scholarly journals Identifying 2010 Xynthia Storm Signature in GNSS-R-Based Tide Records

2019 ◽  
Vol 11 (7) ◽  
pp. 782 ◽  
Author(s):  
Phuong Lan Vu ◽  
Minh Cuong Ha ◽  
Frédéric Frappart ◽  
José Darrozes ◽  
Guillaume Ramillien ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Tide Gauge ◽  
Signal To Noise Ratio ◽  
Atlantic Coast ◽  
Singular Spectrum Analysis ◽  
Global Navigation Satellite Systems ◽  
Blind Separation ◽  
Tide Gauge Records ◽  
Satellite Systems ◽  
Global Navigation Satellite

In this study, three months of records (January–March 2010) that were acquired by a geodetic Global Navigation Satellite Systems (GNSS) station from the permanent network of RGP (Réseau GNSS Permanent), which was deployed by the French Geographic Institute (IGNF), located in Socoa, in the south of the Bay of Biscay, were used to determine the tide components and identify the signature of storms on the signal to noise ratio (SNR) during winter 2010. The Xynthia storm hit the French Atlantic coast on the 28th of February 2010, causing large floods and damages from the Gironde to the Loire estuaries. Blind separation of the tide components and of the storm signature was achieved while using both a singular spectrum analysis (SSA) and a continuous wavelet transform (CWT). A correlation of 0.98/0.97 and root mean square error (RMSE) of 0.21/0.28 m between the tide gauge records of Socoa and our estimates of the sea surface height (SSH) using the SSA and the CWT, respectively, were found. Correlations of 0.76 and 0.7 were also obtained between one of the modes from the SSA and atmospheric pressure from a meteorological station and a mode of the SSA. Particularly, a correlation reaches to 0.76 when using both the tide residual that is associated to surges and atmospheric pressure variation.

scholarly journals Investigating GNSS multipath effects induced by co-located Radar Corner Reflectors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Thomas Fuhrmann ◽  
Matthew C. Garthwaite ◽  
Simon McClusky
Keyword(s):  
Land Surface ◽  
Reference Frames ◽  
Surface Deformation ◽  
Signal To Noise Ratio ◽  
Ground Plane ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Multipath Effects ◽  
Global Navigation Satellite ◽  
Relative Measurements

Abstract Radar Corner Reflectors (CR) are increasingly used as reference targets for land surface deformation measurements with the Interferometric Synthetic Aperture Radar (InSAR) technique. When co-located with ground-based Global Navigation Satellite Systems (GNSS) infrastructure, InSAR observations at CR can be used to integrate relative measurements of surface deformation into absolute reference frames defined by GNSS. However, CR are also a potential source of GNSS multipath effects and may therefore have a detrimental effect on the GNSS observations. In this study, we compare daily GNSS coordinate time series and 30-second signal-to-noise ratio (SNR) observations for periods before and after CR deployment at a GNSS site. We find that neither the site coordinates nor the SNR values are significantly affected by the CR deployment, with average changes being within 0.1 mm for site coordinates and within 1 % for SNR values. Furthermore, we generate empirical site models by spatially stacking GNSS observation residuals to visualise and compare the spatial pattern in the surroundings of GNSS sites. The resulting stacking maps indicate oscillating patterns at elevation angles above 60 degrees which can be attributed to the CR deployed at the analysed sites. The effect depends on the GNSS antenna used at a site with the magnitude of multipath patterns being around three times smaller for a high-quality choke ring antenna compared to a ground plane antenna without choke rings. In general, the CR-induced multipath is small compared to multipath effects at other GNSS sites located in a different environment (e. g. mounted on a building).

Bit Sign Transition Cancellation Method for GNSS Signal Acquisition

2011 ◽  
Vol 65 (1) ◽  
pp. 73-97 ◽  
Author(s):  
Kewen Sun ◽  
Letizia Lo Presti
Keyword(s):  
Doppler Shift ◽  
Signal To Noise Ratio ◽  
Search Space ◽  
Global Navigation Satellite Systems ◽  
Main Peak ◽  
Signal Acquisition ◽  
Satellite Systems ◽  
Gps Modernization ◽  
Improved Performance ◽  
Global Navigation Satellite

The next generation Global Navigation Satellite Systems (GNSS), such as Galileo and Global Positioning System (GPS) modernization, will use signals with equal code and bit periods, resulting in a potential bit sign transition in each primary code period of the received signal segments. A bit sign transition occurring within an integration period usually causes a splitting of the Cross Ambiguity Function (CAF) main peak into two smaller side lobes along the Doppler shift axis in the search space and it may lead to an incorrect Doppler shift estimate, which results in a serious performance degradation of the acquisition system. This paper proposes a novel two steps based bit sign transition cancellation method which can overcome the bit sign transition problem and remove or mitigate the CAF peak splitting impairments. The performance of the proposed technique has been comprehensively evaluated with Monte Carlo simulations in terms of detection and false alarm probabilities, which are presented by Receiver Operating Characteristic (ROC) and Signal-to-Noise-Ratio (SNR) curves. The test results show that the proposed acquisition technique can provide improved performance in comparison with the state-of-the-art acquisition approaches.

scholarly journals Estimating Wave Direction by Using Terrestrial GNSS Reflectometry

2019 ◽  
Author(s):  
Jörg Reinking ◽  
Ole Roggenbuck ◽  
Gilad Even-Tzur
Keyword(s):  
Correlation Length ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Global Navigation Satellite Systems ◽  
Wave Direction ◽  
Satellite Systems ◽  
The North ◽  
Scattered Power ◽  
Length Changes ◽  
Global Navigation Satellite

The signal-to-noise ratio (SNR) data is part of the global navigation satellite systems (GNSS) observables. In a marine environment, the oscillation of the SNR data can be used to derive reflector heights. Since the attenuation of the SNR oscillation is related to the roughness of the sea surface, the significant wave height (SWH) of the water surface can be calculated from the analysis of the attenuation. The attenuation depends additionally on the relation between the coherent and the incoherent part of the scattered power. The latter is a function of the correlation length of the surface waves. Because the correlation length changes with respect to the direction of the line of sight relative to the wave direction, the attenuation must show an anisotropic characteristic. In this work, we present a method to derive the wave direction from the anisotropy of the attenuation of the SNR data. The method is investigated based on simulated data as well by the analysis of experimental data from a GNSS station in the North Sea.

Influence of GNSS Receivers on GPR Results

2018 ◽  
Vol 23 (3) ◽  
pp. 383-389
Author(s):  
Dariusz Tanajewski ◽  
Dariusz Popielarczyk ◽  
Adam Ciecko
Keyword(s):  
Mutual Influence ◽  
Signal To Noise Ratio ◽  
Reference Signal ◽  
Global Navigation Satellite Systems ◽  
Data Sets ◽  
Stability Parameters ◽  
Satellite Systems ◽  
Gnss Receiver ◽  
Satellite Positioning ◽  
Global Navigation Satellite

Even though satellite positioning has been used in ground penetrating radar (GPR) measurements for years, there are no studies ruling out the influence of modern satellite positioning receivers on the operation of GPR antennas. In order to rule out mutual influence between devices, a field study was carried out to determine the possible influence of a Global Navigation Satellite Systems (GNSS) receiver on the results obtained from GPR. To this end, several equipment combinations based on two receivers were compared. This was followed by a numerical analysis of selected samples from the recorded data sets. The following were calculated: average values of signal amplitudes, their standard deviations and the signal-to-noise ratio, coefficient of variation, and signal stability parameters. We also suggested using a modified standard deviation based on the properties of the reference signal. Based on the results, we concluded that there were rather significant changes between the data sets for various equipment combinations, which may indicate that a GNSS receiver affects GPR data in some way. However, the influence was not significant enough to result in the qualitative misinterpretation of data.

scholarly journals Mapping Sea Surface Height Using New Concepts of Kinematic GNSS Instruments

2020 ◽  
Vol 12 (16) ◽  
pp. 2656
Author(s):  
Clémence Chupin ◽  
Valérie Ballu ◽  
Laurent Testut ◽  
Yann-Treden Tranchant ◽  
Michel Calzas ◽  
...  
Keyword(s):  
Sea Level ◽  
Complex Dynamics ◽  
Tide Gauge ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Global Navigation Satellite Systems ◽  
Detailed Knowledge ◽  
Satellite Systems ◽  
Global Mean Sea Level ◽  
Global Navigation Satellite

For over 25 years, satellite altimetry observations have provided invaluable information about sea-level variations, from Global Mean Sea-Level to regional meso-scale variability. However, this information remains difficult to extract in coastal areas, where the proximity to land and complex dynamics create complications that are not sufficiently accounted for in current models. Detailed knowledge of local hydrodynamics, as well as reliable sea-surface height measurements, is required to improve and validate altimetry measurements. New kinematic systems based on Global Navigation Satellite Systems (GNSS) have been developed to map the sea surface height in motion. We demonstrate the capacity of two of these systems, designed to measure the height at a centimetric level: (1) A GNSS floating carpet towed by boat (named CalNaGeo); and (2) a combination of GNSS antenna and acoustic altimeter (named Cyclopée) mounted on an unmanned surface vehicle (USV). We show that, at a fixed point, these instruments provide comparable accuracy to the best available tide gauge systems. When moving at up to 7 knots, the instrument velocity does not affect the sea surface height accuracy, and the two instruments agree at a cm-level.

scholarly journals Estimating Wave Direction Using Terrestrial GNSS Reflectometry

2019 ◽  
Vol 11 (9) ◽  
pp. 1027 ◽  
Author(s):  
Reinking ◽  
Roggenbuck ◽  
Even-Tzur
Keyword(s):  
Correlation Length ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Global Navigation Satellite Systems ◽  
Wave Direction ◽  
Satellite Systems ◽  
The North ◽  
Scattered Power ◽  
Length Changes ◽  
Global Navigation Satellite

The signal-to-noise ratio (SNR) data are part of the global navigation satellite systems (GNSS) observables. In a marine environment, the oscillation of the SNR data can be used to derive reflector heights. Since the attenuation of the SNR oscillation is related to the roughness of the sea surface, the significant wave height (SWH) of the water surface can be calculated from the analysis of the attenuation. The attenuation depends additionally on the relation between the coherent and the incoherent part of the scattered power. The latter is a function of the correlation length of the surface waves. Since the correlation length changes with respect to the direction of the line of sight relative to the wave direction, the attenuation must show an anisotropic characteristic. In this work, we present a method to derive the wave direction from the anisotropy of the attenuation of the SNR data. The method is investigated based on simulated data, as well by the analysis of experimental data from a GNSS station in the North Sea.

scholarly journals An Assessment of Vertical Land Movement to Support Coastal Hazards Planning in Washington State

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 281
Author(s):  
Tyler J. Newton ◽  
Ray Weldon ◽  
Ian M. Miller ◽  
David Schmidt ◽  
Guillaume Mauger ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Puget Sound ◽  
Global Navigation Satellite Systems ◽  
Coastal Hazards ◽  
Cascadia Subduction Zone ◽  
Tide Gauge Records ◽  
Relative Sea Level ◽  
Satellite Systems

The sea and land change elevation spatially and temporally from a multitude of processes, so it is necessary to constrain the movement of both to evaluate how coastlines will evolve and how those evolving coastlines will impact the natural and built environment over time. We combine land movement observations from global navigation satellite systems (GNSSs), leveling of geodetic monuments, and tide gauge records with a tectonic model of the Cascadia subduction zone to constrain absolute rates of vertical land movement in coastal Washington. We infer rates of vertical land movement in areas lacking direct observations by interpolating high-quality land movement observations and a discretely sampled interseismic locking model. Here we present a model of absolute vertical land movement that is combined with sea level rise estimates to inform local relative sea level projections on a community-scale. The most rapid vertical uplift (~3.5 mm/year) of the land is found across the northwest Olympic Peninsula, which currently outpaces sea level rise. Conversely, some areas, including a stretch of the northern Pacific Ocean coast from La Push to Kalaloch and the southern Puget Sound, are found to be subsiding at 0.5–1.0 mm/year, exacerbating the rate of relative sea level rise and thereby increasing the vulnerability of coastal communities.

scholarly journals Measuring Coastal Absolute Sea-Level Changes Using GNSS Interferometric Reflectometry

2021 ◽  
Vol 13 (21) ◽  
pp. 4319
Author(s):  
Dongju Peng ◽  
Lujia Feng ◽  
Kristine M. Larson ◽  
Emma M. Hill
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Global Navigation Satellite Systems ◽  
Coastal Zones ◽  
Sea Level Changes ◽  
Tide Gauge Records ◽  
Sea Levels ◽  
Satellite Systems ◽  
Linear Trends

Rising sea levels pose one of the greatest threats to coastal zones. However, sea-level changes near the coast, particularly absolute sea-level changes, have been less well monitored than those in the open ocean. In this study, we aim to investigate the potential of Global Navigation Satellite Systems Interferometric Reflectometry (GNSS-IR) to measure coastal absolute sea-level changes and tie on-land (coastal GNSS) and offshore (satellite altimetry) observations into the same framework. We choose three coastal GNSS stations, one each in regions of subsidence, uplift and stable vertical land motions, to derive both relative sea levels and sea surface heights (SSH) above the satellite altimetry reference ellipsoid from 2008 to 2020. Our results show that the accuracy of daily mean sea levels from GNSS-IR is <1.5 cm compared with co-located tide-gauge records, and amplitudes of annual cycle and linear trends estimated from GNSS-IR measurements and tide-gauge data agree within uncertainty. We also find that the de-seasoned and de-trended SSH time series from GNSS-IR and collocated satellite altimetry are highly correlated and the estimated annual amplitudes and linear trends statistically agree well, indicating that GNSS-IR has the potential to monitor coastal absolute sea-level changes and provide valuable information for coastal sea-level and climate studies.

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