Simulation of polygon area determination using GPS single frequency code receivers – Case study

2019 ◽  
Vol 158 ◽  
pp. 92-101 ◽  
Author(s):  
Dawid Kudas ◽  
Agnieszka Wnęk
Keyword(s):  
Single Frequency ◽  
Frequency Code ◽  
Polygon Area ◽  
Area Determination

scholarly journals Statistical Deviations in Shoreline Detection Obtained with Direct and Remote Observations

2019 ◽  
Vol 7 (5) ◽  
pp. 137 ◽  
Author(s):  
Giovanni Pugliano ◽  
Umberto Robustelli ◽  
Diana Di Luccio ◽  
Luigi Mucerino ◽  
Guido Benassai ◽  
...  
Keyword(s):  
Intertidal Zone ◽  
Carrier Phase ◽  
Video Camera ◽  
Point Of View ◽  
Single Frequency ◽  
Tyrrhenian Sea ◽  
Beach Slope ◽  
Gps Survey ◽  
Frequency Code ◽  
Positioning Algorithm

Remote video imagery is widely used for shoreline detection, which plays a fundamental role in geomorphological studies and in risk assessment, but, up to now, few measurements of accuracy have been undertaken. In this paper, the comparison of video-based and GPS-derived shoreline measurements was performed on a sandy micro-tidal beach located in Italy (central Tyrrhenian Sea). The GPS survey was performed using a single frequency, code, and carrier phase receiver as a rover. Raw measurements have been post-processed by using a carrier-based positioning algorithm. The comparison between video camera and DGPS coastline has been carried out on the whole beach, measuring the error as the deviation from the DGPS line computed along the normal to the DGPS itself. The deviations between the two dataset were examined in order to establish possible spatial dependence on video camera point of view and on beach slope in the intertidal zone. The results revealed that, generally, the error increased with the distance from the acquisition system and with the wash up length (inversely proportional to the beach slope).

scholarly journals Real-time single-frequency precise positioning with Galileo satellites

2021 ◽  
pp. 1-17
Author(s):  
Berkay Bahadur
Keyword(s):  
Real Time ◽  
Experimental Tests ◽  
Convergence Time ◽  
Single Frequency ◽  
Positioning Accuracy ◽  
Precise Positioning ◽  
Frequency Code ◽  
Substantial Progress ◽  
Phase Combination ◽  
Gps Observations

Abstract Following substantial progress achieved recently, the Galileo constellation provides a considerable satellite resource for the GNSS applications. In this regard, the performance assessment of real-time single-frequency precise positioning with Galileo satellites is the main objective of this research. For this purpose, several experimental tests were conducted in this study with two single-frequency positioning models, namely single-frequency code-based positioning and code-phase combination. The results show that Galileo presents an adequate number of visible satellites sufficient for single-frequency positioning. Also, the study demonstrates that, in comparison to GPS observations, Galileo observations have a significantly lower noise level. For the single-frequency code-based positioning, Galileo presents a better positioning accuracy than GPS by 25⋅8% on average. When compared with GPS, a 9⋅4% better positioning accuracy is acquired from Galileo for the single-frequency code-phase combination, with its average convergence time shorter than GPS by a ratio of 24⋅4%.

scholarly journals Analysis of multiple frequency excitations of a cracked beam using nonlinear vibrations

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Mohammad Amin Motamedi ◽  
Saied Irani
Keyword(s):  
Dynamic Responses ◽  
Single Frequency ◽  
Multiple Time Scales ◽  
Crack Model ◽  
Multiple Time ◽  
Nonlinear Behaviour ◽  
Multiple Frequency ◽  
Proposed Model ◽  
Beam Analysis

In this study, under harmonic multiple frequency excitations, the dynamic response of a cracked cantilever beam is investigated. The breathing crack model is assumed to show the nonlinear behaviour of a transverse crack. The first mode of vibration and the single degree freedom lumped system is considered to simplify the case study. Because of applying the multiple frequency excitations, the analysis is applied in a combinational resonance. Multiple time scales method is employed to solve the motion equation of the crack, and the nonlinear vibrational responses are obtained. Then, by changing the crack parameters and frequency of the excitations, the different dynamic responses of the crack are demonstrated. The proposed model shows that the crack parameters analysis in nonlinear vibration of multiple excitations could be an appropriate method to recognise the crack and the depth of the damage. Results indicate that the beam analysis under multiple frequency excitations is more sensitive than the single frequency excitation to illustrate the impacts of the crack parameters on its vibrational nonlinearity responses.

Deciphering the dynamics of a heterogeneous sea cliff using ambient vibrations: case study of the Sutta-Rocca overhang (southern Corsica, France)

2020 ◽  
Vol 224 (2) ◽  
pp. 813-824
Author(s):  
E Diego Mercerat ◽  
Jean Baptiste Payeur ◽  
Etienne Bertrand ◽  
Marie Malascrabes ◽  
Michel Pernoud ◽  
...  
Keyword(s):  
Data Analysis ◽  
Seismic Monitoring ◽  
Interesting Case ◽  
Single Frequency ◽  
Ambient Vibrations ◽  
Rockfall Hazard ◽  
Single Station ◽  
Sea Cliff ◽  
East West

SUMMARY We report here an interesting case study of dynamic characterization of a limestone sea cliff area, named the Sutta-Rocca overhang, located near the medieval town of Bonifacio (southern Corsica, France). The site belongs to an UNESCO protected area with an important number of visitors per year. Therefore, it is of particular interest to evaluate the potential rockfall hazard along the cliff. With the objective of evaluating the feasibility of an operational technique to monitor the cliff using ambient vibrations, two seismic stations were installed during six months (from 2016 November to 2017 April) in order to identify and monitor the resonant frequencies of the a priori unstable rock mass. Several techniques of classical seismic monitoring are tested on the site: single-station spectral analysis for identification of frequency peaks related to the unstable mass, relative spectral amplifications between stations and the operational modal analysis of the cliff. In particular, data analysis from a temporary campaign of two days of continuous recordings by a linear array of seismometers perpendicular to the sea cliff highlights the main characteristics of the ground motion: the overall motion of the promontory mainly in the north–south direction (perpendicular to the coast) and bending vertical and parallel to the cliff (east–west direction) at higher frequencies. The strong vertical and east–west seismic amplifications are also confirmed by the analysis of five local seismic events recorded at both semi-permanent stations. Even if ambient vibrations and seismic data analysis allows to decipher the dynamics of the Sutta-Rocca overhang, we conclude that classical seismic monitoring of just one single frequency peak with a limited number of sensors is not recommended for this particular site.

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