scholarly journals Diagnostic Tools Using a Multi-Constellation Single-Receiver Single-Satellite Data Validation Method

2014 ◽  
Vol 68 (1) ◽  
pp. 196-214 ◽  
Author(s):  
Ahmed El-Mowafy
Keyword(s):  
Satellite Data ◽  
Satellite System ◽  
Diagnostic Tools ◽  
Data Validation ◽  
Test Statistics ◽  
Validation Parameters ◽  
Global Positioning ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Single Receiver

The use of single-receiver single-satellite data validation parameters for numerical and graphical diagnostics of the multi-frequency observations is presented. This method validates Global Navigation Satellite System (GNSS) measurements of a single receiver where data from each satellite are independently processed using a geometry-free observation model with a reparameterised form of the unknowns. The method is applicable to any GNSS with any number of frequencies. The diagnostic tools are based on checking agreement of characteristics of the validation test statistics against theory. The use of these diagnostics in static and kinematic modes is demonstrated using multiple-frequency data from three GNSS constellations; Global Positioning System (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) and Galileo.

scholarly journals Inventory of Locations of Old Mining Works Using LiDAR Data: A Case Study in Slovakia

2021 ◽  
Vol 13 (12) ◽  
pp. 6981
Author(s):  
Marcela Bindzarova Gergelova ◽  
Slavomir Labant ◽  
Jozef Mizak ◽  
Pavel Sustek ◽  
Lubomir Leicher
Keyword(s):  
Satellite System ◽  
Precise Determination ◽  
Lidar Data ◽  
Positional Accuracy ◽  
Current Form ◽  
Mining History ◽  
Mining Works ◽  
Gnss Measurements ◽  
Global Navigation Satellite

The concept of further sustainable development in the area of administration of the register of old mining works and recent mining works in Slovakia requires precise determination of the locations of the objects that constitute it. The objects in this register have their uniqueness linked with the history of mining in Slovakia. The state of positional accuracy in the registration of objects in its current form is unsatisfactory. Different database sources containing the locations of the old mining works are insufficient and show significant locational deviations. For this reason, it is necessary to precisely locate old mining works using modern measuring technologies. The most effective approach to solving this problem is the use of LiDAR data, which at the same time allow determining the position and above-ground shape of old mining works. Two localities with significant mining history were selected for this case study. Positional deviations in the location of old mining works among the selected data were determined from the register of old mining works in Slovakia, global navigation satellite system (GNSS) measurements, multidirectional hill-shading using LiDAR, and accessible data from the open street map. To compare the positions of identical old mining works from the selected database sources, we established differences in the coordinates (ΔX, ΔY) and calculated the positional deviations of the same objects. The average positional deviation in the total count of nineteen objects comparing documents, LiDAR data, and the register was 33.6 m. Comparing the locations of twelve old mining works between the LiDAR data and the open street map, the average positional deviation was 16.3 m. Between the data sources from GNSS and the registry of old mining works, the average positional deviation of four selected objects was 39.17 m.

scholarly journals Sea Topography of the Ionian and Adriatic Seas Using Repeated GNSS Measurements

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 812
Author(s):  
Sotiris Lycourghiotis
Keyword(s):  
Satellite System ◽  
Geoid Model ◽  
Sea Surface Topography ◽  
Mean Sea Surface ◽  
The Mean ◽  
A New Technique ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Constant Slope ◽  
Ionian And Adriatic Seas

The mean sea surface topography of the Ionian and Adriatic Seas has been determined. This was based on six-months of Global Navigation Satellite System (GNSS) measurements which were performed on the Ionian Queen (a ship). The measurements were analyzed following a double-path methodology based on differential GNSS (D-GNSS) and precise point positioning (PPP) analysis. Numerical filtering techniques, multi-parametric accuracy analysis and a new technique for removing the meteorological tide factors were also used. Results were compared with the EGM96 geoid model. The calculated differences ranged between 0 and 48 cm. The error of the results was estimated to fall within 3.31 cm. The 3D image of the marine topography in the region shows a nearly constant slope of 4 cm/km in the N–S direction. Thus, the effectiveness of the approach “repeated GNSS measurements on the same route of a ship” developed in the context of “GNSS methods on floating means” has been demonstrated. The application of this approach using systematic multi-track recordings on conventional liner ships is very promising, as it may open possibilities for widespread use of the methodology across the world.

Present-day orogenic processes in the western Kalpin nappe explored by interseismic GNSS measurements and coseismic InSAR observations of the 2020 Mw 6.1 Kalpin event

2021 ◽  
Author(s):  
Ping He ◽  
Yangmao Wen ◽  
Shuiping Li ◽  
Kaihua Ding ◽  
Zhicai Li ◽  
...  
Keyword(s):  
Source Parameters ◽  
Satellite System ◽  
Tien Shan ◽  
Dislocation Model ◽  
Maximum Displacement ◽  
Finite Fault ◽  
Instantaneous Deformation ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Finite Fault Model

Summary As the largest and most active intracontinental orogenic belt on Earth, the Tien Shan (TS) is a natural laboratory for understanding the Cenozoic orogenic processes driven by the India-Asia collision. On 19 January 2020, a Mw 6.1 event stuck the Kalpin region, where the southern frontal TS interacts with the Tarim basin. To probe the local ongoing orogenic processes and potential seismic hazard in the Kalpin region, both interseismic and instantaneous deformation derived from geodetic observations are employed in this study. With the constraint of interseismic global navigation satellite system (GNSS) velocities, we estimate the décollement plane parameters of the western Kalpin nappe based on a two-dimensional dislocation model, and the results suggest that the décollement plane is nearly subhorizontal with a dip of ∼3° at a depth of 24 km. Then, we collect both Sentinel-1 and ALOS-2 satellite images to capture the coseismic displacements caused by the 2020 Kalpin event, and the interferometric synthetic aperture radar (InSAR) images show a maximum displacement of 7 cm in the line of sight near the epicentral region. With these coseismic displacement measurements, we invert the source parameters of this event using a finite-fault model. We determine the optimal source mechanism in which the fault geometry is dominated by thrust faulting with an E–W strike of 275° and a northward dip of 11.2°, and the main rupture slip is concentrated within an area 28.0 km in length and${\rm{\,\,}}$10.3 km in width, with a maximum slip of 0.3 m at a depth of 6–8 km. The total released moment of our preferred distributed slip model yields a geodetic moment of 1.59 × 1018 N$\cdot $m, equivalent to Mw 6.1. The contrast of the décollement plane depth from interseismic GNSS and the rupture depth from coseismic InSAR suggests that a compression still exists in the Kalpin nappe forefront, which is prone to frequent moderate events and may be at risk of a much more dangerous earthquake.

Vision Based Indoor Surveillance Patrol Robot Using Extended Dijkstra Algorithm in Path Plannin

2021 ◽  
Vol 3 (2) ◽  
pp. 21-28
Author(s):  
Kiat Teh Choon ◽  
Kit Wong Wai ◽  
Soe Min Thu
Keyword(s):  
Path Planning ◽  
Satellite System ◽  
Measurement Unit ◽  
Dijkstra Algorithm ◽  
Current Path ◽  
Global Positioning ◽  
Multiple Cycles ◽  
To Come ◽  
Global Navigation Satellite ◽  
Robot Path

Vision based patrol robot has been with great interest nowadays due to its consistency, cost effectiveness and no temperament issue. In recent times, Global positioning system (GPS) has been cooperated with Global Navigation Satellite System (GNSS) to come out with better accuracy quality in positioning, navigation, and timing (PNT) services to locate a device. However, such localization service is yet to reach any indoor facility. For an indoor surveillance vision based patrol robot, such limitation hinders its path planning capabilities that allows the patrol robot to seek for the optimum path to reach the appointed destination and return back to its home position. In this paper, a vision based indoor surveillance patrol robot using sensory manipulation technique is presented and an extended Dijkstra algorithm is proposed for the patrol robot path planning. The design of the patrol robot adopted visual type sensor, range sensors and Inertia Measurement Unit (IMU) system to impulsively update the map’s data in line with the patrol robot’s current path and utilize the path planning features to carry out obstacle avoidance and re-routing process in accordance to the obstacle’s type met by the patrol robot. The result conveyed by such approach certainly managed to complete multiple cycles of testing with positive result.

scholarly journals Performance Assessment of PPP Surveys with Open Source Software Using the GNSS GPS–GLONASS–Galileo Constellations

2020 ◽  
Vol 10 (16) ◽  
pp. 5420 ◽  
Author(s):  
Antonio Angrisano ◽  
Gino Dardanelli ◽  
Anna Innac ◽  
Alessandro Pisciotta ◽  
Claudia Pipitone ◽  
...  
Keyword(s):  
Open Source ◽  
Global Positioning System ◽  
Open Source Software ◽  
Satellite System ◽  
Satellite Orbits ◽  
International Gnss Service ◽  
Static Mode ◽  
Global Positioning ◽  
Significant Performance ◽  
Global Navigation Satellite

In this work, the performance of the multi-GNSS (Global Navigation Satellite System) Precise Point Positioning (PPP) technique, in static mode, is analyzed. Specifically, GPS (Global Positioning System), GLONASS, and Galileo systems are considered, and quantifying the Galileo contribution is one of the main objectives. The open source software RTKLib is adopted to process the data, with precise satellite orbits and clocks from CNES (Centre National d’Etudes Spatiales) and CLS (Collecte Localisation Satellites) analysis centers for International GNSS Service (IGS). The Iono-free model is used to correct ionospheric errors, the GOT-4.7 model is used to correct tidal effects, and Differential Code Biases (DCB) are taken from the Deutsche Forschungsanstalt für Luftund Raumfahrt (DLR) center. Two different tropospheric models are tested: Saastamoinen and Estimate ZTD (Zenith Troposhperic Delay). For the proposed study, a dataset of 31 days from a permanent GNSS station, placed in Palermo (Italy), and a dataset of 10 days from a static geodetic receiver, placed nearby the station, have been collected and processed by the most used open source software in the geomatic community. The considered GNSS configurations are seven: GPS only, GLONASS only, Galileo only, GPS+GLONASS, GPS+Galileo, GLONASS+Galileo, and GPS+GLONASS+Galileo. The results show significant performance improvement of the GNSS combinations with respect to single GNSS cases.

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

2019 ◽  
Vol 11 (19) ◽  
pp. 2271 ◽  
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 ◽  
Global Navigation Satellite ◽  
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

1998 ◽  
Vol 51 (3) ◽  
pp. 382-393 ◽  
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 ◽  
Global Navigation Satellite

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.

Accounting for Inter-System Bias in DGNSS Positioning with GPS/GLONASS/BDS/Galileo

2017 ◽  
Vol 70 (4) ◽  
pp. 686-698 ◽  
Author(s):  
Hui Liu ◽  
Bao Shu ◽  
Longwei Xu ◽  
Chuang Qian ◽  
Rufei Zhang ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Simple Algorithm ◽  
Satellite System ◽  
Harsh Environments ◽  
Positioning System ◽  
Gnss Positioning ◽  
Global Positioning ◽  
System Bias ◽  
Global Navigation Satellite ◽  
Reliability And Availability

Code Differential Global Positioning System (DGPS) is widely used in satellite navigation and positioning because of its simple algorithm and preferable precision. Multi-Global Navigation Satellite System (GNSS) is expected to enhance the accuracy, reliability and availability of Differential GNSS (DGNSS) positioning. Traditional DGNSS models should set separate clock parameters due to the clock differences between the different systems. Awareness of the Inter-System Bias (ISB) could help to maximise the redundancy of the positioning model, thus improving the performance of multi-GNSS positioning. This paper aims to examine the inter-system bias of GPS/GLONASS/BeiDou (BDS)/Galileo and their benefits in DGNSS positioning. Results show that Differential ISB (DISB) characteristics vary with different receiver types and systems. The size of DISB could reach metre-level and the precision of estimated DISBs can reach approximately several centimetres within tens of epochs. Therefore, a new real-time DGNSS model that accounts for ISB is proposed. After differential ISBs are initialised, positioning with four satellites from arbitrarily the same or different systems can be realised. Moreover, compared with the traditional DGNSS model, the precision of the positioning results with the new model are obviously improved, especially in harsh environments.

scholarly journals Estimating ocean tide loading displacements with GPS and GLONASS

Solid Earth ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 1849-1863
Author(s):  
Bogdan Matviichuk ◽  
Matt King ◽  
Christopher Watson
Keyword(s):  
Global Positioning System ◽  
Western Europe ◽  
Satellite System ◽  
Ocean Tide ◽  
Ground Displacement ◽  
Ocean Tide Loading ◽  
Global Positioning ◽  
Tidal Constituents ◽  
The Uk ◽  
Global Navigation Satellite

Abstract. Ground displacements due to ocean tide loading have previously been successfully observed using Global Positioning System (GPS) data, and such estimates for the principal lunar M2 constituent have been used to infer the rheology and structure of the asthenosphere. The GPS orbital repeat period is close to that of several other major tidal constituents (K1, K2, S2); thus, GPS estimates of ground displacement at these frequencies are subject to GPS systematic errors. We assess the addition of GLONASS (GLObal NAvigation Satellite System) to increase the accuracy and reliability of eight major ocean tide loading constituents: four semi-diurnal (M2, S2, N2, K2) and four diurnal constituents (K1, O1, P1, Q1). We revisit a previous GPS study, focusing on 21 sites in the UK and western Europe, expanding it with an assessment of GLONASS and GPS+GLONASS estimates. In the region, both GPS and GLONASS data have been abundant since 2010.0. We therefore focus on the period 2010.0–2014.0, a span considered long enough to reliably estimate the major constituents. Data were processed with a kinematic precise point positioning (PPP) strategy to produce site coordinate time series for each of three different modes: GPS, GLONASS and GPS+GLONASS. The GPS solution with ambiguities resolved was used as a baseline for performance assessment of the additional modes. GPS+GLONASS shows very close agreement with ambiguity resolved GPS for lunar constituents (M2, N2, O1, Q1) but with substantial differences for solar-related constituents (S2, K2, K1, P1), with solutions including GLONASS being generally closer to model estimates. While no single constellation mode performs best for all constituents and components, we propose to use a combination of constellation modes to recover tidal parameters: GPS+GLONASS for most constituents, except for K2 and K1 where GLONASS (north and up) and GPS with ambiguities resolved (east) perform best.

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