONING PRECISION

A DGPS positioning model is described, and the elements that influence DGPS positioning precision are analyzed in detail. On this basis, the methods of improving DGPS positioning precision are proposed which include increasing updating rate of DGPS correction, building extended DGPS system and improving quality of DGPS correction signal. In the intelligent monitor and control system of the public transport in Beijing, these methods improve the vehicle positioning precision to 2～5m.

Remote positioning system based on GPS/GPRS

Considering the need of target positioning,a remote positioning system is designed based on global positioning system(GPS)and general packet radio service(GPRS);The data collection terminal is based on microcontroller unit(MCU)PIC24FV301.It uses GPRS network to create wireless link and transmits GPS source information which is collected by LEA-5H board to monitor center on the Internet.The monitor center obtains the target information through processing and analysis of the calculated data.Actual operation results indicate that the designed system has excellent performance and achieves the goal of the remote location.

GPS观测得的2023年2月土耳其双震前后的地壳形变

2023年2月6日土耳其发生7.8级双震,相隔仅9小时、相距近,都是近直立断层走滑型地震,是利用GPS观测研究地震前后地壳形变稀有震例。利用美国网站得到131个GPS站欧亚(板块)参考框架位移数据,分析了2次地震前后的地壳形变。同震水平位移是分析大地震前兆地壳运动的关键现象。GPS分别观测得的2次地震同震位移,特征显著:水平位移最大达4.4 m;向西、向东和向南水平位移3个分区明显,与区域内3个板块构造运动密切相关;而垂直位移较小,无明显分区。2次地震前震中附近的水平位移分别出现(第一次地震)峰值和(第二次地震)闭锁2种类型,但无明显的垂直位移积累。与其他震例一样,在震前两种类型的水平位移区域,同震水平位移是震前位移在时间或空间上的(弹性)回跳,表明大地震有前兆形变。2次地震重合的孕震区内,有对2次地震同震水平位移影响相近的区域。GPS观测明确显示,地壳水平运动是2次大地震的成因。尽管观测不足和未能预报2次地震,但仍突显GNSS可在地震监测、预警和地震预测中发挥作用的优势。

Analysis of Geo Positioning System Using RF &DA

Indoor positioning systems (IPSs) have been intended to provide position information of persons and devices. Higher user percentage of handheld devices such as tablets or mobile phones had led to the development of a number of indoor positioning systems. In this research a work on a real time portable RFID indoor positioning device such as on smartphone will be performed. The personal networks will be designed to meet the users’ needs and interconnect users’ devices equipped with different communications technologies in various places to form one network for better result. Radio frequency identification (RFID) with directional antenna has proved its potential for locating objects in indoor environment. Hence, the proposed device idea will be used to exploit various unknown locations in an indoor environment such as college campus;this interpretation will rely on Wireless LAN, Received Signal Strength values from Access Points (AP) in specific mentioned arenas;these APs will be monitored constantly by RFID with directional antenna (DA) and handheld devices. For obtaining the better results from existing devices, algorithms of Range Estimation are proposed, which can be used on various handheld devices for locating indoor objects.

Analysis of RFID Based Positioning Technique Using Received Signal Strength and Directional Antenna

Automatic robot navigation is being utilized in many industries for the purpose of high speed work delivery. Color follower, fix path follower robots are current solution to this activities but dynamic path configuration is not possible in these robots. Hence new system proposes effective and fully dynamic path follower robots using RFID and directional antenna. Radio Frequency Identification (RFID) system permits automatic identification of objects with RFID tags using radio waves which have been widely used in mobile robot navigation, localization and mapping both in indoor and outdoor environment. This article presents a navigation strategy for autonomous mobile robot using passive RFID system. Proposed robot system is provided with RFID tag functionality which will load tag number and direction instruction. At some turning point, user will put RF tag, this tag will be read by RF reader which is placed on robot. As per direction instruction robot will change the direction and reach to the destination. Also as per the movement, robot will send its GPS location to PC (Personal Computer) which will be displayed on PC. Hence main goal is to provide more reliable and low energy consumption based indoor positioning system which will be achieved using directional antenna.

Influential nodes identification in complex networks based on global and local information

Identifying influential nodes in complex networks is essential for network robust and stability,such as viral marketing and information control.Various methods have been proposed to define the influence of nodes.In this paper,we comprehensively consider the global position and local structure to identify influential nodes.The number of iterations in the process of k-shell decomposition is taken into consideration,and the improved k-shell decomposition is then put forward.The improved k-shell decomposition and degree of target node are taken as the benchmark centrality,in addition,as is well known,the effect between node pairs is inversely proportional to the shortest path length between two nodes,and then we also consider the effect of neighbors on target node.To evaluate the performance of the proposed method,susceptible-infected(SI)model is adopted to simulate the spreading process in four real networks,and the experimental results show that the proposed method has obvious advantages over classical centrality measures in identifying influential nodes.

Spatial Interaction Between the Industrial Undertaking Capacity and Global Value Chain Position of East Asian Countries

A comprehensive understanding of the spatial interaction between the industrial undertaking capability and the position of the global value chain of the 12 East Asian countries is conducive to strengthening regional cooperation, gaining a say in foreign trade and becoming the dominant player in the global division of labor system. The article reveals the operating rules of the interaction between the industrial undertaking capacity and the global value chain position of East Asian countries by calculating the Global Moran Index(Moran’s I), coupling coordination degree and other indicators. The results show that: in time, the values of industrial undertaking capacity and the positions of global value chain in East Asian countries showed a sustained and stable growth trend, and have a consistent trend of change. Spatially, both of the two indexes had significant positive spatial correlation, with Moran’s I showing an ‘inverted U’pattern, and the spatial aggregation distribution of global value chain position lagged behind the spatial aggregation distribution of industrial undertaking capacity by one year. In terms of spatial coupling coordination, the coupling coordination values of the two indicators show a steady upward trend. Combined with the comparative advantage of each country, this paper provides suggestions for promoting the positions of Chinese and other East Asian industries in the global value chain from the perspectives of enhancing independent innovation capability and upgrading industrial structure.

Calibration of GNSS positioning receivers

Nowadays global navigation satellite system(GNSS)receivers are the primary tool not only for precision surveying but also for geodesy,geophysics and many other industrial applications worldwide.The only way to assure the accuracy,universality and longevity of GNSS measurements is by calibration of its receivers.The parameters affecting the calibration accuracy of a single GNSS receiver are discussed in this paper.And a geodetic basepoint is established according to previous empirical studies to serve as a reference for calibration.Additionally,the traceability to the systeme international(SI)unit of such kind of calibrations is discussed.Stability of the base point is also verified through long-term measurements over three years.Eventually,a calibration of a sample single GNSS receiver is performed and the uncertainty budget is derived.

Comparison of Accuracy of Two Global DEMs, and the Extracted DEM from the Topographic Map of the Tafilah Governorate

SRTM DEM （shuttle radar topographic mission digital elevation model） and ASTEMR DEM （advanced space-borne thermal emission and reflection radiometer digital elevation model） are now freely available in two resolutions： 90 m and 30 m. DEM is a computerized representation of the Earth＇s relief, and is used in many applications such as hydrology, climatology, geomorphology and ecology. There are some important differences in assessing the accuracy of digital elevation models for specific applications. The purpose of this study is to investigate the errors in digital elevation models obtained globally from DEMs 90 m, 30 m ground resolution, and the extracted DEM from a topographic map by digitized contour lines of 1：50,000 scale in a rugged mountainous region and a heterogeneous landscape, using KS （kernel smoothing） interpolation method. For validation purposes, datasets of 250-GCPs （ground control points） distributed over the study area were used to evaluate and compare the accuracy of the two global Dems and the DEM extracted from TM. The main results showed that the 30 m resolution global （DEM） is the most accurate one among the three. According to the validation results, SRTM with maximum （＋） and minimum （-） error elevation is -10_9. M, with mean deviation of KS is -0.00238667, and RMS （root-mean-square） error of 0.98, and currently the most accurate model is 30 m DEM of the study area with no significant differences compared with DEM 90 m.