scholarly journals Evaluation of the Possibility of Identifying a Complex Polygonal Tram Track Layout Using Multiple Satellite Measurements

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4408
Author(s):  
Andrzej Wilk ◽  
Cezary Specht ◽  
Wladyslaw Koc ◽  
Krzysztof Karwowski ◽  
Jacek Skibicki ◽  
...  
Keyword(s):  
Measurement Data ◽  
Satellite System ◽  
Infrastructure Management ◽  
Satellite Measurements ◽  
University Of Technology ◽  
Management Processes ◽  
Railway Infrastructure ◽  
Mobile Satellite ◽  
Global Navigation Satellite ◽  
Geometric Layout

We present the main assumptions about the algorithmization of the analysis of measurement data recorded in mobile satellite measurements. The research team from the Gdańsk University of Technology and the Maritime University in Gdynia, as part of a research project conducted in cooperation with PKP PLK (Polish Railway Infrastructure Manager), developed algorithms supporting the identification and assessment of track axis layout. This article presents selected issues concerning the identification of a tramway line’s axis system. For this purpose, the supporting algorithm was developed and measurement data recorded using Global Navigation Satellite System (GNSS) techniques was evaluated and analyzed. The discussed algorithm identifies main track directions from multi-device data and repeated position recordings. In order to observe the influence of crucial factors, the investigated route was carefully selected. The chosen tramway track was characterized by its location in various field conditions and a diversified and complex geometric layout. The analysis of the obtained results was focused on the assessment of the signal’s dispersion and repeatability using residuals in relation to the estimated track’s direction. The presented methodology is intended to support railway infrastructure management processes, mainly in planning and maintenance through an efficient inventory of the infrastructure in service.

scholarly journals Verification of GNSS Measurements of the Railway Track Using Standard Techniques for Determining Coordinates

2020 ◽  
Vol 12 (18) ◽  
pp. 2874 ◽  
Author(s):  
Cezary Specht ◽  
Andrzej Wilk ◽  
Wladyslaw Koc ◽  
Krzysztof Karwowski ◽  
Paweł Dąbrowski ◽  
...  
Keyword(s):  
Measuring System ◽  
Railway Track ◽  
Satellite Measurements ◽  
Railway Line ◽  
University Of Technology ◽  
Railway Infrastructure ◽  
Spatial System ◽  
Mobile Satellite ◽  
Gnss Measurements ◽  
Geometric Layout

The problem of the reproduction of the railway geometric layout in the global spatial system is currently solved in the form of measurements that use geodetic railway networks and also, in recent years, efficient methods of mobile positioning (mainly satellite and inert). The team of authors from the Gdańsk University of Technology and the Maritime University in Gdynia as part of the research project InnoSatTrack is looking for effective and efficient methods for the inventory of railway lines. The research is part of a wider investigation BRIK (Research and Development in Railway Infrastructure, in polish: Badania i Rozwój w Infrastrukturze Kolejowej). This paper presents a comparative analysis of the problem of the reproduction of the trajectory of the measuring system using tacheometry, satellite measurements made using a measurement trolley, and mobile satellite measurements. Algorithms enabling the assessment of the compliance of satellite measurements with classic tacheometric measurements were presented. To this end, the authors held measurement sessions using modern geodetic instruments and satellite navigation on a section of the railway line. The results of the measurements indicate the convergence of the level of accuracy achieved by different measuring techniques.

scholarly journals A Method for Determination and Compensation of a Cant Influence in a Track Centerline Identification Using GNSS Methods and Inertial Measurement

2019 ◽  
Vol 9 (20) ◽  
pp. 4347 ◽  
Author(s):  
Wladyslaw Koc ◽  
Cezary Specht ◽  
Jacek Szmaglinski ◽  
Piotr Chrostowski
Keyword(s):  
Local Coordinate System ◽  
Target Position ◽  
Satellite System ◽  
Railway Track ◽  
Inertial Measurement ◽  
Track Geometry ◽  
Method Of Calculation ◽  
Mobile Satellite ◽  
Global Navigation Satellite ◽  
Geometric Layout

At present, the problem of rail routes reconstruction in a global reference system is increasingly important. This issue is called Absolute Track Geometry, and its essence is the determination of the axis of railway tracks in the form of Cartesian coordinates of a global or local coordinate system. To obtain such a representation of the track centerline, the measurement methods are developed in many countries mostly by the using global navigation satellite system (GNSS) techniques. The accuracy of this type of measurement in favorable conditions reaches one centimeter. However, some specific conditions cause the additional supporting measurements with a use of such instruments as tachymetry, odometers, or accelerometers to be needed. One of the common issues of track axis reconstruction is transforming the measured GNSS antenna coordinates to the target position, i.e., to the place between rails on the level of rail heads. The authors in their previous works described the developed methodology, while this article presents a method of determining the correction of horizontal coordinates for measurements in arc sections of the railway track. The presence of a cant causes the antenna’s center to move away from the track axis, and for this reason, the results must be corrected. This article presents a method of calculation of mentioned corrections for positions obtained from mobile satellite surveying with additional inertial measurement. The algorithm presented in the article and its implementation have been illustrated on an example of a complex geometric layout, where cant transitions exist without transition curves in horizontal plane. Such a layout is not preferable due to the additional accelerations and their changes. However, it allows the verification of the presented methods.

scholarly journals Application of Least Squares with Conditional Equations Method for Railway Track Inventory Using GNSS Observations

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4948
Author(s):  
Krzysztof Czaplewski ◽  
Zbigniew Wisniewski ◽  
Cezary Specht ◽  
Andrzej Wilk ◽  
Wladyslaw Koc ◽  
...  
Keyword(s):  
Measurement Data ◽  
Satellite System ◽  
Theoretical Description ◽  
Railway Track ◽  
Land Surveying ◽  
Gnss Receivers ◽  
Mobile Satellite ◽  
Global Navigation Satellite ◽  
Gnss Observations ◽  
Observation Results

Satellite geodetic networks are commonly used in surveying tasks, but they can also be used in mobile surveys. Mobile satellite surveys can be used for trackage inventory, diagnostics and design. The combination of modern technological solutions with the adaptation of research methods known in other fields of science offers an opportunity to acquire highly accurate solutions for railway track inventory. This article presents the effects of work carried out using a mobile surveying platform on which Global Navigation Satellite System (GNSS) receivers were mounted. The satellite observations (surveys) obtained were aligned using one of the methods known from classical land surveying. The records obtained during the surveying campaign on a 246th km railway track section were subjected to alignment. This article provides a description of the surveying campaign necessary to obtain measurement data and a theoretical description of the method employed to align observation results as well as their visualisation.

scholarly journals Computation Approach for Quantitative Dielectric Constant from Time Sequential Data Observed by CYGNSS Satellites

2021 ◽  
Vol 13 (11) ◽  
pp. 2032
Author(s):  
Junchan Lee ◽  
Sunil Bisnath ◽  
Regina S.K. Lee ◽  
Narin Gavili Kilane
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Global Navigation Satellite System ◽  
Measurement Data ◽  
Satellite System ◽  
Computation Method ◽  
Navigation Satellite ◽  
Local Soil ◽  
Global Navigation ◽  
Global Navigation Satellite

This paper describes a computation method for obtaining dielectric constant using Global Navigation Satellite System reflectometry (GNSS-R) products. Dielectric constant is a crucial component in the soil moisture retrieval process using reflected GNSS signals. The reflectivity for circular polarized signals is combined with the dielectric constant equation that is used for radiometer observations. Data from the Cyclone Global Navigation Satellite System (CYGNSS) mission, an eight-nanosatellite constellation for GNSS-R, are used for computing dielectric constant. Data from the Soil Moisture Active Passive (SMAP) mission are used to measure the soil moisture through its radiometer, and they are considered as a reference to confirm the accuracy of the new dielectric constant calculation method. The analyzed locations have been chosen that correspond to sites used for the calibration and validation of the SMAP soil moisture product using in-situ measurement data. The retrieved results, especially in the case of a specular point around Yanco, Australia, show that the estimated results track closely to the soil moisture results, and the Root Mean Square Error (RMSE) in the estimated dielectric constant is approximately 5.73. Similar results can be obtained when the specular point is located near the Texas Soil Moisture Network (TxSON), USA. These results indicate that the analysis procedure is well-defined, and it lays the foundation for obtaining quantitative soil moisture content using the GNSS reflectometry results. Future work will include applying the computation product to determine the characteristics that will allow for the separation of coherent and incoherent signals in delay Doppler maps, as well as to develop local soil moisture models.

scholarly journals Georeferencing of Laser Scanner-Based Kinematic Multi-Sensor Systems in the Context of Iterated Extended Kalman Filters Using Geometrical Constraints

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2280 ◽  
Author(s):  
Sören Vogel ◽  
Hamza Alkhatib ◽  
Johannes Bureick ◽  
Rozhin Moftizadeh ◽  
Ingo Neumann
Keyword(s):  
State Constraints ◽  
Laser Scanner ◽  
Measurement Data ◽  
Satellite System ◽  
Sensor Systems ◽  
Measurement Models ◽  
Non Linear ◽  
Geometrical Constraints ◽  
Global Navigation Satellite ◽  
The Impact

Georeferencing is an indispensable necessity regarding operating with kinematic multi-sensor systems (MSS) in various indoor and outdoor areas. Information from object space combined with various types of prior information (e.g., geometrical constraints) are beneficial especially in challenging environments where common solutions for pose estimation (e.g., global navigation satellite system or external tracking by a total station) are inapplicable, unreliable or inaccurate. Consequently, an iterated extended Kalman filter is used and a general georeferencing approach by means of recursive state estimation is introduced. This approach is open to several types of observation inputs and can deal with (non)linear systems and measurement models. The capability of using both explicit and implicit formulations of the relation between states and observations, and the consideration of (non)linear equality and inequality state constraints is a special feature. The framework presented is evaluated by an indoor kinematic MSS based on a terrestrial laser scanner. The focus here is on the impact of several different combinations of applied state constraints and the dependencies of two classes of inertial measurement units (IMU). The results presented are based on real measurement data combined with simulated IMU measurements.

scholarly journals Distributed Orbit Determination for Global Navigation Satellite System with Inter-Satellite Link

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1031 ◽  
Author(s):  
Yuanlan Wen ◽  
Jun Zhu ◽  
Youxing Gong ◽  
Qian Wang ◽  
Xiufeng He
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Global Navigation Satellite System ◽  
Orbit Determination ◽  
Measurement Data ◽  
Satellite System ◽  
Navigation Satellite ◽  
Satellite Link ◽  
Global Navigation ◽  
Global Navigation Satellite

To keep the global navigation satellite system functional during extreme conditions, it is a trend to employ autonomous navigation technology with inter-satellite link. As in the newly built BeiDou system (BDS-3) equipped with Ka-band inter-satellite links, every individual satellite has the ability of communicating and measuring distances among each other. The system also has less dependence on the ground stations and improved navigation performance. Because of the huge amount of measurement data, the centralized data processing algorithm for orbit determination is suggested to be replaced by a distributed one in which each satellite in the constellation is required to finish a partial computation task. In the present paper, the balanced extended Kalman filter algorithm for distributed orbit determination is proposed and compared with the whole-constellation centralized extended Kalman filter, the iterative cascade extended Kalman filter, and the increasing measurement covariance extended Kalman filter. The proposed method demands a lower computation power; however, it yields results with a relatively good accuracy.

Experimental results of multipath behavior for GPS L1-L2 and Galileo E1-E5b in static and kinematic scenarios

2019 ◽  
Vol 13 (4) ◽  
pp. 279-289 ◽  
Author(s):  
Alexandra Avram ◽  
Volker Schwieger ◽  
Noha El Gemayel
Keyword(s):  
Signal To Noise Ratio ◽  
Measurement Data ◽  
Absolute Error ◽  
Autonomous Driving ◽  
Satellite System ◽  
Natural Environments ◽  
Navigation Systems ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Measurement Campaigns

Abstract Current trends like Autonomous Driving (AD) increase the need for a precise, reliable, and continuous position at high velocities. In both natural and man-made environments, Global Navigation Satellite System (GNSS) signals suffer challenges such as multipath, attenuation, or loss-of-lock. As Highway Assist and Highway Pilot are AD next steps, multipath knowledge is necessary for this typical user-case and kinematic situations. This paper presents a multipath performance analysis for GPS and Galileo satellites in static, slow, and high kinematic scenarios. The data is provided from car test-drives in both controlled and unrestricted, near-natural environments. The Code-Minus-Carrier (CMC) and cycle-slip implementations are validated with measurement data from consecutive days. Multipath statistical models based on satellite elevation are evaluated for the three investigated scenarios. Static models derived from the car setup measurements for GPS L1, L2 and Galileo E1 and E5b show a good agreement with a state-of-the-art model as well as the enhanced Galileo signals performance. Slow kinematic multipath results in a controlled environment showed an improvement for both navigation systems compared to the static measurements at the same place. This result is confirmed by static and slow kinematic multipath simulations with the same GNSS receiver. Post-processing analysis on highway measurements revealed a bigger multipath bias, compared to the open-sky static and slow kinematic measurement campaigns. Although less critical as urban or rural, this indicates the presence of multipath in this kind of environment as well. The impact of different parameters, including receiver architecture and Signal-to-noise ratio (SNR) are analyzed and discussed. Differential position (DGNSS) based on code is computed for each epoch and compared against GNSS/INS integrated position for all three measurement campaigns. The most significant 3D absolute error occurs where the greatest multipath envelope is found.

scholarly journals An introduction to FY3 GNOS instrument and its performace tested on ground

2014 ◽  
Vol 7 (1) ◽  
pp. 703-726
Author(s):  
W. Bai ◽  
Y. Sun ◽  
Q. Du ◽  
G. Yang ◽  
Z. Yang ◽  
...  
Keyword(s):  
Weather Prediction ◽  
Measurement Data ◽  
Atmospheric Temperature ◽  
Satellite System ◽  
Navigation Satellite ◽  
Neutral Atmosphere ◽  
Satellite Systems ◽  
Lower Elevation ◽  
Electron Density Profiles ◽  
Global Navigation Satellite

Abstract. The FY3 GNOS (GNSS Occultation Sounder) mission is a GNSS (Global Navigation Satellite System) radio occultation mission of China for remote sensing of Earth's neutral atmosphere and the ionosphere. GNOS will use both the Global Positioning System (GPS) and the Beidou navigation satellite systems on the China Feng-Yun-3 (FY3) series satellites. The first FY3-C was launched at 03:03 UTC, 23 September 2013. GNOS was developed by Center for Space Science and Applied Research, Chinese Academy of Sciences (CSSAR). It will provide vertical profiles of atmospheric temperature, pressure, and humidity, as well as ionospheric electron density profiles on a global basis. These data will be used for numerical weather prediction, climate research, and ionospheric research and space weather. This paper describes the FY3 GNOS mission and the GNOS instrument characteristics. It presents simulation results of the number and distribution of GNOS occultation events with the Regional Beidou constellation and the full GPS constellation, under the limitation of the GNOS instrument occultation channel number. This paper presents the instrument performance as derived from analysis of measurement data in laboratory and mountain-based occultation validation experiments at Mt. Wuling in Hebei Province. The mountain-based GNSS occultation validation tests show that GNOS can acquire or track lower elevation radio signal for rising or setting occultation events. The refractivity profiles of GNOS obtained during the mountain-based experiment were compared with those from radiosondes. The results show that the refractivity profiles obtained by GNOS are consistent with those from the radiosonde. The RMS of the differences between the GNOS and radiosonde refractivities is less than 3%.

PPP-AR with GPS and Galileo: Assessing diverse approaches and satellite products to reduce convergence time

2020 ◽  
Author(s):  
Marcus Franz Glaner ◽  
Robert Weber ◽  
Sebastian Strasser
Keyword(s):  
Satellite System ◽  
Convergence Time ◽  
Reference Network ◽  
Research Division ◽  
University Of Technology ◽  
Fixed Solution ◽  
Global Navigation Satellite ◽  
Processing Techniques ◽  
Gnss Data ◽  
Test Scenarios

<p><span>Precise Point Positioning (PPP) is one of the most promising processing techniques for Global Navigation Satellite System (GNSS) data. By the use of precise satellite products (orbits, clocks and biases) and sophisticated algorithms applied on the observations of a multi-frequency receiver, coordinate accuracies at the decimetre/centimetre level for a float solution and at the centimetre/millimetre level for a fixed solution can be achieved. In contrast to relative positioning methods (e.g. RTK), PPP does not require nearby reference stations or a close-by reference network. On the other hand PPP has a non-negligible convergence time. To make PPP more competitive against other high-precision GNSS positioning techniques, scientific research focuses on </span><span>reducing the convergence time of PPP. </span></p><p> </p><p><span>In this contribution, we present results of PPP with focus on integer</span><span> ambiguity resolution (PPP-AR) using satellite products from different analysis centers. </span><span>The resulting coordinate accuracy and convergence behaviour are evaluated in various test scenarios. In these test cases we distinguish between the use of satellite products from Graz University of Technology, which are calculated using a raw observation approach, and nowadays publicly available satellite products of different analysis centers (e.g. CNES, CODE). All those products enable PPP-AR in different approaches. To shorten the convergence time, we investigate and compare different PPP processing approaches using GPS and Galileo observations. The use of 2+ frequencies and alternatives to the classical PPP model, which is based on two frequencies and the ionosphere-free linear combination are discussed (e.g. uncombined model with ionospheric constraint). The PPP calculations are performed with the in-house software raPPPid, which has been developed at the research division Higher Geodesy of TU Vienna and is part of the Vienna VLBI and Satellite Software (VieVS PPP).</span></p>

scholarly journals Evaluation of Street Lighting Efficiency Using a Mobile Measurement System

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3872
Author(s):  
Piotr Tomczuk ◽  
Marcin Chrzanowicz ◽  
Piotr Jaskowski ◽  
Marcin Budzynski
Keyword(s):  
Energy Efficiency ◽  
Road Traffic ◽  
Rapid Assessment ◽  
Measurement Data ◽  
Satellite System ◽  
Street Lighting ◽  
Road Section ◽  
Initial Stage ◽  
Gis Data ◽  
Global Navigation Satellite

The issue concerns the initial stage of work on a method for performing a rapid assessment of the energy efficiency and illuminance of a street lighting installation. The proposed method is based on simultaneous measurement of illuminance from three lux meters placed on the roof of the vehicle. The data are acquired in road traffic, while the vehicle is driving. The proposed solution will allow in the future to quickly and reproducibly obtain data about the lighting parameters of the studied road section. The illumination values are localised using Global Navigation Satellite System (GNSS). Based on the collected measurement data, with the use of terrain maps, geographic information system (GIS) data and installation design documentation, it will be possible to determine in detail the parameters of energy efficiency indicators for a selected section of the street for the entire street according to the EN13201-5 standard. Preliminary tests were conducted on a section of about one kilometer of street illuminated in class C3. Detailed measurements reveal high variation of obtained energy indicators DP and DE for each road section. The reason for this condition is the variation of power, installation geometry and the presence of obstacles to light.

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