scholarly journals Accuracy Assessment of the Network Real-Time Kinematic Techniques for Geodetic and Plane Coordinates

2021 ◽  
Vol 16 ◽  
pp. 1-15
Author(s):  
Ami Hassan Md Din ◽  
Nur Adawiyyah Maziyyah Abu Bakar ◽  
Nur Adilla Zulkifli ◽  
Muhammad Asyran Che Amat ◽  
Mohammad Hanif Hamden
Keyword(s):  
Real Time ◽  
Accuracy Assessment ◽  
Reference Station ◽  
Baseline Length ◽  
Virtual Reference ◽  
Accuracy Measurement ◽  
Geodetic Coordinates ◽  
Real Time Kinematic ◽  
Gnss Network ◽  
High Accuracy Measurement

Virtual Reference Station (VRS), Master-Auxiliary Corrections (MAX) and Individualised Master-Auxiliary Corrections (IMAX) are among the Network Real-Time Kinematic (NRTK) techniques supported by Malaysia Real-Time Kinematic GNSS Network (MyRTKnet) in rendering network-based solution to users. However, different network corrections have different limitations due to different manufacturers hence offering varieties output. Therefore, this study was conducted to assess the accuracy of VRS, MAX and IMAX for geodetic and plane coordinates. Three (3) techniques were implemented to observe points at Universiti Teknologi Malaysia (UTM) and cadastral lot in Johor Bahru. The results were analysed based on assessment with known values and baseline lengths. The findings showed that the accuracy of all techniques ranged from 0.16 to 3.61 cm (horizontal) and 2.86 to 6.20 cm (vertical) for geodetic coordinates. For plane coordinates, the values varied from 0.3 to 4.22 cm (horizontal) and 2.1 to 8.26 cm (vertical). IMAX provided the worst accuracy compared to others due to incompatibility of Radio Technical Commission for Maritime Services (RTCM) format. Moreover, the accuracy decreases as the baseline length between rover and reference station increases. In conclusion, VRS and MAX yielded acceptable accuracy and can be safely chosen rather than IMAX. Furthermore, the baseline length for applications involving high accuracy measurement should also be considered.

scholarly journals Algorithms for Sparse Network-based RTK GPS Positioning and Performance Assessment

2013 ◽  
Vol 66 (3) ◽  
pp. 335-348 ◽  
Author(s):  
Weiming Tang ◽  
Xiaolin Meng ◽  
Chuang Shi ◽  
Jingnan Liu
Keyword(s):  
Real Time ◽  
Long Range ◽  
Ambiguity Resolution ◽  
Reference Station ◽  
Baseline Length ◽  
Sparse Network ◽  
Network Rtk ◽  
Real Time Kinematic ◽  
Wide Lane ◽  
Time Required

The average inter-station distances in most established network Real Time Kinematic (RTK) systems are constrained to around 50 km. A sparse network RTK system with an average inter-station distance of up to 300 km would have many appealing advantages over a conventional one, including a significant reduction in the development and maintenance costs. The first part of this paper introduces the key approaches for sparse network RTK positioning technology. These include long-range reference baseline ambiguity resolution and real-time kinematic ambiguity resolution for the rover receivers. The proposed method for long-range kinematic ambiguity resolution can overcome the network weaknesses through three procedures: application of the interpolated corrections from the sparse network only to wide-lane combination; searching the ambiguities of wide-lane combination; and searching L1 ambiguities with wide-lane combination and ionosphere-free observables. To test these techniques, a network including ten reference stations was created from the Ordnance Survey's Network (OS NetTM) that covers the whole territory of the United Kingdom (UK). The average baseline length of this sparse network is about 300 km. To assess the positioning performance, nine rover stations situated inside and outside the network were also selected from the OS Net™. Finally, the accuracy of interpolated corrections, the positioning accuracy and the initialization time required for precise positioning were estimated and analysed. From the observed performance of each rover receiver, and the accuracy of interpolated network corrections, it can be concluded that it is feasible to use a sparse reference station network with an average inter-station distance up to 300 km for achieving similar performance to traditional network RTK positioning. The proposed approach can provide more cost-efficient use of network RTK (NRTK) positioning for engineering and environmental applications that are currently being delivered by traditional network RTK positioning technology.

scholarly journals Investigation of accurate method in 3-D position using Cors-Net in Istanbul

2012 ◽  
Vol 18 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Kutalmis Gumus ◽  
Cahit Tagi Celik ◽  
Halil Erkaya
Keyword(s):  
Real Time ◽  
Conventional Method ◽  
Global Positioning System ◽  
Complex Structure ◽  
Accurate Method ◽  
Reference Station ◽  
Positioning System ◽  
Virtual Reference ◽  
Global Positioning ◽  
Set Up

In this study, for Istanbul, there are two Cors Networks (Cors-TR, Iski Cors) providing Virtual Reference Station (VRS), and Flachen Korrektur Parameter (FKP), corrections to rover receiver for determining 3-D positions in real time by Global Positioning System (GPS). To determine which method (or technique) provides accurate method for position fixing, a test network consisting of 49 stations was set up in Yildiz Technical University Davudpasa Campus. The coordinates of the stations in the test network were determined by conventional geodetic, classical RTK, VRS and FKP methods serviced by both Cors-TR and Iski Cors. The results were compared to the coordinates by the conventional method by using total station. The results showed a complex structure as the accuracy differs from one component to another such as in horizontal coordinates, Y components by CorsTR_VRS and Cors_TR_ FKP showed 'best' results while the same technique provided X components consistent accuracy with the Y component but less accurate than by real time kinematic (RTK). In vertical components, of all the techniques used for the h components, CorsTR_VRS showed 'best' accuracy with three outliers.

scholarly journals Posicionamento GNSS em Tempo Real: Evolução, Aplicações Práticas e Perspectivas para o Futuro

2020 ◽  
Vol 72 ◽  
pp. 1359-1379
Author(s):  
Claudia Pereira Krueger ◽  
Paulo Sérgio de Oliveira Junior ◽  
Silvio Jacks dos Anjos Garnés ◽  
Daniele Barroca Marra Alves ◽  
Jorge Felipe Euriques
Keyword(s):  
Real Time ◽  
Global Positioning System ◽  
Precise Point Positioning ◽  
Reference Station ◽  
Space Representation ◽  
Positioning System ◽  
Differential Gps ◽  
Virtual Reference ◽  
State Space Representation ◽  
Global Positioning

O posicionamento em tempo real por meio do emprego dos sinais de satélites foi um avanço nas navegações aérea, marítima e terrestre com o surgimento do GPS (Global Positioning System). Contudo as precisões horizontais e verticais de 100 m e 150 m (nível de probabilidade de 95%) alcançadas, estando a SA (Selective Availability) ativada, passaram a não ser satisfatórias para muitas aplicações e os usuários buscaram galgar outros níveis de precisões. Esforços foram investidos no chamado posicionamento diferencial DGPS (Differential GPS), o qual possibilitou obter precisões em torno de dez vezes melhores do que as do posicionamento absoluto.  Posteriormente, usando-se a fase da onda portadora, conseguiu-se realizar posicionamento com maior acurácia por meio do método RTK (Real Time Kinematic), atingindo qualidade centimétrica. Na sequência, houve uma evolução para posicionamentos em rede, empregando, por exemplo, o algoritmo de VRS (Virtual Reference Station). Vários erros nas observáveis dos satélites passaram a ser modelados com uma solução de multiestações em tempo real. A partir de 2012, surgiram serviços e produtos que favoreceram o desenvolvimento do RT-PPP (Real-Time Precise Point Positioning) baseado no conceito SSR (State Space Representation). A busca da solução das ambiguidades no RT-PPP deu origem ao PPP-RTK com menor tempo de fixação das ambiguidades e convergência para a solução acurada do posicionamento. Neste artigo apresenta-se como foi a evolução do posicionamento em tempo real, algumas das aplicações no âmbito nacional e as perspectivas  desta modalidade de posicionamento para o futuro.

Error Analysis Based on Multi-Base Station Network VRS Technology

2011 ◽  
Vol 186 ◽  
pp. 358-362
Author(s):  
Hong He ◽  
Hai Ping Fang ◽  
Hang Li ◽  
Da Jian Zhang ◽  
Ming Feng Hou
Keyword(s):  
Base Station ◽  
Reference Station ◽  
Baseline Length ◽  
Differential Gps ◽  
Virtual Reference ◽  
The Public ◽  
Existing Problems ◽  
Long Baseline ◽  
Subscriber Station ◽  
The Difference

The existing problems of conventional RTK in actual applications specifically show that the difference technology can only eliminate the public error between base station and subscriber station under certain conditions, with the increases of baseline length (more than 20 km), the correlation of errors between tropospheric and ionospheric weakened or even disappeared, making differential GPS technology lose its theoretical foundation, the experimental analysis shows that in network RTK, the Virtual Reference Station RTK technology enables VRS technology the effective distance from the 15 km extended to 50 km or more, greatly enhance the relative positioning accuracy in medium- baseline and long-baseline (20~50km).

scholarly journals First Brazilian Real Time Network DGPS through the Internet: Development, Application and Availability Analyses

2012 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. Alves ◽  
L. Dalbelo ◽  
J. Monico ◽  
M. Shimabukuro
Keyword(s):  
Real Time ◽  
Reference Station ◽  
The Internet ◽  
Atmospheric Effects ◽  
Differential Gps ◽  
Global Positioning ◽  
Gnss Network ◽  
Internet Development ◽  
Development Application

First Brazilian Real Time Network DGPS through the Internet: Development, Application and Availability AnalysesThe Global Positioning System (GPS) is widely used by the civil community. Differential GPS (DGPS) was developed to provide better accuracy than autonomous GPS. The DGPS concept is based on the high correlation of errors due to atmospheric effects, satellite clocks and orbits. However, as the baseline grows, its efficiency decreases because the error correlation is reduced. This limitation can be handled by using a reference station network and applying the network DGPS concept (called NDGPS). In this paper, the goal is to present aspects related to the development and application of NDGPS in real time at the São Paulo state network in Brazil. The NDGPS corrections were computed from data received via the Internet using NTRIP (Networked Transport of RTCM via Internet Protocol). Our implementation was based on BNC (BKG Ntrip Client) software. NDGPS provided RMS improvements of up to 59% in horizontal components and 31% in vertical components when compared to DGPS. The availability of the system, the first of this nature in Brazil, was also analyzed within the context of the SP State GNSS Network, located in the southeastern region of Brazil. The results also serve as an indication of the quality of local internet infrastructure for using in geodetic positioning.

scholarly journals FEASIBILITY VERIFICATION OF VIRTUAL REFERENCE STATION TECHNOLOGY IN GEOLOGICAL HAZARD MONITORING

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 235-240
Author(s):  
Q. Zhang ◽  
M. Chen ◽  
J. Wu ◽  
C. Xu ◽  
F. Wang
Keyword(s):  
Real Time ◽  
Early Warning ◽  
Reference Station ◽  
Geological Hazard ◽  
Virtual Reference ◽  
Geological Disaster ◽  
Calculation Results ◽  
Disaster Monitoring ◽  
Monitoring And Early Warning ◽  
Better Than

Abstract. The surveying and mapping administrative competent departments in 31 provinces (autonomous regions and municipalities) have built provincial-level satellite navigation and positioning reference stations and data centers, and provided CORS services. This provides a good condition for exploring the application of geological hazard monitoring and early warning using Virtual Reference Station (VRS) service based on CORS. At present, the layout mode of "one point one reference station" is usually adopted, when GNSS is used for geological disaster monitoring and early warning. However, the high deployment cost of this plan limits its largescale promotion and application. Using the existing CORS service resources of natural resource system, this paper carried out the application experiment of virtual reference station in geological hazard monitoring application at Huanglongya geological hazard monitoring site in Shaanxi Province, and assessed the virtual reference station data quality, comparative analyzed the precision of static baseline processing results and GNSS real-time deformation monitoring results. The experimental results show that the overall quality of virtual reference station data is better than that of the monitoring station, and the accuracy of the static baseline calculation results is better than 1.0cm in the X direction, and better than 2.0cm in the Y direction and Z direction, which is similar to the static baseline calculation results formed by the physical reference station. The accuracy of the baseline results of real-time observation data calculation is better than 5mm in horizontal RMS and 15mm in vertical RMS. Therefore, it can be seen that the virtual reference station is feasible to be used as the reference station for geological disaster monitoring. In addition, the application experiment of network RTK real-time dynamic single epoch positioning mode is also carried out in geological hazard monitoring. The experimental results show that the RMS values of all three directions are ±3.7mm, ±9.2mm and ±5.0mm respectively, which meet the precision requirements of GNSS disaster monitoring. Therefore, it is also a feasible scheme for geological disaster monitoring and early warning.

scholarly journals Evaluation of Virtual Reference Station Constraints for GNSS Tropospheric Tomography in Austria Region

2019 ◽  
Vol 50 ◽  
pp. 39-48 ◽  
Author(s):  
Zohreh Adavi ◽  
Robert Weber
Keyword(s):  
Unique Solution ◽  
Weather Forecasting ◽  
Weather Forecast ◽  
Reference Station ◽  
Virtual Reference ◽  
Area Of Interest ◽  
Pass Through ◽  
Gnss Network ◽  
The Impact

Abstract. One of the most promising methods of GNSS meteorology is GNSS Tomography. This method can be used for the determination of water vapor distribution, which contributes to the reliability of weather forecasting and early warning of severe weather. Therefore, GNSS Tomography is a valuable source of information for meteorological and weather forecast. The system of equations of this problem is mixed-determined because propagated signals do not pass through some of the model elements within the area of interest. Consequently, the normal matrix is close to singular without any unique solution. To avoid singularity and achieve a unique solution, additional sources or horizontal and/or vertical constraints are usually applied. Here, three schemes have been considered for remedying the rank deficiency of the problem. In the first scheme, minimum horizontal and vertical constraints were imposed on the system of observation equations. Then, we have defined three schemes to evaluate the impact of Virtual Reference Stations (VRS) in comparison to horizontal and vertical constraints in the sparse GNSS network. Within a network of Austrian GNSS reference stations these schemes have been analyzed and validated with available radiosonde profiles for the period DoY 245–256 in 2017. According to our results, the consistency of the estimated refractivity field with radiosonde profiles in the dense GNSS network was generally better (RMSE 2.80 ppm) than for the two other schemes in the period of interest. Moreover, in the sparse GNSS network, the average of RMSE for schemes with VRS stations and constraints equation was about 3.02 and 3.27 ppm, respectively. Hence, the obtained results illustrate that applying VRS stations in the sparse GNSS network can lead to a better solution in comparison to applying horizontal and vertical constraints.

Comparison between multi-constellation ambiguity-fixed PPP and RTK for maritime precise navigation

2015 ◽  
Vol 9 (2) ◽  
Author(s):  
Javier Tegedor ◽  
Xianglin Liu ◽  
Ole Ørpen ◽  
Niels Treffers ◽  
Matthew Goode ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Real Time ◽  
Carrier Phase ◽  
Precise Point Positioning ◽  
High Accuracy ◽  
Reference Station ◽  
Satellite Systems ◽  
Real Time Kinematic ◽  
Gnss Data ◽  
Long Baselines

AbstractIn order to achieve high-accuracy positioning, either Real-Time Kinematic (RTK) or Precise Point Positioning (PPP) techniques can be used. While RTK normally delivers higher accuracy with shorter convergence times, PPP has been an attractive technology for maritime applications, as it delivers uniform positioning performance without the direct need of a nearby reference station. Traditional PPP has been based on ambiguity-­float solutions using GPS and Glonass constellations. However, the addition of new satellite systems, such as Galileo and BeiDou, and the possibility of fixing integer carrier-phase ambiguities (PPP-AR) allow to increase PPP accuracy. In this article, a performance assessment has been done between RTK, PPP and PPP-AR, using GNSS data collected from two antennas installed on a ferry navigating in Oslo (Norway). RTK solutions have been generated using short, medium and long baselines (up to 290 km). For the generation of PPP-AR solutions, Uncalibrated Hardware Delays (UHDs) for GPS, Galileo and BeiDou have been estimated using reference stations in Oslo and Onsala. The performance of RTK and multi-­constellation PPP and PPP-AR are presented.

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