scholarly journals Rapid static GNSS data processing using online services

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
M. Berber ◽  
A. Ustun ◽  
M. Yetkin
Keyword(s):  
Data Processing ◽  
Satellite System ◽  
Geodetic Survey ◽  
National Geodetic Survey ◽  
Dual Frequency ◽  
Online Data ◽  
Vertical Coordinate ◽  
Static Data ◽  
Global Navigation Satellite ◽  
Gnss Data

AbstractRecently, many organizations have begun providing online GNSS (Global Navigation Satellite System) data processing services. Currently, only one of these organizations i.e., OPUS (On-line Positioning Users Service) provides a rapid static data processing option. In case of static online data processing, the users are required to submit at least two hours of data to get reasonably precise results. To provide processing option with less than two hours of data, NGS (National Geodetic Survey) developed OPUS–RS for rapid static data processing so that usersmay submit as little as 15 minutes of dual frequency GNSS data. In this study, multiple observation sessions are conducted at the same locations to compare OPUS-RS generated coordinates among the different sessions to see whether separate values agree with each other. The results indicate that with OPUS-RS results the differences in horizontal coordinates agree with each other within 3.5 cm and vertical coordinates agree within 7.2 cm. For an independent check, OPUS-RS results are also compared against LGO(Leica Geo Office) produced Static results; this comparison yielded up to 4.5 cm variations among horizontal coordinate differences and variations among vertical coordinate differences are up to 11.4 cm.

Preliminary Positioning Results From NGS’s Upcoming Multi-GNSS Processing Software

2020 ◽  
Author(s):  
Bryan Stressler ◽  
Jacob Heck ◽  
Andria Bilich ◽  
Clement Ogaja
Keyword(s):  
Data Processing ◽  
Satellite System ◽  
Geodetic Survey ◽  
Double Difference ◽  
National Geodetic Survey ◽  
Dual Frequency ◽  
International Gnss Service ◽  
Processing Software ◽  
Global Navigation Satellite ◽  
Gnss Processing

<p>The U.S. National Geodetic Survey (NGS) is undertaking a project to replace and modernize its global navigation satellite system (GNSS) processing software that has been in use for several decades. The goals of this project are to: 1) transition from dual-frequency GPS-only to multi-constellation multi-frequency data processing, 2) develop well-documented modular and extensible software written in modern programming and scripting languages, and 3) replace the operational PAGES software suite as the processing engine responsible for monitoring the NOAA Continuously Operating Reference System Network (NCN), orbit production for the International GNSS Service (IGS) combinations, and the Online Positioning User Service (OPUS). To date, the GNSS software team at NGS has developed the foundational software libraries and tools needed for GNSS data processing (e.g, RINEX readers, standard GNSS models) and has begun to produce double-difference baseline solutions with the new software. This valuable first step enables us to compare solutions from the new software with those of the legacy PAGES software. Here we present our preliminary solutions, compare them with those of PAGES, and discuss the next steps to improve the positioning accuracy and to take full advantage of multi-GNSS observations.</p>

scholarly journals Subsidence determination in the Central Valley, California

2018 ◽  
Vol 106 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Marcelo Romero ◽  
Mike Mustafa Berber
Keyword(s):  
Central Valley ◽  
Satellite System ◽  
Geodetic Survey ◽  
Reference Station ◽  
National Geodetic Survey ◽  
The North ◽  
Elevation Changes ◽  
System Data ◽  
Global Navigation Satellite ◽  
Gnss Data

Abstract Twenty four hour GNSS (Global Navigation Satellite System) data acquired monthly for 5 years from 8 CORS (Continuously Operating Reference Station) stations in Central Valley, California are processed and vertical velocities of the points are determined. To process GNSS data, online GNSS data processing service APPS (Automatic Precise Positioning Service) is used. GNSS data downloaded from NGS (National Geodetic Survey) CORS are analyzed and subsidence at these points is portrayed with graphics. It is revealed that elevation changes range from 5 mm uplift in the north to 163 mm subsidence in the southern part of the valley.

Integrated GNSS Attitude and Position Determination based on an Affine Constrained Model

2017 ◽  
Vol 71 (1) ◽  
pp. 134-150
Author(s):  
Haiying Liu ◽  
Lei Xu ◽  
Xiaolin Meng ◽  
Xibei Chen ◽  
Junyi Li
Keyword(s):  
Attitude Determination ◽  
Satellite System ◽  
Determination Method ◽  
Position Determination ◽  
Static Data ◽  
Constraint Information ◽  
Constrained Model ◽  
Global Navigation Satellite ◽  
Constraint Model ◽  
Gnss Data

Global Navigation Satellite System (GNSS) attitude determination and positioning play an important role in many navigation applications. However, the two GNSS-based problems are usually treated separately. This ignores the constraint information of the GNSS antenna array and the accuracy is limited. To improve the performance of navigation, an integrated attitude and position determination method based on an affine constraint model is presented. In the first part, the GNSS array model and affine constrained attitude determination method are compared with the unconstrained methods. Then the integrated attitude and position determination method is presented. The performance of the proposed method is tested with a series of static data and dynamic experimental GNSS data. The results show that the proposed method can improve the success rate of ambiguity resolution to further improve the accuracy of attitude determination and relative positioning compared to the unconstrained methods.

scholarly journals Reduction of ZTD outliers through improved GNSS data processing and screening strategies

2018 ◽  
Vol 11 (3) ◽  
pp. 1347-1361 ◽  
Author(s):  
Katarzyna Stepniak ◽  
Olivier Bock ◽  
Pawel Wielgosz
Keyword(s):  
Data Processing ◽  
Satellite System ◽  
Double Difference ◽  
Reference Network ◽  
Tropospheric Delay ◽  
Daily Data ◽  
Data Gaps ◽  
Short Baselines ◽  
Global Navigation Satellite ◽  
Gnss Data

Abstract. Though Global Navigation Satellite System (GNSS) data processing has been significantly improved over the years, it is still commonly observed that zenith tropospheric delay (ZTD) estimates contain many outliers which are detrimental to meteorological and climatological applications. In this paper, we show that ZTD outliers in double-difference processing are mostly caused by sub-daily data gaps at reference stations, which cause disconnections of clusters of stations from the reference network and common mode biases due to the strong correlation between stations in short baselines. They can reach a few centimetres in ZTD and usually coincide with a jump in formal errors. The magnitude and sign of these biases are impossible to predict because they depend on different errors in the observations and on the geometry of the baselines. We elaborate and test a new baseline strategy which solves this problem and significantly reduces the number of outliers compared to the standard strategy commonly used for positioning (e.g. determination of national reference frame) in which the pre-defined network is composed of a skeleton of reference stations to which secondary stations are connected in a star-like structure. The new strategy is also shown to perform better than the widely used strategy maximizing the number of observations available in many GNSS programs. The reason is that observations are maximized before processing, whereas the final number of used observations can be dramatically lower because of data rejection (screening) during the processing. The study relies on the analysis of 1 year of GPS (Global Positioning System) data from a regional network of 136 GNSS stations processed using Bernese GNSS Software v.5.2. A post-processing screening procedure is also proposed to detect and remove a few outliers which may still remain due to short data gaps. It is based on a combination of range checks and outlier checks of ZTD and formal errors. The accuracy of the final screened GPS ZTD estimates is assessed by comparison to ERA-Interim reanalysis.

scholarly journals Reduction of ZTD outliers through improved GNSS data processing and screening strategies

2017 ◽  
Author(s):  
Katarzyna Stepniak ◽  
Olivier Bock ◽  
Pawel Wielgosz
Keyword(s):  
Data Processing ◽  
Satellite System ◽  
Double Difference ◽  
Reference Network ◽  
Tropospheric Delay ◽  
Daily Data ◽  
Data Gaps ◽  
Short Baselines ◽  
Global Navigation Satellite ◽  
Gnss Data

Abstract. Though Global Navigation Satellite System (GNSS) data processing has been significantly improved over years it is still commonly observed that Zenith Tropospheric Delay (ZTD) estimates contain many outliers which are detrimental to meteorological and climatological applications. In this paper, we show that ZTD outliers in double difference processing are most of the time caused by sub-daily data gaps at reference stations which cause disconnections of clusters of stations from the reference network and common–mode biases due to the strong correlation between stations in short baselines. They can reach a few centimetres in ZTD and coincide usually with a jump in formal errors. The magnitude and sign of these biases are impossible to predict because they depend on different errors in the observations and on the geometry of the baselines. We elaborate and test a new baseline strategy which solves this problem and significantly reduces the number of outliers compared to the standard strategy commonly used for positioning (e.g. determination of national reference frame) in which the pre-defined network is composed of a skeleton of reference stations to which secondary stations are connected in a star-like structure. The new strategy is also shown to perform better than the widely-used strategy maximising the number of observations which available in many GNSS software. The reason is that observations are maximised before processing whereas the final number of used observations can be dramatically lower because of data rejection (screening) during the processing. The study relies on the analysis of one year of GPS (Global Positioning System) data from a regional network of 136 GNSS stations processed using Bernese GNSS Software v.5.2. A post-processing screening procedure is also proposed to detect and remove a few outliers which may still remain due to short data gaps. It is based on a combination of range checks and outlier checks of ZTD and formal errors. The accuracy of the final screened GPS ZTD estimates is assessed by comparison to ERA-Interim reanalysis.

scholarly journals Monitoring Surface Displacement of a Deep-Seated Landslide by a Low-Cost and near Real-Time GNSS System

2020 ◽  
Vol 12 (20) ◽  
pp. 3375
Author(s):  
Ela Šegina ◽  
Tina Peternel ◽  
Tilen Urbančič ◽  
Eugenio Realini ◽  
Matija Zupan ◽  
...  
Keyword(s):  
Low Cost ◽  
Local Population ◽  
Surface Displacement ◽  
Warning System ◽  
Satellite System ◽  
Dual Frequency ◽  
Server Side ◽  
Surface Displacements ◽  
Global Navigation Satellite ◽  
Gnss Data

A prototype of a low-cost GNSS (Global Navigation Satellite System) monitoring system was installed on a deep-seated landslide in north-western Slovenia to test its performance under field conditions. The system consists of newly developed GNSS stations based on low-cost, dual-frequency receivers and open-source GNSS processing software. It automatically receives GNSS data and transmits them over the Internet. The system processes the data server-side and makes them available to the end user via a web portal. The detected surface displacements were evaluated through a comparison with the network of classic geodetic measurements. The results of a nine-month monitoring period using seven GNSS stations provided a detailed insight into the spatial and temporal pattern of deep-seated landslide surface movements. The displacement data were correlated with precipitation measurements at the site to reveal how different parts of the landslide react to rainfall. These data form the basis for the further development of an early-warning system which will help to manage the risk the landslide poses to the local population and infrastructure.

scholarly journals Special Issue on GNSS Data Processing and Navigation

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4119
Author(s):  
Adria Rovira-Garcia ◽  
José Miguel Juan Zornoza
Keyword(s):  
Data Processing ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Special Issue ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
Gnss Data

Global Navigation Satellite System (GNSS) data can be used in a myriad of ways. The current number of applications exceed by far those originally GNSS was designed for. As an example, the present Special Issue on GNSS Data Processing and Navigation compiles 14 international contributions covering several aspects of GNSS research. This Editorial summarizes the whole special issue grouping the contributions under four different, but related topics.

scholarly journals Estimation of fractional cycle bias for GPS/BDS-2/Galileo based on international GNSS monitoring and assessment system observations using the uncombined PPP model

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jin Wang ◽  
Qin Zhang ◽  
Guanwen Huang
Keyword(s):  
Estimation Method ◽  
Satellite Orbit ◽  
Satellite System ◽  
Assessment System ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Fractional Cycle Bias ◽  
The Stability ◽  
High Consistency ◽  
Global Navigation Satellite

AbstractThe Fractional Cycle Bias (FCB) product is crucial for the Ambiguity Resolution (AR) in Precise Point Positioning (PPP). Different from the traditional method using the ionospheric-free ambiguity which is formed by the Wide Lane (WL) and Narrow Lane (NL) combinations, the uncombined PPP model is flexible and effective to generate the FCB products. This study presents the FCB estimation method based on the multi-Global Navigation Satellite System (GNSS) precise satellite orbit and clock corrections from the international GNSS Monitoring and Assessment System (iGMAS) observations using the uncombined PPP model. The dual-frequency raw ambiguities are combined by the integer coefficients (4,− 3) and (1,− 1) to directly estimate the FCBs. The details of FCB estimation are described with the Global Positioning System (GPS), BeiDou-2 Navigation Satellite System (BDS-2) and Galileo Navigation Satellite System (Galileo). For the estimated FCBs, the Root Mean Squares (RMSs) of the posterior residuals are smaller than 0.1 cycles, which indicates a high consistency for the float ambiguities. The stability of the WL FCBs series is better than 0.02 cycles for the three GNSS systems, while the STandard Deviation (STD) of the NL FCBs for BDS-2 is larger than 0.139 cycles. The combined FCBs have better stability than the raw series. With the multi-GNSS FCB products, the PPP AR for GPS/BDS-2/Galileo is demonstrated using the raw observations. For hourly static positioning results, the performance of the PPP AR with the three-system observations is improved by 42.6%, but only 13.1% for kinematic positioning results. The results indicate that precise and reliable positioning can be achieved with the PPP AR of GPS/BDS-2/Galileo, supported by multi-GNSS satellite orbit, clock, and FCB products based on iGMAS.

Implementation of a Dual-Frequency GLONASS and GPS L1 C/A Software Receiver

2010 ◽  
Vol 63 (2) ◽  
pp. 269-287 ◽  
Author(s):  
S. Abbasian Nik ◽  
M. G. Petovello
Keyword(s):  
Global Navigation Satellite System ◽  
Critical Role ◽  
Satellite System ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Software Receiver ◽  
The Public ◽  
Global Navigation ◽  
Global Navigation Satellite

These days, Global Navigation Satellite System (GNSS) technology plays a critical role in positioning and navigation applications. Use of GNSS is becoming more of a need to the public. Therefore, much effort is needed to make the civilian part of the system more accurate, reliable and available, especially for the safety-of-life purposes. With the recent revitalization of Russian Global Navigation Satellite System (GLONASS), with a constellation of 20 satellites in August 2009 and the promise of 24 satellites by 2010, it is worthwhile concentrating on the GLONASS system as a method of GPS augmentation to achieve more reliable and accurate navigation solutions.

Study the Effect of Radio Interference of the EHV Transmission Line on GNSS Signals

2013 ◽  
Vol 805-806 ◽  
pp. 851-854
Author(s):  
Zhi Ge Jia ◽  
Zhao Sheng Nie ◽  
Wei Wang ◽  
Xiao Guan ◽  
Di Jin Wang
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Internal Noise ◽  
Field Testing ◽  
Satellite System ◽  
Field Analysis ◽  
Radio Interference ◽  
Gnss Receiver ◽  
Global Navigation Satellite ◽  
Gnss Data

This work describes the field testing process of Global Navigation Satellite System (GNSS) receiver under 220KV, 500KV UHV transmission line and standard calibration field. Analysis for GNSS data results shows that the radio interference generated by EHV transmission lines have no effect on GNSS receiver internal noise levels and valid GNSS observation rate. Within 50 meters of the EHV transmission lines, the multi-path effects (mp1 and mp2 value) significantly exceeded the normal range and becomes larger with the increase of the voltage .outside 50 meters of the EHV transmission line, the multi-path effects have almost no effect on the high-precision GNSS observations.

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