Field evaluation of GNSS/GPS based RTK, RTN, and RTX correction systems

Correction System

This Coastal and Hydraulic Engineering Technical Note (CHETN) details an evaluation of three Global Navigation Satellite System (GNSS)/Global Positioning System (GPS) real-time correction methods capable of providing centimeter-level positioning. Internet and satellite-delivered correction systems, Real Time Network (RTN) and Real Time eXtended (RTX), respectively, are compared to a traditional ground-based two-way radio transmission correction system, generally referred to as Local RTK, or simply RTK. Results from this study will provide prospective users background information on each of these positioning systems and comparisons of their respective accuracies during in field operations.

Covariance Analysis of Real-Time Precise GPS Orbit Estimated from Double-Differenced Carrier Phase Observations

Remote Sensing ◽

10.3390/rs11192271 ◽

2019 ◽

Vol 11 (19) ◽

pp. 2271 ◽

Cited By ~ 1

Author(s):

Sunkyoung Yu ◽

Donguk Kim ◽

Junesol Song ◽

Changdon Kee

Keyword(s):

Fault Detection ◽

Real Time ◽

Global Positioning System ◽

Carrier Phase ◽

Satellite System ◽

Additional Parameter ◽

Global Positioning ◽

Correlation Information ◽

Orbit Errors

The covariance of real-time global positioning system (GPS) orbits has been drawing attention in various fields such as user integrity, navigation performance improvement, and fault detection. The international global navigation satellite system (GNSS) service (IGS) provides real-time orbit standard deviations without correlations between the axes. However, without correlation information, the provided covariance cannot assure the performance of the orbit product, which would, in turn, causes significant problems in fault detection and user integrity. Therefore, we studied real-time GPS orbit covariance characteristics along various coordinates to effectively provide conservative covariance. To this end, the covariance and precise orbits are estimated by means of an extended Kalman filter using double-differenced carrier phase observations of 61 IGS reference stations. Furthermore, we propose a new method for providing covariance to minimize loss of correlation. The method adopted by the IGS, which neglects correlation, requires 4.5 times the size of the covariance to bind orbit errors. By comparison, our proposed method reduces this size from 4.5 to 1.3 using only one additional parameter. In conclusion, the proposed method effectively provides covariance to users.

Urban Fleet Monitoring with GPS and GLONASS

Journal of Navigation ◽

10.1017/s0373463398007929 ◽

1998 ◽

Vol 51 (3) ◽

pp. 382-393 ◽

Cited By ~ 14

Author(s):

M. Tsakiri ◽

M. Stewart ◽

T. Forward ◽

D. Sandison ◽

J. Walker

Keyword(s):

Global Positioning System ◽

Public Transport ◽

Urban Areas ◽

Dead Reckoning ◽

Satellite System ◽

Basic Function ◽

Positioning System ◽

Positioning Systems ◽

Global Positioning ◽

The increasing volume of traffic in urban areas has resulted in steady growth of the mean driving time on fixed routes. Longer driving times lead to significantly higher transportation costs, particularly for vehicle fleets, where efficiency in the distribution of their transport tasks is important in staying competitive in the market. For bus fleets, the optimal control and command of the vehicles is, as well as the economic requirements, a basic function of their general mission. The Global Positioning System (GPS) allows reliable and accurate positioning of public transport vehicles except within the physical limitations imposed by built-up city ‘urban canyons’. With a view to the next generation of satellite positioning systems for public transport fleet management, this paper highlights the limitations imposed on current GPS systems operating in the urban canyon. The capabilities of a future positioning system operating in this type of environment are discussed. It is suggested that such a system could comprise receivers capable of integrating the Global Positioning System (GPS) and the Russian equivalent, the Global Navigation Satellite System (GLONASS), and relatively cheap dead-reckoning sensors.

Assessment of the Positioning Accuracy of DGPS and EGNOS Systems in the Bay of Gdansk using Maritime Dynamic Measurements

Journal of Navigation ◽

10.1017/s0373463318000838 ◽

2018 ◽

Vol 72 (3) ◽

pp. 575-587 ◽

Cited By ~ 20

Author(s):

Cezary Specht ◽

Jan Pawelski ◽

Leszek Smolarek ◽

Mariusz Specht ◽

Pawel Dabrowski

Keyword(s):

Satellite System ◽

Main Task ◽

Dynamic Measurements ◽

Positioning Accuracy ◽

Positioning Systems ◽

Global Positioning ◽

Measurement Session ◽

Gnss Network ◽

Marine Navigation

Differential Global Positioning Systems (DGPS) and the European Geostationary Navigation Overlay Service (EGNOS) are included in a group of supporting systems (Ground-Based Augmentation System (GBAS)/Space-Based Augmentation System (SBAS)) for the American GPS. Their main task is to ensure better positioning characteristics (accuracy, reliability, continuity and availability) compared to GPS. Therefore, they are widely applied wherever GPS failures affect human safety, mainly in aviation, land and marine navigation. The aim of this paper is to assess the predictable positioning accuracy of DGPS and EGNOS receivers using a vessel manoeuvring in the Bay of Gdansk. Two receivers were used in the study: a Simrad MXB5 (DGPS) and a Trimble GA530 (EGNOS), which were simultaneously recording their coordinates. The obtained values were compared with the trajectory computed using a geodetic Global Navigation Satellite System (GNSS) receiver (Trimble R10) connected to a GNSS network, ensuring an accuracy of 2–3 cm (p = 0·95). During a four-hour measurement session, the accuracy statistics of these systems were determined based on around 11,500 positionings. Studies have shown that both positioning systems ensure a similar level of accuracy of their positioning services (approximately 0·5–2 m) and they meet the accuracy requirements set in published standards.

Method of Evaluating the Positioning System Capability for Complying with the Minimum Accuracy Requirements for the International Hydrographic Organization Orders

Sensors ◽

10.3390/s19183860 ◽

2019 ◽

Vol 19 (18) ◽

pp. 3860 ◽

Cited By ~ 8

Author(s):

Specht

Keyword(s):

Global Positioning System ◽

Satellite System ◽

Positioning System ◽

Navigation Satellite ◽

Positioning Accuracy ◽

Positioning Systems ◽

Global Positioning ◽

Gnss Receivers ◽

Alternative Solutions

According to the IHO (International Hydrographic Organization) S-44 standard, hydrographic surveys can be carried out in four categories, the so-called orders—special, 1a, 1b, and 2—for which minimum accuracy requirements for the applied positioning system have been set out. These amount to, respectively: 2 m, 5 m, 5 m, and 20 m at a confidence level of 0.95. It is widely assumed that GNSS (Global Navigation Satellite System) network solutions with an accuracy of 2–5 cm (p = 0.95) and maritime DGPS (Differential Global Positioning System) systems with an error of 1–2 m (p = 0.95) are currently the two main positioning methods in hydrography. Other positioning systems whose positioning accuracy increases from year to year (and which may serve as alternative solutions) have been omitted. The article proposes a method that enables an assessment of any given navigation positioning system in terms of its compliance (or non-compliance) with the minimum accuracy requirements specified for hydrographic surveys. The method concerned clearly assesses whether a particular positioning system meets the accuracy requirements set out for a particular IHO order. The model was verified, taking into account both past and present research results (stationary and dynamic) derived from tests on the following systems: DGPS, EGNOS (European Geostationary Navigation Overlay Service), and multi-GNSS receivers (GPS/GLONASS/BDS/Galileo). The study confirmed that the DGPS system meets the requirements for all IHO orders and proved that the EGNOS system can currently be applied in measurements in the orders 1a, 1b, and 2. On the other hand, multi-GNSS receivers meet the requirements for order 2, while some of them meet the requirements for orders 1a and 1b as well.

Methodology for the Correction of the Spatial Orientation Angles of the Unmanned Aerial Vehicle Using Real Time GNSS, a Shoreline Image and an Electronic Navigational Chart

Energies ◽

10.3390/en14102810 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2810

Author(s):

Krzysztof Naus ◽

Piotr Szymak ◽

Paweł Piskur ◽

Maciej Niedziela ◽

Aleksander Nowak

Keyword(s):

Real Time ◽

Spatial Orientation ◽

Orientation Angle ◽

Satellite System ◽

Angle Measurement ◽

Angle Correction ◽

Lidar Measurements ◽

Aerial Vehicle ◽

Marine Applications ◽

Undoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical axis of the camera or LiDAR sensor. Usually, UAVs use a small and light Inertial Navigation System (INS) with an angle measurement error of up to 0.5∘ (RMSE). The methodology for spatial orientation angle correction presented in the article allows the reduction of this error even to the level of 0.01∘ (RMSE). It can be successfully used in coastal and port waters. To determine the corrections, only the Electronic Navigational Chart (ENC) and an image of the coastline are needed.

APLICAÇÃO DE GEOTECNOLOGIAS NA ANÁLISE DE VIABILIDADE TÉCNICA E ECONÔMICA DO PROJETO DE IMPLANTAÇÃO DO IFMA - CAMPUS ITAQUI-BACANGA.

Acta Tecnológica ◽

10.35818/acta.v14i2.949 ◽

2021 ◽

Vol 14 (2) ◽

pp. 105

Author(s):

Maelckson Bruno Barros Gomes ◽

André Luis Silva Santos

Keyword(s):

Real Time ◽

Global Navigation Satellite System ◽

Satellite System ◽

Navigation Satellite ◽

Real Time Kinematic ◽

Global Navigation ◽

<p class="04CorpodoTexto">Este artigo tem por objetivo aplicar geotecnologias para obtenção de informações planialtimétricas a fim de avaliar a viabilidade de implantação do campus Centro Histórico/Itaqui-Bacanga do IFMA. Considerando que para realização de levantamento por métodos tradicionais é recomendado que seja realizado o destocamento e a limpeza do terreno previamente, avaliou-se a realização do levantamento planialtimétrico a partir de um par de receptores <em>Global Navigation Satellite System</em> (GNSS) pelo método <em>Real Time Kinematic</em> (RTK) pós processado e também a partir da realização de levantamento fotogramétrico, utilizando aeronave remotamente pilotada (ARP), popularmente conhecida como drone. Esta análise permitiu demonstrar que o aerolevantamento com a ARP pode ser aplicado na concepção inicial de um projeto de engenharia, conforme classificação do Tribunal de Contas da União (TCU) para níveis de precisão, pois obteve-se uma diferença orçamentária de 19% entre os projetos elaborados a partir das duas geotecnologias.</p><div> </div>

Online Near real-time Mine Disaster Monitoring System Based on Geosensor Networks

International Journal of Online Engineering (iJOE) ◽

10.3991/ijoe.v12i03.5450 ◽

2016 ◽

Vol 12 (03) ◽

pp. 64

Author(s):

Haifeng Hu

Keyword(s):

Real Time ◽

Monitoring System ◽

Satellite System ◽

Open Pit ◽

Observation Data ◽

Complex Data ◽

Disaster Monitoring ◽

Process Observation ◽

Safety And Stability

Abstract—An online automatic disaster monitoring system can reduce or prevent geological mine disasters to protect life and property. Global Navigation Satellite System receivers and the GeoRobot are two kinds of in-situ geosensors widely used for monitoring ground movements near mines. A combined monitoring solution is presented that integrates the advantages of both. In addition, a geosensor network system to be used for geological mine disaster monitoring is described. A complete online automatic mine disaster monitoring system including data transmission, data management, and complex data analysis is outlined. This paper proposes a novel overall architecture for mine disaster monitoring. This architecture can seamlessly integrate sensors for long-term, remote, and near real-time monitoring. In the architecture, three layers are used to collect, manage and process observation data. To demonstrate the applicability of the method, a system encompassing this architecture has been deployed to monitor the safety and stability of a slope at an open-pit mine in Inner Mongolia.

Leveraging Intelligent Compaction and Thermal Profiling Technologies to Improve Asphalt Pavement Construction Quality: A Case Study

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118758285 ◽

2018 ◽

Vol 2672 (26) ◽

pp. 48-56 ◽

Cited By ~ 5

Author(s):

George K. Chang ◽

Kiran Mohanraj ◽

William A. Stone ◽

Daniel J. Oesch ◽

Victor (Lee) Gallivan

Keyword(s):

Real Time ◽

Satellite System ◽

Material Transfer ◽

Intelligent Compaction ◽

Two Factors ◽

Thermal Profiling ◽

Compaction Control ◽

Pavement Construction ◽

Intelligent compaction (IC) is an emerging technology with rollers equipped with global navigation satellite system (GNSS), an accelerometer-based measurement system, and an onboard color-coded display for real-time monitoring and compaction control. Paver-mounted thermal profiling (PMTP) is used to monitor asphalt surface temperatures behind a paver with a thermal scanner, and to track paver speeds, stops, and stop durations. Leveraging both IC and PMTP technologies allows for paving and compaction controls in real time, and for executing appropriate adjustments as needed. A case study is used to demonstrate the advantage of using both IC and PMTP over conventional operations. Postconstruction asphalt coring and tests, as well as pavement profile surveys were conducted to provide asphalt density data and pavement smoothness acceptance data for comparison and correlation analysis with IC and PMTP data. The data from 2 days of operations, one without the Material Transfer Vehicle (MTV) and another with the MTV, were analyzed and compared to illustrate the benefits of using IC, PMTP, and MTV for producing quality pavement products. Durability and smoothness are two key construction qualities for agencies and users of hot mix asphalt (HMA) pavements. These two factors also affect the long-term structural and functional pavement performance.

Real-Time Precise Point Positioning Using Orbit and Clock Corrections as Quasi-Observations for Improved Detection of Faults

Journal of Navigation ◽

10.1017/s0373463317001023 ◽

2018 ◽

Vol 71 (4) ◽

pp. 769-787 ◽

Cited By ~ 7

Author(s):

Ahmed El-Mowafy

Keyword(s):

Real Time ◽

Precise Point Positioning ◽

Exclusion Process ◽

Satellite Orbit ◽

Satellite System ◽

Navigation Satellite ◽

System Service ◽

Point Positioning ◽

Predicted Values ◽

Real-time Precise Point Positioning (PPP) relies on the use of accurate satellite orbit and clock corrections. If these corrections contain large errors or faults, either from the system or by meaconing, they will adversely affect positioning. Therefore, such faults have to be detected and excluded. In traditional PPP, measurements that have faulty corrections are typically excluded as they are merged together. In this contribution, a new PPP model that encompasses the orbit and clock corrections as quasi-observations is presented such that they undergo the fault detection and exclusion process separate from the observations. This enables the use of measurements that have faulty corrections along with predicted values of these corrections in place of the excluded ones. Moreover, the proposed approach allows for inclusion of the complete stochastic information of the corrections. To facilitate modelling of the orbit and clock corrections as quasi-observations, International Global Navigation Satellite System Service (IGS) real-time corrections were characterised over a six-month period. The proposed method is validated and its benefits are demonstrated at two sites using three days of data.